327_TPI_77_Maro

iTrader: (8)

Hi guys, I used a 1989 trans am gta intake duct for my MAF setup on the 1977 camaro (I flipped the intake upside down to locate the air box on the drivers side, but the entire duct, MAF, and air box is stock 1989 gta). I used to pull 98.5 mph trap speeds consistently with my 327 when carbed. I now pull only 97.5, with a Holley Stealth Ram and MAF 165 ecu, and my custom prom tuning. Aside from possible afr/timing differences from when I was carbed, I also have heard that the Firebird intake duct is very restrictive (especially since I shift at 6200-6300 rpms). Can anyone tell me how much power / et they improved JUST by changing out the stock Firebird intake duct with a home made or aftermarket replacement? I am probably going to fab a piece of crap custom intake and head back to the track to see if I can find my lost 1 mph trap speed.

shawn87gta

iTrader: (1)

When I made my CAI I noticed an immediate improvement in the engine starting, revving and SOP performance. No timeslips or anything to verify but it was a noticeable difference. The factory thing is garbage. I made mine out of 3" thin-walled PVC and with the filter it was ~$50.

speed88

The factory air ducting on the thirdgen Firebirds is very restrictive, as far as the TPI'ed cars are concerned. That is why the Camaro of the same year usually made more hp. Get rid of the stock air ducting and make yourself a nice CAI. I did with my '88 GTA and noticed a 2mph difference in the 1/4 mile.

327_TPI_77_Maro

iTrader: (8)

Speed88, thanks, thats exactly what I needed to know. I lost 1-1.5 mph in the 1/4 going carb to TPI, and the HSR is certainly not holding me back, so I know where that mph went -- the damn firebird air duct. 3" pipe it is

1989GTATransAm

iTrader: (3)

I can tell you Dyno Don picked up 17 horsepower on his Pontiac by going to a 3.50" tube intake system and bigger K&N air filter. His car is a 1990 with the speed density system and the stock intake is a little better than the ones on the MAF cars. Yes the Pontiac intakes are restrictive. Allen

Dyno Don

iTrader: (7)

Here it is

BigWhiteGTP

Dyno Don, I want one of those!!!! You made that? Can you make me one?

Zepher

iTrader: (1)

4" is the way to go, but you'd have to convert to SD,




My intake setup on my 88 305 doesn't seem that restrictive, I've got a big 4x8x3 Cone Filter on the end,

GOY

I'm sure I could find 2 90 degree mandrel bend, and about 2-3 feet of straight 3 inch piping and make one pretty easy using "Turbo" pipe rubber clamps and still use my MAF. Might only pick up 10 or so HP, but it shouldn't cost more than $30