Question for people who know exhaust! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

MandarinSixSeven · 08-01-2005, 09:53 PM

Hi all,

First off, I must say, my truck has never been all that loud. This is not to say that this is on purpose

. The truck has had dual exhaust since the get go, first 1 7/8 now 2 1/4, and 3 different types of mufflers from glasspacks, to cheapy turbos, to now Flowmaster 40 series Delta flows.

My beef is mostly with the sound at idle...it's just too quiet. The engine is quite mild, so far it's just a 350 4-bolt main, edel 1406 carb, HEI ignition, edel performer aluminum intake and corvette style ram horns. At idle is it very mellow, no lump at all and yes it has a wussy cam, but still...I have seen other cars with the Exact same setup that sound a lot lumpier at idle and I don't mean cam lumpy, just the sound of hearing every cylinder fire basically, mines just one steady mellow "flow" of sound.

Can anyone tell me why this would be? I was thinking that it might be due to low compression maybe? Like being that each cylinder doesnt explode at strongly it's just mellow?

I know this sounds kinda funny, but basically what I'm asking is what makes exhaust louder? (other than straight pipes) Because even with the old blown out glasspacks it was not really loud at all...

you thoughts???

thanks

**hilljob26** · 08-01-2005, 10:10 PM

are you running headers or manifolds

tripp · 08-01-2005, 10:13 PM

i think it may be because you're using the ramhorn manifolds. i've noticed on my trucks that everything that has cast iron manifolds has a more mellow less aggressive sound. on my '72 fleetside, i have a basically stock 283 with 305 heads and an "rv" cam with full length headers and 40 series flowmasters and this thing at idle sounds like it will eat your lunch. you may want to try some sort of header. my .02 worth.

c10crazy · 08-01-2005, 10:16 PM

Having a relatively mild duration on your cam will keep it quiet and 2.25" pipe is quiet as well. It's perfect for your cam but is really quiet in comparison to 2.5" pipe. Wher does your exhaust terminate?. The shorter the louder.

matthufham · 08-01-2005, 10:22 PM

big pipes, short distance, less bends, big tip, performance muffler, and free flowing exhaust manifold or headers all = more sound. also consider exit location for determining how loud, inside the cab with exhaust turning down at the rear is quieter than side pipes

bowtie · 08-01-2005, 10:54 PM

Sounds like you have a finely tuned engine.

MandarinSixSeven · 08-01-2005, 10:55 PM

I kind of thought it would be because of the manifolds, someday I do plan to get some sort of headers, but I want to wait until I can totally re-do the engine.

As far as exit location, it was exiting in front of the rear wheel until about a month ago, now it's behind. That, I know made a huge difference in the cab, I actually like that its quieter in there now, and extending the pipe changed the sound, but really the volume...

Oh well, I thank you all for answering my question...someday it will be LOUD!

SweetandLong68 · 08-02-2005, 12:18 AM

No tailpipes behind the mufflers....It will be loud and mean then

lata
CHRIS

MandarinSixSeven · 08-02-2005, 11:19 AM

Quote:

Originally Posted by SweetandLong68

No tailpipes behind the mufflers....It will be loud and mean then

lata
CHRIS

This is true. The thing is, even when I had tailpipes in front of the rear tires it was super loud inside, but nothing crazy outside.

farside847 · 08-02-2005, 11:31 AM

Im kinda partial to the mellow idle myself (yes, I have manifolds with a dual 2.25 pipes exiting behind the wheels)

It kinda sits there, peeerrrrrring. Then at a grean, it GROWLS and makes everyone look

Johns70 · 08-02-2005, 11:57 AM

compression ratio has a lot to do with it.

71-longbed · 08-02-2005, 12:12 PM

is your truck a daily driver ??? attention is nice when your driving but not when its the fuzz

im running ramhorns with dual glasspacks that exit behind the rear wheel .. mines alittle loud but not at idle .. only when i press the go pedal .. but glasspacks dont give off the rumble that most people like ....

*wolfthing2000* · 08-02-2005, 12:12 PM

Just enjoy the peace and quiet! Horsepower doesnot have to be loud.

**'70_402** · 08-02-2005, 12:43 PM

It is because you go the delta flow 40 series... there is a big diffence between the delta's and the regular two chamber flows... i mean BIG difference.

