Hi everyone,

My Walker Quiet Flow muffler is unravelling after twelve years of service and it is time to replace it. IIRC, it is a single 2.5 inch inlet with dual 2.5 inch outlets.

What I want now is a perfectly quiet muffler that isn't going to sacrifice much in the way of horsepower. I just want the car to sound as quiet as your average mundane sedan, even when I step on it.

I already have Hooker shorties and also their y-pipe feeding into a 2.5 inch intermediate pipe. At the other end is the Walker Quiet Flow muffler with duals coming out the back. I have a nicely built 305 putting out about one hp per cubic inch.

Who makes a reasonably priced but really quiet muffler that will work with this setup?

 

I have always found the borla pro XS muffler to be fairly quiet

http://www.borla.com/products/proxs_centerdual.html

 

How quiet is it your walker?

 

I have heard Magnaflow makes a quiet at idle and cruise muffler, but louder than flowmaster at WOT.. Haven't tested it though.. Can anyone attest to this? I think it's cheaper than the Borla as well.

 

Almost as quiet as a stock muffler until you step on it.

What I want is a muffler that is as quiet as a stock muffler, even when you step on it.

 

Good luck

 

Why not just replace the Walker you have with the same because I honestly don't believe there's anything quieter than that ? I mean that's supposed to be quieter than stock right. Is it possible to install a baffle in the tailpipes of some kind ?

 

Quiet muffler+ perforated resonator should do the trick.

 

magnaflow part #12267

 

This might be of interest, but, on the new vette, there is a throttle activated cable that opens a baffle inside the exhaust tailpipes once you pass a certain threshold of throttle. This could probably be done with a similar type of setup on a thirdgen.. With some fab work ofcourse.. It would definitely be quieter at idle and part throttle.

 

I dont get it. All that horse power and you want to hide what is in my opinion beautiful music.

 

Unfortunately, like some symphonies, it might not have universal appeal, in addition some places have laws.

 

Friends of mine just put Flowmaster 50-series mufflers on their 454 powered Suburban. I think they sound really good. It has ceramic coated long tube headers, 2.5" dual and "high-flow" cats. Inside the cab you can barely hear it running until you hit 1/4 throttle or so. Going down the highway you can just barely hear the exhaust over wind and tire noise.
Pulling a big trailer into the camp ground it was louder than ideal, but there probably no avoiding that.
I am thinking about putting one on my 91 LB9 car, either 3" or 3.5"

 

prepare to have your neighbors to not like you very much,also the blue meanies WILL have a new found interest in you.plus the tinny rattle that flows get after a while grows old, and quickly. IMHO magnaflow is the way to go.i have one on my LB-9 car ,and the sound is great.not too loud.and the performance is very good

 

Dyno Max Ultra Flo stainless.

 

I have a spintech and it is stock range quiet at idle and part throttle. At WOT it is a little louder than stock and its also the best sounding muffler I have ever heard; IMHO. I think a good muffler combined with a chambered exhaust section might be the ticket for a great exhaust system and manageable sound levels.

 

I'd look at a Dynomax Super Turbo muffler. They're almost stock-like in their sound, except that they allow a little bit more of a deep rumble. They flow very well for what they are. I had one on my IROC and my modified TPI 350 sounded almost totally stock. That same motor with a 3" Ultra Flow sounds like a rabid animal.

 

the hooker aerochamber is a quiet muffler

 

my $0.02 is magnaflow, they seem the quietest of the "performance" mufflers.

 

Walker Shows a SoundFX As A Stock Repacement Muffler For A 305 Liter Engine,That Must Be The Closest To Stock Factory Sound.

 

I'd be interested to see documented decibel readings for different mufflers and exhaust setups. As simple as taking a cheap decibel meter from Radio Shack and seeing what the car reads at idle, revving, interior readings, etc. Then for the adventurous, strap one on the bumper and take it for a spin!!

 

Dynomax Super Turbo on my 88, nice mellow tone for several years but after 20k miles or so it's pretty loud. Probably burned out some absorber material. These cars are noisy enough without exhaust roar, on the highway anyway. But I'm getting old and crotchety.

 

You need 671 cfm to support 305hp. You should be looking at mufflers in this CFM range, then sort by noise reduction qualities.

-- Joe

 

I find it hard to believe you get 300 HP out of 305.
I get ~350RWHP from a professionally built 350.
Did have put it on a dyno?

 

I have a magnaflow on my car, sounds great but in no way would I call it quiet.
The quieter the muffler the more HP is lost.

 

Sounds like you need a new professional

300hp out of a 305 doesn't sound out of the question. Heck, new v6's make 300hp stock. A 4.8l (LS motor) with cam and head work makes 450hp all day.

-- Joe

 

305 TPI stock makes roughly 175-180 hp and (i believe) 250-ish ft. lbs. of torque.....a stock 350 TPI makes about 275 hp. a stock 350 TPI with a mild cam will bring about 300-315 to the table. these motors arent huge hp makers, but they can crank out torque!

