Jul 9, 2019
10
2
VetteCoins
251
Car
2005 Corvette
Province
ON
Purchased a terrific ‘’05 convertible with many upgrades including Corsa sport exhaust. Only issue is that I get severe droning at certain RPMs, and highway speed coasting. I’ve read other threads that say this should not be happening, and even called Corsa to confirm. They say convertibles are louder than couples, but this isn’t a loudness issue - exhausts sounds great with some throttle applied, but the. Just resonates too loudly at some RPMs. My brother-in-law has an ‘06 coupe with recently purchased Corsa sports, and sounds nothing like mine.
Any ideas? Suggestions for a private GTA garage that can take a look and maybe correct a bad install? Thanks.
 
Hi Sebastian.

I had Corsa Extremes on a 2006 convertible and had zero drone..... at any/all RPMs. With that in mind I'd check two things:
  • CAI - I had a cold air intake on a sweet little 99 pickup and THAT box caused a lot of drone. Any time I was accelerating it sounded like my head was inside an aquarium with someone banging on it! I removed that piece of cr@p and returned to a stock box.
  • Exhaust - Crawl under your car to see if you actually have a Corsa system.
Finally, please let us know what you find.

EDITS: My C6 was a 2006. My truck did use a "box" for the CAI filter and I know the Vettes are more of a snorkel for an air intake. My C6 had a Vara-Ram installed but still zero drone issues....

Cheers!
 
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Purchased a terrific ‘’05 convertible with many upgrades including Corsa sport exhaust. Only issue is that I get severe droning at certain RPMs, and highway speed coasting. I’ve read other threads that say this should not be happening, and even called Corsa to confirm. They say convertibles are louder than couples, but this isn’t a loudness issue - exhausts sounds great with some throttle applied, but the. Just resonates too loudly at some RPMs. My brother-in-law has an ‘06 coupe with recently purchased Corsa sports, and sounds nothing like mine.
Any ideas? Suggestions for a private GTA garage that can take a look and maybe correct a bad install? Thanks.
My 09 with Corsa Sports had zero drone as well. Was it an axleback ot catback system? Does your car have headers? Were new gaskets installed at the time. Were the clamps re-torqued a few days after the install. If it turns out to be a loose joint leak, those gaskets will have to be replaced. All else fails, Race Ready Garage in Cambridge can help you out. @RaceReadyGarageInc here on the forum or Race Ready Garage | Car Performance Shop servicing Kitchener, GTA, Toronto and Southern Ontario
 
Like others have said on here, the corsa sport shouldn't drone at all. Even if the car has headers and no cats it would be loud but still shouldnt drone. Unfortunately the 05s corvettes have differential issues, so you may be hearing the differential gears whining. Loud humming at high speed and coasting..
 
I took a few pictures of the muffler connection to the X pipe. I'm assuming that this carbon blowback from the fitting is evidence of a leak? The drone I hear occurs when foot is heavier on the throttle. Do you think a re-torque is enough, or would I have to disconnect and clean the pipes again?

IMG_6299.JPG
 
There should be an internal gasket in the pipe connection if it's like my C6. Guessing that gasket will need replacing, or never was installed. Maybe a C5 owner will chime in and advise..
 
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That, to me, almost looks like carbon from an exhaust leak. Does it rub off?? On my old Camaro, when I installed the Magnaflow exhaust, there were pieces that were similar to tinfoil that I had to put in the joins where the band clamps were. I wonder if there should have been something similar here.
 
Looks like I'm late to the picnic. Did you manage to get this sorted yet? That definitely look like a leak which could be a drone culprit. You appear to have the stock H mid pipe which is a slip over connection with band clamp at the rear where it connects to the muffler axel over pipes, and a flange with gasket connection at the front where the mid pipe connects to the cats, and is the same way the stock mufflers connected. If you can turn a wrench and have ramps, backing the car up on ramps is enough clearence. I'd check the torque on the band clamp bolts at the rear as they need to be tight enough to crush the outer pipe down against the inner pipe. If they're tight then it probably needs to be readjusted and then tightened. There is also another set of band clamps where the axel over pipes connect to the mufflers so check them too. If something is loose or you have to loosen and readjust, movements will move the pipe, muffler, and consequently the tip alignment which can be a bit of a pain. The best way I found is to semi tighten the clamps enough to hold, get the tips where you want them, then tighten down.
 
@Sebastian your exhaust leak got me curious, so I checked my car this afternoon since it was nice out, and turns out I had a small leak in the same place between the axel and mid pipe, so I tightened them down, went for a drive, and it quieted the exhaust a bit, making it a bit more smoother with less bark. I recommend checking the clamps if you haven't already as it's really not that hard to do, and there's only one other way to make your living on your back. :) I didn't even need to jack the car or use ramps to get enough clearance, I just drove the rear up on a couple pieces of 2x8 that I use for jacking since my jack isn't low profile enough to fit under the cross member with a piece of 2x6 across.
 
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@12cents and @ Creedence85; After tightening up those 2 clamps where the H-pipe meets the muffler pipes, I definately heard an improvement. To be clear, I never got any droning just cruising, only when pushing on the throttle at high RPMs which might confirm it's this connection leaking when higher pressure is flowing. After a few drives, I see some new carbon residue after that clamp - so I think the design isn't very good. Should be a tighter torque setting. But will I bust those clamps? They don't look like they can squeeze much more.
 
@12cents and @ Creedence85; After tightening up those 2 clamps where the H-pipe meets the muffler pipes, I definately heard an improvement. To be clear, I never got any droning just cruising, only when pushing on the throttle at high RPMs which might confirm it's this connection leaking when higher pressure is flowing. After a few drives, I see some new carbon residue after that clamp - so I think the design isn't very good. Should be a tighter torque setting. But will I bust those clamps? They don't look like they can squeeze much more.

If there is room in the connection, you could pull it apart and put a wrap of high heat silicone tape on the smaller diameter pipe where the clamp position is. We use to be able to buy muffler tape at CDN Tire as well. That might work.
 
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@Sebastian, glad you made some progress. How hard do you think you're torquing? Before I installed my exhaust I did some reading on exhaust band clamps, and surprise the specs and opinions are all over the place, so I had no idea what to torque them to and I just made them reasonably tight. Depending on the size many of them seem to be rated for 40-60 ft-lbs so you should be able to torque them fairly hard without breaking. Obviously I didn't go tight enough and/or they needed retorquing over time. The larger diameter pipe has to be crushed by the clamp to fit the smaller pipe, so a certain a mount of torque is going to be needed to get a seal especially if the outer pipe was expanded further to help with assembly. I like @Rruuff Day's idea of high heat silicone tape or exhaust tape. I'm not very strong on a 5/8" socket wrench, especially laying on my back with my arm in a weird position, so estimate I'm getting 20 lb-ft if I'm lucky. Once getting that as tight as I could comfortably, I used a breaker bar and very carefully gave it a couple 1/3 turn sweeps so am going to guess that it's around 40-50 now. I guess I could set the click torque wrench to progressive settings or also use the old torsion bar wrench to see where the needle is pointing.
 
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Does it still sound like it's leaking? I was doing some reading on another forum about exhaust clamps and leaking on Corsa systems, a few people said they had small carbon residue, one person talked to someone at Corsa, and they said a little bit of carbon residue was normal. I don't know how that would be normal, maybe it just seeps a little bit when heat cycling?
 
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