MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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DonB
Don Bonar
Prairie Village, KS
(80 posts)

Registered:
09/09/2011 10:06AM

Main British Car:
1971 MG-B 95 GM 3.4 V-6

Too much of a good thing
Posted by: DonB
Date: November 17, 2014 12:09PM

I'd like to reduce the exhaust noise coming from my car. At the 11th hour, I decided to add side pipes. Kits found in lots of places offer mufflers,heat shields, brackets and down turn tips in kit form. After 1,000+ miles, they are simply too loud.

Jeggs, Speedy Bills' and Ebay (among others) offer a variety of "solutions" less expensive than replacing the mufflers... plus I've already sunk the costs of bead blasting off the chrome and coating everything with flat black ceramic coating.

The most common offers include an "auger" style insert, a fiberglass/heat wrap hollow plug and a vortex "soup strainer" cone shaped insert. I have no room to add a second set of additional mufflers anywhere.

The few reviews I read both supported... and/or discounted the thought that it would increase back pressure and drop performance. Seems a number of performance bikes and racers at tracks with Db ristrictions use them... I just want a cruiser without wearing ear plugs!

Anyone have experience with any of these options and offer an opinion?
Thanks
Don B.


DiDueColpi
Fred Key
West coast - Canada
(1365 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: Too much of a good thing
Posted by: DiDueColpi
Date: November 19, 2014 06:44PM

Before you try anything else Don. Plumb in a crossover pipe. You'll be surprised at the difference.

Cheers
Fred


HealeyRick
Rick Neville

(489 posts)

Registered:
12/19/2007 05:01PM

Main British Car:
1963 Austin-Healey 3000 Ford 5.0L

authors avatar
Re: Too much of a good thing
Posted by: HealeyRick
Date: November 19, 2014 07:28PM

You know who knows a lot about trying to quiet noisy side pipes? Cobra guys. Lots of articles on the Factory Five Forum. Search "Breeze quiet pipes", "Classic chambered", augers, "cobra packs". Here's a sample: [www.ffcars.com]


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6468 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Too much of a good thing
Posted by: BlownMGB-V8
Date: November 20, 2014 07:50PM

I ran across some inserts some time back that I want to try eventually. They create several chambers of varying length around a perforated central tube. The chambers are separated by a wall with through holes (baffle). So flow is both down the central tube and down through the baffles on the outside. The different sized chambers are supposed to dampen different frequency ranges and the dual flow is supposed to create an offset in flow to cancel sound waves. Seems like soundly engineered theory. At the moment I can't find the link but does this seem familiar to anybody?

Jim


danmas
Dan Masters
Alcoa, Tennessee
(578 posts)

Registered:
10/28/2007 12:11AM

Main British Car:
1974 MGBGT Ford 302

authors avatar
Re: Too much of a good thing
Posted by: danmas
Date: November 20, 2014 09:13PM

Jim,

Are you talking bout something like this? [www.classicchambered.com]

That's what I have on my car - they're loud!
powerstick.jpg
powerstickinside.jpg


DonB
Don Bonar
Prairie Village, KS
(80 posts)

Registered:
09/09/2011 10:06AM

Main British Car:
1971 MG-B 95 GM 3.4 V-6

Re: Too much of a good thing
Posted by: DonB
Date: November 21, 2014 08:24AM

Guys,
Thanks for the help... Could you be thinking of Vance & Hines or Paughco Harley stuff? If so, right idea but they all seem to be 2" dia only.

Couldn't get pics to copy... but if you go to www.speedwaymotors.com and search for part # 910-13102

As well as that particular product... at the right side of the page... hit... View Others: exhaust Insert muflers for a large array of pics.

Any experience with any of these?
Thanks

Don B.


MustangSix
Jack Collins

(30 posts)

Registered:
12/16/2011 10:53AM

Main British Car:


Re: Too much of a good thing
Posted by: MustangSix
Date: November 21, 2014 09:57AM

I had had louvered 3" ID glasspack sidepipes on the Locost. Might as well have been a straight pipe. I found that the best way to quiet the thing down was to make some rather small inserts into the ends of the muffler section itself. They actually looked like the speedway inserts.

I borrowed that idea for header inserts and built a 2" tube about 12" long with a buch of 1/4" holes drilled in it, with 3" discs on each end that allowed it to fit inside the muffler insert. The inner disc was also drilled with a dozen or so 1/4" holes. I know squat about exhaust theory, but figured it couldn't hurt.

I slipped that inside the sidepipe muffler, put in a couple of sheetmetal screws to keep it from moving, then reinstalled the turndown. The difference is sound level was an order of magnitude less. I think the increased backpressure let the glasspacks actually do their job and muffle the sound more.

It probably raised the backpressure to the point that I may have lost some peak hp, but this was no race car and I really didn't need (nor could I use) every last hp anyway, but I would rather have the quieter system for street use. If I ever did make it to the track or dyno those could easily be pulled out.



BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6468 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Too much of a good thing
Posted by: BlownMGB-V8
Date: November 21, 2014 08:43PM

No Dan, they looked sort of like the CarChemestry inserts would if you stretched them out to 20 or 30 inches and added more sections so you created about four progressively larger chambers. The center tube went straight through and was open on both ends.

Jim


Jim Stabe
Jim Stabe
San Diego, Ca
(829 posts)

Registered:
02/28/2009 10:01AM

Main British Car:
1966 MGB Roadster 350 LT1 Chevy

authors avatar
Re: Too much of a good thing
Posted by: Jim Stabe
Date: November 23, 2014 12:53PM

I had a resonance from about 1800-2500 rpm that I wanted to get rid of. I have a 2 x 2 1/2" into a single 3" with a 50 series Flowmaster at the very back with very little pipe after the muffler. I put a 3" Moroso spiral flow muffler in front of the Flowmaster and it got rid of the raspiness - exactly what I wanted. I didn't have a "before" dyno run but it made 450 rwhp and 543 rwtq with the spiral flow installed. Much more pleasant to drive on the freeway now.


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