ECU's

[Mazda's Supra]

I have a cx now3 and I'm doing an Si swap and was wondering if the cx ecu will work or if I need an Si ecu? If it won't work will a dx ecu work? I know vtec has to be wired but other wise what's the diff?

 

[posol]

you need the si ecu if you want it to run correctly.

 

[Mazda's Supra]

yeh i figured but wasn't sure...thanks for the quick reply

 

[Z6CRX]

it will run, but you'll get codes for vtec and i think it will run lean.
Also if the "Si" swap is a b series motor, you'll also get a code for the knock sensor

 

[B16RacerN2NR]

Quoted post[/post]]
it will run, but you'll get codes for vtec and i think it will run lean.
Also if the "Si" swap is a b series motor, you'll also get a code for the knock sensor

if the ecu doesn't look for vtec or knock in the first place, then you can't throw a check engine for either code. Just run the Si ECU or one from an EX, and wire up the Vtec.