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”?