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.

Prologue

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!

http://vittuned.com/2016-civicx-1-5t-3-downpipe-front-pipe-combo-pre-order.html

N/A Bolt On Nissan 370Z E85 Test Results

What I really wanted to title this is “ignorance is bliss — no WAY could ethanol possibly even a single HP over pump gas”. I was inspired to do this test by a very bold claim on a certain online forum — I’ll keep the names out of it, but it definitely gave me a chuckle.ignorance_is_bliss

 

There are so many faults with this bold claim — but the very first thing any reader should get out of it is that when someone posts something in absolutes like this you should take their statement with skepticism and simply do your own research.

Not a single hp.

Really? The one thing I’ve learned in the 12+ years of tuning ALL kinds of motors, is you simply can’t deal in absolutes. Something may make power that could be taken as “margin of error” for the type of dyno you’re on or just very negligible gains that will never be noticed in the “real world” (say like 2-3hp for example, but it really is relative to the platform, etc — this is a question best left for another discussion).

The irony here is the statement preemptively tries to attack the skills and credibility of anyone doing a pump gas to E85 (ethanol) tune. I can’t say if this is really just the ignorance of the author of the post or just a gigantic ego that blinds him to reality.

My response is simple — “Oh please”. Fortunately for us, there are a few of us that are quite capable at what we do and we have actual tools at our disposal to do quantifiable testing instead of listening to someone spew hearsay on the internet.

Now for the sake of transparency — our pump gas is 92 octane, not 93 octane. However — big deal — the gains from going to 92 octane to 93 octane on a motor that isn’t ignition limited on 92 octane will be minor or nonexistent (and ours wasn’t — I could roll past MBT on the ignition map and not get detonation, there was just no more power to be had — which is what the statement about 91 octane implies). Hey don’t take my word for it — try it yourself.

As for the argument of WHY would E85 have gains over pump gas? What the author of said post seems to miss is the properties of the fuel — it is naturally oxygenated and has much better cooling properties than pump gas (regardless if said pump gas is 91-93 octane). I’ve done hundreds upon hundreds of E85 tunes — N/A or F/I — and I have yet to see a motor that doesn’t gain SOMETHING over pump gas (see what I did there?).

The Test

OK enough with the bull shit — here’s the results and the actual FACTS.

The car is a 2015 Nissan 370Z, with bolt ons:

  • Stillen Intakes
  • G35 test pipes (modified to fit)
  • Agency Power 2.5″ dual exhaust

VVEL and VTC had been previous tuned for this setup on pump gas, and were left alone for the E85 portion.

After the vehicle was filled up with E85 (tank took 16.5 gallons), fueling was pump_vs_e85_fuel_only_wmtuned to maintain a proper air/fuel ratio without touching the timing map — the motor continued to run the same timing curve as it did on pump gas. Simply running E85 and maintaining proper fueling netted us 8whp. Wow, this is already certain more than Not A Single HP. And well above any kind of margin of error.

Next I adjusted the timing map to see if we could extract a bie85_fuel_vs_e85_timing_wmt more power — and 4whp was found. The amount of timing added was very negligible (could run this timing map on pump octane without seeing detonation — it however netted no gains on pump gas), and what we can gather from this is that due to the larger volume of fuel we are injecting with E85, we needed to ignite the mixture a minute amount of time sooner to get a complete burn of the mixture in the cylinder.

e85_all_in_vs_pump_wmWhat does this look like overall? We picked up 12whp and as much as 12wtq through parts of the torque curve. Wow, that certainly looks like it’s a lot more than Not A Single HP. The best part about it all? This is free power — the stock fuel system supported E85 without upgrading anything — we ran stock injectors and the stock fuel pump. And to top it all off — fuel economy during freeway cruising was not impacted at all — if anything it was 1-2mpg better than what I was used to seeing on pump gas.

Conclusion?

Really, what should be said about E85 gains on this motor is depending on the quality of your pump gas (because yes, even quality of 93 octane can vary), you may see between 2-4% gain in power with E85. You will also see it through out the whole power curve — more than can be said about the Stillen intakes I tested on this car, which had margin gains through a couple of spots of the power curve. Quite literally the dollar per HP gains from just running E85 (which is readily available at the pump by the shop) surpasses a $560 intake system.

There you have it — quantifiable results vs hearsay (or apparently I have some kind of secret to making power with E85).

bullshit