Exhaust leak maybe?
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,185
Likes: 265
From: Virginia
Exhaust leak maybe?
Guys I’ve posted about this a couple times but wanted to share one more video I made today after driving a bit because it’s driving me crazy...I’m not so sure this excessive noise I’m hearing isn’t an exhaust leak. If that’s all it is that would be a relief but I just can’t tell. Videos are tough to diagnose a noise but has anyone had a header leak that sounded like this.? These are JBA long tubes, not top of the line but not Chinese eBay headers either. I’ve tried two sets of header gaskets with really no change. All the rockers are tight and no sign of trouble any problems looking Under the valve cover.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,185
Likes: 265
From: Virginia
Yes, several times. I just cannot pinpoint this noise and don’t know if it’s valvetrain related, exhaust related or bottom end. I’m to the point where I wish whatever it is would get worse just so I could figure it out. I pulled the valve cover again today after driving and cannot find anything at all wrong.
Racer
Joined: Dec 2017
Posts: 331
Likes: 74
From: Florida
I cant hear anything odd in the video but I am a little familiar with the JBA system. Maybe it is leaking at the Catalytic/midpipe clamp? I'm a firm believer of high temp copper RTV and don't care if its messy, it works. Sometimes OEM tolerances can be tighter than after market things.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,185
Likes: 265
From: Virginia
I cant hear anything odd in the video but I am a little familiar with the JBA system. Maybe it is leaking at the Catalytic/midpipe clamp? I'm a firm believer of high temp copper RTV and don't care if its messy, it works. Sometimes OEM tolerances can be tighter than after market things.
Racer
Joined: Dec 2017
Posts: 331
Likes: 74
From: Florida
Yeah I don't like how messy it is, but it works! When I removed and reinstalled my exhaust a few months ago, the factory donut gaskets at the cats would not seal with out the RTV.
Okay in that video, the low rumble sounds really good. Am I hearing a high pitched "pffft pfffffft psssst pfffft pssst" that is kind of rhythmic? If I'm not crazy that sounds like a header leak.
Im sure you have torqued the bolts before and after the heat cycles of the motor. You might wanna try some more of that RTV on the header gaskets
Arent the JBAs welded to the stock cats? If the very rigid V angle of where they sit on both sides of the heads isn't 100% flat, you might have those leaks
Edit: You could also maybe losen the Cat/midpipe clamps, tighten header bolts, and then retighten the cat/midpipe
clamps. That might align one portion of the V angle correctly, but only rotational-wise not up and down.
Okay in that video, the low rumble sounds really good. Am I hearing a high pitched "pffft pfffffft psssst pfffft pssst" that is kind of rhythmic? If I'm not crazy that sounds like a header leak.
Im sure you have torqued the bolts before and after the heat cycles of the motor. You might wanna try some more of that RTV on the header gaskets
Arent the JBAs welded to the stock cats? If the very rigid V angle of where they sit on both sides of the heads isn't 100% flat, you might have those leaks
Edit: You could also maybe losen the Cat/midpipe clamps, tighten header bolts, and then retighten the cat/midpipe
clamps. That might align one portion of the V angle correctly, but only rotational-wise not up and down.
Last edited by 02torchred; Jun 24, 2019 at 11:20 PM.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,185
Likes: 265
From: Virginia
Yeah I don't like how messy it is, but it works! When I removed and reinstalled my exhaust a few months ago, the factory donut gaskets at the cats would not seal with out the RTV.
Okay in that video, the low rumble sounds really good. Am I hearing a high pitched "pffft pfffffft psssst pfffft pssst" that is kind of rhythmic? If I'm not crazy that sounds like a header leak.
Im sure you have torqued the bolts before and after the heat cycles of the motor. You might wanna try some more of that RTV on the header gaskets
Arent the JBAs welded to the stock cats? If the very rigid V angle of where they sit on both sides of the heads isn't 100% flat, you might have those leaks
Edit: You could also maybe losen the Cat/midpipe clamps, tighten header bolts, and then retighten the cat/midpipe
clamps. That might align one portion of the V angle correctly, but only rotational-wise not up and down.
Okay in that video, the low rumble sounds really good. Am I hearing a high pitched "pffft pfffffft psssst pfffft pssst" that is kind of rhythmic? If I'm not crazy that sounds like a header leak.
Im sure you have torqued the bolts before and after the heat cycles of the motor. You might wanna try some more of that RTV on the header gaskets
Arent the JBAs welded to the stock cats? If the very rigid V angle of where they sit on both sides of the heads isn't 100% flat, you might have those leaks
Edit: You could also maybe losen the Cat/midpipe clamps, tighten header bolts, and then retighten the cat/midpipe
clamps. That might align one portion of the V angle correctly, but only rotational-wise not up and down.
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
Racer
Joined: Dec 2017
Posts: 331
Likes: 74
From: Florida
By V I just basically mean the V of the engine block and heads, and how the header flanges sit on the block can be yawed and/or tilted lightly. It's possible the way they attach to the cats flare them out one way or another so much that tightening the bolts doesn't get it sealed. All my recommendations above still stand!
On another note, how does the car feel power-wise with the headers versus stock (if you drove it stock)? Has it been tuned for all the mods?
On another note, how does the car feel power-wise with the headers versus stock (if you drove it stock)? Has it been tuned for all the mods?
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,185
Likes: 265
From: Virginia
By V I just basically mean the V of the engine block and heads, and how the header flanges sit on the block can be yawed and/or tilted lightly. It's possible the way they attach to the cats flare them out one way or another so much that tightening the bolts doesn't get it sealed. All my recommendations above still stand!
On another note, how does the car feel power-wise with the headers versus stock (if you drove it stock)? Has it been tuned for all the mods?
On another note, how does the car feel power-wise with the headers versus stock (if you drove it stock)? Has it been tuned for all the mods?
It runs great I have no complaints about that. It pulls hard and has never had any kind of miss or stumble. When I bought the car it had shorty headers instead of stock manifolds, The rest of the exhaust was bone stock... cats, H pipe and ti mufflers. It pulls much harder with the long tubes, x-pipe and high flow cats vs stock. Everything has been dyno tuned.