i just hooked up my new exhaust(much harder than it should have been) and now my car has a loppy idle. what can i do. the exhaust is apex'i GT catback, rb dp, and a bonez race pipe.

 

Changing an exhaust on it's own will not change the idle..

You have either stuffed something else up in the process or you just couldn't hear this 'loppy' idle before.

 

you've changed the breathing characteristics of the engine, sensed by the ECU via the boost/ pressure sensor...allow the ECU to "relearn", or try disconnecting the battery for a while to see if that helps, or jumper the initial set coupler to readjust the idle...sounds funky, I know, did it to me, too...

 

Sorry, I don't believe it.. the main fuel load sensor for the stock ECU is the AFM... NOT the boost sensor.

When I had the stock ECU I too changed my exhaust.
From a totally 100% stock one to _nothing_

I actually ran my car (at idle..) without any exhaust manifold on at all.
No change in the idle.

I also then changed it to just a striaght 2.5in pipe from the header back.
No change in the idle.

Repeated this process(for other reasons...) even with my microtech, which going by your logic above should matter even more since it only uses the MAP sensor for load. But .. alas..
No change in the idle.
Rock solid 750rpm.

Only thing that change was the tone and timbre of it. (oh and volume.. )

 

I'll bet money that not only did the exaust on this car get changed. I bet the ACV and or the airpump has been removed/blocked off.

I'd also venture that the ACV had an internal leak that was feeding into the intake (should not do that unless broken) and that extra air was involved in the ORIGINAL IDLE. Now that that *extra*air ain't thar no mo, it idles funny. How's that for guess work???

 

you put an apexi GT on a n/a? i was going to do the same.. isnt that really really loud?

 

^

He said "apex'i GT catback, rb dp, and a bonez race pipe" doesn't downpipe only exist on turbo'ed vehicles?

 

turbos and majical rotarys