First mod a flop, please help!

  • Thread starter Thread starter Bigreddawg
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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.
G-Tech is crap, and often inaccurate....take the car to the track and you should notice a huge difference in spool up, and with the free flowing exhaust it should pick up a few MPH....What kinda boost are you running? Any Knock?
On the crappy digital stock gage it go's into the red but always settles out at what should be about 10 psi. At full throttle it knocks very slightly now that I've been putting Sunoco 94 in it. Was alot worse when I first got it from the dealer, I bet they had 87 octane in it. All the tracks around here are now closed for the season so I have to use the g-tech, its better than seat of the pants. I got a best of 15.85@87-88 when bone stock. Does that sound right for a 84?
Mid 15's Sounds about right.

Remember..when the exhaust flows more the Boost somtimes goes up a few you might not have the fuel for the added boost.

Car have a Walbro Pump? Hot-Wire kit? Adj Fuel pressure Reg?...If not stop beating on it, and do those mods....Car is probably leaning out.
Just wondering? Still have the stock air cleaner hooked up? I have an ATR 3" SS single shot and when i put it on the car pulled real hard. How about the stock cat? I gutted mine. Know i have a 3" test pipe. Good luck.
G-tec is ok to check your car some times but don't really work on a car with a little power. I tryed mine and it said 14.01 @ 106mph , then at the track it was in the mid 12's at 108.5 . I will say the same thing get a fuel pump , adj reg and hot wire. Make sure you don't have any exhuast leaks or vac leaks this will kill your power to.

good luck
Thanks for all the help guys. It definitely sounds like I should have upgraded the fuel first. I will most likely go for the Walbro and an adj. fuel reg. Do I need the harness for the max. voltage to the pump or will hot wiring be the same. Are there any tech articles on hot wiring, that harness is like 60 bucks. Is 100.00 for the Walbro 307 sound fair, thats what the Buick Part Finder has it for. They also have the reg. for 102.00 I think.
Originally posted by TurboRegal84
The stock harness and the Hot-Wire kit somewhat work is all plug and play, and very easy to install.

Just ordered the Walbro, Billet Reg. and Hot wire harness. I will post back with new results. Thks for all the help to everyone.