lowvette

Not considering sound or looks, what type of exhaust system do you believe makes the most power on a C3 with a built-up 383? For undercar exhaust, I'm considering 2-1/2" I.D.

Thanks for your thoughts and opinions!

PRNDL

1. You want headers
2. You want an X or H pipe
3. I hear mandrel bends create better flow
4. 2.5" should be enough for most applications. Some guys have 3" with the more powerful engines.
5. I am still trying to figure out which muffler actually performs the best... or at least better than the Flowmaster 50s I have now.

VETDRMS

In reality, one that is designed specificly for the motor, ie tuned pressure and wave/pulse properties of the air-pump(motor).

However that takes more time and money than most of us would care to spend. Including myself. The end result is marginal... but when your after margins, you PAY for them. :lol:

A good 2.5" exhaust with a balance pipe is a good combination. This also depends on elevation, rpm range, ect.

Hopefully those who know more than me, as the crowds roll in...will chime in.

Good Luck.

I found this exhaust works well for me, and turns the cabin of the car into an amazing resonance chamber (this was later modified to exit in front of the tires, which fixed the bad resonance issuse). I could gain a fair amount of low end torque with a smaller diameter tube, but with a 4000+rpm stall I am not concerned with low-end torque.


:cheers:!


[Modified by VETDRMS, 9:27 PM 4/20/2004]

Shark Racer

Dynomax Ultraflo mufflers really are the way to go IMO... relatively cheap ($65/ea), and the 2.5" variants flow well enough to support ~515hp.

-Steve

flynhi

On my 383 TPI, I have
ceramic coated headers with mid sized primaries.
4-2-1 collectors
2 1/2" mandrel bend pipes
X crossover
Edelbrock RPM mufflers
OE tips with inlet replaced with 2 1/2" pipe

works great. limited resonance, X raises sound an octave or two

SanDiegoPaul

I have the 2.5" ultraflows but the around town drone is too much for me. They sound GREAT on the freeway and when I drive it hard. But 25-40MPH is horrible!
:mad

Shark Racer

SD Paul- You running an H-pipe? Mine are quieter than my super turbos were!

(Edit: That is, they resonate less. Louder @ high rpm, but cruise nice and quietly! Before I installed the h-pipe, they were a bit drony on the freeway.) (Super Turbos had no h-pipe...)


[Modified by Pacin'California, 9:58 PM 4/20/2004]

munday

I have a 383 and i felt a difference when i switched from my hedman long tubes to dynomax ceramic coated..(not happy with how the finish is holding up though) But I have 2.5 inch exhaust going into flowmaster (the redneck mecca of mufflers) 2 chambers.. I do not have a x pipe, just two 2.5 inch pipes running out the back of the car. On the freeway it's very tolerable. Around town...well I just hope your not next to me in a convertible. Also since I do not have a Xpipe( according to other members, I don't know that much about exhaust) when I let of the gas quickly and slow down using the engine it sounds like I am taking out have the block with a S.A.W.

SuprJames

I have a 383 c.i. with Hooker full length headers with 1 3/4" primaries running into 2.5" duals with "X" and out through Dynomax mufflers. No cats. Sounds OK.

Edit: a little quieter then I'd like.


[Modified by SuprJames, 9:02 AM 4/21/2004]

norvalwilhelm

I would definitely go for duals under the car, a cross over , 2 1/2 inch mandral bends and mufflers that you can live with.
I can not take a droon in the car nor anything too loud. I like my hearing and also talking to my passengers.

kaiserbud

Can you incorporate aftermarket exhaust manifolds into factoryu side exhausts? Is a cross-oiver out of the question in this scenario?

Big Fish

There is at least one fellow here that uses 2-1/2" duals that carry 2 cylinders each out the back, and 2-1/2" side pipes that carry the other 2 on each side. That sounds like a very good combination to me, I don't think you could overload that with anything that is even close to being "streetable". Maybe someone else know's who I'm thinking about, can't remember his forum name.

AlwaysWave

I saved this from a few posts over a year ago. I can't verify these numbers.

