Replace cat with 'test pipe'
Thread Starter
Burning Brakes
Joined: Sep 2017
Posts: 1,073
Likes: 65
From: Belgium
Replace cat with 'test pipe'
Hi everyone
I removed my mufflers yesterday, and wanted to hear the sound from the 'semi-straight pipes'.
I'm still running the original 2-1-2 system.
Everybody said, it was going to be 'LOUD', but when I started the engine, it wasn't loud at all. Just the same level as before.
I only could notice a slightly deeper tone. It was a bit of a disappointment ...
The cat (original) is still in place, so maybe the sound is still **** because of that?
I've been thinking of removing the cat, and putting a test pipe in place, but I can't find one with 4 bolt flanges on both ends.
I also can gut out the cat... or is it better to keep it original (How much is it worth?).
What are your thoughts and recommendations?
I removed my mufflers yesterday, and wanted to hear the sound from the 'semi-straight pipes'.
I'm still running the original 2-1-2 system.
Everybody said, it was going to be 'LOUD', but when I started the engine, it wasn't loud at all. Just the same level as before.
I only could notice a slightly deeper tone. It was a bit of a disappointment ...
The cat (original) is still in place, so maybe the sound is still **** because of that?
I've been thinking of removing the cat, and putting a test pipe in place, but I can't find one with 4 bolt flanges on both ends.
I also can gut out the cat... or is it better to keep it original (How much is it worth?).
What are your thoughts and recommendations?
Melting Slicks
Joined: Sep 2004
Posts: 3,223
Likes: 666
From: Northeast
https://www.ebay.com/itm/CONVERTER-T...sid=m570.l1313
I would save it and decide later to rid yourself of it. Does your state require a cat? they will see if don't have one with the test pipe in place.
I would save it and decide later to rid yourself of it. Does your state require a cat? they will see if don't have one with the test pipe in place.
Race Director
Joined: Jul 2004
Posts: 12,696
Likes: 329
From: Scottsdale Arizona
Your original stock cat is probably clogged. Simplest solution is to gut it so that it at least looks like it's there. I'm on my phone so can't see what state you're in but you need to take into account any local smog regs that you need to meet.
Having said the above, a modern, high flow cat is so efficient that you can have your cake and eat it too. You'll barely notice the difference in flow from a test pipe. Sound should be similar though I've never tested this.
Having said the above, a modern, high flow cat is so efficient that you can have your cake and eat it too. You'll barely notice the difference in flow from a test pipe. Sound should be similar though I've never tested this.
Last edited by CA-Legal-Vette; Jul 27, 2018 at 10:03 AM.
Thread Starter
Burning Brakes
Joined: Sep 2017
Posts: 1,073
Likes: 65
From: Belgium
https://www.ebay.com/itm/CONVERTER-T...sid=m570.l1313
I would save it and decide later to rid yourself of it. Does your state require a cat? they will see if don't have one with the test pipe in place.
I would save it and decide later to rid yourself of it. Does your state require a cat? they will see if don't have one with the test pipe in place.
A cat is not required for oldtimers here.
Thread Starter
Burning Brakes
Joined: Sep 2017
Posts: 1,073
Likes: 65
From: Belgium
Your original stock cat is probably clogged. Simplest solution is to gut it so that it at least looks like it's there. I'm on my phone so can't see what state you're in but you need to take into account any local smog regs that you need to meet.
Having said the above, a modern, high flow cat is so efficient that you can have your cake and eat it too. You'll barely notice the difference in flow from a test pipe. Sound should be similar though I've never tested this.
Having said the above, a modern, high flow cat is so efficient that you can have your cake and eat it too. You'll barely notice the difference in flow from a test pipe. Sound should be similar though I've never tested this.
Are there side effects (in sound or safety) when doing this, Or does a 'gutted' cat simply works a straight pipe?
Last edited by Novusuhu; Jul 27, 2018 at 11:13 AM.
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,213
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
If laws permit, get headers and a true dual exhaust. This will give you the sound your looking for with the added bonus of more performance.
Racer
Joined: May 2018
Posts: 297
Likes: 43
use a decent mask when u drill out the cat, the platinum beads also contain lots of unpleasant particles from lead to hydrocarbons. also it can be messy as all else so id would recommend doing so inside a large carboard box, that sooty mess from the old cats makes a hell of a mess on the garage floor.
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
Race Director
Joined: Jul 2004
Posts: 12,696
Likes: 329
From: Scottsdale Arizona
I know that the stock cat has a built in opening through which you can change the beads. I’ve never done this before and can’t imagine that it would come off easily, but I’d thank that’s the simplest and least messy route. All of the baffles and screens would still be in place though so I’m not positive this would get you the sound that you’re looking for.
Team Owner
Joined: May 2001
Posts: 87,334
Likes: 1,589
From: Western NY
If you can't or don't want to install headers. a couple of the American Corvette suppliers offer "true dual" exhaust systems that bolt up to the stock manifolds.
Racer
Joined: May 2018
Posts: 297
Likes: 43
years ago I cant remember where, I think jc whitney or jegs had a kit that welded into the pipe with a hood release type lever mounted in the cab that would open the pipes as much as u wanted to, this was supposed to give more power and allow you to "tune" the exhaust sound to your liking. I did a brief search and coulnt find it but im sure someone out there knows where/what this is.