VitR — Scraping the Bottom of the Barrel

No the title isn’t a shot at the car — I’m finding it to be a great car and the motor is turning out to be pretty solid. There’s just one thing that’s quite annoying — Honda gimped the potential of the motor with the fuel system. The D/I fuel pump is pegged out very easily once you turn the power up, which in fact leaves you literally scraping the bottom of the barrel to make a clean power curve as you’re riding a very fine line with the fuel system.

This turns out to be even more true once we put on the PRL Motorsports Intercooler on the car and found out it improves cooling efficiency to a point we were making the power we had before while running less boost. Of course we wanted to make more power and run more boost — which proved futile given the limitations we kept hitting in the fuel system.

The car is 100% OEM aside from the PRL Intercooler and we used E35 blend fuel for this test (as we wanted to see how much more we could push the motor).


So what did the results look like? We were able to make a clean power curve and pick up more power before the fuel system maxed out — and make roughly the same top end with less boost.

But that’s not good enough! Let’s make more… and we certainly tried. The motor wants to make power — but takes a slump after 6000 rpm. Why is this?

Well here’s why — in our MoTeC programming we’ve added code that estimates how much injection time you have left before your spark event. You need a certain amount of time left over for a clean mix in the combustion chamber before the fuel is ignited. Do not leave enough time for this to happen the engine doesn’t make power or even worse — misfires. It appears that on this motor we want at least 1.5ms of “Injection Time Remaining” to get a complete mix.

But as fuel demand on the D/I pump goes up it skips a beat and we see a large fuel pressure drop — from a target of 22.5MPa to 16.6MPa (a 6MPa or almost 900psi drop in fuel pressure). As a result of the pressure drop the injector pulse width has to increase and now we’re running out of injection time!

Really Push It

How bad does it get if you REALLY push the D/I fuel system? Well take a look at this. Wow it’s just a roller coaster ride after 5500 rpm — we were making over 390whp and would of made well over 400whp if we had the fuel…


You can see how tapped out the D/I fuel system was on this 29psi pull as we dropped 8MPa of fuel pressure.

Injection time remaining was super low… and the motor even misfired at 6600 rpm.



So Did the Intercooler Help?

Absolutely. Here’s some useful data from actual hard acceleration runs on the stock intercooler and with the PRL intercooler. You should note — we actually used a bit less boost on the stock intercooler runs and the stock intercooler had colder ambient temperatures versus when we ran the PRL intercooler test. However the stock intercooler still heat soaked rapidly. For comparison are runs at WOT from 1st to 3rd gear.

First on the left is the stock intercooler. Note the following — “Airbox Temperature” is the temperature sensor in the intake BEFORE the turbo and the “Inlet Air Temperature” is the temperature sensor in the intake manifold. The sensor in the intake manifold tends to heat soak at idle/low air volume conditions (not much fresh air flowing through the intake manifold).


On the right is the run w/ the PRL intercooler. You can note that with the stock intercooler the Inlet temperature never touches the airbox temperature and in fact starts to climb almost immediately after dropping. With the PRL intercooler the aircharge is rapidly cooled and comes down to match the temperature at the airbox — and stays steady all the way through 3rd gear and would *maybe* start to slowly climb in 4th gear.

Clearly the intercooler upgrade is worth it — especially for our road course folks.

Some Fun

After having the car for a while and getting more comfortable with the clutch — I wanted to see if it would hold a bit more torque. I brought in 23-24psi earlier in the powerband, held 24psi through the top end — and made ~390hp and just a hair shy of ~400tq.

Is there more potential there? I believe so — I think we can probably make 450wtq quite easily — if we had reliable fueling. We had a 6MPa pressure drop and the fuel pressure just did not look that great.



Some Thoughts

Yes — this is E35 fuel (we had made 360whp on 92 previously), but there will be comparable gains from this intercooler on pump gas as well. The E35 actually doesn’t bring up fuel demand *that* much over pump gas (which is E10 to begin with) — it’s about 10% more fuel. So what’s that tell us? Where the hard limit is for fuel volume with this D/I fuel system.

How much can we do on just pump gas? Maybe 400whp before we need to do secondary injection. Maybe less, maybe more. We’ll find out once we have a the PRL downpipe on the VitR!

The other option is to use a race gas that reduces fuel system demand over pump gas….



The 10th Gen Civic Si Basemaps

It feels like I’ve been bombarded lately with questions on what X basemap on Y device maps for power (“numbers”). I admit I’ve been slacking on getting these results for you guys as my attention has been on taking care of customers and elsewhere (busy busy!).

Turns out I had a lazy Sunday this Labor Day weekend so I rolled the Si into the shop and spent  a few hours testing the various supplied basemaps provided by Hondata and KTuner. It’s a pleasure to be in a somewhat unique position where I can use and support both systems — as such I can fairly readily go between them.


This needs to be nipped in the bud. Some people seem to confuse “preference” with “bias”, and they simply are not the same. I’ve already seen some keyboard warriors claiming “bias”.

Prefer – like one thing better than another; tend to chose.

Bias – prejudice in favor of or against one thing or another.

The definitions are quite simple, and I can completely understand how one person that favors a product would think someone else is “bias” because they favor another.

Simple fact though: I’m in different. It’s like claiming I’m biased for Skunk2 since we sell and recommend their header on older platforms. Silly — as I tune cars with a plethora of parts. Not any different here — I tune either system for my customers since I support both which leaves the CivicX community with a choice of two systems (refreshing!).

Testing Procedure

The procedure used is fairly simple — flash the ECU with the basemap of choice, put the car in gear, let the dyno load it, and off it goes. The dyno was run the EXACT same way every pull. No trickery or “heat soaking” was employed — all runs were started around 170 ECT and steady state IAT for the current shop/weather conditions. All the basemaps were run as they come — no changes (with Hondata starting at ~.57-.58 knock control and KTuner starting at ~0.59 knock control — which is how my car started at ‘key on’ with both systems). Easy enough test for anyone else to replicate.

