Stock ECU w/ High Compression Pistons
 

Question for you guys. I'm putting my car back together after a years long project and am running out of money. Long story short is, I'm putting the engine back together and won't be able to come up with the scratch for an AEM stand-alone right now. The motor is completely stock aside from high compression pistons (12.3:1).

Would I be able to run the stock ECU on this? I understand it obviously wouldn't perform to its potential, but could I make it work for awhile without breaking anything? I thought maybe I could throw on a Apexi VAFC to tune fuel a bit since I already have it lying around.

Let me know what you guys think and thanks for the input.

bump

Why risk it off advice you get from a random person on the internet?

With raised compression ratio ignition would probably be of more concern than the fueling.
Using an Apexi VAFC is a probably a bad idea unless you really know how they work since adjusting fuel with that will affect ignition tables as well.
I would never run it with a stock ecu tune, yes it may work but you definitely risk destroying the motor as well.

Aem ems v1 can be had for 500$, seems like an investment

You can call Inlinepro and ask them of there thoughts of running the stock ECU as they build high compression engines all the time. The JDM F20 engine was 11.8:1 CR.

It is interesting to note that ASM/Toda engine package with the 12.3:1 pistons does not say a retune is required. On the other hand it doesn't say stock ECU is ok either.

However the dyno sheet looks like it has stock VTEC engagement:
https://autobacs-asm.com/original200...O=ASM-AP100207

Blog post also mentions Toda performs bench test with stock ECU (google translated though):
https://autobacs-asm.com/blog/asm/in...s_view&no=3287

Gotuning's listing for a discontinued ASM/Toda engine product says stock ECU, not sure of compression ratio:
Go Tuning Unlimited

Could it be that 12.3:1 compression would be ok with stock ECU in places with high octane fuel? Japan uses 96RON/92AKI as their high octane fuel.

I guess with high octane race fuel it could be ok.
Or just regular fuel and hope the knock sensor will pull enough ignition to avoid detonation.