The Nissan 370Z — Testing Bolt Ons & Tuning

It’s that time again — got my hands on a 2015 Nissan 370Z and the typical bolt ons we see on this platform for some tuning and parts testing! As always, I tune the car completely stock first to get a good “tuned” baseline, and then retune after every set of mods. This is a very fun platform to tune due to the very flexible VVEL system.

So what we will have on this test is:

  • Bone stock vs Bone stock tuned
  • Stock tuned vs Full Exhaust (Test Pipes + Exhaust) tuned
  • Full Exhaust vs Intake & Full Exhaust tuned

The parts in question are the following:

  • Agency Power dual 2.5″ exhaust
  • G35 test pipes modified to fit compliments of Old Man Dan’s hack and weld skills (certain vendor screwed up and sent me the wrong parts, I was not amused)
  • Stillen V3 long tube intakes

So without further ado, here we go.

Stock vs Stock Tuned

stocktunedIt was pleasant to see there was actually a fair bit of room to improve over the stock mapping on the ECU — especially with the refined ignition control available to us now. One of the nuances I was able to fix was the throttle closer on the top end and the delayed throttle opening on the low end the stock ECU exhibits — this opened up some good torque gains down low and helped smooth the power curve up top.

The VVEL system is also extremely tune-able, and I was able to net extra torque down low with adjustments to this system — however through the rest of the curve Nissan got it mostly right, not surprising since the vehicle is stock.

Stock Tuned vs Full Exhaust Tuned

Not a whole lot to say about these results — clearly the exhaust modificationsexhaust_vs_stock_tuned_wm made power after we bolted them up to the car — but since our starting point was already a “tuned” calibration, very minor changes were necessary to extract peak gains from the parts and the fueling was still dead on since the stock intakes had been retained for this portion of the test. I expect this would not be the case if the car was still running a 100% factory tune on the ECU instead of my tuned calibration.

Full Exhaust Tuned vs Intakes & Full Exhaust Tuned

Depending on the intakes you chose to put on a vehicle tuned via MAF (aka AFM), you can skew the fueling dramatically — fortunately with the Stillen V3 long tube intakes I found that the mass air flow calibration was very close to the stock intakes and only required some minor adjustments to maintain proper fueling throughout the curve. However, even with perfect fueling, these intakes actually LOST power throughout the WHOLE power curve.

You might be thinking to yourself, “Whoa, what? They’re just filters on a stick….”. Indeed I was quite surprised as well.

That’s where the tuning begins — the engine required significant remappinstillen_vs_stock_with_exhaust_wmg of the VVEL system to not only return to the power the stock intakes were making, but also gain power over the stock intakes. After fully retuning the ECU, our results are some minor torque gains down low and through the mid range, and about 10-12hp on the top end.

My personal thoughts? Wow that was a lot of work for minor gains — but it does go to show how a naturally aspirated engine is a finely tuned machine with all the parts working “in harmony” with the ECU mapping to actually make power. Sometimes one small change can have drastic effects.

Some fun

Well, with that out of the way, what do the gains look like over the “stock tuned” setup overall?


And what does it look like over a completely stock vehicle?


Scion FR-S/BRZ Tomei Unequal Length Race Header

It’s always quite fun and interesting to progressively install new parts and retune a car to see what kind of relative change we see with those parts. This weekend I had the opportunity to help Jay retune his 2015 Scion FR-S after he installed his Tomei UEL race header. We had previously tuned this car when it was stock (well, stock being relative — he had a slightly modified stock airbox and the stock muffler delete, nothing major).

Jay FRS Stock TunedThe results with the car “stock” tuned looked like so. Very healthy pick up for just a tune.


Well on to the race header — after Jay installed it, we baselined the car on the existing tune to see just what the changes were from the part alone. It looked like stock_tuned_vs_header_untunedso.  I was a little surprised to see the results as we gained almost no power through most of the power curve with the part — it did however fill in the torque dip area, which was pleasant to see.

Next up is the retune. I exclusively used ECUTek for tuning these vehicles — they have the best stock ECU solution on the market with superb support. I knew there was definitely more in it — the motor on the car has dual VVT and quite a bit of work can be done to squeeze out any “hidden” power the neheader_untuned_vs_tunedw parts (the race header in this case) can support. Sure enough, we got solid gains! The graph on the right shows the gains from tuning  over the race header baseline, very pleased with the power pick up.

Let’s compare that to our stock tuned power curve — and you can see a very solid power gain all across the board over the previously “stock tuned” car. The
stocktuned_header_tunedmid range torque pick up was quite impressive — as much as 28 torque to the wheels with the header and retune. I have seen other headers on this platform pick up more power on the top end — but they did not fatten up the torque curve (especially in that mid range dip) as much as this header does. So it’s definitely a trade off if you’re looking at this header as your next mod.

Where does the car stand overall from when it was “stock”?