I ran the Hondata +9 calibration, then the +6 calibration, then completely stock (reverted to stock, settled knock control at 0.55). Lastly I ran the KTuner 21psi and then the KTuner 23psi calibrations. If anything, this would of favored the Hondata calibrations as they were run first before the car raised the dyno bay area temps a bit — for anyone claiming “bias”.

We are using 92 octane pump gas fuel (no blends — wouldn’t work anyway).

The car has a PRL downpipe on it — that’s the only mod besides the Clutchmasters clutch. Originally the car had dyno’d about 206hp completely stock, in a bit better weather conditions. This time around it made about 210hp stock — so even without a tune it’s safe to say the PRL downpipe made 5-6hp or so. This is really irrelevant to the test at hand as the results are comparable to the baseline (more of an FYI).

Hondata Results

First, the Hondata +9 calibration. This calibration makes about 23psi peak boost. About 257wtq and 210whp. Roughly 30whp and 40-45wtq over stock.

Then the Hondata +6 calibration. This calibration makes about 21psi peak boost. About 214whp and 245wtq. Looks like about 25wtq and 25whp over stock.

What I found peculiar is we actually lost some initial spool and the +6 calibration actually had a better power curve after about 5000 rpm (made 3-4hp more). Power curve above ~5800 rpm really wasn’t any better than stock.

I can hear it now — but but but Hondata says they made 232whp! And once again I have to repeat like a broken record: EVERY DYNO IS DIFFERENT. They are a tuning tool, nothing more. Some read low, some read high. In my test on this car I found their figures to be about 10-11% higher than how my dyno reads — I haven’t touched or altered their supplied tunes in any way. Historically the dyno they use reads 10-15% higher for the Hondas I’ve tuned in that area (I’ve used the dyno they use countless times on trips to SoCal). Remember — you’re not racing your dyno sheet, you’re racing your CAR.

KTuner Results

First, the 21psi calibration. Peak boost is 21psi as noted. Looks like about 214whp and 260wtq. Roughly 40-45wtq over stock and also about 30whp over stock.

Next the 23psi calibration. Peak boost is 23psi as noted. About 214-215whp with 275wtq and a wider power curve to boot. Looks like about 50wtq over stock and 30-35whp over stock.

The only thing that was peculiar is the same issue where the power curve above ~5800 really isn’t any better than stock.

Custom Tuning

It goes without saying that custom tuning is recommended for either system – not only can you dial in the extra settings in the calibration (“tune”) . You also get the assurance that the tune was looked at on YOUR car, YOUR fuel, as YOU drive it and get the support that comes with custom tuning.

Tuning services are available for both systems:

As well as combo packages for both:

And I know it’s going to be asked — we use KTuner on our car as it is my God given right to CHOSE what I use on MY car. As it is everyone’s right.

Laying Into the 2017 Honda Civic Si

Well now that I’ve changed out the clutch on our test mule 10th Gen Civic Si I’m able to lay into it and see what this baby turbo with the 1.5L motor can really do. Thank you to ClutchMasters for providing us with a very strong clutch — it held up through all the abuse I just put this car through.

I am currently using KTuner on our test vehicle as this is the only software available to me that provides me with all the necessary control to really work on the innards of this ECU and dig deep into what this motor, turbo and ECU can do. Big thank you to them for providing the software we needed to get some serious testing under way.

Shut Up and Tell Me How She Did Already?

I have to say I am very pleased with the way this car not only drives, but makes power — it’s a VERY broad power curve and this is very noticeable when driving the car. She laid down over 255whp and 320wtq, and you can see the power curve is quite “fat”. This power was still made running quite an aggressive tune — but nowhere near any ECU or software limits.

However — for the sake of longevity I dialed the car back into the ~240-245whp and ~290-300wtq area for myself as I want the car not to just “make power” — which is something people tunnel vision on — but I also want it to be reliable. This car is our test mule and we have some more plans for it.

What About These Limits You Mentioned?

This was actually quite fun — in the ECU we’ve already raised all sorts of “limits” to allow us to make power (no throttle pullback, increasing boost targets, etc). However there’s always *something* lurking when you really push things. Which is exactly what I did — I went all out on the baby turbo to see what she could do, and sure enough, I clipped a very brutal boost “limp mode” type situation in the ECU that you can see killed power quite aggressively after 4500 rpm.

There’s two things we can discuss and analyze from this.

First — clearly the baby turbo can do LOTS of boost in the mid range — which continues to make a LOT of torque. As a result, our peak HP spot goes down in the powerband (and I drew in what a potential curve without the limits would look like given what I already know about the turbos capabilities after 5500 rpm). But as horsepower is just a function of torque — if you make enough torque you can make “more horsepower”. As you can see — we’re in the 270whp area! The side effect of this is you have to run the motor with a LOT more torque as your usable powerband for best acceleration actually goes down.

Which brings us to the second point — do you really want to be laying 340wtq into this motor? I think it’s very cool from a testing perspective to see what we can do — but may not be practical for day to day use or the longevity of the motor.




Introducing the 2017 Honda Civic Si

So this just happened. Yup, it’s been a hectic couple months and through it all I’ve been waiting for our 2017 Si to arrive. We traded our 17 EX-T sedan test mule in for this one. I picked up the car with just 12 miles on it, fresh off the truck. The fit, feel and drive of this Si is way different from the EX-T Sedan, and even different to that of the previous generation Si’s — but that’s for another post.

After rolling 142 miles on the car between driving it home from the dealer and to the shop, I put it on the dyno for some baseline testing and a mild tune. Right off the bat I was not happy with the clutch — it’s the same setup (other than the flywheel) as the base model 1.5T vehicles and on a couple of street tests in 3rd gear I already noticed clutch slip between 2500 and 3000 rpm at WOT. Wonderful. More on that later.

