TPI performance enhancement question...need some guidance!
Thread Starter
Melting Slicks
Joined: Aug 2001
Posts: 2,753
Likes: 1
From: Fishkill NY
TPI performance enhancement question...need some guidance!
If I just do porting and polishing on the runners and plenum and not do any work on the lower intake, what performance enhancements can I expect?
Burning Brakes
Joined: Mar 1999
Posts: 858
Likes: 5
From: Fl,USA
Re: TPI performance enhancement question...need some guidance! (1991C4)
I wouldn't waste my time if I were you. Probably not much gain if any. You could remove the humps behind the throttle plates for a slight gain. Porting the stock runners is a big waste of time though!
John
John
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: TPI performance enhancement question...need some guidance! (1991C4)
apparently the single biggest thing you can do is siamese the runner end of the intake manifold....about 4" down the runners.....and maybe with a cam change, it's supposed to wake the engine up a whole lot....as in about 40 hp...or so.....see another thread on this issue here on forum...
GENE
GENE
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: TPI performance enhancement question...need some guidance! (Vic'89)
Heres my belief...if you remove the runners and plenum and gasket match everything,then have them cleaned out in a steam tank,the most gains would more likely be if yours have so much carbon it became a restrictor to begin with.In a sense,getting any lost airflow back.
The plenum holes arent always consistant with each other,and Ive gasket matched my plenum holes and had everything cleaned.
She ran like a champ more so afterwards.
The stock runners really cant be ported out because theres no material to remove because the tubes are so thin and are seperated.
I had a bit of carbon build up inside the plenum,runners and intake.The intake manifold is more difficult to clean out if its not off the car.
I believe the most gain one might see if its really dirty and mis matched gasket to holes,and thats cleaned up and ported to full gasjket size,one might get maybe 5 HP.
Thats just a guess.If you have high mileage or over 55,000 miles,it may be wise to clean the TPI out real good just for maint.
:)
The plenum holes arent always consistant with each other,and Ive gasket matched my plenum holes and had everything cleaned.
She ran like a champ more so afterwards.
The stock runners really cant be ported out because theres no material to remove because the tubes are so thin and are seperated.
I had a bit of carbon build up inside the plenum,runners and intake.The intake manifold is more difficult to clean out if its not off the car.
I believe the most gain one might see if its really dirty and mis matched gasket to holes,and thats cleaned up and ported to full gasjket size,one might get maybe 5 HP.
Thats just a guess.If you have high mileage or over 55,000 miles,it may be wise to clean the TPI out real good just for maint.
:)
Thread Starter
Melting Slicks
Joined: Aug 2001
Posts: 2,753
Likes: 1
From: Fishkill NY
Re: TPI performance enhancement question...need some guidance! (Bill's86Coupe)
I have seen many post about the "Y" pipe. What is this about? Replacing the "Y" pipe without the cats?
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Drifting
Joined: Aug 2000
Posts: 1,521
Likes: 0
From: West Islip New York
Re: TPI performance enhancement question...need some guidance! (1991C4)
I have seen many post about the "Y" pipe. What is this about? Replacing the "Y" pipe without the cats?
I'm told how ever the car will still pass emissions without any problems (at least mine did). Just don't have anyone do a good visual (if they know what there're looking for !!)
Le Mans Master
Joined: Jul 2001
Posts: 8,183
Likes: 3
From: Santa Maria, CA
Re: TPI performance enhancement question...need some guidance! (1991C4)
If I just do porting and polishing on the runners and plenum and not do any work on the lower intake, what performance enhancements can I expect?
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: TPI performance enhancement question...need some guidance! (89 Paul in cal)
Walker makes what they call a 3 way 49 state emissions legal front Y pipe with no precats and a new main cat.
So if anyone would ask,you tell them its the walker 3 way E-legal replacement pipes.
I have the front Y pipe with n precats and a new main cat.Dont know if I gained any real power but it was much cheaper then buying the 600 dollar Y pipe from GM.
I hear a good catless Y pipe can help free up almost 10 HP.Cant hurt to switch over the precats which is prob. more so a restriction anyways when its over 50K miles.
:)
So if anyone would ask,you tell them its the walker 3 way E-legal replacement pipes.
I have the front Y pipe with n precats and a new main cat.Dont know if I gained any real power but it was much cheaper then buying the 600 dollar Y pipe from GM.
I hear a good catless Y pipe can help free up almost 10 HP.Cant hurt to switch over the precats which is prob. more so a restriction anyways when its over 50K miles.
:)
Thread Starter
Melting Slicks
Joined: Aug 2001
Posts: 2,753
Likes: 1
From: Fishkill NY
Re: TPI performance enhancement question...need some guidance! (89 Paul in cal)
Well, I don’t know how much I will gain doing the porting, polishing and also doling the base. I was just curious if I just did the runners and plenum, what the gain would be.
Drifting
Joined: Aug 2000
Posts: 1,521
Likes: 0
From: West Islip New York
Re: TPI performance enhancement question...need some guidance! (Bill's86Coupe)
Walker makes what they call a 3 way 49 state emissions legal front Y pipe with no precats and a new main cat.
So if anyone would ask,you tell them its the walker 3 way E-legal replacement pipes.
So if anyone would ask,you tell them its the walker 3 way E-legal replacement pipes.
Well, I don’t know how much I will gain doing the porting, polishing and also doling the base. I was just curious if I just did the runners and plenum, what the gain would be.
Le Mans Master
Joined: Dec 1999
Posts: 8,540
Likes: 1
From: And on the fifth day, subpoenas were served to Obama senior staff
Re: TPI performance enhancement question...need some guidance! (1MoorTym)
1MoorTym, Walker has a Y-pipe and main cat setup that is EPA approved for 49 states. The republic of California (CARB) has not approved this setup. It is perfectly legal everywhere else. We are talking about the EPA here, and they approved the Walker setup. They make the rules, except of course in California that likes to make their own rules. It will not fail a visual inspection anywhere except in California.
Drifting
Joined: Aug 2000
Posts: 1,521
Likes: 0
From: West Islip New York
Re: TPI performance enhancement question...need some guidance! (PeteL)
PeteL - We seem to be on opposite sides of the fence tonight. I've seen the pipe, the ads and I know exactly what you're saying. However, the emission regulations I paraphrased earlier are correct. Any changes to the way the manuafacturer had the car certified are not permitted. I found this out while I was trying to convert a C3 to true duals with the installation of two cats where the car only had one to begin with.
We can agree to disagree.
We can agree to disagree.
Le Mans Master
Joined: Dec 1999
Posts: 8,540
Likes: 1
From: And on the fifth day, subpoenas were served to Obama senior staff
Re: TPI performance enhancement question...need some guidance! (1MoorTym)
Maybe, but in this instance you are wrong. I have the Walker setup, I researched the Walker setup. They have 49 State EPA approval for the Y-pipe / cat for direct replacement on the L-98 (at least on my 89) without pre-cats. This is not approved in California, but it is approved (at least now) for every other state in the Union.
So you can disagree, but then again you would be wrong. Call Walker, Call the EPA, call your State (long as you are not in CA), I did!
Best regards, Happy New Year, and so on;
Pete
So you can disagree, but then again you would be wrong. Call Walker, Call the EPA, call your State (long as you are not in CA), I did!
Best regards, Happy New Year, and so on;
Pete
Safety Car
Joined: Jun 2000
Posts: 4,870
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From: Long Island, NY
Re: TPI performance enhancement question...need some guidance! (1991C4)
I was just curious if I just did the runners and plenum, what the gain would be.
Vic
