i have a 94 with 67k miles rebuilt at ~55k

i did a search and didnt find quite what i was looking for so...

would it be safe to add a downpipe and aluminum ast to a car that already has a koyo aluminum rad and blitz intake without getting an ecu upgrade or power fc? i dont plan on getting any more modifications done after that until the engine goes-which hopefully will be a while.

would it be safer if i went back to the stock air box and change to a downpipe without the ecu? because i really dont want to spend $400 more for an ecu to put on only $400 worth of mods and right now all im looking for is to squeeze as much life as possible out of this engine.

edit:forgot to say, it also has a turbo timer, dont know if that makes much of a difference

 

Don't sweat the radiator and AST, those are just reliability/safety mods. If all you have is an intake then a DP is not a problem, in fact, alot of people consider that a safety mod too, since it gets rid of the microwave/nuclear reactor heat from under the hood, thus saving more wear and tear on turbine housings and the miles of vacuum hoses.
You should have a boost gauge, so be sure you don't boost more than about 11 pounds if/when you add the DP, this will keep you safe and out of the boost fuel cut.
Have fun, and do alot of research before doing any power mods.

Regards,
Frank

 

you gotta pay to play. a lot of people talk about the 3 mod rule. where as in your safe with 3 mods without any proper fuel managment, but why take any chances? its all up to you though. i know a few people running intake, dp, and catback on the stock ecu. they seem pretty safe for now. if your paranoid about it just wait to install your dp with an ecu when you are more financially stable.

 

actually i dont really have a problem with the money its just i am reluctant to spend more on the ecu than the mods when i dont plan to take it any further than the intake and dp(for the life of this engine). also i would be planning to get the boost guage and temp guage along with the dp and ast. and i dont plan on boosting past 10(thats stock right?).

 

money is money. you only live once. forget about your grandchildren! LIVE!

 

Ahh, but you will eventually. In case you didn't know, power mods are like drugs. "I used to do a little but a little wouldn't do it so a little got more and more"
I used to think my car was fast, then came the DP. That was good for awhile then I added the catback. "Man" I thought. "Why would I need this to be any faster"? Then came the hiflow cat, IC, Intake, and computer. So for now I'm happy, but I know I will feel the "Jones" again soon
I realize that you are taking it easy on your engine for now, maybe with plans for more mods on the next engine, all I'm saying is that pretty soon you'll want this engine to go so you can finally start pumping the HP up.


10-8-10 is the standard, stock boost pattern.

Regards,
Frank

 

one more thing, around how much power and torque should i expect with just intake and dp at stock boost? the engine is pretty strong, im getting it compression checked this weekend.

 

If I were to guess, about 235-250 HP to the wheels, hard to say, there are alot of factors.
Dyno it and let us know.

Frank

 

https://www.rx7club.com/forum/showth...&highlight=ecu

 

A new aluminum AST won't affect boost but the DP will. Get a boost gauge along with the DP. You don't want to go over 11lbs and you need to monitor spikes and creep. Don't forget to heat coat the DP. Unles your overboosting, look into a water temp gauge and IC before the ECU.

 

The three mod rule is a myth. As long as you keep your boost to 10 psi, you are fine for the most part.

BTW, I wouldn't consider spending $400-500 on a used Pettit or M2 ecu a waste of money because you will be able to sell it for about the same price you bought it for. Something to consider if you feel uncomfortable adding the downpipe.

It's also good insurance to run your car on the dyno with a wideband o2 sensor to verify your A/F ratios are still safe. Mine were still very rich with a downpipe and cat-back on the stock ecu. You will likely put down somewhere around 240 rwhp if your car is healthy.

 

Just as a point of reference, I ran a DP, HF cat, Catback, KN Drop in filter with no problems. I also ran a manual boost controller setup at 11 pounds, and also a J&S knock computer as insurance. I always used Texaco or Chevron 92 octane too. My J&S is set too sensitive, but I never heard any knock. I never had it hooked up to a wideband either but my A/F gauge showed I was at about .86 volts, or about 11.0:1 (give or take). I realize that this is not the way to tune (standard O2 sensor) so I was nervous all the time when my foot was in it, I relied on the J&S to save me. Anyhow, just an FYI, YMMV.

Frank

 

i hate living in CA with this $2 91 octane premium crap.btw, thanks for the info everybody

 

My car is pretty much stock but it has a new engine in it, but its the OEM mazda rx7 tt 93' one. anyways so its cool if i add a radiator and dp, maybe intake, wont the intake mess my atf ratio??

 

It's ok. See my first post above, 2nd from top, and read this thread one more time too, it may help.

Frank