The Baseline

First — the car came with a tank of 87 octane, not ideal for a sports model Civic, and we know these things will make more power on premium grade fuel (92-93 octane in our tests). I baselined it on 87 octane anyway. Solid is the Si, dashed is the EX-T. The upgrades on the Si clearly make more power than the base 1.5T — and at “only” ~17.8psi (yup, our car never hit advertised boost levels by Honda). 191whp and 208wtq. Not bad.

I ditched the 87 octane and got premium fuel in the car. I also sped the dyno up slightly as I was concerned with clutch slip (Dynapack allows you to control the acceleration rate of the motor — the “ramp rate”).  The graph on the right shows what the Si makes on premium grade fuel (Si is solid again) vs our base EX-T. I noted no slip at this ramp rate, so I put the dyno back to the original speed and did another pull — and of course with the boost coming in sooner the car made more torque, and we hit some clutch slip (as you can see — chart on the left).  So looks like on 92-93 octane we will see anywhere from 200-206whp and 210-220wtq (depending on your luck with the clutch). So right around advertised power at the crank, but to the tire… with more torque than advertised (actually).

How Does This Compare Vs The Previous Si?

I’ve been around long enough to watch the Internet explode with drama every time Honda releases a new generation of Civic. The subjective arguments of it “looks like blah blah” or blasting for Honda not doing this or that (only 205hp what?). I think we all need to settle down and just accept that Honda builds the Civic Si as a sporty econobox. That’s what they’ve always done, that is their target audience — and the cars seem to sell, so they can’t possibly be getting it all wrong?

So, here’s what they’ve done this time around. To the right — solid is the 2017 Si, bone stock. Dashed is a bone stock 9th gen Si. Wow, the 2017 Si makes a good 50-60 wheel torque and a good 40whp more than the last generation Si it’s replacing.

How about a stock 8th gen Si? It’s not even a comparison, it makes 100wtq more through the usable power range than the 8th gen Si and 75whp more (sure, only “30” hp peak — the K20 has always been high strong and peak HP doesn’t win you any races).

Well, let’s throw some bolt ons at the 9th gen Si and see how it compares to the 2017 Si? Solid is the 2017 Si again.


How about the bolt on 8th gen? Solid is the 2017 Si once again.

Clearly Honda got it all wrong? I don’t think so. I’ve owned and driven all the generations of these cars in every fashion — stock, bolt on, supercharged and turbocharged. While we did get rid of our 2013 Si, I still have our 2008 Si (a 900whp+ built car is hard to part with — a lot of upkeep but oh so much fun).

Let’s Throw a Mild Tune At It

With the clutch not wanting to hold even stock power on premium fuel, I didn’t want to get too crazy with the tune on the 2017 Si — yet. Hopefully 142 miles just isn’t enough break in on the clutch and it’ll improve with some drive time (already have a better clutch waiting as well). So just to be clear — I intentionally limited potential power gains and stayed under 230wtq to avoid damaging the obviously fresh clutch on the car. I actually detuned and lowered boost from 3000 to 4000 rpm. My goal was to fatten up the powerband and tune out the “pullback” even this sports model suffers from (throttle closures which also cause boost to get pulled back).

Mission accomplished. While keeping the mid range/low end relatively stock we were still able to net 50wtq and 40-45whp over stock through the curve (with about 20hp peak). This is a nice improvement in the way the car accelerates.

Is there more in it? From what we’ve seen on the base 1.5T which make over 240whp and 300wtq, absolutely. Stay tuned to see us squeeze the Si for all she’s got once it’s got a few more miles on it — only 24 hours old and I’m already putting her through the grinder.




Tested: PRL Motorsports CivicX RACE Downpipe

Well, after not getting any results worth talking about using my high octane fuel PRL has dubbed as my “secret sauce”, it was time to go back to low octane fuel and see what this downpipe could do — if anything. As much fun as it is to just push the motor and turbo to it’s full potential using the best stuff you can throw at it — testing on the average every day fuel most people will use is more realistic. And well — nothing gets more real than running this car on 87 octane, probably the lowest octane you can get in the USA (I’ve seen a few remote locations with 85 or 86 octane, but that’s really rare).

The results were pleasing.


I feel that I have to explain a little bit of the innards of the ECU here, so some of the results will make sense. For anyone installing the PRL downpipe and expecting some results with either the factory tune or one of the basemaps with their tuner of choice, you need to understand where some of the “gains” are coming from.

The CivicX ECU doesn’t use a standard turbo wastegate for boost control — it uses an electronic wastegate run by the ECU. This is more complex and actually very cool. Most “standard” boost control systems use a boost solenoid (mac valve or similar) and when you ask for, say, 20psi, it tries to target that immediately and let the turbo wind up as fast as it can.

This is not the case with the CivicX. Honda uses a “slope” or “ramp” style boost control. Essentially it knows “X” wastegate position means “Y” boost and will actually “ramp” or “spool” the turbo at a fixed rate to get there. This induces artificial turbo lag. I believe this is done in part to protect the CVT trans and possibly to protect the motor — as this little turbo has the potential to “wind up” (spool) VERY quickly if it’s unleashed.

So why is this distinction important? Advertising that anything will make “peak torque sooner” is actually not quite true. In repeatable and consistent tests peak torque is always the same spot as that is where the ECU finally lets the turbo reach it’s target boost. If we didn’t have this control in the ECU I can imagine peak torque being 2200-2500 rpm on this motor with this downpipe.

However, since the ECU is programmed for a STOCK downpipe, when you install an aftermarket downpipe (PRL’s in this case), the exhaust flows more freely and as a result the turbo will TRY to make more boost than the ECU wants and at potentially a little different “ramp” as the wastegate control in the ECU isn’t compensated for this new part.

