exhaust wraps
Author
Discussion

one eyed mick

Original Poster:

1,189 posts

185 months

Wednesday 10th August 2011
quotequote all
Has any one out there got opinions ,veiws on wrapping exhaust manifolds?The reason for my question is does it affect manifold life ? .I run a 7 clone with a mild 2.1 pinto and have had issues with under bonnet heat ,I wrapped the manifold3/4 years ago and it did help greatly with the temp issue .Recently the manifold cracked quite severely ,I have replaced it with a manifold from the same source also wrapped, recently a member of RHOC had similar problems with a similar manifold i.e. severe cracking at 2 into 1 joint on a 4/2/1 manifold The metal is not corroded [slight surface rust ] but has cracked extensively , it would probably repair ,weld /patch strengthen .I'm qurious to know if any one has had similar probs and how if possible to cure or defend against a reccurance .As said earlier wrapping helped greatly with under bonnet temps , any opinions ,cures etc greatfully requested

Steve_D

13,801 posts

282 months

Wednesday 10th August 2011
quotequote all
Wrap causing cracking has been a well documented issue for many years.
Ceramic coating is the ideal solution but I would expect the price to be an issue. On something like my Ultima it is briliant but I expect you could buy replacement Pinto manifolds several times over for the cost of a coating.
If you stay with the wrap use a mild steel manifold rather than stainless as it will deal with the heat cycles better as it is not as brittle.

Steve

stevieturbo

17,987 posts

271 months

Wednesday 10th August 2011
quotequote all
I would only ever consider wrapping as a last resort. It destroys manifolds.

one eyed mick

Original Poster:

1,189 posts

185 months

Wednesday 10th August 2011
quotequote all
Thanks for replies fellas ,I'll see how long this one lasts, will also repair cracked one as a spare!May I ask why you would never wrap ? .It solved alot of probs with excess under bonnet heat for me!and amnot phsed by a weld repatr now and again it don't cost only time to do it ,bye for now

fatjon

2,298 posts

237 months

Friday 12th August 2011
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I have wrapped many and not had a cracked one yet, maybe I'm just lucky though. I have cracked a couple of unwrapped ones by being a bit heavy footed when starting from cold, the welds are thicker and warm slower than the thinner bits and that seems to be the cause. As regards ceramic coating, in my opinion a waste of time and money, it looks nice but has virtually no effect on heat losses. It can be easily demonstrated, touch a hot ceramic coated manifold and you will have a big blister and swear a lot, try that on a wrapped one and you won't. You can also point an IR thermomemter at both and measure the difference in performance which is huge.

chuntington101

5,733 posts

260 months

Friday 12th August 2011
quotequote all
So what is the best method of reducing under bonnet / clam temps without causing damage to the exhaust? I have seen inconel used to good effect (supposed to be better than heat wrap) but not heard anyhting about what it dose to the exhaust material....

Chris.

OlberJ

14,101 posts

257 months

Friday 12th August 2011
quotequote all
Just watch the stored heat doesn't build up in the head and warp things!

andygtt

8,345 posts

288 months

Tuesday 16th August 2011
quotequote all
Wrapping and coating the outside increases the heat in the matierial a huge amount... So the metal in the manifold will have to cope with a lot more heat.

Thus poor quality materials fail... The answer is to ceramic coat inside and out

Mr Sparkle

1,935 posts

194 months

Wednesday 17th August 2011
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Is it just the wrapping of connections/welds that causes problems? Would it be safe to wrap straight/relativity straight sections or would there be two high risk of fatigue in the area where the wrap ends.

K87

2,111 posts

211 months

Wednesday 17th August 2011
quotequote all
OlberJ said:
Just watch the stored heat doesn't build up in the head and warp things!
This

Yuxi

650 posts

213 months

Wednesday 17th August 2011
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Just wrap the pipes under the bonnet, mine has a 4 into 1, the collector is way outside the bonnet so no welds are wrapped.

The other thing to watch is to make sure you have enough fore and aft movement on any mounts to allow for the engine moving backwards and forwards during braking and acceleration, mine had a fixed mount at the back of the silencer when I bought it and it cracked the front of the silencer where the pipe goes in because the exhaust was trying to hold the engine in position.

tristancliffe

357 posts

237 months

Thursday 18th August 2011
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Just build a heat shield to keep hot air away from the intake and/or duct in some cold air directly to the airbox/filter/inlet.

That way you don't have all the problems associated with exhaust wrapping, like lower power, warping/cracking pipes etc.

If it was beneficial in itself to wrap exhausts, then WRC or F1 cars would use it. They don't, because it's detrimental to performance. So get cold air to your engine via another method.

one eyed mick

Original Poster:

1,189 posts

185 months

Thursday 18th August 2011
quotequote all
Probably the reason F1 cars are not exhaust wrapped is weight! if they only fuel them with just enough for the same reason. Bye for now

K87

2,111 posts

211 months

Thursday 18th August 2011
quotequote all
one eyed mick said:
Probably the reason F1 cars are not exhaust wrapped is weight! if they only fuel them with just enough for the same reason. Bye for now
Or maybe it's because the exhausts are nowhere near the air intake like on a road car.

Yuxi

650 posts

213 months

Thursday 18th August 2011
quotequote all
tristancliffe said:
Just build a heat shield to keep hot air away from the intake and/or duct in some cold air directly to the airbox/filter/inlet.

That way you don't have all the problems associated with exhaust wrapping, like lower power, warping/cracking pipes etc.

If it was beneficial in itself to wrap exhausts, then WRC or F1 cars would use it. They don't, because it's detrimental to performance. So get cold air to your engine via another method.
Its a 7 clone, the problem is not hot air going into the intake, its general under bonnet temperatures, the exhaust is usualy very close to the brake master cylinder, brake pipes and the fibreglass bonnet does not like getting too hot.

one eyed mick

Original Poster:

1,189 posts

185 months

Thursday 18th August 2011
quotequote all
It isn't a problem with ---- 1 performance 2 destroying a fi glass bonnet 3 things melting under the bonnet 4 probs with brakes . Under bonnet temps were to high in my veiw and I wanted to lower them . Performance was improved ,engine running temp was lowered to a sensible level and better temps in the footwell were achieved so really it achieved what I wanted. Btw the bonnet is stainless steel ,all other thing were insulated or wrapped ,I would imagine that at the level of materials used at my end of the market and my pocket depth I will be repairing manifolds on a 10 to 15000 mile intervals that dosen't bother me at all bye for now