T.P.I. plenum?
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From: Inez kentucky
Car: 87 iroc z
Engine: 358 tpi
Transmission: 700r4 with transpack
Axle/Gears: 3.42 with powertrax
T.P.I. plenum?
I have noticed there are 2 different types of plenum's I have the one with the triangle on the bottom, and am currently running the stock throttle body, and was wondering if I can port it out like they do on the one without the triangle and still use my stock throttle body. Here are some pics of what Im talking about. And if anyone has a pic of the triangle type ported out to max post it or e-mail it to me so I can see what to do. Thanks..
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From: Huntsville, AL
Car: 87 GTA, 88 GTA, 92 TA, 72 RS SS
Engine: 350, 350, 305, 396
Transmission: T56, 700r4, 700r4, T56
Axle/Gears: 3.42, 3.23, 3.23, 3.73
Re: T.P.I. plenum?
Yes, you can port it just the same, I can post a pic of mine ported this afternoon if you like.
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Joined: May 2004
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From: Inez kentucky
Car: 87 iroc z
Engine: 358 tpi
Transmission: 700r4 with transpack
Axle/Gears: 3.42 with powertrax
Re: T.P.I. plenum?
Yes, plese post the pic I would very much appriciate it!!! Im guessing yours is the type with the triangle and, I can run the stock throttle body after porting it out to max? Im going to get the largest I can (It's going to be a 386 stroker when Im done) when money permits but I have to stick with stock for now. And agin super thanks for quick reply and the pic's that will help alot!!!!!!
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From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
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Re: T.P.I. plenum?

Cutting the center part out as shown has no effect ; only did on mine because someone had already started cutting on the plenum I bought.
Once the two holes are out to 58mm there is no more benefit to be had
Last edited by vetteoz; Dec 2, 2009 at 02:55 PM.
Joined: Apr 2005
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From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
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From: Flowood,MS
Car: 87 IROC Z
Engine: 5.7 L98 TPI
Transmission: 700r4,2500 stall
Axle/Gears: G80,10 bolt 3.42's
Re: T.P.I. plenum?
It does help to port it with a stock TB.You really dont need a larger tb yntil you have the rest of the intake upgraded.Large tb would be one of the last things I`d do.Money could be better spent on something that would benifit you.Go ahead and port it and keep the stock tb untill you really need a bigger one.The RamJet 502 makes 502hp through a stock 48 mm tb.Good enough for me.
check this out https://www.thirdgen.org/forums/tpi/...bk-tb-one.html
check this out https://www.thirdgen.org/forums/tpi/...bk-tb-one.html
Joined: Apr 2005
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From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: T.P.I. plenum?
The EGR humps in the bottom of the plenum behind the TB entry are a BIG restriction even when running a stock 48mm.
If you are going to be in there playing around you may as well take it out to 58mm so you don't have to do it later
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Joined: May 2004
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From: Inez kentucky
Car: 87 iroc z
Engine: 358 tpi
Transmission: 700r4 with transpack
Axle/Gears: 3.42 with powertrax
Re: T.P.I. plenum?
Yea that was what I did take out the egr shrouds and I am going to put the 58mm tb on later but was mainly just making shur I can do my plenum and not have to buy another one. I already polished it to mirror(found how to do that in the tech section here and after I was done probly one of the most satisfide I have ever been with any cleaning upgrade I done I LOVE IT and HIGHLY RECCOMEND everyone try it) and would have hated to have to buy another. But thanks everyone I will problu just wait till I get the 58 or 52 and stroke it to 386 till I do any more since I have already removed the egr shrouds.THANKS AGAIN!!!!!!!!
Last edited by 3rdgengmachine; Dec 2, 2009 at 05:56 PM.
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From: Huntsville, AL
Car: 87 GTA, 88 GTA, 92 TA, 72 RS SS
Engine: 350, 350, 305, 396
Transmission: T56, 700r4, 700r4, T56
Axle/Gears: 3.42, 3.23, 3.23, 3.73
Re: T.P.I. plenum?
Here is mine with the EGR walls knocked down, and one without for reference.
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From: Fayetteville, NC
Car: '92 Camaro RS
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Re: T.P.I. plenum?
That Jantzer Performance in the top pic did a real nice job smoothing outthe one on the left. Hope I can get mine looking that good.
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