Hi Monty,

I'm not sure you saw my reply, so I've re-posted it in a new thread.
=================
Monty,

W/ a 3" diameter pipe, your options are somewhat limited. I'd pass on glass packs, unless they are of the perforated tube style instead of the very restrictive "cup" style. Having said that I'm unaware of 3" diameter case glass packs. You may wish to consider some form of a header muffler, as from Dynomax, Flowmaster and Borla. You may have room although I suspect this approach will take some creative plumbing.

The Dynatech line of exhaust components look interesting. Jeg's carries them. They have a header muffler assembly that looks particularly compact. And they have their version of collecter inserts, called "Vortex Insert Cones". I have no experience w/ these products however.

And there are the "baffles" that MassVette and GDaina have been raving about. These are available from JCL79383@aol.com but I have been unable to find out any real information about them. I suspect they are similar in design to the mufflers I'm running, Moroso spiral cores, although that is speculation on my part.

I agree the last thing you want to do is choke up that beautiful engine.

Good luck and keep us posted.

Mark




[Modified by ML67, 9:22 AM 8/10/2001]

 

Mark,

Thanks for the info. I was talking to the chassis guy today that's going to build my headers and exhaust system. He had a few ideas. He said he's going to contact one of his friends that builds alot of high-performance Shelby Cobra replica's and see what they use.

I've seen the reports about the baffles JCL is suing for the Hooker pipes, but I thought they were 3.5". I have been told that a 3" pipe is the largest that will fit behind the '69 sidepipe covers.

How do you like the Moroso spiral cores?

 

Monty,
JCL e-mailed me and says he is finishing up a system for the '69 style covers next week. Also, I found a guy who worked for Walker and has the crimping machinery to make his own chambered pipe, up to 4", s/s/ or aluminized, I'm told! His name is Jim Klingensmith, and his phone # is] 1-937-427-7149 He was referred to me by Matt Murphy of the firstgen.com (Camaro) website.

 

Massvette,

Thanks for the info. If you hear anything from JCL, please pass along the info, incase I don't see it as well.

As for chambered pipe, I thought it was pretty restrictive. I know it's popular due to it's sound qualities, but would it be applicable, considering I'm trying to minimize restrictiveness.

 

How long ( inches )are the mid year pipes????

Yes I'm thinking about ...

 

Monty,

The Moroso spiral cores flow well, but are loud! I have problems every time I get the car inspected, although I'm usually able to work out some deal w/ the inspection station -- agreeing that if it ever gets back to them, I had a quiet system installed at the time of the inspection.

Or I have my wife take it in -- she's never had them questioned.

I don't mind them around town, but on the highway they are merciless w/ the 4.11's. An RG 5-sp and 3.08's is next on my list which will solve part of the problem. Unfortunately that will have to wait for another year.

I have read somewhere Corvette owners w/ sidepipes using multiple Spiral Cores in series, although I have not heard this setup myself. Previous to the Moroso Spiral Cores, I ran a very similar muffler from LoBak called the RPM muffler. The only difference was the case length was significantly longer, and the center tube was smaller. It was quieter and slightly more restrictive than the Moroso setup. I have since lost the contact information for LoBak.

Hopefully the Cobra guys would have some ideas, although most of the muffler cases I've seen on them are at least 4" diameter.
And a note of caution: In the R&T 1989 Supercars annual, they tested an original Cobra with a stroked side oiler (454"). The article claimed the owner ran 71 dyno runs, "and to Bernard's surprise, the combination of Cobra exhaust manifolding and mufflers [side pipes] was costing more than 200 bhp, with the primary problem laying in the spiral insert mufflers. Bernard fiddled w/ silencers of his own design, but finally chose the elegant simplicity of open pipes."

The Cobra (unsilenced) ran 11.5 @ 128.

Muffler technology has come a long way since that article, but the bogey of a quiet tube style muffler that does not cost HP compared to a similarly silencing "case" muffler does not, IMO, exist.

Good luck and please keep us posted of your final exhaust configuration.

Mark

 

Did anyone try to find out what vipers are using???
From what I see, they too have side pipes and (not the greatest sounding) they are not noisy
I know that my cousin have "special" set for racing (very noisy)but when using originals his snake gets fairly average sounding.
If you see it, it's all tubular and first they have short cat and than they have about 4~5" diameter ~2' long muffler with tip sticking out of the side sill.

It's just an idea....

Ziggy

 

The only way to reduce sound is to lower the temp of the exhaust gas.

Since you are going to have very little space to do that in, it will be quite a job.

The more metal the gas hits before exiting and the faster the metal transfers to the outside air, the quieter it will be.

I believe you will have to think outside of the box to get a quiet and open system within the confines of the side pipe.

How about a finned copper tube inside of a circulating water jacket. Just kidding, but maybe.....

