L-98 Tpi Porting
Thread Starter
Racer
Joined: Jul 2007
Posts: 478
Likes: 1
From: Nesquehoning PA
L-98 Tpi Porting
I have seen many posts about ported tpi plenums etc. I have searched the forum and have not seen anything about the procedure for doing this...I have done several sets of heads all with good results so I feel that this is something I could tackle myself with a bit of guidance.
Can anyone steer me in the right direction?
Thanks,
JeepCycle
Can anyone steer me in the right direction?
Thanks,
JeepCycle
Intermediate
Joined: Feb 2008
Posts: 49
Likes: 0
From: Langley British columbia
Plenium porting:
I'm no professional but this is what I did; I enlarged the openings behind the TB so it matched my BBK TB, (don't so this unless you have a larger TB), I also enlarged all the ports to match my oversized eldelbrock runners, then I ground down the little support that blocks off some of the area behind the two openings at the front of the plenium, and polished the surface, also I got rid of any sharp edges, like the ones b/w the runners and smoothed out the cast finish. I also had my entire intake ceramic coated cause it looks good and I heard it keeps the intake charge a little cooler. Thier might be a special way to port the plenium but this is what I did and it helped the engine breath a little better above 4400 rpm, no big difference though.
Just to be clear this is for the plenium only not the base.
Just to be clear this is for the plenium only not the base.
Last edited by Car Guy 88; Mar 9, 2008 at 10:10 PM.
Pro
Joined: Jul 2000
Posts: 508
Likes: 0
From: Vancouver WA
I just ported the TB opening of my plenum last month. Enlarged the two holes, grinded out the block on the forw'd bottom behind the tb blades, and smoothed out the sides. Here's a pic; took my about 2 hrs.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
I ground the max out of my plenum when I matched it to a 58mm.
Had no bad effects with stock TB
Ran exactly the same times with either stock 48 or aftermarket 58mm TB.
( Was testing the myth that too big a TB killed bottom end ;
same ET , same 60 ft over 30 passes with either TB so 58mm a waste of $$$ on small / stockish engine )
Porting pics
http://www.eecis.udel.edu/~davis/z28/buildup/plenum/
http://sethirdgen.org/TPIbase.htm
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
I have seen many posts about ported tpi plenums etc. I have searched the forum and have not seen anything about the procedure for doing this...I have done several sets of heads all with good results so I feel that this is something I could tackle myself with a bit of guidance.
Can anyone steer me in the right direction?
Thanks,
JeepCycle
Can anyone steer me in the right direction?
Thanks,
JeepCycle
Race Director
Joined: Jun 2004
Posts: 13,956
Likes: 706
From: WI
Porting was a fun project! I picked up a used base, larger runners, and plenum to work on then swapped it onto the car and sold the stock parts.
Picture of cleaning up the base:
I did not port the base much if any, I did clean it up a lot. The ports were really messy.
Pictures of the plenum:
I relocated the MAT and made a plug while I was porting, the MAT sensor sticks up in front of the back port.
I took a few pictures while working on port matching the runners:
It took a lot of hours but I wasn't in a hurry. I also used a brass brush to clean/polish the plenum.
Picture of cleaning up the base:
I did not port the base much if any, I did clean it up a lot. The ports were really messy.
Pictures of the plenum:
I relocated the MAT and made a plug while I was porting, the MAT sensor sticks up in front of the back port.
I took a few pictures while working on port matching the runners:
It took a lot of hours but I wasn't in a hurry. I also used a brass brush to clean/polish the plenum.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Intermediate
Joined: Feb 2008
Posts: 49
Likes: 0
From: Langley British columbia
In answer to the question of why I said not to enlarge the opening on the front of the plenium if you don't have a larger than stock TB, this is not because it will because you to lose performance it is mearly because if you don't have a larger TB thiers no point in wating your time enlarging the holes in the front of the plenium.
I agree thiers not much point in getting an oversized TB on an otherwise stock engine, since the stock 48x2 will flow as much as a stock engine will need anyway.
I agree thiers not much point in getting an oversized TB on an otherwise stock engine, since the stock 48x2 will flow as much as a stock engine will need anyway.
Last edited by Car Guy 88; Mar 12, 2008 at 01:31 AM.
