OBX cat installation
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Joined: Dec 2003
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From: chandler az
OBX cat installation
I noticed a few guys had installed OBX headers, but I was wondering if anybody had installed a real set of cats with them.
I already had a set of Dynatech 2.5 inch cannister style cats so I was going to use those. The problem is nobody makes a ball flange reducer. Even if I did have an adapter, I'm not sure if the additional length added would allow the cats to fit without going too far back.
My back up plan is to simply adapt the phony cats the headers come with to the real cats. Nothing hard, but it requires some welding and I'm sure how well the cats or the collector flange will weld up with my MIG welder. Plus it means going out and getting another bottle with a different gas than what I would use for mild steel. I even thought about just cutting off the flange ends and using staight pipe with a reducer, but I like the idea of having some flex with the donut style coupling in the exhaust to prevent cracking.
BTW the header collectors are 3 inches not 2.5 inches.
I already had a set of Dynatech 2.5 inch cannister style cats so I was going to use those. The problem is nobody makes a ball flange reducer. Even if I did have an adapter, I'm not sure if the additional length added would allow the cats to fit without going too far back.
My back up plan is to simply adapt the phony cats the headers come with to the real cats. Nothing hard, but it requires some welding and I'm sure how well the cats or the collector flange will weld up with my MIG welder. Plus it means going out and getting another bottle with a different gas than what I would use for mild steel. I even thought about just cutting off the flange ends and using staight pipe with a reducer, but I like the idea of having some flex with the donut style coupling in the exhaust to prevent cracking.
BTW the header collectors are 3 inches not 2.5 inches.
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From: chandler az
Okay, I modified a 2.5 dynatech cat I had sitting around with part of the original resonators and they came out about a quarter inch shorter. Looks like they should work like a charm.
I just need to do a final grinding on the inside to take the lip out.
If I can figure out how to post some pics I will.
I just need to do a final grinding on the inside to take the lip out.
If I can figure out how to post some pics I will.
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Joined: Dec 2003
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From: chandler az
I couldn't figure out how to post the pics, but the links work okay. Cut, weld and if you are picky do some porting as well.
http://forums.corvetteforum.com/memb...-resonator.jpg
http://forums.corvetteforum.com/memb...into-place.jpg
http://forums.corvetteforum.com/memb...wheels-001.jpg
http://forums.corvetteforum.com/memb...wheels-004.jpg
BTW, I used a bubble level to check my squaring before I tack welded. Check at two axis X,Y unless of course you use a dot level.
http://forums.corvetteforum.com/memb...-resonator.jpg
http://forums.corvetteforum.com/memb...into-place.jpg
http://forums.corvetteforum.com/memb...wheels-001.jpg
http://forums.corvetteforum.com/memb...wheels-004.jpg
BTW, I used a bubble level to check my squaring before I tack welded. Check at two axis X,Y unless of course you use a dot level.
Last edited by chevylad; May 10, 2009 at 02:21 PM. Reason: tried to add picture
Drifting
Joined: Mar 2003
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From: Oklahoma City OK
Nice!!!! I need to get this done for my set also....
I have been looking for some used dynatech cats, but havent been able to find any.....
Do you think that the Dynatech Cats for the Dynatech headers would bolt right up?
I have been looking for some used dynatech cats, but havent been able to find any.....
Do you think that the Dynatech Cats for the Dynatech headers would bolt right up?
Last edited by Chrisrokc; May 10, 2009 at 03:37 PM.
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From: chandler az
I couldn't say for sure without having the two side by side for comparison, but it looks very close.
The dimensions on the female side of the flange are 3.5" tapering down to 3" at a depth of about and inch.
The 4 bolt pattern is 3" x 3" hole center to hole center square.
The cats I modified are 2.5 inch. If you were going to buy a set and have them modified, I would look at the magnaflows canisters. They are less than half the price of the dynatechs. When I bought the dynatechs they were the only ones made that were that small. It was for a small block powered 240z and space for exhaust was extremely tight.
The dimensions on the female side of the flange are 3.5" tapering down to 3" at a depth of about and inch.
The 4 bolt pattern is 3" x 3" hole center to hole center square.
The cats I modified are 2.5 inch. If you were going to buy a set and have them modified, I would look at the magnaflows canisters. They are less than half the price of the dynatechs. When I bought the dynatechs they were the only ones made that were that small. It was for a small block powered 240z and space for exhaust was extremely tight.
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Drifting
Joined: Mar 2003
Posts: 1,533
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From: Oklahoma City OK
I couldn't say for sure without having the two side by side for comparison, but it looks very close.
The dimensions on the female side of the flange are 3.5" tapering down to 3" at a depth of about and inch.
The 4 bolt pattern is 3" x 3" hole center to hole center square.
The cats I modified are 2.5 inch. If you were going to buy a set and have them modified, I would look at the magnaflows canisters. They are less than half the price of the dynatechs. When I bought the dynatechs they were the only ones made that were that small. It was for a small block powered 240z and space for exhaust was extremely tight.
The dimensions on the female side of the flange are 3.5" tapering down to 3" at a depth of about and inch.
The 4 bolt pattern is 3" x 3" hole center to hole center square.
The cats I modified are 2.5 inch. If you were going to buy a set and have them modified, I would look at the magnaflows canisters. They are less than half the price of the dynatechs. When I bought the dynatechs they were the only ones made that were that small. It was for a small block powered 240z and space for exhaust was extremely tight.
http://www.planetmagnaflow.com/shop/...59956-688.html
Drifting
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From: Oklahoma City OK
AMP Racing
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2023 C5 of the Year Finalist - Modified
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St. Jude Donor '09-'10-'11-'12
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From: chandler az
These??? I noticed they say they flow the maximum, but they don't state they are high flow. Hmmm
http://www.planetmagnaflow.com/shop/...59956-688.html
http://www.planetmagnaflow.com/shop/...59956-688.html
