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Straight through mufflers

General engine tech -- Drag Racing to Circle Track

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ptuomov
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Re: Straight through mufflers

Post by ptuomov » Tue Jun 23, 2020 8:27 am

A question to the original poster:

Which one of these arrangements best approximates your exhaust? I'm guessing (a) dual v8 - no bank to bank mixing?

viewtopic.php?f=1&t=49628&start=15#p662181

Image
Image

These graphs illustrate to me that simple crossovers suppress noise at certain rpms pretty significantly.

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Re: Straight through mufflers

Post by autogear » Tue Jun 23, 2020 11:22 am

MadBill wrote:
Mon Jun 22, 2020 5:30 pm
Those GM factory chambered systems were ear-splitting; I don't know how they could have passed any sound standard! [But of course in that era there were also such systems as the GTO V.O.E. (Vacuum Operated Exhaust) that laid down all the baffles via what looked like a vacuum advance canister...]
Mine is much quieter, my father has the longest 2.5" cherrybombs Ive ever seen, under his '55 chevy, I'd say my 2.5" pipe 21" long CC mufflers are a little bit louder, but not bad, and certainly don't have the poppity-pop-pop on decell. He doesn't have a crossover though. I added one because I can't get pipes over the axle.
Theres videos on the website. http://www.classicchambered.com/classic/products.html
The owner is a super nice guy and I can vouch for the quality of manufacture, these cases are THICK wall tubing and the ends can be expanded quite a bit if necessary.

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Re: Straight through mufflers

Post by autogear » Tue Jun 23, 2020 11:33 am

enigma57 wrote:
Tue Jun 23, 2020 3:03 am
autogear wrote:
Mon Jun 22, 2020 5:01 pm
I use Classic Chambered mufflers with a crossover pipe. Sounds great, very vintage burble, a little bit of popping on decell, and thats without tailpipes, just turnouts

Very reminiscent of the Turbo Tube muffler (same developer) and the original chambered straight pipes of the late 60s. American made and very high quality. Couldn't be happier.
:D Just for kicks...... Got a wild hair and decided to experiment with chambered exhaust on the '57 when I drop the 292 inline 6 in. Thought I'd install the system and see how it works. And if there is any droning or if its too loud, maybe experiment with adding Helmholtz resonators (J pipe nodes).

Scrounged quite a few pieces of pipe and bends off e-bay including some long chambered 'Vette sidepipe replacement pieces from Classic Chambered having the correct inner tubing size. Have no bending mandrels here at home, so will need to cut and weld them to form the under car exhaust system for the '57 sedan when I fabricate the exhaust.

Will be running split manifolds and 2-1/2" duals all the way out the back with turndowns just beyond the rear bumper. And a crossover (balance) pipe up front near the transmission.

Best regards,

Harry
send me a message with your cellphone or email and i'll send you some video clips of my '94 LT1 Henry J if you like.

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Re: Straight through mufflers

Post by enigma57 » Wed Jun 24, 2020 5:52 am

EDC wrote:
Tue Jun 23, 2020 6:21 am
HARM mufflers for the Cobra.

Image
Image
Image
Interesting concept. How well do these attenuate sound? What sort of packing do they use?

Thanks,

Harry

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Re: Straight through mufflers

Post by enigma57 » Wed Jun 24, 2020 6:05 am

autogear wrote:
Tue Jun 23, 2020 11:33 am
send me a message with your cellphone or email and i'll send you some video clips of my '94 LT1 Henry J if you like.
Thanks! Will do! I'm an old guy. Don't have a smart phone. E-mail sent.

Best regards,

Harry

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Re: Straight through mufflers

Post by EDC » Wed Jun 24, 2020 6:09 am

enigma57 wrote:
Wed Jun 24, 2020 5:52 am
EDC wrote:
Tue Jun 23, 2020 6:21 am
HARM mufflers for the Cobra.

Image
Image
Image
Interesting concept. How well do these attenuate sound? What sort of packing do they use?

Thanks,

Harry
He's got more info on Farsebook...

https://www.facebook.com/Herfurth-Alumi ... 918293539/
"Quality" is like buying oats. You can pay a fair price for it and get some good quality oats,
or you can get it a hell of a lot cheaper, when it's already been through the horse.

Nil Satis Nisi Optimum

Ed Curtis - www.FlowTechInduction.com

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Re: Straight through mufflers

Post by enigma57 » Wed Jun 24, 2020 1:01 pm

Thanks, Ed! I don't do facebook but was able to view the post and hear the 4" single exhaust on the Firebird without logging in. Much appreciated.

Best regards,

Harry

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Re: Straight through mufflers

Post by bob460 » Thu Jun 25, 2020 12:33 am

enigma57 wrote:
Wed Jun 24, 2020 1:01 pm
Thanks, Ed! I don't do facebook but was able to view the post and hear the 4" single exhaust on the Firebird without logging in. Much appreciated.

Best regards,

Harry
Go to paige 2 i posted some sound clips of his mufflers.

