Spiral Baffle Questions
Thread Starter
Burning Brakes
Joined: Apr 2003
Posts: 1,071
Likes: 2
Spiral Baffle Questions
I'm building my '69 up with an LS1 and a custom arrangement to run JCL Spiral Baffles under '69 style covers.
The covers will apparently accept 3.5" pipes without modification. 4" pipes can be crammed under them if you want to cut em and glass in a 0.5" spacer.
Is there really a performance difference between the 3.5" and 4" sidepipes with the JCL baffles?
Also I was just reading about folks cutting the cap on the baffles. I am guessing that this is removing the end caps from the central tube in the JCL baffles. Is this correct? How much louder does this make the car?
I understand the JCL baffles are mild steel, has anyone had them coated? What's the life expectancy of uncoated baffles?
For reference I'm using 2.5 Z06 manifolds on my LS1. They are cast iron but look like a very short header. I'm going to use the existin ball/cone fitting on these and transition to pipe drop down near the frame rail, using a Dr. Gas ovalized frame clearance tube and then into a 90 elbow into the sidepipe. I had hoped to do it all in stainless but the JCLs don't come in stainless and neither do the frame clearance tubes. I believe I can increase pipe diameter before or after the frame clearance tubes, just waiting to get my covers and start mocking it up.
Any info is greatly appreciated.
Ryan
The covers will apparently accept 3.5" pipes without modification. 4" pipes can be crammed under them if you want to cut em and glass in a 0.5" spacer.
Is there really a performance difference between the 3.5" and 4" sidepipes with the JCL baffles?
Also I was just reading about folks cutting the cap on the baffles. I am guessing that this is removing the end caps from the central tube in the JCL baffles. Is this correct? How much louder does this make the car?
I understand the JCL baffles are mild steel, has anyone had them coated? What's the life expectancy of uncoated baffles?
For reference I'm using 2.5 Z06 manifolds on my LS1. They are cast iron but look like a very short header. I'm going to use the existin ball/cone fitting on these and transition to pipe drop down near the frame rail, using a Dr. Gas ovalized frame clearance tube and then into a 90 elbow into the sidepipe. I had hoped to do it all in stainless but the JCLs don't come in stainless and neither do the frame clearance tubes. I believe I can increase pipe diameter before or after the frame clearance tubes, just waiting to get my covers and start mocking it up.
Any info is greatly appreciated.
Ryan
Racer
Joined: Nov 2001
Posts: 326
Likes: 19
From: Napa CA
Re: Spiral Baffle Questions (reidry)
I'm building my '69 up with an LS1 and a custom arrangement to run JCL Spiral Baffles under '69 style covers.
The covers will apparently accept 3.5" pipes without modification. 4" pipes can be crammed under them if you want to cut em and glass in a 0.5" spacer.
The covers will apparently accept 3.5" pipes without modification. 4" pipes can be crammed under them if you want to cut em and glass in a 0.5" spacer.
Are you sure that you can fit 3" diameter pipe under the stock covers? I just mounted a set from Paragons on my 69 and test fit a 3" pipe, but did not try a 3.5".
Is there really a performance difference between the 3.5" and 4" sidepipes with the JCL baffles?
Also I was just reading about folks cutting the cap on the baffles. I am guessing that this is removing the end caps from the central tube in the JCL baffles. Is this correct? How much louder does this make the car?
I understand the JCL baffles are mild steel, has anyone had them coated? What's the life expectancy of uncoated baffles?
and transition to pipe drop down near the frame rail, using a Dr. Gas ovalized frame clearance tube and then into a 90 elbow into the sidepipe.
Ryan
Also I was just reading about folks cutting the cap on the baffles. I am guessing that this is removing the end caps from the central tube in the JCL baffles. Is this correct? How much louder does this make the car?
I understand the JCL baffles are mild steel, has anyone had them coated? What's the life expectancy of uncoated baffles?
and transition to pipe drop down near the frame rail, using a Dr. Gas ovalized frame clearance tube and then into a 90 elbow into the sidepipe.
Ryan
1) How do the spiral baffles mount in the sidepipes?
2) Is the connection from the header collector to the side pipe (containg the baffle) a slip fit?
3)What is a "Dr. Gas ovalized frame clearance tube"
Thanks, Eric.
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
Re: Spiral Baffle Questions (EricU)
The baffels are bolted to the sidepipe with 2 bolts. Requires drilling the holes in the pipe. They work MUCH better than the mufflers that Hooker sells for their sidepipes. They are fairly loud, so I don't think I would cut the end off of them. It would be a straight pipe.
Burning Brakes
Joined: Feb 2001
Posts: 854
Likes: 0
Re: Spiral Baffle Questions (Duke94)
The baffles will go under 69 fiberglass repro covers, but not the"real" covers.
There's too much holding the real ones together in behind.
The repro 69 will hold a 4.0" pipe, if a 1/2" alum. spacer is used to move the cover out. It' is tight and needs a lot of fitting. This is not a bolt on deal.
As far as the flow between 3.5" & 4.0", it is a lot depending on your engine mods. JCL :yesnod: :yesnod:
There's too much holding the real ones together in behind.