So what did I find? When I tuned the car stock on 87 octane bone stock, I targetted 18.4psi and the boost level stayed very close to target boost. To try and give us 1:1 results at the same boost level, I actually had to target 17.5psi to get the same boost level I had before installing the downpipe. You can see this in the side by side comparison in the image to the left. I forgot to get this dyno comparison off the dyno computer before I left the shop, but keeping boost the same we saw 8-9whp on the top end and 10-20wtq gained. Keep in mind this is over our “stock tuned” 87 octane test — so we’d already worked on the timing map and fueling a bit as well. You’ll also note as we put load on the car before starting the pull — the turbo was already making almost 2psi more than before the downpipe — this will come into play later.

What does this mean to YOU? If you’re running the same tune with a freer flowing downpipe you will artificially increase the boost level a bit. This will have gains on lower octane fuel as you’re not at peak turbo performance on the stock downpipe on lower octane fuels. Just understand where those gains are coming from — it’s not all just the “tune” at this point. The ECU *will* try to normalize the boost control and bring it back down to the target as the pull goes on (as you can see it happening).

The Install

The PRL items, as always, are quality pieces. Very well done items and fitment on our car was like a glove. No rattles, no rubbing. If you don’t have a lift the install will be a bit more entertaining. On my lift it took about 2 hours to get the stock items off and this one installed. The studs in the turbo can be interesting — PRL broke theirs. I managed to get mine off without any breakage or stripping with the use of some magic lube.

Some pics, of course.

So What About The Toon?

Note: blue is HP, yellow is TORQUE, orange is BOOST.

So let’s try to give it a bit more boost and see what happens? Increased the boost level about 1psi (don’t want to go crazy with 87 octane) after adjusting the timing map and such — and the results were nice. 20whp and 30-32wtq gained.

Torque came in sooner too, right? Of course — if we didn’t have the “ramp” based boost control it would of come in even sooner, but we got maybe a 200-300 rpm improvement because the turbo just wants to GOOOO with the free flowing downpipe, even if the ecu doesn’t want to let it! Peak torque however — was still the same spot. This should never really change as long as the load & ramp rate of the pull is consistent (not all dynos can control this — and certainly load will vary on the street).

But hey, let’s try to give it a little bit more. In the dashed line we increased boost a bit more (with a few other changes), and as you can see the gains were marginal — a bit more torque, but top end HP actually suffered a bit. We’re now at the limits of the fuel and I was starting to see the knock limit approaching very rapidly — don’t want to run here long term at all for reliability’s sake. But hey, overall we still saw 5-8wtq more which amounted to 35-40wtq through the mid range and we still picked up 20wtq up top.

So if you want to run on readily available fuels and not go hunting for race gas or some sort of “secret sauce” (lol), then PRL has a great RACE downpipe. Expect to see diminishing returns in how much HP you can make with better fuel — on 93 expect maybe 8-10whp more with this downpipe. Of course more torque as well — if your clutch can take it.

Vs Bone Stone?

Don’t really need an explanation I think?

87 octane fuel.





Where can you get all these goodies? Right here, along with tunings and custom tuning!

Project Civic X Begins

Ever since the announcement that the new generation of Civic was going to be turbo we have all been anxiously waiting to see what Honda had in store for us. Turns out it’s a 1.5L turbo engine which the factory reports is “only” 174 HP and 162 ft-lb of torque. And this engine is also being released in the Si — with some cosmetic upgrades, transmission upgrades (limited slip — we’ll get to that later) and *maybe* a slight turbo upgrade.

The announcement of the 1.5L was met with a lot of criticism, as the aftermarket and enthusiasts are used to B18 and K20 style engines dominating in the four cylinder market making absurd power figures (1k+ hp). Hell, I like making that kind of power too and support quite a few people in their endeavors to chase big power goals in the Honda scene. But we need to step back and look at the actual market segment that these cars sell to — even the Si to a big extent.

So just take a deep breath…. and imagine you’re an average Civic buyer. What do you want? If I had to take a wild guess from years and years working with customers tweaking their rides — and you certainly have the folks throwing superchargers and turbo kits on the cars — the vast majority (by a huge margin) just want a peppy economical car. So where do most stop? Just simple bolt on modifications.

How much power do bolt ons pick up on a naturally aspirated Civic? Not a ton. How much do bolt ons pick up on a factory turbo car? Well from having done quite a few factory turbo cars on another platforms (Mazda, Subaru, Mitsubishi) I can say it’s a lot more than an N/A Civic, regardless if it’s a 2.0 or 2.4 motor in the N/A Civic.

Dyno Disclaimer

Before I get to the cream — I have to do this as this is just a never ending battle. “Bro your dyno reads high”, blah blah. Right, sure. Magically reads high for just one specific car and not a single one of the other ones we’ve baselined completely stock and are either right on the money or slightly lower than the average power figures we see elsewhere. I personally won’t claim a dyno reads “high” until it’s consistently high, over and over, across multiple platforms (you know who you are).

Bone Stock, Not a Single Mod

This little guy showed up today, fresh from the dealer (they even delivered it!). I drove it around and got some grub to get a feel for the car — it certainly felt peppier than a stock 9th gen Si.

It went on the dyno, bone stock, no mods. Just a Hondata FlashPro to get some testing under way… and a bit of tuning. A whopping 196 miles on the car.


What did she make stock? 181 wheel horsepower and 188 wheel torque. Wait… what? Yes I was a little surprised, I expected 160-170 area. This is also on 87 octane… not the best fuel. Of course I wanted to see if there was more in it. I proceeded to frantically smash on my laptop keyboard and I managed to pound out 192whp and 235wtq out of a completely stock 2017 6MT Civic EX-T on 87 octane.

I really can’t hate on these results. The “hp” is decent and the torque is fantastic — and this was only peak. Through areas of the curve we got as much as 55wtq and 30-35whp over stock. Not bad at all — for just a tune.

Comparing To The 9th Gen Si

This is going to go quick and easy. I’m not going to say a whole lot as the graphs speak for them selves.

First, a completely stock 2015 Civic Si and the stock 2017 Civic EX-T.

