We're picking up the wife's '20 CX-5 Signature on Monday and I was quite impressed with the torque this 2.5T has. Since this car takes 87 or 93 (94 up here in Canada), I'm really curious about how the ECU retards or advances timing in these engines. I'm completely new to Mazda and their engines but have some experience tuning Subarus. We have tuning parameters in the ECU such as feedback knock correction, fine learning knock correction, and the ignition advance multiplier (IAM or sometimes called DAM). Does the Mazda ECU use a similar approach?
Looking at that dyno chart above, it appears that the engine is tuned below 4000 rpm to assume 87 octane, where the engine is most likely to spend the majority of its time. It's not until 4200 rpm that the octane differences become noticeable. This makes me wonder if the engine is mostly tuned for 87, even when running 94, and at the higher RPMs the dynamic ignition advance / knock detection does its thing.
That dyno chart does make me wonder about a few things:
- Does 89 or 91 octane give you a little bit more power? What about 94?
- Given the 2020 CX-5 makes 10lb-ft more torque on 93+ vs 87, I have to wonder how conservative the ignition timing is and if, for engine longevity, they've left some untapped potential. The top-end is likely a function of the size of the turbo, heads, etc, so probably not a lot more to get out of it.
- Does the car allow you to rev out to ~6000 rpm when in manual shifting mode? I never tried it during the test drive. If no, then once the ECU learns to advance the ignition timing when running 94, is it smart enough to increase the shift point? The default programming seems to shift around ~5200 rpm and those extra 800 rpm might result in a bit better 0-60 times and overall quicker acceleration. Obviously, this vehicle isn't meant to be a rocket, but it seems that 3rd shift to get to 60 hurts the acceleration a bit.
This is all just curiosity though as with this being my wife's daily driver, there are strict rules about touching the programming.
BTW Does anyone know of good tuning resources for these cars? Just curious to read a bit more about these 2.5T engines.