Cracked Exh manifolds: where r u?
- Thread starter MP3racer
- Start date
I have done some more research....found that the WRX had a very similar problem....most likely this problem does stem from uneven thermal expansion, so I don't think a "bracket" is the complete solution. Also, with the variety of part combos everyone has (ie OE vs aftermarket s-pipes, j-pipes, and soon manifolds) making something to work with all would be impossible.
One thing I did find with the WRX.....many of them solved the cracking problem by coating their exhaust manifold. This is somehing we have used on the race car from day one and have never had (and hope not to have any cracks). The correct type of coating improves the performance of the exhaust and turbo system by keeping the exhaust gases flowing faster. It does this by preventing heat transfer to the manifold and keeping it in the gases themselves. (This is an oversimplification). In turn, this seems to also help prevent the cracking problem. Not 100% sure whether this is from evening out the heat or not allowing the manifold to get to the temps were cracks will form...I know for sure the manifold still gets hot as I have experienced in the race car!!!
Anyway, I am looking to get a cracked OE MSP manifold so that I can repair it and have it coated....will then test as this should be the ultimate in determining if this will work for the MSP.
If anyone is interested in the coating for their manifold PM or email me and I will give you the info.....Attached is a pic of the coated OE MSP exhaust manifold on the race car....
One thing I did find with the WRX.....many of them solved the cracking problem by coating their exhaust manifold. This is somehing we have used on the race car from day one and have never had (and hope not to have any cracks). The correct type of coating improves the performance of the exhaust and turbo system by keeping the exhaust gases flowing faster. It does this by preventing heat transfer to the manifold and keeping it in the gases themselves. (This is an oversimplification). In turn, this seems to also help prevent the cracking problem. Not 100% sure whether this is from evening out the heat or not allowing the manifold to get to the temps were cracks will form...I know for sure the manifold still gets hot as I have experienced in the race car!!!
Anyway, I am looking to get a cracked OE MSP manifold so that I can repair it and have it coated....will then test as this should be the ultimate in determining if this will work for the MSP.
If anyone is interested in the coating for their manifold PM or email me and I will give you the info.....Attached is a pic of the coated OE MSP exhaust manifold on the race car....
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SOME MORE INFO REGARDING MANIFOLD RELIEF CUTS:
quoted from clusrsx.com
"they are slots we cut into the manifold for stress relief. It helps to ensure a perfect seal at the gasket, no exhuast leaks! an exhaust leak on a turbo car (whether from a leaky gasket or a cracked manifold) can make the turbo spool up ~2000 rpm later, and will drop power close to 150whp"
http://forums.clubrsx.com/showthread.php?t=417788&page=4
Page 4 of that thread regarding the stress cuts.
Some more info:
http://forum.ih8mud.com/showthread.php?t=114390&referrerid=15458
Here are some pictures also.
Side note:
I dont really see a need to boss the holes of the manifold. Does anyone find bossing (reinforceing) the holes necessary given the application. I think washer at the end of the bolt should suffice. Any comments or ideas on bossing the holes??
quoted from clusrsx.com
"they are slots we cut into the manifold for stress relief. It helps to ensure a perfect seal at the gasket, no exhuast leaks! an exhaust leak on a turbo car (whether from a leaky gasket or a cracked manifold) can make the turbo spool up ~2000 rpm later, and will drop power close to 150whp"
http://forums.clubrsx.com/showthread.php?t=417788&page=4
Page 4 of that thread regarding the stress cuts.
Some more info:
http://forum.ih8mud.com/showthread.php?t=114390&referrerid=15458
Here are some pictures also.
Side note:
I dont really see a need to boss the holes of the manifold. Does anyone find bossing (reinforceing) the holes necessary given the application. I think washer at the end of the bolt should suffice. Any comments or ideas on bossing the holes??
Attachments
I'd probably save up and have them do my corksport downpipe while I was gettin stuff done.. maybe my turbine too MP3racer said:
a race cars manifold is made out of pipe. not casting. casting has impurities in it and under the right amount of heat and flex will just give out. and you cant just weld casting it has to be preheat'd and welded with a certain rod. nickel i believe?!?!? not sure exactly.
kys10x said:
You are correct that many race cars use tube manifolds...however, due to the rules we have been using the OE Calloway cast exhaust manifold on our race car with no problems to date....
As for the welding, yes it does take some special care when welding on cast parts, especially when they are made of exotic alloys like the one the OE Calloway manifold is made from....we have talked with Calloway and received the necessary info.....
JCell said:
Well, yes, I was referring to ceramic coating but as with anything there are various levels and types of ceramic coating....where are you having it done??
The race team uses Swain Tech Coatings in Scottsville, NY. They are very helpful and have a ton of experience. I'm trying to work out a deal for members here....