Then to the left, a fully bolted on (even RBC swap) 2015 Civic Si and a stock tuned 2017 Civic EX-T.

To put the picture in words: even stock the Civic EX-T makes more power through the whole power curve over the 9th gen. Almost as much as 80wtq more than the 9th gen Si. This makes for some great get up and go.

Comparing To The 8th Gen Si

Same idea here…

A completely stock 8th gen Civic Si and the stock 2017 Civic EX-T.

And then a fully bolt on 8th gen Civic Si (your typical quality bolt ons — nice 3.5″ CAI, Skunk2 RH, 3″ exhaust, etc) and the stock tuned 2017 Civic EX-T.

Historically the K20 has never been big on torque (well, until you slap a good turbo kit on it — but this isn’t what we’re comparing and that’s a whole other discussion). Almost 110wtq through most of the low end.

What Next?

Well as you see these results for the Civic EX-T were on 87 octane. Next up is some tuning on a higher octane fuel — 92 octane. Then possibly either 100 octane or some ethanol!

We also have some additional bolt ons coming soon for more and more testing…

The car definitely needs a limited slip! Maybe we’ll be able to snag one from the Si that is coming out?

What about a turbo upgrade? Yup, already doing some scheming here too.

And of course, we have our renowned  FlashPro + Tune combo offer you can take advantage of. For $800, it’s the best money you can spend on your car. I’ll make sure your Civic X is dialed in to suit your mods, your needs and the fuel you are using — and make sure it continues to run smooth and reliable for a long time to come. And as Hondata adds more features I’ll make sure your calibrations stay tweaked and up to date with the latest and greatest in the software — something I’ve been proud to do for customers on all the platforms we support.


2016 Subaru WRX DIT Platform Tuning & Parts Testing

What a boring title… but I’ve got nothing catchy for the title as I gaze at my monitor through allergy induced tears and catching up on the “where’s my toon bro” emails after a crazy week that involved 3 days of parts testing & tuning at the shop that pulled me away from my normal routine at the desktop computer. Yes there was a joke in there, I know my humor doesn’t translate well on the interwebs at times so can I at least get a “Haha” before someone calls me an asshole?

But down to business! We have ECUTek as our tuning software for all SubaruIMG_0744 platforms, and this week our victim was the VitTuned 2016 Subaru WRX. Love them or hate them — I don’t care, I enjoy working on a variety of platforms and Subaru is no different. I want to give PRL Motorsports a big shout out for supplying me with a full array of bolt ons to test on our car. This was also a great opportunity to break in the new AWD Dynapack setup at the shop.

The parts we’ll be using.

  • PRL Motorsports TGV Deletes & EGR Delete
  • PRL Motorsports Intake Kit & Charge Pipe Upgrade
  • PRL Motorsports J Pipe
  • PRL Motorsports Front Pipe
  • PRL Motorsports Front Mount Intercooler
  • STM Exhaust

I broke up the testing into 3 parts. First I did the car completely stock — just tuned it. Next I installed the intake upgrades (less the intercooler) and retuned. Finally I installed the full turbo-back exhaust setup and the front mount intercooler (you’ll see why…).

All these tests were performed on our Oregon 92 octane. No extra ethanol blending at all.

Part 1 – Stock Tuned

We’re using a Dynapack — so obviously it’s going to read super highstock_tuned_vs_stock and we’re going to be seeing rated crank numbers at the hubs… right? LOL, right… Not on this Dynapack. With an AM (Advance Multiplier) of .88 we had a baseline of about 210whp. After spending some time retuning the car I got it up to 240whp and 265wtq. Not a bad gain at all for a stock car. I spent time mapping the dual cam timing system and found that the stock settings were pretty much spot on with the stock car. Most of the extra power was found in cleaning up the boost curve and raising boost targets — a little bit in the timing map, but not a whole lot as the motor was definitely a bit touchy on the pump gas.

Part 2 – Intake Side

I was able to install all the intake parts without even removing the car off the dIMG_0751IMG_0752yno. On went the intake & charge pipe upgrade for the stock top mount. On went on the TGV deletes & EGR delete. The TGV’s were a very quick swap — each side came out in seconds (no trouble with the driver’s side getting stuck anywhere when removing it). The intake fit like a glove as well. I was able to hop back in the car and retune it again. It was a bit hotter this dastock_tuned_vs_tgv_intakey and I was seeing 10-15* higher charge temps than when the car was tuned completely stock — however we saw a solid gain over our “stock tuned” baseline (to the right). It was pleasant to see that boost came in a considerable astock_vs_tgv_intakemount sooner, resulting in more torque a lot sooner in the curve. The gains over completely stock are on the chart to the left.


Part 3 – Exhaust (and FMIC)

The car came off the dyno and went on to the lift for some surgery. I started with the full exhaust setup. One look and I knew the stock J pipe was going to require some luck — those damn studs and nuts love to strip or come out as one piece. Luck was definitely on my side, two of them came out with no problem and the other two were saved by our tap kit and one Honda nut (haha!). Seems Subaru just loves their seized hardware — only other car this bad is the shop 370Z (good luck removing those cats!).

IMG_0755IMG_0756IMG_0757But once the stock exhaust components were off — all the PRL parts went on smoothly. The items were well crafted and up to the quality I’ve come to expect coming from PRL. The STM exhaust bolted without much fuss at all as well.

Finally I put took the bumper off and fitted the PRL front mount intercooler IMG_0758IMG_0759setup. Having done quite a few PRL turbo kit installs (we run two of their kits on our shop S2000 & FR-S even!) the intercooler for the WRX is just as beautiful as the ones they provide for all their other kits. The bypass valve is relocated to the passenger side of the bumper — which is a nice location as it makes servicing or replacing it easier in the future.

Now I had wanted to test the FMIC all by itself towards the end… but I’ll get to why I installed it while the car was already on the lift (other than it’s a royal pain to take AWD cars on and off the dyno, hah!) a bit later.

