Tom93R1

iTrader: (2)

What is the most I can do before I really must get an ECU? Right now I have DP, high flow cat, boost controller (used to keep boost down to 11, was spiking to 15 before). Can I do any intake mods and cat back, possibly intercooler as long as I keep boost down to 10-11?

rx7eaven

I am pretty sure that you need to get an ecu quick. I don't think that you can run too much more on stock.
94 rx7 blk. r2

maxcooper

Different people have had different experiences with their cars, but there are real and understandable reasons why you need to upgrade the ECU even if you stay at the stock boost level.

The basic points are:

- The ECU decides how much fuel to deliver based on RPM, manifold pressure, and intake temperature. There is NO FLOW SENSOR.

- Upgrading the exhaust, intake and intercooler all increase the amount of air that flows through the engine at a specific boost level. This is not intuitive, as it is common to think that as long as the boost is the same the flow will be the same. That is not true, you will get more flow at the same boost level if you make the system more free-flowing.

- When you make the engine flow better, the ECU has NO IDEA ANYTHING CHANGED, since all it looks at is RPM, boost, and intake temps. So, your engine runs more and more lean as you open things up, and eventually you will get to the point that you detonate and blow the engine.

You *might* be able to get away with a cat-back or intake, but probably not both. I suggest that you get an ECU as your next mod. The bang for the buck will be greater than with any other mod, because you will be able to safely turn up the boost.

Here's a work-in-progress web page I wrote with more info on this subject:
http://www.maxcooper.com/rx7/how-to/...ystem/why.html

-Max