True dual vs 2-1-2 catless
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,416
Likes: 291
From: dayton oh
True dual vs 2-1-2 catless
would the extra volume of the 2 pipes for the short 2-1-2 section really add more perf than just a "test pipe" in place of the cat???
Motor: 9.75-1 AFR180 heads, Dynomax LT headers, RPM AIRGAP intake, Holley Pro-Jection TBI
~400hp
Motor: 9.75-1 AFR180 heads, Dynomax LT headers, RPM AIRGAP intake, Holley Pro-Jection TBI
~400hp
Race Director
Joined: Oct 2000
Posts: 11,891
Likes: 3
From: Kansas City, MO ...I'd like to go fishing and catch a fishstick. That'd be convenient. - Mitch Hedberg
Depends on how large the single section is. If it is larger than the two individual sections then you will see more torque from the engine than complete dual exhaust. If it is the same size tubing, it will be less than dual exhaust.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
I'm required to still smog my 78 SA L-82 in Cali...so I went to a performance mufflershop,and they installed a CARB approved 3" High flow cat and and 2 1/2" exhaust out the rear...(still have 2-1-2 system,stock manifolds) Just doing that made a noticible difference in acceleration...
Last edited by rihwoods; Apr 21, 2008 at 02:29 PM.
Drifting
Joined: Feb 2005
Posts: 1,738
Likes: 2
From: San diego ca
Thats essentially what i did.. my exhaust is 2 1/2" from the full length hedman headers into a smooth "Y-pipe" that merges the 2 - 2 1/2" pipes into a single 3" pipe...this mates to the 3" high flow cat... back out through another 3" to 2 1/2" Y to the mufflers...
Very little difference in "seat of the pants" feel between this and the true duals I ran once, volume level is lower of course.
I'd rather have the true duals of course, but like Rich I'm still on the hook for smogging...this sytem works just fine...has about the same cross sectional area as 2 1/8" duals...
Very little difference in "seat of the pants" feel between this and the true duals I ran once, volume level is lower of course.
I'd rather have the true duals of course, but like Rich I'm still on the hook for smogging...this sytem works just fine...has about the same cross sectional area as 2 1/8" duals...
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
and they weighed a bunch...
No muffler shop would install two cats...so i went back to the 2-1-2 lash up I have now.
Last edited by rihwoods; Apr 21, 2008 at 03:52 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
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
Melting Slicks
Joined: Sep 2004
Posts: 2,412
Likes: 3
Run cats, do our lungs a favor. A Magnaflow high flow cat flows almost twice as good as a Flowmaster. I'm making more power at the wheels then you're making at the engine, and I run cats. And I don't have to smog.
And yes, dual pipes will make a big difference. So will long tube headers, and with that engine you need both. Run high flow Magnaflow catalytic converters (they can be found online for less than $85) and high flow mufflers.
And yes, dual pipes will make a big difference. So will long tube headers, and with that engine you need both. Run high flow Magnaflow catalytic converters (they can be found online for less than $85) and high flow mufflers.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,416
Likes: 291
From: dayton oh
when i got FAST81 it had a test pipe with original stock mufflers (stamped Dec 1980) and rams horns. then added Dynomax LT headers, cat and super turbo mufflers (twin chrome tips) when i moved to Colorado and it still sounded good, BUT closer to the muted sound when i first got it. Idiot me tossed the test pipe. The cat acted like a 3rd muffler. I now want to unleash more sound that i'm exempt here in OH and LOVED the sound when i drove it down to the muffler shop thru open headers for them to mate up the rest of the system.
Originally i was going to follow everyones advice on true duals then stopped to wonder if just the test pipe with LTs and perf mufflers i already had would be 95% as good as spending $250 plus finding a shop to cut it back for my Dynomax's.
Originally i was going to follow everyones advice on true duals then stopped to wonder if just the test pipe with LTs and perf mufflers i already had would be 95% as good as spending $250 plus finding a shop to cut it back for my Dynomax's.
Le Mans Master
Joined: Apr 2001
Posts: 5,000
Likes: 1
From: Minneapolis, Mn USA
Fast 81, do you have pic of the headers mating to the original exhaust pipes.
Right now Im running the test pipe (EBAY) with the OEM 2-1-2 pipe and 2 1/2 system overall. I think the large oval single area is equivalent to ~3 inch as its huge. Mufflers are free flowing Monza type.
The original shorty 82 factory headers are probably the only holdup on the exhaust side.
Would be interested in how the headers mated up to the OEM pipes.
Brent..
Right now Im running the test pipe (EBAY) with the OEM 2-1-2 pipe and 2 1/2 system overall. I think the large oval single area is equivalent to ~3 inch as its huge. Mufflers are free flowing Monza type.
The original shorty 82 factory headers are probably the only holdup on the exhaust side.
Would be interested in how the headers mated up to the OEM pipes.
Brent..
Melting Slicks
Joined: Sep 2004
Posts: 2,412
Likes: 3
Orig cats sucked, modern high flow cats flow 10 times better! You can see through a modern cat, you can't see through a pancake cat. Orig cats muffled the sound more than the mufflers. New high flow cats hardly muffle the sound. Totally different animal.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,416
Likes: 291
From: dayton oh
Fast 81, do you have pic of the headers mating to the original exhaust pipes.
Right now Im running the test pipe (EBAY) with the OEM 2-1-2 pipe and 2 1/2 system overall. I think the large oval single area is equivalent to ~3 inch as its huge. Mufflers are free flowing Monza type.
The original shorty 82 factory headers are probably the only holdup on the exhaust side.
Would be interested in how the headers mated up to the OEM pipes.
Brent..
Right now Im running the test pipe (EBAY) with the OEM 2-1-2 pipe and 2 1/2 system overall. I think the large oval single area is equivalent to ~3 inch as its huge. Mufflers are free flowing Monza type.
The original shorty 82 factory headers are probably the only holdup on the exhaust side.
Would be interested in how the headers mated up to the OEM pipes.
Brent..