MandarinSixSeven · 08-02-2005, 12:55 PM

Quote:

Originally Posted by 70'_402

It is because you go the delta flow 40 series... there is a big diffence between the delta's and the regular two chamber flows... i mean BIG difference.

Reeeeeally? I knew there was a difference, but I didn't know there was a BIG difference. But now that you mention it, my friend just took off some 40's because they were too loud, I never put 2 and 2 together and thought of that.

Damn, I should have grabbed those off of him when I had the chance...Although really, I do like the sound of mine, I just wish there was more of it

So, does this mean that the delta flows are not 2 chambers?

72MARIO · 08-02-2005, 02:59 PM

Go Super 40's. I have them in my 3" system and the sound awesome.

**'70_402** · 08-02-2005, 03:15 PM

super 40's have the delta flow technology also.

LUV2XCLR8 · 08-02-2005, 03:39 PM

Quote:

Originally Posted by 70'_402

It is because you go the delta flow 40 series... there is a big diffence
between the delta's and the regular two chamber flows...
i mean BIG difference.

Even though I hate FLOWS, used to install em, never will own em again

paintpyro · 08-02-2005, 03:48 PM

Haha, thats what I have, and yes, its loud

Quote:

Originally Posted by SweetandLong68

No tailpipes behind the mufflers....It will be loud and mean then

lata
CHRIS

MandarinSixSeven · 08-02-2005, 03:48 PM

Quote:

Originally Posted by LUV2XCLR8

Even though I hate FLOWS, used to install em, never will own em again

Well, even though I HATE excessive emoticon use, people still use them - to each their own...thanks for the useless post.

LUV2XCLR8 · 08-02-2005, 03:51 PM

Quote:

Originally Posted by MandarinSixSeven

Well, even though I HATE excessive emoticon use, people still use them - to each their own...thanks for the useless post.

Wansn't useless, I was reafirming what was said about the differance in the
flows, they do sound dramitically different, I'm sorry that you feel that way.
My reply was based on the fact that I worked at a muffler shop for 2.5 years

MandarinSixSeven · 08-02-2005, 03:53 PM

My Bad...

**'70_402** · 08-02-2005, 04:00 PM

Quote:

Originally Posted by MandarinSixSeven

My Bad...

haha I love flows just not a big fan on the delta flow technology.

hey mandrin, i have a few videos of what mine sounds like for some reference. i can't post vidoes but i can email them to ya.

i have 2.5" mandrel bent pipe with regular 40 series flows dumped after the muffler.

kxmotox247 · 08-02-2005, 04:12 PM

Whatever you do, don't get the small drag race 1 chamber mufflers that flowmaster makes. I have them on my 67 with a very similar motor. The exhaust dumps in front of the diff. and it's relatively quiet at idle but sounds like crap once you throttle it.
These were put on by the previous owner. Louder is not neccesarily any better. Those mufflers make it sound like the truck is one giant exhaust leak.

MandarinSixSeven · 08-02-2005, 04:19 PM

Quote:

Originally Posted by kxmotox247

Whatever you do, don't get the small drag race 1 chamber mufflers that flowmaster makes. I have them on my 67 with a very similar motor. The exhaust dumps in front of the diff. and it's relatively quiet at idle but sounds like crap once you throttle it.
These were put on by the previous owner. Louder is not neccesarily any better. Those mufflers make it sound like the truck is one giant exhaust leak.

LoL!
Thanks for the tip, I'm glad you said that, because in my mind I keep thinking "gotta go louder, louder, LOUDER"...you just reminded me that an engine like mine with really loud exhaust, just sounds like a wussy v8 with a broken muffler. However, some more volume is needed in my opinion.

I will take some videos after work and see what you guys think.

