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.

Making Power On The Civic X: Full Disclosure

One of the most fun parts of a new platform is experimentation — not with just the innards of the ECU but testing various fuels. We entered for the foray with the 2017 EX-T turbo 1.5L “base” Civic in December 2016 and started making great power with a completely stock car. What we didn’t disclose publicly are what fuels or fuel blends (more on that!) we were using to make power.

We have D/I experience dating back over 5-6 years and a lot of that carries over to the new Honda platforms. This isn’t something that can be said of the general Honda performance community as D/I for Honda is very fresh (and it’s an exciting change!).

To test the various fuels we needed proper ECU control to do so and to make sure the vehicle drivability maintained perfect — KTuner was able to provide us with rapid development and table access to get this done, and in that time we’ve helped countless customers make not just good power, but also clean, smooth pulling power curves.

So what’s the trick?

It’s really quite simple — ethanol. E85 is all the rage, however it is not needed in large quantities on D/I motors. A couple gallons actually suffice just fine. The optimal blend is actually around 25-30% ethanol content in the fuel to reach an MBT timing map (timing map for best power), after that the benefits of ethanol is actually outweighed by the stress on a limited fuel system on most cars — you get a tad more charge cooling (most of it is already realized in the 25-30% area). What’s that come out to? 2.5 gallons of “E85” mixed with 7 gallons of 91-93 octane works superbly (we actually went so far as doing 2.5 gallons and 7 gallons of 87 octane, which also worked just fine!)

The next step is to be able to bump direct injection pressures a bit — the stock CivicX D/I fuel system runs at about 18MPa of fuel pressure, and you can safely raise up to ~21.5MPa which gives you a significant amount of injector overhead (have to be careful — ~22MPa you start hitting the pressure relief, and it’s not something you want to hammer on).

On the ‘base’ EX-T we were able to make ~245-247whp & 300wtq safely on a COMPLETELY stock car and a stock clutch before it slipped — and we got on the horn with ClutchMasters very early on to have a clutch developed for this platform — which was ready for us as soon as we picked up our 2017 Si first week of June!

Si? Yes yes!

Once we got the Si and a clutch we repeated the same tests — making 255whp on a safe level, and ~275whp on a very aggressive level (33psi! — can’t do this long term because the map sensors max out at 29psi) using the same ethanol blend.

But that’s not all, there are better blends of ethanol. Ignite Red or what we really liked — VP’s C85. Using the same blend ratio of C85 we were able to SAFELY (without pegging the factory map sensors) make another 10-12whp.

The little 1.5T in these cars is very potent — torque levels as high as 350wtq can be attained easily, but caution is advised as who knows how long the rods will handle that kind of torque level in the low end/mid range, especially if you like lugging this motor in high gear.

And before you ask — yes, you can do this on the CVT, but KTuner is highly advised as they are the only ones to offer a fully “unlocked” solution for tuning the CVT as we see fit. We can bring down the torque levels and get the cars another ~20whp easily and safely.

Also — expect to see roughly ~10% higher figures in other locations as we have a fairly conservative reading dyno, historically (stock 8th does 172, 9th does 160-170, on and on).

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.




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!