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Re: Straight through mufflers

Post by travis » Thu Jun 25, 2020 3:28 am

ptuomov wrote:
Tue Jun 23, 2020 8:27 am
A question to the original poster:

Which one of these arrangements best approximates your exhaust? I'm guessing (a) dual v8 - no bank to bank mixing?

viewtopic.php?f=1&t=49628&start=15#p662181

Image
Image

These graphs illustrate to me that simple crossovers suppress noise at certain rpms pretty significantly.
“A” would be correct, but for now it’s just a temporary exhaust system. I’m going to add a crossover of some sort, probably an X pipe

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Re: Straight through mufflers

Post by ptuomov » Thu Jun 25, 2020 8:26 am

travis wrote:
Thu Jun 25, 2020 3:28 am
“A” would be correct, but for now it’s just a temporary exhaust system. I’m going to add a crossover of some sort, probably an X pipe
My car went from true separate duals with a single straight thru muffler on both sides to this, also with straight thru mufflers, and the sound improved dramatically despite the pipes being upsized from dual 3" to dual 3.5":

Image

Image

Functionally, it has a Y-pipe that divorces into two legs again, which have (Borla) straight thru mufflers. After the straight-thru mufflers, the divorced pipes are unequal length before they merge again into a (custom) tail pipe-muffler. So the system has two cross-overs and unequal length path between the two, which I am guessing is important for the success.

I think that a "two-crossover" system with an X-pipe, two straight-thru mufflers, unequal pipe lengths routed to one side, and a single tail-pipe muffler merging both pipes is a recipe that might work more generally for any car where it's aesthetically acceptable to have a single tailpipe exiting from one side (looks IMO good on for example pickup trucks). One would have to basically win the lottery to by chance get it fabricated with enough equal length segments for it to drone at any rpm. It will also usually use a lot of the available volume for mufflers which is key to noise suppression.

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Re: Straight through mufflers

Post by enigma57 » Fri Jun 26, 2020 1:45 am

bob460 wrote:
Thu Jun 25, 2020 12:33 am
enigma57 wrote:
Wed Jun 24, 2020 1:01 pm
Thanks, Ed! I don't do facebook but was able to view the post and hear the 4" single exhaust on the Firebird without logging in. Much appreciated.

Best regards,

Harry
Go to paige 2 i posted some sound clips of his mufflers.
Thanks, Bob! Yes, I watched and listened to those videos the other day and went back tonight and revisited them, as well. Considering the spiral cuts in the inner flow tube which would aid flow over the usual louvers (unless the louvers were reversed out of the flow path and placed in the packing side). Considering the size and length of the mufflers, sound attenuation is surprisingly good.

In short, I'm impressed with the functionality of the design. Being an old codger now (yes, President Kennedy was shot on my 16th birthday), I would probably go with the longest such muffler or (mufflers) I could physically fit in the space available under the car. At my age, I'm not out to impress anyone with a loud exhaust system. As long as the car does what I want it to do when I get down on it and is not excessively loud, that's all I really care about. :D

Best regards,

Harry

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Re: Straight through mufflers

Post by SpeierRacingHeads » Fri Jun 26, 2020 10:04 am

17225 Dynomax straight through. Not sure I like it.

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Re: Straight through mufflers

Post by enigma57 » Fri Jun 26, 2020 1:47 pm

:shock: That's pretty loud, Chad. My youngest son scored some parts SLP had left over from their '91 - '92 Firehawk program. We are putting these in his '92 Camaro ragtop. Amongst these are the Firehawk exhaust. Consists of headers, a Y-pipe and a single 3" exhaust and a transverse mounted muffler at the rear (factory position) with short dual 2-1/2" turnouts (both on the drivers side).

Couldn't find any identifying manufacturer's marks on the muffler but it looks quite similar to a DynoMax Super Turbo with the large oval body. Has a nice, tone. But not too loud. Errr...... The cat seems to have gotten 'lost' somewhere. :-$ But other than that, its the same system that SLP installed on the limited edition Firehawks they built for GM. Son's Camaro is a road car and we are building a fairly mild 350 for it (probably makes and honest 340 - 350 HP at the flywheel), so the Firehawk exhaust should be fine for what he is doing.

I believe SLP intended on building 250 cars over the '91 - '92 model years but only ended up building 25. Nonetheless, we were fortunate to get the parts some years back. Especially the exhaust and the Dana 44 posi rearend.

Happy Motoring,

Harry

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Re: Straight through mufflers

Post by travis » Fri Jun 26, 2020 3:31 pm

I would imagine that would get highly annoying very quickly if you drive it much.

One thing that would probably help though would be pointing the exhaust straight out the back, with the tip sticking out just a bit. I’ve noticed on mine, even with the really loud mufflers, that pointing the turn downs out from under the truck instead of pointed at the ground makes a huge difference inside the cab. The sound waves bouncing off the ground and back up under the bed gives it a really bad resonance, even when using quieter mufflers

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Re: Straight through mufflers

Post by gmrocket » Fri Jun 26, 2020 5:59 pm

For me, on the Dyno the only muffs that didn’t lose anything were Magnaflow strait through style.

Not even a single hp or jet change required...it did defiantly kill the open headers ear hurt...we ran it one pull open...3.5” right off the collector

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