heat will be an issue. you'd need shields, insulation, etc
Sidepipe question (have I lost my mind)?
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Sidepipe question (have I lost my mind)?
I'm planning to build my own sidepipes, using either 2.5" outlet ram's horn manifolds or the C4 factory headers (feeding into 3" pipe). The idea is to run them down and back like stock exhaust, then take a 90 degree bend toward the frame, then a 90 degree bend to the actual pipes. Since my engine is going to be fuel injected, I need the solid pipes near the engine for the O2 sensors. Anyway, after Norval's discussion of installing catalytic converters to be environmentally friendly, I came up with a really nutty idea - why not cats with sidepipes? Magnaflow makes some really short round cats with 3" inlets and outlets. I measured last night, and there is about 18" to work with between the rear-facing pipe from the engine and where the sidepipe will be along the frame rails.
I drew up a rough sketch last night in Microsoft Paint (sorry guys, I don't have any of those cool 3D modeling tools...) The purple section of pipe is the section parallel to the ground after it comes down from the manifold outlet. The red section is where the cat would be installed.
Have I totally lost my mind, or can I pull this off?
I drew up a rough sketch last night in Microsoft Paint (sorry guys, I don't have any of those cool 3D modeling tools...) The purple section of pipe is the section parallel to the ground after it comes down from the manifold outlet. The red section is where the cat would be installed.
Have I totally lost my mind, or can I pull this off?
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Try to take as strait a line as possible from the exhaust manifold to the
front of the outside pipe 90 degree turns really hurt exhaust flow, 30 or
45 degrees bends would help a lot for flow.
front of the outside pipe 90 degree turns really hurt exhaust flow, 30 or
45 degrees bends would help a lot for flow.
Last edited by Little Mouse; May 17, 2006 at 03:52 PM.
Racer
Joined: Mar 2005
Posts: 487
Likes: 0
From: Jacksonville FL
you should probably check with the DMV in MO.
from what i've read on this site, your idea would not fly in CA, but maybe in MO....
check with somebody at the DMV befor you go forward with it.
edit : cool idea though....
from what i've read on this site, your idea would not fly in CA, but maybe in MO....
check with somebody at the DMV befor you go forward with it.
edit : cool idea though....
Melting Slicks
Joined: Dec 2004
Posts: 2,101
Likes: 3
From: Cruising somewhere in St. Louis, Missouri
I have already done that in California as long as the car is before 1974. I would highly recommend going to a muffler shop the does custom bends...most places do but the mom and pop shops can for about $200 or less you can have them bend and weld it all together for you in about 2 hours total time. I would recommend glasspacks or some other muffler system to go along with it.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
It wouldn't be federal emissions legal as it's a modification from the stock design...but MO doesn't do emissions tests on vehicles older than either 25 or 30 years. As long as I don't tick off the roadside sniffer vans I'll be fine. The car has had a non-compliant true dual exhaust with no cats for over 15 years and it passes OK anyway, but I figure it will be safer this way.
I know 90 degree bends aren't the best idea, I might look at angling the cats. It all depends on clearance. If I have to go with 90 degree bends, I will. Using 3" tube should at least help with the bend issue, as the whole mess won't be as restrictive as 2.5" tube.
Plan is to use the spiral muffler inserts in the pipes.
I'll probably just buy a box of mandrel bends from one of the big parts vendors and weld it up myself. I made some intake pipes for my old Talon that way.
I'm a law student...maybe I should draft an amendment to the federal emissions laws and get SEMA to push it through: any modification to the exhaust pattern is legal as long as it can pass a "sniffer" test. Hmm...have to look into that...
I know 90 degree bends aren't the best idea, I might look at angling the cats. It all depends on clearance. If I have to go with 90 degree bends, I will. Using 3" tube should at least help with the bend issue, as the whole mess won't be as restrictive as 2.5" tube.
Plan is to use the spiral muffler inserts in the pipes.
I'll probably just buy a box of mandrel bends from one of the big parts vendors and weld it up myself. I made some intake pipes for my old Talon that way.
I'm a law student...maybe I should draft an amendment to the federal emissions laws and get SEMA to push it through: any modification to the exhaust pattern is legal as long as it can pass a "sniffer" test. Hmm...have to look into that...
Last edited by I'm Batman; May 17, 2006 at 05:35 PM.
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
I did a similar thing, but put glasspack mufflers in that same location. I was going deaf! I'm still using the factory pipe and covers.
The mufflers were only 12 " long, but because of the bend radius, they barely fit, even angled back at 45 degrees. I dont think you'll easily fit an 18" catylitic converter in that space.
Another issue is heat. Those sit right under your feet, and catylitic converters get pretty hot. I wouldn't bother with it.
I'm probably going to replace the whole system this summer and add the longest glasspack that will fit in place of the factory sidepips. But no catalytic converter!
The mufflers were only 12 " long, but because of the bend radius, they barely fit, even angled back at 45 degrees. I dont think you'll easily fit an 18" catylitic converter in that space.
Another issue is heat. Those sit right under your feet, and catylitic converters get pretty hot. I wouldn't bother with it.
I'm probably going to replace the whole system this summer and add the longest glasspack that will fit in place of the factory sidepips. But no catalytic converter!
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
The position I'm looking at is in front of the firewall, perpendicular to the back of the engine.
The cat I'm looking at is the MagnaFlow 53009 - 13" total length, 9" body length. I shouldn't have much problem getting it to fit. http://www.car-sound.com/catalog/universal/530.aspx
Like all cats, it has an integrated heat shield, but I might need to add some extra to the firewall.
The cat I'm looking at is the MagnaFlow 53009 - 13" total length, 9" body length. I shouldn't have much problem getting it to fit. http://www.car-sound.com/catalog/universal/530.aspx
Like all cats, it has an integrated heat shield, but I might need to add some extra to the firewall.
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Melting Slicks
Joined: Jan 2006
Posts: 3,028
Likes: 2
From: North NJ
Might also have to contend with the frame. The area your speaking of is right where the frame curves from the inside to the outside around the wheel well. Depending how thick your cat is...keep an eye on ground clearance, but definitely put extra insualtion. I'm looking for the best spray heat/sound insualtion right now (apply on bottom of car and interior/doors) and on top of that I'll be installing some second skin damplifier on the inside of the car and inside doors. Bottom of the car will covery with the cheap car show heat insulation. I use to sweat my a$$ off in my 74 t-tops, won't be doing that again.
Good luck, if it doesn't work I doubt you'll waste that much $ on the cats and misc pipe, although you are a student and I know how tight budgets get.
Good luck, if it doesn't work I doubt you'll waste that much $ on the cats and misc pipe, although you are a student and I know how tight budgets get.
