Stop the Drone - Helmholtz Style

[Stitch]

Originally Posted by Saint Alban

Who's trying to do that? Are you under the impression that doing this mod will make the car quiet? This isn't silencing the exhaust tone, it's eliminating drone in aftermarket setups.

...and next I'll be trying to eliminate the whistle from my turbo. Or maybe I'll just go buy an Accord.

[Saint Alban]

Originally Posted by Stitch

...and next I'll be trying to eliminate the whistle from my turbo. Or maybe I'll just go buy an Accord.

...Seriously? I wasnt being rude or sarcastic with you, so I don't get why you've gotta make a comeback like that. You're obviously not understanding or even trying to understand what this thread is helping members with. If you didn't get it, why not just ask instead of assuming and coming in here sounding like a jerk? I'm not trying to turn this is to an argument, but I'm noticing more and more how members like you get their entertainment instigating things like this. I'm not even gonna bother trying to explain this again to you because you don't really care. Just wanted to pop in, state your ignorance, and sit back while people get pissed at you.

[Dr. Evil]

I swapped out my stock mufflers today for some off brand flowmaster knockoffs I picked pretty cheap. The sound is better and there is no drone like I had feared. One thing I noticed in my other cars and I took the opportunity to experiemt with it this time is muffler tip placement. I replaced just the mufflers but had not put anything on the exit side. If you looked at my car from behind it looked like it was missing its exhaust. The mufflers were on, but nothing was attached to the outlet side yet. I drove the car like that to go and pick up my son from school. The drone at 1600 - 200 rpms was awful. I already had it in my mind to put the stock ones back on.

Fast forward to finished product.

I welded the extensions with the stock tips on and placed them to where they stick out about an inch further than stock placement. No drone at all. I mean there is none, it doesnt exist. The car sounds much better but still drives quiet. You can hear the increased exhaust note and volume but without the drone. This was a win/win for me. In the past I've had a C4 corvettes, which are notorious for the drone due to shape and exhaust placement and I never want anything like that again.

I had played around with my last vette and found that moving the exhaust tips out just a tick further helped direct alot of the drone away from the cabin. Just something else to consider for folks trying to eliminate it.

Lastly, I've modified cars in the past to the point they were no longer fun to drive on the street for any length of time. I am determined not to do that this time. The whole point of getting the camaro was for a backseat and something the family could enjoy doing car related stuff in. I still find my way to the tracks and would hazard a guess that I have more seat time on tracks than most of the people wondering why anyone would complain about exhaust drone. Some of us just have different priorities, thats all. I'd like to be able to carry on a conversation with my wife beside me and 7 year old son in the back seat without yelling while we're on our way to the racetrack.

[Roger Ramjet]

Yet another version of the Helmholtz drone solution.

[IndeedSS1]

^^^ I wonder how well that will work with where it is tapped. Also the pipes appear to be angled down as compared where welded on. Over time wouldn't condensation build up to the point of sloshing? I know when I pull my J pipes off they have moisture in the ends and mine don't angle down that much. It is a cool looking install though.

[BigRed585Lbs]

They look great to me. Can't criticize "Dr. Innovation".
What will he come up with next?
Stay tuned, boys and girls!

Whatever, works.

[cm5217]

Thats my car and let me tell you it sounds so much better it got rid of at least 75% of the drone. I am real happy with the results and thanks to SM City motorsports great guys to work with. Im sure i will be back for more work in the future.

[Roger Ramjet]

Glad you like the pipes CM. The big Magnaflows in the rear kept us from putting them in the normal place.

[BigRed585Lbs]

The best part is the oil pan in the second photo.
Tells it all.

[midnighter]

Originally Posted by Roger Ramjet

Yet another version of the Helmholtz drone solution.

Why is there all that motor oil everywhere under the oil pan? A leak? I ask because mine has a small oil leak and I am curious as to why this may be.

[BigRed585Lbs]

Rust prevention.

[AquaRSSS]

Originally Posted by midnighter

Why is there all that motor oil everywhere under the oil pan? A leak? I ask because mine has a small oil leak and I am curious as to why this may be.

This is not the right forum for this, but if you have an oil leak, it is most likely from the oil cooler. I had the same thing and found that there was a bulletin to fix it. The dealer fixed mine under warrranty.
(THANKS RODGERS CHEVROLET!!!).
The stock gasket is too thin and requires an earlier version of the gasket to help seal it up. No leaks since and we drove it back from Detroit to Colorado to test it!

Rob

[Russell James]

For a 3" catback and LT set up, what dia J pipes would work best? I've read to try to stay close to the system pipe size. But I probably don't have room for adding big pipes in the rear.

I have an LG 3" catback with huge mufflers. Are the Solo J-pipes 2.5"? I know they wouldn't be a direct fit with those big mufflers, but maybe have a muffler shop modify them further? Or if I go all custom, would 2.5" pipe be the right size to go with, then an adjustable length end?

[BigRed585Lbs]

2.5" will be fine. Notice that most of the set-ups shown in the pix have smaller diameter j-pipes that the main tailpipes. Personally, I think this gives a better fit for welding. Fish-mouthing the ends at the joints may also help, but that's getting sort of "anal".