MISSTHAT 7

have a downpipe and hks exhaust. i just installed a midpipe and removed my megnaflow cat.was that a mistake or did i do the right thing.im not much or a racer love the speed but knew to all this.the midpipe makes it very loud.does the midpipe cause more problems to your motor?is it more dangerous to blow the motor? need some help please help. dont know wether to put bak magnaflow cat of leave as is.

rynberg

Put the cat back on immediately. Assuming those are your only mods, you are going to blow the motor with a midpipe. Leave the car alone and spend about 2 months reading the 3rd gen FAQ, archives, and forum.

g3rx7nut

a mid pipe will blow ur motor if u dont have ur car tuned for it. If u have a stock ecu u shouldnt have anything more than an intake, down pipe, and exhaust. Anything else will up ur boost and blow the motor.

rynberg

Not quite true, but I don't feel like getting into it.

AntiVenom7

a midpipe can give problems even with a tuned ECU with the stock wastegate(search "boost creep"). definitely a no-no with the stock ECU. Like was said, make sure to read through the forum before modding your car any further.

ronbros3

I have heard that a mid pipe leans out the fuel mixture on stock FDs, we did at customers request and blew seals 1st day, some type of fuel managment is a must on FDs, they seem to be on the edge from the factory I guess to meet emissions and fuel economy.

rynberg

No, a midpipe does not make the car run too lean at 10 psi, it's just that, uncontrolled, it will cause spiking/creep above 10 psi. The stock ecu apparently does not have adequate fuel maps/ignition maps for above 10 psi use (there is a stock fuel-cut above 10.7 psi, but it requires constant boost and does nothing for spikes). The stock ecu actually runs pig rich -- below 10:1 above 4000 rpm. There is plenty of room for mods as long as boost is kept at 10 psi or below.

Joe Geiman

I have a 3" down & mid pipe w. stock cat back. I have a solid, steady 11psi
boost with no problems.

with other turbo cars i have owned, lack of exhaust restriction after the turbo has always been a plus.

Joe Geiman
aka: 2turbos

rynberg

That stock cat-back is helping you out a LOT. Don't remove it without a boost controller.