TPIS Cat-back and headers
Thread Starter
Racer
Joined: Oct 2001
Posts: 466
Likes: 27
From: Hendersonville tn
TPIS Cat-back and headers
I already have TPIS headers on an LT1 car and need to do something about the cat-back system. I need to make it pass emmissions and need a cat to pass. Is the LT1 cat-back that TPIS makes to go on their headers any good. It at least allows the placement of a cat that can be switched with an off-road pipe. Who's used their cat-back and how does it sound? Any fitment problems?
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: TPIS Cat-back and headers (BryanC)
If the LT1 cat-back is like the L98 unit it will need some work to fit it up. I needed an exhaust shop to cut out sections from each Y leg as did Vic'89 when I had the TPIS cat-back put into my '88 Vette. It does have some resonance but not too much for my taste; I realy like the FlowMaster sound.
Do their headers for LT1 run into a single Y like they do for the L98? If so you can get their Random Tech cat and won't have to swap it in/out. In that case you may need to get the cat-back for L98.
Do their headers for LT1 run into a single Y like they do for the L98? If so you can get their Random Tech cat and won't have to swap it in/out. In that case you may need to get the cat-back for L98.
Team Owner
Joined: Sep 2003
Posts: 25,295
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From: I'm the walkin dude I can see all of the world...
St. Jude Donor '03
Re: TPIS Cat-back and headers (BryanC)
Obviously you don't have visual inspections. Is it possible to fab somthing up with the stockers with kinda a bolt-on bolt-off system? Do you have access to a welder or better yet your own weld machine?
Yes I know stock cats dont fit with LT's but it would be possible with some chops and welds. Although with a Borla system and I think TPIS have those long extensions. So I guess I'm answering myself. :lol:
Yes I know stock cats dont fit with LT's but it would be possible with some chops and welds. Although with a Borla system and I think TPIS have those long extensions. So I guess I'm answering myself. :lol:
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Re: TPIS Cat-back and headers (BryanC)
Bryan,
Exotic Muscle makes a kit that utilizes the slip fit header like the TPIS version. It is the pipes to go from the headers to where the resinator is mounted. At this point you can add 2 of the bullet cats and then tie back into the orig. exhaust. It is my understanding that on a factory system you will need to eliminate the resinator and get a piece of pipe to extend from the cats to the orig. exhaust. IMO the advantage of this verses the TPIS system is you keep 2 cats like the orig. came with verses 1. I believe I paid $195.00 for the kit.
By the way, I still have not heard from your friend. (John)
Exotic Muscle makes a kit that utilizes the slip fit header like the TPIS version. It is the pipes to go from the headers to where the resinator is mounted. At this point you can add 2 of the bullet cats and then tie back into the orig. exhaust. It is my understanding that on a factory system you will need to eliminate the resinator and get a piece of pipe to extend from the cats to the orig. exhaust. IMO the advantage of this verses the TPIS system is you keep 2 cats like the orig. came with verses 1. I believe I paid $195.00 for the kit.
By the way, I still have not heard from your friend. (John)
Thread Starter
Racer
Joined: Oct 2001
Posts: 466
Likes: 27
From: Hendersonville tn
Re: TPIS Cat-back and headers (93 ragtop)
I know. I told him last night again "Decide something already."
What you describe is similar to what I have except the cats have failed and they are only 2.5" while the rest of my borla is 2.75". The cats have to sit diagonally to clear the tunnel nad they scrape speed bumps. The 2.5" x- pipe and cats in the position of the stock resonator created a bottle neck that cost me 4 mph in the 1/8 mile. I'd like something better than what I have now. The exotic muscle system has 3" slip fit to go on headers? That might work. I'll check it out.
What you describe is similar to what I have except the cats have failed and they are only 2.5" while the rest of my borla is 2.75". The cats have to sit diagonally to clear the tunnel nad they scrape speed bumps. The 2.5" x- pipe and cats in the position of the stock resonator created a bottle neck that cost me 4 mph in the 1/8 mile. I'd like something better than what I have now. The exotic muscle system has 3" slip fit to go on headers? That might work. I'll check it out.