08-01-2005, 09:53 PM	#1
MandarinSixSeven Seasonal Poster Join Date: Apr 2002 Location: Kelowna BC Canada Posts: 896	Question for people who know exhaust! Hi all, First off, I must say, my truck has never been all that loud. This is not to say that this is on purpose . The truck has had dual exhaust since the get go, first 1 7/8 now 2 1/4, and 3 different types of mufflers from glasspacks, to cheapy turbos, to now Flowmaster 40 series Delta flows. My beef is mostly with the sound at idle...it's just too quiet. The engine is quite mild, so far it's just a 350 4-bolt main, edel 1406 carb, HEI ignition, edel performer aluminum intake and corvette style ram horns. At idle is it very mellow, no lump at all and yes it has a wussy cam, but still...I have seen other cars with the Exact same setup that sound a lot lumpier at idle and I don't mean cam lumpy, just the sound of hearing every cylinder fire basically, mines just one steady mellow "flow" of sound. Can anyone tell me why this would be? I was thinking that it might be due to low compression maybe? Like being that each cylinder doesnt explode at strongly it's just mellow? I know this sounds kinda funny, but basically what I'm asking is what makes exhaust louder? (other than straight pipes) Because even with the old blown out glasspacks it was not really loud at all... you thoughts??? thanks __________________ 67 GMC Short Step 350/4-Speed/3.08 Posi Front/Rear Sway Bars Kelowna BC, Canada Member of DTPW

08-01-2005, 10:10 PM	#2
hilljob26 Registered User Join Date: Dec 2004 Location: Gypsum Kansas 67448 Posts: 1,681	are you running headers or manifolds __________________ 21 2500hd duramax 58 apache HILLJOB GRAPHIX--for all your graphic needs My build thread http://67-72chevytrucks.com/vboard/s...d.php?t=542497 LS ENGINE SWAP INFORMATION THREAD http://67-72chevytrucks.com/vboard/s...d.php?t=377348 4l60 to an NP205 http://67-72chevytrucks.com/vboard/s...43#post3697343

08-01-2005, 10:13 PM	#3
tripp Registered User Join Date: Mar 2003 Location: Meansville, Georgia Posts: 218	exhaust i think it may be because you're using the ramhorn manifolds. i've noticed on my trucks that everything that has cast iron manifolds has a more mellow less aggressive sound. on my '72 fleetside, i have a basically stock 283 with 305 heads and an "rv" cam with full length headers and 40 series flowmasters and this thing at idle sounds like it will eat your lunch. you may want to try some sort of header. my .02 worth. __________________ 68 SWB Stepside 72 Cheyenne 20 72 SWB Fleetside 72 Suburban 72 2wd Blazer Last edited by tripp; 08-01-2005 at 10:14 PM.

08-01-2005, 10:16 PM	#4
c10crazy Like a Rock! Join Date: May 2002 Location: USA Posts: 1,092	Having a relatively mild duration on your cam will keep it quiet and 2.25" pipe is quiet as well. It's perfect for your cam but is really quiet in comparison to 2.5" pipe. Wher does your exhaust terminate?. The shorter the louder. __________________ 69 LWB Runs great - work in progress Mess with me and you mess with the whole trailer park!

08-01-2005, 10:54 PM	#6
bowtie Senior Member Join Date: Dec 1999 Location: Saskatchewan Posts: 1,050	Sounds like you have a finely tuned engine. __________________ ~70 GMCprostreet swb 396/700r NOS 575 hp "the Brick" ~72 chev swb w/68 front clip "GM Millenium corvette yellow" I use and accept Paypal

08-01-2005, 10:22 PM	#5
matthufham Registered User Join Date: Feb 2005 Location: Carl Junction, Missouri Posts: 2,061	big pipes, short distance, less bends, big tip, performance muffler, and free flowing exhaust manifold or headers all = more sound. also consider exit location for determining how loud, inside the cab with exhaust turning down at the rear is quieter than side pipes

08-01-2005, 10:55 PM	#7
MandarinSixSeven Seasonal Poster Join Date: Apr 2002 Location: Kelowna BC Canada Posts: 896	I kind of thought it would be because of the manifolds, someday I do plan to get some sort of headers, but I want to wait until I can totally re-do the engine. As far as exit location, it was exiting in front of the rear wheel until about a month ago, now it's behind. That, I know made a huge difference in the cab, I actually like that its quieter in there now, and extending the pipe changed the sound, but really the volume... Oh well, I thank you all for answering my question...someday it will be LOUD! __________________ 67 GMC Short Step 350/4-Speed/3.08 Posi Front/Rear Sway Bars Kelowna BC, Canada Member of DTPW

