I figured I would eventually need to do the exhaust so I did a 3" high flow cat with 3" mandrel bent pipe out over the axle and out behind the passenger side rear tire(no muffler). Initial impressions were good, sound wise and spool up and it even feels stronger sometimes however when I g-teched it lost a few mph. Does anyone know what may have caused this. Should I adjust my TPS, change plugs and/or plug wires? What could be the cause, I thought that mod was a no brainer. Oh yeah, I have a 84 T-Type(Hot air ofcourse) bone stock except for exhaust.
Not sure what u mean by g tech but does the car make more boost now? Do you hear ping now? Its possible that now since you got rid of the crap exaust it may need a small tweak to maximize your mod. Such as fuel press. What are your o2 millivolt reading at wot?
First I don't think the g-tech is a very good device to use to tune our cars.. Unless you have it exactly positioned the same every time, your results can be skewed. And I mean extactly... having it a 1/8" different in respect to parallel to direction of car can make over a 10% change in your readings. (take it out of car and put it back in 3 days in a row and see how differnt your data is) At least it was for me
Changing exhaust would not cause a need for changing TPS. Since the car is basically stock..I suspect if it feels better it probably is. If you want to comtinue to tweak your car, then you need to get some sort of scan tool so you can look at o2 and retard use those 2 things to tune your car for optimim performance. Free flowing air filter, adjusting Fuel Pressure and adjusting boost will be next...
Hope that helps
Sully
87 GN
10.95@122
Thanks guys, I didn't realize the stock fuel system was marginal to begin with, so I should have started there I guess. My boost was about 10, now it does appear to be higher, maybe like 12 psi.