This is for my Rx7 and im posting here because the guys over at rx7club are not very helpfull. I just bought a JIC 3" single exhaust for my turboII rx7.... Im bosting around 9psi and the motor is pretty much stock. I had the racing beat dual 2.5" exhuast and my friend suggested i went with a single 3". well i took his advice and now my car feels a bit slower but sounds awesome do i need a tune? im clueless to what it could be but maybe someone here can help me out.

thanks
jimmy

 

how much rwhp are you pushing?

 

the 3" might be too much for it

 

havent dyno'd yet but will soon ...its a bit faster than my G ...what do you mean to much for it? for the stock motor?

 

im planning on doing a greddy turbo upgrade and a few other mods so im not sure if i should just keep it till then or switch back to the racing beat.

 

that's interesting. i've had a couple of converstations with a shop about my twin turbo z, and the recommendation was that the turbos need some amount to backpressure to get the most out of them.

 

when you said boosting i just figured that it was turbo...anyways, i am not an expert but i think that you need to be running over 4-500rwhp to use a 3" exhaust

 

the car is turbo but still on the stock turbo im going to do a greddy turbo upgrade with fmic. yeah it feels like i lost all my back pressure ..its not a big loss in power but it does feel like i lost some.

 

if you get bigger turbos, it should balance out the bigger exhaust. the combination of the two should give you maximum gain. what year is your rx. i owned a 93 tourning myself a long while back. beautiful car...the only problem i had with mine was an intermittent second turbo. it only kicked in half the time.

 

its an 89 gtu with a full tII swap, motor, tranny and driveline. im pretty sure i'll need this exhaust when i upgrade to a bigger turbo ... haha im just upset cause i spent $700 to make my car slower

 

smaller turbos dont do good with large exhausts... when i had my honda prelude i was running a 18G turbo and with the 3'' exhaust w/no cat i slapped on it gave me an extra 15whp on the dyno

 

yeah i felt it right away but its no biggy since im upgrading to a bigger turbo later on... i might just throw the racing beat back on in the meanwhile

 

pics?

 

Despite what many claim, N/A engines do NOT like backpressure. But you need to evaluate your hp before slapping a big *** exhaust on. I was running a 3 1/2" single on my 10 sec LS1. When I went to 4", no gains..........

A turbo is a different animal. I've only had two turbo cars, but my understanding is that too big of an exhaust will cause the turbos to spool slower (back pressure helps them spool quicker) and thus can loose power down low.