 

Monty,
How can a 3" i.d. pipe be restrictive? Maybe on 800+ H.P., or 600+ C.I.----

 

I'm not worried about the 3" pipe itself, but rather the muffler. The factory style sidepipes use a small diameter (1 3/4") tubular baffle that is very restrictive but provides a good sound (tone and volume). The alternatives reduce restriction, but are very load, almost as loud as straight pipes.

I'm adding twin turbos this winter so I want it to accomodate that power level as well.

 

Where can I get more info on Moroso spiral cores? Are they louder than the standard factory pipes? I have headers and std factory sided pipes with a stroker in my 67' and it is VERY loud. Much louder than any other big block Vette I have been next to this Summer. They are all running iron manifolds or Hooker side pipes with muffler inserts.

 

They are LOUD!

http://www.moroso.com/catalog/catego...?CatCode=35001

 

I am helping JCL create a website that will answer alot of your questions about his company Spiral Turbo Specialities and his line of Spiral Turbo Baffles for factory side pipes, and Hooker 4" Side pipes. He is also developing applications for 18 wheelers, marine, motorcycles, and more to come. I will post the URL as soon as it becomes available. Stay tuned.

 

ML67,
That is one great looking ride. VERY NICE!! Looks like you have stock wheels and regular tires in the rear. I imagine that 540 will just about melt them. Where did you get the L-88 cold air hood?

 

Clearrun,

Thanks for the kind words. Although it looks factory correct (by design) I'm actually running 15 x 7" rallys and 255/60 BFG Comp TA R1 on the back. I have offset control arms. And yes, traction is a major problem!

Unfortunately BFG discontinued the R1 in this size, and I have been unsuccessful in finding a performance tire in that size. When it comes time to replace them, I'll probably move up to 17" rallys from Wheel Vintiques. As I'm sure you know, there are a lot more options for 17" performance tires.

I got the Eckler's cold air hood insert, and a friend of mine bonded it to the stock 427 hood. I cut the cowl with 4 oval openings to mimic the factory L88 setup. It needs finishing, as there was some excessive bonding compound that will require additional grinding and paint. I'm too busy enjoying the car to have it painted now -- cruising season is too short here in southern NH!

Take care,

Mark


[Modified by ML67, 9:58 AM 8/10/2001]

 

ML67. DO YOU KNOW OF ANY OTHER SOURCES FOR 63-68 AND 69 FACTORY STYLE "EXHAUST TIPS". THE COMPANY THAT I WAS SUPPOSED TO BE ABLE TO GET THESE FROM IS PLAYING POLITICS. DIDN'T THINK I WOULD BE STEPPING ON THEIR TOES BY JUST PURCHASING THIS ITEM!! IF I CAN'T FIND A SOURCE THEN I'LL MAKE A CLONE MYSELF. IF YOU HAVE ANY IDEAS, PLEASE REPLY ASAP!! THE TUBE AND BAFFLE ARE DONE. JUST NEED THE DAMN TIPS. THE FRONT EXHAUST PIPE WILL HAVE TO BE UP TO THE INDIVIDUAL FOR THE TIME BEING. TO MANY DIFFERENT SET UPS. YOUR LOCAL BUSY BEE MUFFLER SHOP SHOULD BE ABLE TO POP THESE OUT "NO PROBLEM". THANKS, JCL :chevy :cool:

 

JCL,

I honestly forgot where I purchased my exhaust turnouts. They look factory, but are 3 1/2" diameter compared to the factory 2 1/2". They are of the slip on type, and I had to have them chrome plated after I purchased them.

There are several sources for similar turnouts (Jeg's, Summit, local speed shop, etc.), although to be honest, all are way overpriced. If you have a source of "U" pipes in the desired diameter, just take a chop saw and make your own. Of course chrome plating these days is not cheap.

Just remember if you go the chrome route, you don't want to weld after chroming as that will blue the finish.

I'm looking forward to learning more about your baffles.

Good luck,

Mark

 

THANKS MARK. IF YOU HAPPEN TO REMEMBER WHERE LET ME KNOW! LIKE I SAID IF I HAVE TO I'LL MAKE MY OWN!! PLATINGS NO PROBLEM. GOOD FRIEND OWNS CUSTOM CHROME IN GRAFTON,OHIO. BY THE WAY THE TIP WILL BE "CLAMPED" ON TO ELIMINATE THE ONE PIECE PROBLEMS THE OTHER SYSTEMS HAVE!! :cool: :chevy WEB SHOULD BE RUNNING BY WEDNESDAY. JCL http://WWW.SPIRALTURBOBAFFLES.COM

 

JCL,

I wasn't able to read your email response you sent me last week. I'm interested in your pipes/mufflers that will fit under the '69 chrome sidepipe covers. I haven't been able to find any that are not restrictive or too loud. Please let me know when you have something ready.