I needed help on how to port my plenum. Somebody said there was a tech thing on it. If anyone could help me I would appreciate it.

 

I will be doing my plenum soon. Here are some of the htings i was told.

1 When porting behind the throttle body mating surface, be careful when grinding down the side edges. The casting is a poor design, and if you grind too much, you could go right through. When grinding, listen for a ringing tone, or tinny tone... this will be an indicator that you have reached your limit.

2 I will be lining up the gasket to the bolt holes and gasket matching the port holes. I am not sure if that what others do.

3 Maybe try smoothing as much of the cast surface as you can.

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1988 Pontiac Trans Am GTA L98 5.7L, Black on Black with 114,000kms.

Best ET 14.559 @ 95.25MPH
Custom 3" Stainless Exhaust Y-Pipe back (High flow Cat and Flowmaster Mufler)

 

its actualy alot easier once u get in there, your start to realize what needs to be ported and stuff, thats what happend to me anyways. good luck

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake

http://www.geocities.com/david_angel_16

 

There's some stuff on my page: http://members.home.net/rcrabine/porting.html and on Dan Burk's page: http://www.isthq.com/~dan/fcar.html and a tech article on the intake, which applies to the plenum here: https://www.thirdgen.org/newdesign/t...meseport.shtml

 

I had never ported anything before, but once I got going it seemed pretty intuitive. I don't know if its mentioned anywhere, but your best bet is to use a "NF burr" for the porting, because it doesn't load up AT ALL with aluminum.. I had much poorer results with steel burrs and grinding stones!

 

SO, after portin the TPI manifold, and plenum, runners, you will lose torque down low and gain it up top, since u said it felt slower out of the gates. R there any good mods that add HP, but dont sacrifice torque.

 

i dont know about you guys, but on every TPI car i have owned i had more low end torque than i knew what to do with.

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Bone stock blue 85' Z28 42k original miles.

*previous car: lightly moded 89' Formula 350