Muffler Flow:
OEM..................................... ........................................ ...225
Gibson SuperFlow 788200.................................. ............311
TTS Bullet Cat Converter............................... ..................324
Flowmaster 40 series 42540................................... .......352
Flowmaster 50 Series.................................. ...................362
Flowmaster 40 series 43040................................... .......392
Dynomax Super Turbo................................... .................410
Flowmaster 62631................................... .......................435
Carsound Cat Converter............................... ..................436
FLP Cat Converter............................... ............................440
Edelbrock Victor 5535.................................... ..................562
Flowmaster 40 series 435409.................................. ........576
Edelbrock RPM series 5511.................................... ..........579
Flowmaster Delta Force Racing 54040-10........................634
Edelbrock 304 series 5560.................................... ...........640
Edelbrock Gen App 5505.................................... ..............708
Dynomax Race Magnum Welded 17216...........................711
Borla XR-1 40600................................... ..........................836
Borla XR-1 40615................................... ..........................854
Dynomax UltraFlow SS 17263................................... .......1000
Dynomax Race Magnum Welded 17218...........................1000
Borla XR-1 40575................................... ..........................1100
Dynomax UltraFlow............................... ...........................1133
Edelbrock Victor 5537.................................... ..................1400
Borla XR-1 40450................................... ..........................1400
Borla XR-1 40741................................... ..........................1450
Dynomax UltraFlow SS 17296, 17268..............................2200
Dynomax Race Magnum Welded 17220, 17224...............2200
Dynomax Race Magnum Welded 17225...........................2600

The formula for required exhaust flow is: horsepower times 2.2. Pretty simple eh?
So if your car makes 400 hp, you will need a total of 880 cfm muffler capacity for an unrestrictive exhaust system. So for dual exhaust, you would need mufflers that flow 440 cfm.
For reference, a 2.5 inch diameter pipe flows ~500 cfm. Adding non-mandrel bends will lessen that amount.

Ganey

The headers straight back, under car through the crossmember duals w/ crossover is ideal & works great.
New guys might want to see what many refer to as my Exhaust topic for more info. http://www.corvettefaq.com/c3/ganeyexhaust.htm

Yes, it can be done, have been rec. a crossover for sidepipes. At least Dave, moderator of C1/2 has done it.

The Money Pit

I was looking for the bang for the buck,plus max performance when I got mine done,but was thrown a slight curve by the Midas shop that did the work.He insisted on a converter installed in the stock location when I went for my 3" duals,so I let him bust his butt bending the 3" pipe to make it happen.I supplied the 3"Edelbrock straight through mufflers and the sound is great for all but one spot around 2000 rpms,where there's a bit more resonance than I'd like,but it still isn't bad.On the highway it purrs,idling I get lots of comments on the sound,and when I crack the throttle it sounds like open sidepipes.

I noticed the flow chart posted and I've seen it before here.The mufflers I got flow in the 700cfm range,which is way more than I need,but are a straight through design.Most performance type mufflers use a reverse flow for sound control,which essentally bounces the sound waves front to back trying to cancell each other out.This type of muffler does not flow as well as a straight through design,but gets the job done.Just thaught I'd throw this out for general info. :cheers:

verskel

Headers are obvious......2 1/2" pipes are a must. :yesnod:

Then you could go sidepipes (no baffles), chambered exhaust, or just plain straight pipes like me ! :reddevil

MEGALADON

I used to be a BIG fan of FLOWMASTER till I seen the MAGNAFLOW"S.
they have a straight through design and are quiet till you get on it.
and if you got a cam it even sounds sweeter. No cabin noise like flow's
I have headers with an X pipe behind the trans, 2.5 aluminium pipes
with mag's on the end, I could feel every bit of differance. If you get to hear a vette with MAGNAFLOWS you would like it to. Unless your into noise. :)

73 Vet

Can you tell me what type of "Mag's" you have?

69stingray

I have seen someplace a company or a computer program (one of the two) that would design an exhuast based on the required length and your engine parameter. Drawing a blank.

lostpatrolman

does anyone know the JCL flow #s? both standard and with the end cut off?