 

An LSx is completely different animal than a SBC TPI. My 305 had an under whelming 165 HP. I really doubt changing the cam is going to add 135 hp, the 305 just can't flow enough air.
Really comparing an LSx anything to a TPI is an apples to oranges conparison. Dyno Don built my motor and he got 400+HP with a better custom modified TPI intake and a larger throttle body.

 

For starters, I said "cam and head work".

I generally don't debate engine building with guys who don't build engines. 305's don't "flow air", unless you are trying to explain swept volume of a 305 vs a 350 to draw some sort of conclusion of how much air naturally aspirated that the engine can draw in at 100% efficiency or valve shrouding with the smaller bore.

A CS292-H-10 cam, RHS iron heads, and a decent intake will make 400hp on an L69 all day. Any idiot should be able to make 300hp out of a 305 TPI with a cam and head work. Should be even easier if your paying someone to do it.

-- Joe

 

DynoMax Super turbo is as close to stock rumble you can get. Just put one on the GTA 350 and has a pleasant rumble like stock. Cheap to, cat backs are like $200 and change from summit.

 

Dyno Don built my motor for his car and made over 400 HP with in his Trans AM with T56. They cut and welded up the plenum so they could port them well beyond what was possible with the best of the after market smog legal intakes in CA. Don with the help of Allen (1989GTATransAm) and JerryWho spent years building and rebuilding intakes and porting both the base, plenum, and runners to match the heavily ported heads to the absolute maximum possibly and have ended up with several members of the local socal TPI club with 400HP+ cars.

Don has several 305 sitting in his shop. He practical gives them away cause the just can't make power and used only as temp motors when he works on the 350s when they are out of the car for repairs and mods. Maybe super charging or running nitrous could get them to make the kind of HP your talking about'

Here is a list of the long block of the motor Don (x Pro Drag racer) built that is now in my car.

The Short Block:
4-bolt main roller Vortec "880 casting #
TRW forged pistons .030 over (357cu. in.)
ZZ4 powdered metal rods
Cast crank offset ground
.020 deck height
Compression 10.6/1


The Heads:
Edelbrock E-tec 200's 60989 #
Fully ported by "Jerrywho"
Flow #'s 270/218 w/o pipe
Milled to 60 CC's
Dual springs good to .600 lift 135/360 pressure #'s
With 10 degree locks.

Camshaft:
Crower cam 225/232 114 LSA (installed on 110* intake centerline)
Lift .585 intake .550 Exhaust
Roller rockers 1.65 intake/ 1.5 Exhaust
Cloyes double roller chain
Melling 55A oil pump
Manley head bolts and washers

 

I don't really know how to answer you. If my builds were slower I could come up with some sort of excuse, but you really should be asking the socal guys why they are stuck in the 400s.

880 vortec block + .030 = 355.11 cubic inches.

You realize that same block with AFR 195 heads, a comp cam XE294 camshaft, and super victor intake makes 574 hp ?

Anyhow. I'm sure the OP's engine makes 1hp per cubic inch. That's not exactly hard to accomplish. You are not an engine builder, your just a consumer that consumed a little too much SoCal koolaid when he purchased his engine.

-- Joe

 

Sure it will and if you super charged that motor and gave it a shot of nitrous it would probably get close to 1000 hp. So if were building a pure drag racer and didn't have the need to pass smog they're would be a lot more options.
The same can't be said for the 305 the cylinders are too small and can't be bored anywhere near the size of a 350. The OP exhaust is 2.5" headers to tail pipe. Dyno Dons headers are 1.75" primaries, 2.5" collector to 2 magnaflow cats with his custom Y-pipe to 3" cat-back exhaust with a magnaflow exhaust. Others in the club have 3 1/2" to 4" exhausts.
Don't like Kool-aid.
I would have to see proof that his 305, even with a carburetor could put 300hp to rear wheels especially with a 2 1/2" exhaust.

 

He said 1HP per cubic inch, which I assume is flywheel not to the wheels.

Bore size doesn't really matter. I'm sure you heard this thrown around in the shop. I'm not advocating building 305s but your tech is incorrect.

I'm familiar with Dyno Don's headers, I have a pair of SLP headers myself.

You do bring up a valid point, you guys in California are handicapped by your smog laws. Perhaps that's why when one of you breaks into the 12s you throw a party.

I remember a couple years ago reading a thread about a drag racing event that Dyno Don and Jerrywho ran in. The ET's were all high 13s. A poster in the thread said "And you guys wore helmets for this?" which I found quite funny at the time and still do today.

-- Joe

 

Allen (1989GTATransAm) has the record in our local TPI club. 7.1 in the 1/8 and around 11.4 in the 1/4 mile. At least 3 others are in the 11s in the 1/4 mile.
Allen has a new project a 65 Buick which is exempt from the smog laws and he going with an LS3, this time.

http://ls1tech.com/forums/conversion...6l80-swap.html

 

BTW

He is talking 300-350-400 to the rear wheels.

 

Who is ?

-- Joe