The car went back on the dyno, and now that I had all the exhaust components done I wanted to see what this little turbo could really do — and I found some annoying ECU related nuances along the way. No big deal, something for the engineers at ECUTek to dig into in the ECU code — have to make sure their day isn’t boring either.

Once I was comfortable with how the motor was behaving with the new mods (checking all the cam phasing as well), I wanted to see what kind of power I could get out of our car by going “all in” on the boost levels — let’s see what the turbo can do.

Given we have a roughly 2.7 bar manifold pressure sensor on the vehicle stock, I wanted to get up to those boost fbo_all_in_vs_intakeslevels — and I did. The graph to the right demonstrates what happens when I target right up to the clipping limit of the map sensor and then taper boost down (as the turbo can’t hold this boost level anyway). The torque is fantastic — even with a conservative timing map in the peak torque area. 330whp and 365wtq on 92 octane — not bad. But you’re going to ask me about that torque dip at 4400 rpm — and you’d be right to! At first I thought it had something to do with the fuel system (pump not keeping up, DI pressures dropping) — but nope, everything is rock solid. After a few days of street testing since these dyno tests were done I can repeatedly duplicate this issue — it happens anytime boost pressure get up to the 2.6 bar absolute or higher area. In the datalogs you’ll see the AFR on the factory sensor read 12.4-12.6 (not that scary right? on the dyno tail sniffer it was 13.4-13.8, so a bit more concerning…), and it appears the ECU is applying some sort of torque limit or power reduction via fueling (seen this behavior on other ECU’s). I’ve been on the horn with ECUTek and we definitely have some digging to do.

So calling this our “all in” pull, let’s see what happfbo_all_in_vs_safeens when we run a more conservative tune? Calling this our “safe” full bolt on run, you can see that dialing down the boost levels the torque level gets flatter and the ECU behavior going through that area isn’t pronounced (in fact power gets a bit better). One of those “tuning” battles… is fighting what the stock ECU wants you to do, even if that’s not what you want to do. How I would love me some MoTeC right now…

But bafbo_safe_vs_intakesck to the point, gains with the “safe” bolt on tune versus just intake side mods? Pretty good power pick up.

fbo_safe_vs_stockHow about versus completely stock? Mmm, even better. Hard to hate factory forced induction when you see these kind of gains with just bolt on parts and tuning.

That Intercooler!

This is where the pretty graphs come in! After spending two days tuning against the climbing charge temps with the factory hot mount, I was ready for the FMIC upgrade. Having owned and tuned other platforms with top mount intercoolers and run them at the track, the heat soak is brutal (even at the drag strip — we’d see staging temps of 50-60 degrees Celsius on a good pass).


With the PRL FMIC and even more boost our charge temps actually continued to DROP after the pull started — and the temps started lower to begin with. With the factory hot mount temps would just climb every pull. Does this have an impact on power? Absolutely. There shouldn’t even be any argument here.

Now I’m ready for some rest and my weekend — and the car is begging for E85 (next week?).

MAF Tooning

I just wanted to briefly touch upon this point as a little birdie mentioned that some have claimed the PRL Intake has a “whack” or “terrible” MAF curve. I’ve found this to be absolutely false. I found a very clean MAF curve when tuning this  intake, stock I/C or their FMIC.mafvoltage I’ve been tuning MAF for something like 14-15 years, it’s actually a break to tune a MAF vehicle — it’s quite easy compared to some of the other projects we tackle.


But what about your fuel trims you ask? Here we have a nifty graph that not only includes the fuel trims from a 45 minute drive, but a nice mean line to fueltrimsdemonstrate the average of all the data sampled across the whole datalog. Note how the mean stays very close to zero — our long term has a 2% drift in a couple of areas and our short term is overall  +/- 4% from the mean with one spot that drift ab it towards 6 with some blips in the 8% region. Not exactly bad for a MAF curve that literally came off the dyno and I drove the car home. One minor tweak and she’ll be tight around +/-5%. That’s pretty damn good for an aftermarket intake.

Jackson Racing Supercharger on the FT-86 (FR-S/BRZ)

James had us install the Jackson Racing supercharger kit on his BRZ last summer, and now he’s gone for more power and the upgrade to the C38 supercharger that Jackson just released. I had the unique opportunity to do a nice comparison between both units on the standard “low boost” pulley before upgrading the C38 blower to the “high boost” pulley.

This test was done on 92 octane fuel. Our dyno baselines a stock FT86 at 148-150whp (not the typical 170 you see elsewhere).

So after swapping over the C38 blower onto the car, dropping in the 900cc port injectors (you’re going to need an upgraded port injector for the high boost pulley), this is what we got. Solid lines are the C38 blower w/ the standard pulley, c38_lb_vs_c30dashed lines are the C30 blower w/ the standard pulley.

The results were exactly as expected — the low end was basically a wash (slightly lower with the C38 blower — it made the same or a little less pressure ratio, aka “boost”), but the efficiency of the C38 compressor started to shine on the top end, and we had a decent power pick up on the top end over the C30 blower.

On goes the high boost pulley. Internet experts quiver in fear as we swap on this pulley. The world is going to come to a grinding halt with the uber boost levels this pulley makes and is apparently going to make it impossible tohb_vs_lb_c38 run the motor safely at such “extreme” boost levels. Imminent danger to manifold — obviously.

Well I’m going to have to let the experts down on this one… but this “high boost” pulley is perfectly safe to run on pump gas (91, 92 or 93 octane). We actually picked up a solid amount of power through basically the whole curve — as much as 25whp over the low boost pulley @ 7000 rpm — making just shy of 290whp. And yes, it’s perfectly safe to drive. You don’t “need” a built motor to run this power level — or E85 to make it “safe” (but we’ll get to that later..).

c38_hb_vs_c30What’s the overall difference over the C30 blower? I’d say that’s a pretty noticeable difference over the C30 now… almost 50whp gained.

c38_hb_vs_stockAnd to compare it to stock….. lots more power  everywhere. So what do I think? I think our Internet Experts need to do less “blah blah” on their keyboards, and more work in the shop. And I think if you’re looking for a centrifugal setup, this is the way to go — the nice C38 blower with the high boost pulley. I would just skip the standard “low boost” pulley. There is nothing “scary” about this power level and it’s not particularly hard to tune it to be reliable in the hands of a competent tuner — our 290hp is 1.9x more power over a stock FT86, so on a higher reading dyno that baselines an FT86 in the ~170 area, you should be seeing 320hp, or so.