The repro 69 will hold a 4.0" pipe, if a 1/2" alum. spacer is used to move the cover out. It' is tight and needs a lot of fitting. This is not a bolt on deal.
As far as the flow between 3.5" & 4.0", it is a lot depending on your engine mods. JCL :yesnod: :yesnod:
Thread Starter
Burning Brakes
Joined: Apr 2003
Posts: 1,071
Likes: 2
Re: Spiral Baffle Questions (JCL)
JCL,
Well as for engine mods I'm starting out with a stock crate LS1, 348 ci, 370 ish HP with a good tune. I plan on a heads/cam swap later to put me up around 475 HP. I'm seeking 400 at the rear wheels without destroying the relatively flat torque curve of the LS1.
I have NO plans for turbos, superchargers or nitrous.
If the 4" pipes are better for a modded motor are they necessarily bad for a milder motor?
What about the longevity of the uncoated baffles?
JCL - do you have an opinion on the "uncapping" of the center tube?
I'm just looking for a little guidance here. I intend to buy something before summer.
Thanks,
Ryan
Well as for engine mods I'm starting out with a stock crate LS1, 348 ci, 370 ish HP with a good tune. I plan on a heads/cam swap later to put me up around 475 HP. I'm seeking 400 at the rear wheels without destroying the relatively flat torque curve of the LS1.
I have NO plans for turbos, superchargers or nitrous.
If the 4" pipes are better for a modded motor are they necessarily bad for a milder motor?
What about the longevity of the uncoated baffles?
JCL - do you have an opinion on the "uncapping" of the center tube?
I'm just looking for a little guidance here. I intend to buy something before summer.
Thanks,
Ryan
Racer
Joined: Nov 2001
Posts: 326
Likes: 19
From: Napa CA
Re: Spiral Baffle Questions (JCL)
JCL,
When you say "The repro 69 will hold a 4.0" pipe, if a 1/2" alum. spacer is used" do you mean the glass repro covers or the metal ones like I have?
I do want a free flowing exhaust and would prefer to use a 3.5" diameter pipe versus the 3" diameter pipe. I am currently having a 428 small block built for my 69.
Thanks, Eric.
The baffles will go under 69 fiberglass repro covers, but not the"real" covers.
There's too much holding the real ones together in behind.
The repro 69 will hold a 4.0" pipe, if a 1/2" alum. spacer is used to move the cover out. It' is tight and needs a lot of fitting. This is not a bolt on deal.
There's too much holding the real ones together in behind.
The repro 69 will hold a 4.0" pipe, if a 1/2" alum. spacer is used to move the cover out. It' is tight and needs a lot of fitting. This is not a bolt on deal.
I do want a free flowing exhaust and would prefer to use a 3.5" diameter pipe versus the 3" diameter pipe. I am currently having a 428 small block built for my 69.
Thanks, Eric.
Melting Slicks
Joined: Apr 2000
Posts: 3,286
Likes: 8
From: San Jose California
Re: Spiral Baffle Questions (reidry)
reidry,
I use JCL's baffles in my '69 L88. I also removed the cap from the center tube. Using a db meter, the car was 4 db's louder at both 1200 rpm and at 2500 rpm compared to the caps in place. The difference at the rear wheels was about 45hp in my car. I only lost 6 hp from running straight 4" open pipes compared to baffles without the caps.
The car is loud, but nothing close to what it is without the baffles. My digital db meter goes to 126 db's. I hit the max reading by 2000 rpm's with open pipes. Baffles without the center cap measured about 86 at 1200 rpm and 95db's at 2500 rpm free rev.
The design is a good one. Shooting from the hip, I would guess that the difference in hp with your engine would probably be 25-35 hp different between 3.5" and 4" pipe if you are making 400hp at the wheels. Perhaps much less difference if you are running the 2.5" cast iron shorty headers instead of full length tuned headers.
On a side note, I would love to have a new LS6 engine in a C3 with a carb and manifold instead of FI. The new NASCAR engines are gorgeous! Such a 427 LS6 would more than equal my L88 all within a very tight little package.
Chuck
I use JCL's baffles in my '69 L88. I also removed the cap from the center tube. Using a db meter, the car was 4 db's louder at both 1200 rpm and at 2500 rpm compared to the caps in place. The difference at the rear wheels was about 45hp in my car. I only lost 6 hp from running straight 4" open pipes compared to baffles without the caps.
The car is loud, but nothing close to what it is without the baffles. My digital db meter goes to 126 db's. I hit the max reading by 2000 rpm's with open pipes. Baffles without the center cap measured about 86 at 1200 rpm and 95db's at 2500 rpm free rev.
The design is a good one. Shooting from the hip, I would guess that the difference in hp with your engine would probably be 25-35 hp different between 3.5" and 4" pipe if you are making 400hp at the wheels. Perhaps much less difference if you are running the 2.5" cast iron shorty headers instead of full length tuned headers.
On a side note, I would love to have a new LS6 engine in a C3 with a carb and manifold instead of FI. The new NASCAR engines are gorgeous! Such a 427 LS6 would more than equal my L88 all within a very tight little package.
Chuck
