Experiences of wrapped headers/exhaust/turbine on RX7s?
01-08-10, 12:10 AM
#26
5th is most fun
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No offense to you but those are all myths and half-truths
1. Both coatings and wrap deteriorate over time. NONE of the heat reduction options are permanent.
2. Rusting of the metal is due to the quality of metal used in the item being wrapped. Bandages do not cause rust any faster than typical metal and water reactions. The reason this gets reported as being a wraps fault is that an exhaust becomes so hot that the actual aging process is accelerated due to heat. Wrapping and coatings retain the heat within the metal and thus causing a faster-than-normal rusting phenomenon. A mild steel pipe will rust regardless of wrapping or coating.
3. To help protect mild steel piping every exhaust wrap manufacturer recommends sealing the wrap with a silicone coating to help slow mild steel rust due to heat retention.
4. NEVER wrap an item that is already ceramic coated.
1. Both coatings and wrap deteriorate over time. NONE of the heat reduction options are permanent.
2. Rusting of the metal is due to the quality of metal used in the item being wrapped. Bandages do not cause rust any faster than typical metal and water reactions. The reason this gets reported as being a wraps fault is that an exhaust becomes so hot that the actual aging process is accelerated due to heat. Wrapping and coatings retain the heat within the metal and thus causing a faster-than-normal rusting phenomenon. A mild steel pipe will rust regardless of wrapping or coating.
3. To help protect mild steel piping every exhaust wrap manufacturer recommends sealing the wrap with a silicone coating to help slow mild steel rust due to heat retention.
4. NEVER wrap an item that is already ceramic coated.
01-08-10, 01:49 AM
#27
Possibly too much heat retention? Double insulate a stainless manifold that has some length to it and it's gonna move all over with heat cycles. I know I don't want to test how well my manifold holds up a 25lb turbo when the tubing is 1600* and I'm driving over bumps and hills.
01-08-10, 04:22 PM
#28
Isn't that where bracing the turbo mounting would help out? A lot of the manifolds I see don't have bracing on to the flange to help with the heat of the turbo. Would it be a good safeguard TO brace the turbo, considering what I see as most often used in turbo manifold fab is 16gauge, thin walled SS tubing? I've been fabricating for about a year now, but have never built a turbo manifold and need to build two for myself. If I were to brace the turbos at the flange and to the motor, and use a flex section on the downpipe, can't I ultimately counteract any or most of the movement due to heat from ceramic coating and wrapping the manifolds and downpipe?
-J
-J
01-08-10, 07:19 PM
#29
Senior Member
Thread Starter
I agree, its madness that everyone doesnt run a hanger to support turbos, but I dont currently either on my car, never got round to it im ashamed to say.
I was brought up tuning Ford Cosworth turbo engines, and these have turbo hangers as standard, and know from bitter experience that if you remove the turbo hanger a manifold whch was fine for years of abuse, will start blowing within a few weeks. On them it was only ever at the joins, but regardless.
When I got in to Jap cars all I ever heard was people moaning that their manifolds were constantly cracking, and to me it was obvious, no hangers- massive turbos with the manifold taking all the weight.
Ive tried to tell people in the past, but as ever, them and their tuners think they know best despite never trying one, and never take any notice.
They certainly do help, obv they are no foolproof solution, but considering the extra stresses heat wrap will give, its certainly near the top of my to-do list!
I was brought up tuning Ford Cosworth turbo engines, and these have turbo hangers as standard, and know from bitter experience that if you remove the turbo hanger a manifold whch was fine for years of abuse, will start blowing within a few weeks. On them it was only ever at the joins, but regardless.
When I got in to Jap cars all I ever heard was people moaning that their manifolds were constantly cracking, and to me it was obvious, no hangers- massive turbos with the manifold taking all the weight.
Ive tried to tell people in the past, but as ever, them and their tuners think they know best despite never trying one, and never take any notice.
They certainly do help, obv they are no foolproof solution, but considering the extra stresses heat wrap will give, its certainly near the top of my to-do list!
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