Okay, I have had a downpipe for some time, I have had the midpipe just sitting in my room gathering dust due to my fears of its use with a stock ECU or even my M2:stage3.

I'm finishing up several modifications to my car this week, block-off plates, airpump removal, fixing a minor exhaust leak, enfini Y-pipe, fuel pump upgrade and trans swap. While I'm under I want to go ahead and sticking the midpipe on. I cannot afford the expendature of a PowerFC + tuning just yet and I'm rather content with the performance of the M2 anyways. Now I have a RX7.com ECU that is said to be safe with the midpipe but I dont know if I can trust that still...

My solution to getting rid of the main cat and installing my midpipe is to have a 'restictor plate' added inline with the exhaust so that my turbos dont creep up or spike from too much flow.

My first question would be, is something like this readily available for a 3" exhaust pipe and if so where can I get it?

Second, what size should I get, I would think that 2.5" would be an adequate restriction without impeding too much flow -- keep in mind I will still have the stock cat-back system.

Thanks,
~Kris

 

The creep mainly comes from trying to run a good amount of boost. If you need to just run this setup for a while as you sort things out, turn your boost way down or simply keep your foot out of it.

Dale

 

I'd say start with 2 inches and work your way to 2.25 and then 2.5. they are easily made. Just a flat peice of metal acting as a gasket with a hole drilled in it.
A grinder and some 1/8 inch steel and you can make your own. Don't risk too much flow even though you are controlling your boost.

 

Yea, with the M2 I'm running 12PSI and the RX7.com ECU is designed for 14PSI (I'd still run a MBC limiting it to 12PSI for reliability and safety)

~Kris

 

I'm planning this as a permanent solution, that is something that I can trust for several months to protect me from too much flow. I intend to get a PowerFC + Dataloggit eventually but that is a ways away, I just want rid of the heavy cat since all my other emissions stuff is gone anyways.

~Kris

 

the car may not "creep" at 13 but it may at 10. you will have to be careful and stay off the gas. you have a boost controller? a profec may be all you need. you will need one anyway so why not now