Sounds like you've finished installation, yes? Would you mind sharing exactly what you did, the components you used, etc.

I'm to the point now where I need to order parts and start fabrication and I'd appreciate any advice you may have, having just went thru it. The 3.5" pipes fit ok under the covers with the factory heat insulators still in place? Loudness compared to the factory pipes?, Who's baffles, and how many inches per side?, etc…..

Thanks ! :seeya

 

I am very happy with the Spiral baffle set up.
Here is an e-mail I sent another forum member.

It may be a bit louder at idle, but quieter at fwy speed?
(Sounds good to me) But its still new to me.
Have not had a chance to really drive it yet. Just home from the muffler shop.
Much lower tone now through out, more consistent tone through the normal rpm range. I would say DB's its close to stock, maybe a bit louder at idle, but the lower tone makes it easy on the ears. Has a super low mechanical sound
(That I like) Not like flow masters, better.
Cost was $300.00 for the baffles, $100.00 for 10' stick of 3 1/2" 14g aluminized pipe, $80.00 for a 3" SS u-tube for the tips, $80.00 for (2) 3" mandrel bent 90's. 4 hrs at Bake muffler was $200.00 for a total of $760.00. Had the baffles installed, new rear brackets made up, SS tips cut and polished prior to taking it in to get welded. (BTW, Tim at Bake muffler in Irvine Is GREAT! Highly recommended for us picky Vette owners. Great rates as well! Tim is a real craftsman. And yes this system fits fine under stock covers, but it takes some finesse at the weld shop.
He made it look easy. And it came out perfect the 1st time.
No rattles at all. Better fit than my 2" set up was with more clearance.
He just did a better job than what I had before. An orig hacked up 67 BB
side pipes on its 2nd or 3rd glass pack section welded in. It was ugly.

Since that e-mail I have put some miles on it.
There is a definite seat of the pants IMPROVEMENT over the same headers with
glass packs. (I can really tell at higher rpms, it's impressive) I am sure its a sizable gain, but dont have any dyno numbers to compare to the old system.
The only thing I found a bit odd, is at 700 rpm to 4500rpm It sounds normal. High 4000's to 6500 it gets this "wooshy" "turbo" type sound.
Hard to explain a sound, but prior to the baffles it just kept getting louder with rpm. Now, it changes its sound completely over 5000 rpm.
Sounds like the exhaust is getting sucked out with a vacuum!
Kind of a rocket/turbo/whooshy sound? 1st time I heard it I thought what the heck? Then noticed the car was really flying...........
I talked to the guy who makes the baffles and he was familiar with the sound and refereed to it as a "Turbo" sound. (Really!) To eliminate that sound he claims by drilling (8) 1/8" holes in the caps (or removing the caps will do it) With a penalty of more DB's. I am going to leave it for now. Its not a bad thing, just different. The tips came out slick! Used a 3" SS U-Tube & really took my time getting the right angles & buffing out. Its not noticeable at all! Looks stock, you would have to get down on the ground to tell. Used an angle finder at the muffler shop to get the pitch of the tip to match a stock side pipe.
Here is the link to the Spiral Baffles. http://www.spiralturbobaffles.com/customers.html
Yes, I would do it again. A bit of a pain, but it really seemed to wake things up.
I had 300.7 RWHP at 5750 with the old system, retarded on Ca. pump gas. If I get back on a RW dyno I will post the numbers. I know its an improvement,
Just cant say how much. The only think I liked better about the old system is it got a higher pitched and would scream with a road race sound over 5000, now it does not sound as mean, but goes quite a bit faster! Scared my self 1st time to redline as It didn't sound like I was going much faster, but the Speedo went from 75 to well over 120 in what seemed like just a few yards!
Let me know if I can be of any more help. Really yacked up a storm didn't I.
:lol:

Here is more..
I used (2) 38" sections of 3 1/2" 14g aluminized, (2) 3" 90's with a 6" bend, the 4" bend 90 is too close. the rest was aluminized 3" pipe. The rear tabs are 1/8" carbon steel (traced the factory tabs) Use felpro header gaskets, as copper gaskets do not work. (learned that on this job) Headers were ceramic coated by Olympic coatings in Escondido Ca. Lifetime warrenty, inside and out for $160.00 :seeya


[Modified by 396 RAT, 4:06 PM 11/1/2003]

 

Pretty please, post some pictures if and when you can.

 

Didnt take any digital photos.
Picture a 3" collector to a smooth 3" 90 to 3 1/2 to 3" to a 3" SS tip.
Says "Turbo Jet" on the side, now in kinda sounds like one over 5 grand. :lol:
I am really starting to warm up to it. Drove it again today. :smash: :smash: :smash:

Jim at (below) has some photos of a 3 1/2" system.
Super nice guy to work with. Must have sent 20 e-mails back and forth.
He gets a big :thumbs: http://www.spiralturbobaffles.com/customers.html


[Modified by 396 RAT, 6:54 PM 11/1/2003]

 

Mark. Thanks for the thumbs up on the your under factory cover set up. It really does make for a great system. Have over a dozen C2 BB installs, mostly 502's, with the same set up. Some even with 4" under cover. 396. Great motor...........JCL :yesnod: :yesnod: :yesnod: