I’m done with engine tuning, and have wanted to post an update here to tie up loose ends, but have been wary of touching this controversial thread. So much aggro. I figure now that this volcano’s lain dormant for months, it should be safe to poke, right? Famous last words, I know…
Anyway, here’s a dyno graph superimposing my most recent dyno run (July 2017; green line) with an earlier one in January 2017 (red line) and my very first one in October 2016 (blue line). Same dyno, same ramp rate, same ambient temperature/humidity:
Since the CVT shifts at just over 6k rpm, ignore the portions above the 6.1k rpm mark.
So what we’ve got here is a stock baseline of 120whp (blue line), aftermarket intake + ECU tune yielding 124 whp (red line), and aftermarket intake + axleback exhaust + ECU tune yielding 138whp (green line).
The red and green lines are different versions of a road-tuned ECU reflash by the same tuner (Matt Mcleod aka Throttlehappy).
If we assume that my 2.5 engine does indeed make 175hp at the crank in stock trim, then the 120whp roughly translates to a 30% drivetrain loss. If we apply that to my latest 138whp run, that extrapolates to an estimated 200hp at the crank.
Regardless of whether you take the dyno measurements at the wheel, or my estimates at the crank, it works out to a 15% power gain.
Is that worth the time, effort and money? That’s a matter of opinion but if numbers are all you’re after, then perhaps not. However, the hp numbers come with a similar increase in overall torque, and don’t measure faster/crisper CVT shifting and the big boost in everyday drivability and enjoyment - all of that makes an ECU tune, at the very least, a no brainer from my perspective. If you look at my numbers pre-and-post exhaust mod, it’s clear that axleback exhausts do in fact give a worthwhile power boost with a tune. Conversely, it’s also clear that even with a tune, an aftermarket intake alone yields negligible power gains.
For those who haven’t seen my earlier posts in this thread, my relevant mods are an aFe Power Takeda intake and Kakimoto ClassKR axleback exhaust.
And before someone asks me again why on earth someone would want to mod a 2.5 instead of buying a 3.6 - a big reason is that the 2.5 is the only engine available in many markets, including Japan. I couldn’t have bought a 3.6 even if I wanted to.
Alright, that’s a wrap, folks.