467-Ratman

I just talked to the guys at the dyno shop and they told me about a 69 vette with a 427 and factory style side pipes. The car before had 2.5inch pipes going back to a set of flowmaster mufflers and they converted it to side pipes. The motor made 60 more HP on the chasis dyno before they switched to side pipes. Are the original style that restrictive? How about the Hooker ones, any better?

78 Vette

The Hooker Headers with the spiral baffles is the way to go with side pipes. All of the other combinations are very restrictive.

Jughead

I think the hierarchy from least restrictive to most is:

1. Hooker sidemounts/JCL spirals
2. Hooker sidemounts/mufflers
3. Hooker supercomps/free flow mufflers
4. Stock manifolds/side exhaust
5. Stock manifolds/stock 2 inch pipes.

Corey_68

:withstupid:

GrandSportC3

My setup is the least restrictive:

Hooker Sidemount headers (1 7/8 inch primaries) and open side pipes (4 inches) :party: :party: :party:

shoptek

And possibly OVER scavenging?????!!!!!:confused:

Any exhaust EXPERTS out there??

Cali,68,L-79

Least restrictive.

1. Hooker headers 1 7/8 primaries to 3" stainless all the way back to the these

Two 2" openings per muffler, could look right thru the things and see light, i.e. straight shot. Louder than sin. backpressure = 0, on the old 77 I had.

Chuck Harmon

467-Ratman,

I made 483rwhp with open Hooker headers, and 477rwhp with the JCL spiral baffles in place. I haven't seen anything else come close to being as efficient. The JCL's do a decent job cutting down on the noise too.

The factory side pipes that fit under the finned aluminum cover are a reverse flow design which is more restrictive than the chambered (dimpled) design used for the C2 cars.

Chuck

Rbbmoose427

I just installed the Stainless works headers and the C2 style sidepipes on my 427/390 '68 - I also did Keisler and Steeroids install at the same time so I don't have it on the road yet, but I did fire it up last weekend and the sound is great - a very throaty rumble.

Judging from the open design of this system, I can't believe I'm going to lose much horse power...

Ray

Twin_Turbo

JCWhitney fake sidepipe setup should be in that list too, I suspect somewhere between 3 and 4

427V8

No such thing as over scavenging...

GDaina

I believe the 427 stock pipes were 2.5", at least mine were when I bought the car in 69.

Edit: Oooops....talking about factory side pipes...forget what I said above. My under chassis exhaust was 2.5".


[Modified by GDaina, 8:04 PM 3/9/2004]

Ganey

Yes, very restrictive. Probably came from 50s Lakes pipes which were run open. Then when mufflers are added stock type are very restrictive. Even if run open there are the sharp bends that should be avoided. Header type sidepipes & better mufflers will help. The normal reason given for sidepipes over & over is "looks".

Least restrictive: Headers & a straight back exhaust w/o sharp turns.

:cool:

lvrpool32

The actual pipes in the stock factory sidepipes are only 1-3/4".
I just changed mine to headers and a 3" stainless sidepipes care fo stainless works.

Nick

Madmikeee

GSC3's 68 is an 11 second car, alot of people go to HIM with questions on C3's I think your implying that he is less than an expert is a little insulting.

Sorry if I misinterpreted your meaning but I felt this should be said as his posts have been a great help to me with my 77 mods and IMHO I think he is as much of an expert as any.
:cheers:

shoptek

No need to be sorry for misunderstanding! Let me explain a few things to clear up any confusion you might have....
Olivier and I are very close friends. We see each other AT LEAST 3 times a week. As a matter of fact, I sometimes spend more time with GSC3 and Electron Blue '02 during the course of a week than I do with my own wife and kids!!! :D Absolutely no flames were intended, and I am sure he knows this as we have discussed this topic ad nausem, and if I wanted to be "a little insulting", I would say it to his face....not on a semi public forum.

When I used the word "expert", I meant that in the actual definition of the word. I would consider a professional high performance engine builder an EXPERT. I would consider an engineer for Hooker, Dynomax, Borla, Flowmaster, and other well known exhaust system components manufacturers an EXPERT.
Lars, who regularly post here and who helps out anyone who asks, builds h.p. engines. He is an EXPERT. Mountainmotor (Curtis) is an EXPERT. I repair very high volume B/W digital copiers, faxes, scanners, full color high speed digital copiers and printers. I am an expert in my field. I am NOT an expert in the field of h.p. engines and their related components, even though I have been working around sports and performance cars for 33 years. Olivier is an EXPERT in his field of computer prgramming. He knows programs that the mainframes use....very detailed and technical.
Also, I tuned and adjusted Oliviers car before he ran his FIRST 11 second run, when he couldn't break the 12's not because I claim to be an expert, but because we are great friends, and can each learn something from each other.

I've heard.......and could very well be 100% wrong.....that certain radical cams( nice lift, overlap, and duration) when matched to a free flowing performance set of heads (like Oliviers set up) benefit from a SLIGHT bit of backpressure.....it helps to keep some of the incoming charge inside the combustion chambers during overlap. Once again, I am not an expert, but I do like to get as much knowledge as possible.
:cheers:

I hope this clears things up.


PS--Olivier,

Lisa and I will see you tomorrow night at dinner...6:30 as usual buddy :cheers:


[Modified by shoptek, 11:53 PM 3/9/2004]