I put an exhaust cutout on my 92 camaro. Ive got flowtech shorty headers and no cat. The cutout is under the passenger right about where the old cat used to be. I took it to an 1/8th mile dragstrip and ran a 10.184 with the cutout closed and when I opened it I ran a 9.878 but only the first time. Every run after that was around 10.1 and when i closed the cutout after about 5 more runs the car wouldnt run. I started it 3 times and 3 times it died. On the 4th try i put my foot in it a little and it ran but very roughly, i got it moving and once it came up a little in the RPM's it smoothed out and ran exactly like it used to. Did the computer change things? or do I maybe have a different problem that jus happend to come up at that time. If it was the computer is this bad? Should I not mess with the cutout any more? Im just not exactly sure what could of happend, sorry for the long explination, but anything anybody's got is more than i know. Thanks much.

 

I'm a little out of my league here, but this is my 2 cents...

On my car, my timing changed after I hooked up my Y-pipe to my exhaust.

So I would check your timing with the cutout open & closed. The computer may be re-adjusting the timing.

Again, just my 2 cents but might be worth a try.

Hope this helps!

 

do you have an o2 sensor in your headers?

 

an O2 sensor too close to the cutout could be reading false content by having outside air present in the area. the O2 will read fresh oxygen and compensate for it by adding extra fuel when its not need and cause an overly rich condition. i know when i was running open headers with my O2 sensor 6 inches from the collector my BLM's would max out at 160 when it went into closed loop, open loop and WOT wouldn't matter because the O2 is ignored at that point.

 

thanks for the help, it must of been a weird fluke because it hasnt done it since i posted this. go figure! but i guess its a good thing. thanks again!