And the info graphic on the boost levels with the blowers. Blue graph is the C30 blower with the standard pulley. Orange is the C38 blower with the standard pulley. Grey is the C38 blower with the high boost pulley.boost_c38_c30

c38_e65Now the awaited E85 update… or in this case, E65 as I only got 10 gallons of E85 into the tank, and it blended with the remaining ~3 gallons of 92 octane. The results are fantastic — the car makes 2.3 times more power than stock, and c38_e65_vs_stockwell over 200whp more than stock at rev limit. The graph to the right are the gains over 92 octane. Graph to the left are the gains over a stock FR-S/BRZ.

With the extra 20% ethanol a full E85 blend would bring, we’d probably pick up another 6-10hp on our dyno. On the more high in the clouds style dynos, this setup is “400hp” 😉

Making Some Real Power on the Toyota FT86 (FRS/BRZ) — Turbo!

Starting the new year out with some bang — been driving around on our boosted 500hp FR-S for a couple months now and dealing with one of the nuances of making more and more power — the need for fuel system upgrades and tweaks. Now it’s time to go over what I’ve done to the car, what options I went with, etc.

The Turbo Kit

01I was very close to building our own turbo kit for the FR-S — however PRL Motorsports had an option available and as I already have a very good relationship with them I decided to give their kit a try after we had some back and forth. I did make a few tweaks based on what I like to run02 on turbo vehicles — making it a little custom “VitTuned” off shoot, but the heart of the kit is their work and fabrication.

Before you say you can’t find it on their site — you’re right, you can’t. You can contact them directly, or myself — and I can help you build the package that’s right for your FT86.

Now getting into it– I chose to run a Comp Turbo CT4X-5862 .82 a/r turbocharger on my car. This is quite a bit larger than what most people run (it’s a large 4″ in, 2.5″ out cover — most kit options will have something like a 3″ 09in and 2″ out cover, which is quite a bit “smaller”). But I knew I was going to shoot for more power — and I just happened to have the turbo sitting on a shelf as well.

Basic fuel system upgrades included a DW300c in tank fuel pump and Deatschwerks 900cc port fuel injectors.

Let’s See Some Power Figures!

4psi_vs_stockOK, enough with the build info — what’s this thing make? I have to say, I was quite impressed with the power output of this motor with this turbo. On 4psi (wastegate pressure) we made roughly 100hp more than stock on 92 octane fuel.

12psi_vs_stockCranking it up to 12psi running a conservative tune for the 92 octane fuel, we were able to hit just shy of 320whp. Quite a solid power figure considering this was more than 2 times stock power and still running on the stock clutch.

Speaking of the stock clutch — when I tried to crank it up a couple weeks later on E40 (40% ethano16.5psil content) it let go. So I put in an ACT 6 puck sprung setup and got back on the dyno with E55 (55% ethanol content). Boy did it make power… 16.5psi made an awesome 450whp, 3 times stock power!

18psiAbout a week later I came back in with E75 in the tank to push it a bit more. Did it pick some more up? You bet, she put down 485 whp without even breaking a sweat at 18psi (3.2x stock power relatively).

But this is where some of our troubles begin… And no, it’s not the motor. I’m happy to report it is currently running smooth and strong.

Oh The Fuel System Woes — Fuel Return Time!

You got it — at this power level the stock returnless fuel system is complete e85_18psimaxed out. As you can see from the following datalog plot — port injector run at 17ms pulse width — this is beyond even 100% “duty cycle”. Since this is a dead head system, I did not have a fuel pressure sensor mounted yet to monitor the fuel pressure — but one can assume it was about 20-25psi “differential pressure” (actual pressure over the injectors), given the PW the ECU was commanding to hit fuel targets.

So it’s time to build a fuel return.

There are a couple ways and already a couple kits out for the platform — some that I don’t particularly like (because, bluntly — the fitment is complete shit). I chose to build a return the same way I have done it on other platforms. Over the course of troubleshooting the fuel system, I also chose to run a new -6 AN feed line in addition to the -6 AN return line. Here is a rough parts break down of the fittings necessary.

  • 3/8″ Straight EFI Hose End
  • -6 AN bulkhead fitting for the top of the bucket.
  • Two 5/16″ EFI Hose Ends
  • -6 AN Male “T” adapter/union
  • Three 90 degree -6 AN Hose Ends
  • Two Straight -6 AN Hose Ends
  • 180 degree -6 AN Hose End
  • 20-30 feet of -6 AN Hose
  • Aeromotive 1:1 Rising Fuel Pressure Regulator
  • VitTuned FPR Blank

The fittings and line were sourced from — I used mostly Russell items, with some odd balls dropped in depending on what was in stock (or what I had available already).

I used the stock rails and recommend you do the same (less line and less fittings, better fitment). I had a set of aftermarket rails, they fit terrible, no room to mount the DI computer (which is grounded to the head via the mounting bracket — your car won’t run otherwise), couldn’t clip in one of the injector clips… it was so bad I threw them in the trash.

File_003To give you a verbal description of how the fuel return works — start at the tank. The feFile_001ed comes out into a 3/8″ EFI fitting and goes into the matching hose end. The feed line then snakes into the engine bay and splits with the T fitting.

