Porting TPI Intake Plenum
Thread Starter
Instructor
Joined: Dec 2009
Posts: 236
Likes: 0
From: Houston Texas
Porting TPI Intake Plenum
Hi, I have a 1989 corvette with a 58mm throttlebody that I believe is sticking to the plenum, so regardless I need to port the plenum to 58mm. My question is, does anyone know how I can do this without pulling the intake off, like with a wet vac or somthing. also what kind of bit would I need, please a walk through would be great!
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,062
From: altered state
St. Jude Donor '05
It can be done but it would bother me to do that. Couple metal shavings get sucked in there it could either blow out the exhaust or do some minor damage causing premature wear. Your call.
YOull need to remove the IAC etc also so those dont get boogered up.
Pull it off if you can and eliminate the risk
YOull need to remove the IAC etc also so those dont get boogered up.
Pull it off if you can and eliminate the risk
Race Director
Joined: Nov 2003
Posts: 12,220
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
It can be done but it would bother me to do that. Couple metal shavings get sucked in there it could either blow out the exhaust or do some minor damage causing premature wear. Your call.
YOull need to remove the IAC etc also so those dont get boogered up.
Pull it off if you can and eliminate the risk
YOull need to remove the IAC etc also so those dont get boogered up.
Pull it off if you can and eliminate the risk
Unless you have an aftermarket/upgraded intake, the added benefit of a 58mm TB outweighs the risks you'll encounter. In that regard, I'd go back to a stock TB and FORGETABOUTIT!
If there is some benefit you really feel you can gain, you also have to consider that (significant) porting involves using a burr with oil. IMO, that oil can cause shavings to be more difficult to vacuum out after completion. (Oil makes shavings heavier/stickier) Plus, some of the smaller "chunks" might go down the IAC passage holes (located just behind/below the plenum's TB bores.
Rarely do you find people trying to take that kind of shortcut -- if they really want to improve their car!
Last edited by GREGGPENN; Apr 6, 2010 at 11:13 AM.
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Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 7
From: Tampa Florida
it only takes a few minutes to pull the thing. Ensure the parts are clean and shaving free before reinstallation. If engine intake/heads/exaust is pretty much stock stuff stay with the 48MM. If your stocker is worn out and a new TB is cheaper than having a rebuild done then I wouldn't go over a 52 MM. Save the 58MM for applications like a mini or a super ram with all the high $ flow fixin'sPics of my '89 ported plenum hogged out to 58MM (fits 48-58MM dual bladed TBs with no issues):
Pro
Joined: Mar 1999
Posts: 678
Likes: 0
From: Oslo, Norway
take the plenum off. It is not that difficult and quite fast.
I magine if a little fraction of aluminium come betweetn the valveseat and valve and the valve closes. There will be a leakage which may burn the exhaust seat/valve or intake will take a too hard punishment. In these cases Murphys Law come into work.
I magine if a little fraction of aluminium come betweetn the valveseat and valve and the valve closes. There will be a leakage which may burn the exhaust seat/valve or intake will take a too hard punishment. In these cases Murphys Law come into work.
Burning Brakes
Joined: Oct 2005
Posts: 824
Likes: 30
From: San Pablo California
Remove it by all means!
I bought a ported plenum from fellow forum a fellow forum member who does this for a living.
It is a thing of beauty and it certainly did help in the performance department. But then my engine does have a few after market items and is a 377 stroker and anything that I could do to enhance the breathing of it had to help.
www.Corvetteplenum.com
I bought a ported plenum from fellow forum a fellow forum member who does this for a living.
It is a thing of beauty and it certainly did help in the performance department. But then my engine does have a few after market items and is a 377 stroker and anything that I could do to enhance the breathing of it had to help.
www.Corvetteplenum.com