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Race Director
Joined: Oct 2000
Posts: 14,064
Likes: 1,166
From: N. Alabama
Re: TPIS Cat-back and headers (BryanC)
Bryan, I used the randoms. Onks had them welded to the TPIS long headers and bolt at the corsas. That way I can bolt up original manifolds and cats if I so desire in the future. I just passed emissions but they only plugged into the OBD 2 connector.
I have seen your posts on emission problem on the LT1 edit page. I'll have to find out from you how to post a reply. Right now I am only understanding how to get a lot of e-mail....LOTS of email!! :lol:
Give me those emission numbers again and let me look up the parameters in one of my troubleshooting volumes for you.
I have seen your posts on emission problem on the LT1 edit page. I'll have to find out from you how to post a reply. Right now I am only understanding how to get a lot of e-mail....LOTS of email!! :lol:
Give me those emission numbers again and let me look up the parameters in one of my troubleshooting volumes for you.
Thread Starter
Racer
Joined: Oct 2001
Posts: 466
Likes: 27
From: Hendersonville tn
Re: TPIS Cat-back and headers (southern_son)
I was getting 349 ppm HC's. Last year it was 70 ppm HC's, no changes since then. I think the guts of the cats are gone. Remember I looked at the underside of your car? Only promblem is I have the vert. x-brace and it makes for tight clearance with the exhaust. Your Corsa was cut like my Borla to mate to the headers, right? Did you keep an intact piece from the front of the Corsa cat-back so you could reinstall stock manifolds and cats?
Race Director
Joined: Oct 2000
Posts: 14,064
Likes: 1,166
From: N. Alabama
Re: TPIS Cat-back and headers (BryanC)
Have you scanned for misfire? Sometimes it is hard to feel it. My previous plugs were misfiring like crazy on cylinders 1 and 2 with no code set.
You know, the 300 to 400 ppm of HC would be expected without cats. hmmmm....further more, if the A/F is too lean OR too rich, by way of misadjusted timing or misfires, CO2 is reduced.....High CO2 is indicative of best performance...the exact level of which is vehicle dependent as for as what would be considered normal.
You know, the 300 to 400 ppm of HC would be expected without cats. hmmmm....further more, if the A/F is too lean OR too rich, by way of misadjusted timing or misfires, CO2 is reduced.....High CO2 is indicative of best performance...the exact level of which is vehicle dependent as for as what would be considered normal.
Race Director
Joined: Oct 2000
Posts: 14,064
Likes: 1,166
From: N. Alabama
Re: TPIS Cat-back and headers (BryanC)
Bryan, your time is not set correctly on your puter or something.......look at the time of your last post on this thread....wasssupp doc??? I can't get a response to post at bottom.... :eek:
Race Director
Joined: Oct 2000
Posts: 14,064
Likes: 1,166
From: N. Alabama
Re: TPIS Cat-back and headers (BryanC)
The pipes from the front of the center piece to the original cats had to be cut and fitted to the randoms. I will only need those two pieces should I decide to go back to original configuration.
You have some unburned fuel somewhere for sure. Basically there are 3 possibilities for the misfire; compression problems, ignition or lean misfire.
And then, of course, the obvious rich A/F ratio.
If you knew someone with a good gas analyzer to check all 7 gases; CO2, H2O, N2, CO, HC NOx and O2, the guessing game would be a lot easier.
You have some unburned fuel somewhere for sure. Basically there are 3 possibilities for the misfire; compression problems, ignition or lean misfire.
And then, of course, the obvious rich A/F ratio.
If you knew someone with a good gas analyzer to check all 7 gases; CO2, H2O, N2, CO, HC NOx and O2, the guessing game would be a lot easier.
Thread Starter
Racer
Joined: Oct 2001
Posts: 466
Likes: 27
From: Hendersonville tn
Re: TPIS Cat-back and headers (southern_son)
And of course the big lopey cam. The CO was only .08%. And CO2 was 14.x% So it's not to rich. I have yet to pull all the plugs and look at them, but they aren't very old. The plug wires are pretty new also. It has no noticible miss, just the cam lope.