The T fitting then splits and one end runs into a 5/16″ EFI hose end into the DI pump. The last out on the T runs into the side of the regulator. Then you start at the next regulator side and feed that end into the port injector rail with the remaining 5/16″ EFI hose end — or in my case (as the pictures show) you run this into your flex fuel sensor, and then into tFile_000he rail. Same exact concept though. Side note — you can with a fuel return relocate the flex sensor into the return line. I chose not to do this since I already ran the flex sensor with the dead head fuel system and it was “easier” to leave it in the feed line.

The final line — is the return line off the bottom regulator running back into your tank via the bulkhead fitting.

In the cage itself — you do have to replace the stock regulator with a blank to feed all the fuel into the feed line and towards our external regulator — as the following 3 pictures depict.


Now some people might debate this choice of blocking off what is known as the “Venturi” feed in the cage itself — and might be concerned about the in tank siphon from one side of the tank to the other on the FT86 platforms. I have been doing fuel returns this way for years when converting dead head fuel systems — it works, and it works great.

Here’s some facts about the Venturi feed — it is NOT designed to work the in tank siphon. The in tank siphon works like any other siphon — gravity and pressure! Simply put, the pressure in the tank will normalize the fuel level between the two sides. I’m not just saying this — I have been driving the car like this, the siphon works perfectly FINE without the Venturi. What the Venturi is designed to do is create a type of vortex/swirl feed at the inlet to the factory cage — this is designed to create a low pressure area that pulls fuel into the cage and helps keep it full during low fuel level conditions in the tank (and works so-so as anyone that’s ever done any aggressive driving on high powered vehicles can tell you — my dead head fuel systems running 100% OEM cages will starve the pump still). This is an effect you ultimately break the moment you use your return to feed the Venturi — under power the return line flows very little fuel and pressure, whereas the OEM Venturi is fed directly by pressure from the pump! With a Walbro 485 in the tank — I can hit it in boost with 1/4 of a tank and still maintain fuel pressure. Ultimately for someone running aggressively at a track event — a surge tank setup with their fuel return is the way to go (no in tank setup will ever be 100% when it comes to avoiding fuel pump starvation).

Se85_15psi_fixedo what did all this work net us? Tons of room on the fuel system — at the normal 15psi boost pressure I run day to day, I have a ton of breathing room to push it harder if I want to in the future. Without the return, I was already at 13ms pulsewidth on the port injector, now I’m not even at 10ms.

Maybe more power in the future? We’ll see…

Just a Couple Headers and a Slow FT-86: Skunk2 EL vs Tomei UEL

Now I want to get into this and say that I was not in any way displeased with the Skunk2 Alpha race header on our Scion FR-S — the power pick up over stock was significant, and I expected it to maintain a bit of a torque dip being it is of equal length design and we see that dip remain in some form with all the equal length headers.

I have been running this header since it came out on the platform and after helping a few customers with their Tomei unequal length race headers, it really peaked my curiosity and I wanted to do a legitimate comparison. None of this “open two dynos from two different cars” as is so common with the vast majority of “comparisons” being done. It opens a can of worms and seemingly endless debate about this and that.

Some information about the parts and vehicle as it sits now. After spending countless hours testing and tuning the car using ECUTek (which I still offer for customer cars), I have switched it to a MoTec M1 stand alone ECU for it’s advanced features and ability to rapidly tune new configurations on the vehicle (no more “Flash and Wait” — given this car is a test mule, this saves countless hours on R&D and as they say: time is money). This comparison is done with both configurations tuned on the MoTeC.

Other relevant information:

  • Skunk2 Intake
  • Perrin 3″ Exhaust
  • Perrin Over Pipe
  • HKS Front Pipe
  • E85 fuel

The use of E85 fuel makes the vehicle much more consistent and the comparison much more reliable — the correction factor used on a dyno gives you an “estimate” to compensate for weather differences, but it is only an estimate. The use of E85 ensures the motor is able to be run at MBT for ignition timing even if we have a temperature swing — something that cannot be said of 91-93 octane pump gas. From my tests on this vehicle I found a whopping 1hp difference from running E85 in 40*F weather vs E85 in 90*F weather while tuning on the Dynapack. This helps aid in the consistency of the test. With pump gas a pull used for comparison that was done in 40*F can and will make a fair bit more power than a pull done in 90*F, so you really have to be careful when doing parts comparisons on pump gas which can just lead to more debate. That being said, even with the E85 fuel, I went to great lengths to make sure the conditions were pretty much identical between the two tuning sessions.

My Expectations

With the swap to an UEL race header it goes without saying that I expected to flatten out the torque in the area where the dip remained with the EL race header. However, I was also expecting to lose out on top end as this seemed to be the “expected” results between the two styles of header. And so I was about to find out how true this was… Bearing in mind the Skunk2 Alpha is a header I’ve been running for 9 months through many tuning sessions where I’ve eeked out everything there is to be had on this setup.

The Results

So without further ado — the test was simple. The vehicle was fully tuned in great detail with the existing setup — all fuel, timing and cam timing dialed in. As soon as the Tomei UEL was delivered it installed after the Skunk2 was removed and the car went right back on the dyno for more tuning.


I was indeed partially surprised by the results — the story is that EL should have better top end? Doesn’t look like it’s even remotely an accurate statement as not only did the UEL match the EL, it carried torque much better up top and didn’t drop off as soon. The mid range also filled in significantly and the low end was no worse than the EL — unless you count the blip at 2600 rpm. Which I don’t, as that blip is literally nothing more than a blip and I can assure you from driving the car with the Tomei on it, you won’t ever miss that blip, it’s like it doesn’t exist.

For the curious, the data from the two runs (which were about 5 days apart) demonstrates the weather conditions were virtually identical (RemoteTmp, Baro & RelHum).




This was an interesting test, and I’m happy I could fit it in before the car gets torn down for our turbo kit build — yet there are many more items I would love to test. It would definitely please me to have a full “header comparison” database for this vehicle — if I could borrow every header and take a week to test them all out, I would.

As it stands now — the car makes more torque than it did horsepower in stock form, which is quite amusing.