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bonehead007
06-01-2005, 10:43 PM
I have one more question regarding the exhaust system for an R1 Avanti. Basically, the previous owner put on a new system and it sounds real loud, as if the muffler has a hole in it. Being an Avanti novice, is this how it is supposed to sound ?? Thank you..

N8N
06-02-2005, 04:36 AM
there were several options for an Avanti exhaust, but the "standard" exhaust was dual pipes without a crossover and glasspack mufflers, so yes, it was fairly loud.

nate

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

Transtar56
06-02-2005, 10:45 AM
And the problem with that is????
As we Hog riders say,loud pipes save lives.You should hear my 88" Twin Cam through her Screaming Eagle exhaust,people notice me coming(G)

N8N
06-02-2005, 02:13 PM
Did I say it was a problem? :)

Seriously I am running the same basic setup on my '62 Lark and it sounds good at most speeds but there is a decent resonance at about 45-50 MPH. I would probably change to "real" mufflers were I driving it every day.

nate

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

wagone
06-02-2005, 09:54 PM
When I bought my '63 Avanti about two years ago it had a stainless steel 2" exhaust on it with glass packs AND a crossover. I don't consider it loud at all. My only comment to the (be nice now) guy who sold me the car is "why go to all the stainless expense and not put in a 2-1/4" exhaust". A 2-1/4 inch diameter is at least 25 percent larger in cross sectional area than is a 2" diameter. I'd never had a car with a crossover before and I gather from earlier comments that the purpose is to reduce the noise. As I say mine is not objectionable at all--even on a long trip and the car does not have air. The only drawback to the crossover that I can see is when you go to remove the exhaust when laying on your back under the car--especially when over 60 years of age--I hope I still think I'm a kid the day I die, but that is unlikely.
wagone/waygone in Iowa

hank63
06-03-2005, 12:53 PM
I was told by an exhaust specialist that the cross-over is used to ensure optimum scavenging effect.
/ H

studegary
06-03-2005, 01:25 PM
I agree that 2.25 inch pipes are 25% larger than 2 inch pipes, but I don't think that anything bigger than 2 inch duals is necesssary, or helpful, on a stock Studebaker 289 V8 (especially with a balance pipe). IMHO, you would have to change the exhaust manifolds to something that flows better than stock and probably have to improve the intake manifold and valves to make use of bigger than 2 inch dual exhausts.

N8N
06-03-2005, 09:21 PM
The crossover both improves scavenging and quiets the exhaust some. It makes more power, but you lose a little bit of that aggressive tone... win some, lose some...

I've talked to Don Simmons and had thoughts about using a crossover on various projects and he seemed to think that the slight power gains weren't worth it. I think we discussed this with "studebakerbob" over on JP's site, sadly that discussion has been lost what with his site being hacked and all.

nate

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

Sonny
06-03-2005, 10:36 PM
Hank hit the nail on the head Gary. A 2 1/4 " exhaust is a great scavenger, then add the x-tubes and you have the best of the best, until as you pointed out, we get something more efficient/effective at the engine.

One point that I’d like to bring up though. The stock manifolds keep getting a spanking almost every time somebody talks about them. I gotta disagree, somewhat. Bein’ a Ford man for so many years, I’ve seen a LOT worse, and not all Fords either.

The later Stude manifolds aren’t any worse than something like the “ram horn” style Chevy manifolds. In fact, I’d say that the Stude manifold was a tad better. There’s nothing square on ‘em, no place to impede the flow. They ARE way too short to ever be considered tunable. However, from recent experience, (and I can’t prove it because I have no flow numbers), I think they CAN be improved a bit.

We just recently “did” a set of Stude manifolds for a club member who has a 2 1/4”, stainless exhaust system. He re-did the manifolds because he has the header and tail pipes polished and the polished stainless pipes on the old manifolds really looked like chitt. (BTW, do NOT believe ANY of the BS about being able to powder coat exhaust manifolds, the “new hi-temp” coatings suck as bad as the old stuff. His car always looked like it was on fire until almost all of that crap burnt off!). So we port matched, cleaned/opened up the big hole at the pipe connection, smoothed the insides as much as possible, knocked the big casting knobs off, smoothed the outsides, had ‘em ceramic coated and I swear it changed the sound of the exhaust!

I'm getting a 2 1/4" exhaust on the Lark in the near future, and after I saw what can be done with the stock manifolds, I'm gonna do a set for mine too. I'm just hoping that Jeff Rice finishes developing a set of headers for us soon! [}:)]:D

Sonny
http://RacingStudebakers.com

hank63
06-04-2005, 09:04 AM
A cross-over in itself is no guarantee of better flow and power gain. It has to be in the right spot as well.
As far as I’m aware, this all originates with Newton’s law about action and re-action.

(When your engine pushes spent gases from one cylinder into the exhaust system, there’s pressure-pulse traveling through the system towards the exit. By Newton’s law, there will be a pulse traveling in the opposite direction, ie forwards towards the engine.)

We don’t want that “return pulse” to “fight” the next outward bound pulse. I’ve recently seen a report on dyno-testing of several different exhaust systems on the same car. (4 into 1, 4 into 2, different pipe sizes, different mufflers, etc, etc. The upshot was that one system outperformed all the others, thanks to being best suited to that particular engine. Some “expert” systems actually performed worse than the standard system.

Many moons ago, I was involved with a Chev SB, where an incredible gain was realized by changing the length and taper of the collector section (after the headers) and by moving the cross-over 2.25” rearwards. It felt like the engine had gained a couple of cylinders.
/ H

lark55
06-04-2005, 10:50 AM
Many years ago,(over 30)when I was circle track racing I was looking at headers for a 259 and ran across an interesting article that a British engineer had come up with to help with the siamesed center exhaust port on the old Austin-Healys(I think). What he proposed doing was adding another closed tube at a specific length on the outlet of the center tube that would reverse the sonic wave and help to scavenge the exhaust gasses.I never followed it up but I thought it might be of interest to someone.