I just purchased a 94' RX-7 that needs a motor. I'm replacing the motor with a remanufactured Mazda motor. I plan on doing numerous modifications during the installation(radiator,intrercooler,y-pipe,intercooler pipes,clutch, and downpipe). I don't plan on upgrading my ECU right now. I've heard if you change the downpipe you must upgrade your ECU, or risk motor damage. Is this true? Can anyone give me some info?

 

nope - should be fine. Usually it's the midpipe that does the damage. You should add a boost gauge to that list, if there isn't one already - that'll let you know the state of things.

 

I have one already. Thanks for your reply.

 

note that I said 'should'

I haven't heard of anyone having trouble with just a dp - but stranger things have happened

 

I think the trouble people run into after the DP is boost creeping up over stock levels. IMO, this is usually because the DP is the average persons 3rd mod (after intake and CB).
You mentioned you have an intercooler, I assume you have an aftermarket intake also? If so, there is a chance you'll be boosting above stock levels. Nothing to get too worried about. Just keep an eye on the boost gauge and if it goes much beyond the stock 10psi you may have to get a boost controller.

 

Don't forget - if you are getting a Mazda reman, only buy from Ray Crowe at Malloy Mazda. His are the best. Do a search and see for yourself.

 

I have purchsed a aftermarket intake. I'll keep an eye on it. Thanks