HUGE loss of top-end power

[Vip09]

Lately since I've added my intake/exhaust/power-fc.. i noticed that my top end has suffered. I thought that it might be the pfc tune, but even with the stock ecu the top end is crap. I have a few ideas as to what might be causing it.

1) A while back when I replaced my lift bolts. I lacked a torque wrench and over-tightened one of the bolts which stripped the block. Now the bolts just spins in place... could that be a problem??

2) I have some exhaust leaks around the flange gaskets.

3) Dent in the exhaust.. everyone knows about the funky bend in the stock gt-s exhaust between the resonator and the axle back portion. Well yeah.. i have a nice sized dent right on the funky bend.

Soo.. do you think these problems could cause me to go from running 14's stock to running 15.3-15.7 and going from 95mph traps stock to 89-90mph traps in the 1/4 with i/e/pfc ???

[91 Celica St]

its teh dent for sure, dents in your exhuast can make ur car run like shit, and no the leask wont do anything i have a ton of them

example, my frined was boosting 15psi on his 2g dsm and ended up botteming out and denting about the size of a golfball cut in half and pressed in, he couldnt boost past 12psi and he lost ALOT of power

fix the dent, either pop it back out or find a way to do it

if you dont wanna wast your time/money reset your ecu, you cant do it by just unplugging the posotive battery terminal, you have a cmos chip in your ecu and it rememebrs stuff, you have to look online to find out how to reset it, and turn the power fc off untill this problem is fixed

are u running lean or rich? car hotter or colder?

[91 Celica St]

^of yea i meant reset the ecu to see if anything chages, if it dosent then its the exhuast, and what bolt are you talking about?

[Vip09]

The tune on the Power FC is fine.. i'm running 13.8 AFR at wide open throttle on the low cam and 13.2 AFR at WOT on the high cam. I'm sitting right around 14.7 AFR at idle and partial throttle.

To reset my ecu, I just have to pull the battery cable or the EFI fuse. But.. my ecu has been sitting in my back seat for few weeks.. so it's surely reset by now haha.

I'm talking about the bolts that attach the valve cover. I took the valve cover off a while back to replace my lift bolts. When i was putting one of the valve cover bolts back on I overtightened and stripped the block.. so I'm thinking i could be losing some pressure around the valve cover gasket.

Oh and the car is running normal temps.

[91 Celica St]

the valve cover gasket thing wont matter, ive driven around the block w/out one, lol what do u think the pcv valve is for?

its deff the exhuast, if its not the exhuast then its somthing u dont know about

my $0.02

[jwaj2002]

all of the above, the exaust leaks are a major reason, celicas run off of backpressure from the exhaust, if you have a leak its sucking air back into the engine from the exhaust, found that out when I made my straight pipes without the muffler, even a small leak will screw you up, as far as the dent, you could go to a muffler shop and have them splice in a new peice shouldn't cost much, and the lifter bolt is probably a good part of it, you can retap the hole, then get a torque wrench and tighten everything to its specs, toyota engines are picky when it comes to tightening stuff

[91 Celica St]

^lol celicas run off backpresure from the exhuast? it thought they ran off an internal combustion engine? how do u figure a loose valve cover bolt will make him lose power, yes its a closed system and yes he thoretically coudl suck in air all the way down his crankcase, but with one loose bolt? very highly unlikely

a leak in your exhuast will not make your car run any worse, im probably loosing about 1/2 the exhuast out all my leaks and my car hasnt gotten anyslower scince before the leaks

btw if you run staright headers, yes you can suck air back in and burn your exhuast valves, but a small leak dosent have the power, or pressure to even get close to sucking in, and btw how the fuck is it goig to suck back in while the car is on if exhaust runs through the pipe constantly?

its the dent

.

[lilsteeg]

well its not the leaks or the valve cover bolt, if im not mistaken those bolts dont go in to the block, just the head so that wont do anything to the power, it is probally just the dent nothing big just go get it fixed