08-02-2005, 12:18 AM	#8
SweetandLong68 Your UncleBen Join Date: Dec 2002 Location: Indian Trail, NC Posts: 590	No tailpipes behind the mufflers....It will be loud and mean then lata CHRIS __________________ 68 C10 shortbed -- Street/Strip

08-02-2005, 11:31 AM	#10
farside847 Registered User Join Date: Feb 2005 Location: Bay Area, California Posts: 995	Im kinda partial to the mellow idle myself (yes, I have manifolds with a dual 2.25 pipes exiting behind the wheels) It kinda sits there, peeerrrrrring. Then at a grean, it GROWLS and makes everyone look __________________ 1971 Chevy C10 Shortbed Stepside, 307v8 3-on-the-tree

08-02-2005, 11:57 AM	#11
Johns70 Registered User Join Date: Dec 2001 Location: Spring Creek, nevada. U.S.A. Posts: 456	compression ratio has a lot to do with it. __________________ 69 chevy short wide box project 70 GMC jimmy project

08-02-2005, 12:12 PM	#12
71-longbed Its Magically Delicious Join Date: Jan 2003 Location: oregon Posts: 2,398	is your truck a daily driver ??? attention is nice when your driving but not when its the fuzz im running ramhorns with dual glasspacks that exit behind the rear wheel .. mines alittle loud but not at idle .. only when i press the go pedal .. but glasspacks dont give off the rumble that most people like .... __________________ 71 C10 LWB 350sbc -TH350 12 bolt 3.42 Posi Of all my favorite things to do, The utmost is to have a brew. My love grows for my foamy friend, with each thirst-quenching elbow bend. Beer so frosty, smooth, and cold it's paradise pure liquid gold. Yes beer means many things to me that's all for now cus I gotta pee.

08-02-2005, 12:12 PM	#13
wolfthing2000 Account Suspended Join Date: Oct 2004 Posts: 1,276	Just enjoy the peace and quiet! Horsepower doesnot have to be loud.

08-02-2005, 12:43 PM	#14
'70_402 Senior Member Join Date: Dec 2003 Location: Pampa, Texas Posts: 1,554	It is because you go the delta flow 40 series... there is a big diffence between the delta's and the regular two chamber flows... i mean BIG difference. __________________ https://www.ebay.com/itm/295742064443

08-02-2005, 02:59 PM	#16
72MARIO Registered User Join Date: Nov 2000 Location: Huntsville Ontario Canada Posts: 4,052	Go Super 40's. I have them in my 3" system and the sound awesome. __________________ 1968 Suburban numbers matching all original truck now equipped with 6.0/4L80 on Accuair http://67-72chevytrucks.com/vboard/s...d.php?t=625017 1967 C/20 6.0/4L80 Roofing Truck 1990 V2500 Suburban "Plow Truck" 2005 TAHOE DD

08-02-2005, 03:15 PM	#17
'70_402 Senior Member Join Date: Dec 2003 Location: Pampa, Texas Posts: 1,554	super 40's have the delta flow technology also. __________________ https://www.ebay.com/itm/295742064443



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08-02-2005, 03:53 PM	#22
MandarinSixSeven Seasonal Poster Join Date: Apr 2002 Location: Kelowna BC Canada Posts: 896	My Bad... __________________ 67 GMC Short Step 350/4-Speed/3.08 Posi Front/Rear Sway Bars Kelowna BC, Canada Member of DTPW

08-02-2005, 04:12 PM	#24
kxmotox247 Senior Member Join Date: Jul 2002 Location: Champaign, IL Posts: 1,396	Whatever you do, don't get the small drag race 1 chamber mufflers that flowmaster makes. I have them on my 67 with a very similar motor. The exhaust dumps in front of the diff. and it's relatively quiet at idle but sounds like crap once you throttle it. These were put on by the previous owner. Louder is not neccesarily any better. Those mufflers make it sound like the truck is one giant exhaust leak. __________________ Baby Blue's Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=652776 Project 68's Build Thread: http://67-72chevytrucks.com/vboard/s...17#post8442117 www.stonecolumnclassics.com Email: Josh@stonecolumnclassics.com

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