Discussion
Hi all,
Thinking of wrapping the manifold on Westfield Duratec, initially to reduce the heat from the pipes around the engine bay. Seem to only find negative comments re rotting metal and fire risk from heat escaping if it moves and creates a concentrated escape route.
Is there a performance gain?
Is it worth doing?
Thanks
Michael
Thinking of wrapping the manifold on Westfield Duratec, initially to reduce the heat from the pipes around the engine bay. Seem to only find negative comments re rotting metal and fire risk from heat escaping if it moves and creates a concentrated escape route.
Is there a performance gain?
Is it worth doing?
Thanks
Michael
It will only increase the risk of rusting if it's left wet against the pipes. If you make sure it's dried out before the car is parked up it should be fine. Alternatively make sure it's fully protected with the appropriate coating so that it doesn't absorb water in the first place.
It's not physically possible for all the heat in the pipe to rush towards any exposed area so I don't see how a 'concentrated' heat path can form.
It's not physically possible for all the heat in the pipe to rush towards any exposed area so I don't see how a 'concentrated' heat path can form.
gtmdriver said:
Nikpro
...why keeping the heat in the exhaust using a ceramic coating is safe whereas keeping the heat in the exhaust using wrap is not?
I was wondering the same thing. The previous (25+ years old) mild steel manifold on my car had been wrapped for seven years prior to its recent replacement with the stainless jobby shown in the pics. No noticeable performance problems. It hadn't rotted through or fallen to bits....why keeping the heat in the exhaust using a ceramic coating is safe whereas keeping the heat in the exhaust using wrap is not?
As the 2 last posts I cannot see why it afects perf or damages cyl head or valves I have run wrapped 4/2/1 on a pinto for8/9 years no probs with corrosion or valve life but grat reduction in under bonnet heat as to being wet it drys very quickly if you have washed engine bay down ,run it for 10 mins bonnet open /off no probs
When you use the exhaust wrap your are putting a very effective thermal blanket over the exxhaust manifold - this does the job it is advertised to do and keeps the heat in the manifold itself.
Unfotunately this causes the exhaust system to run much hotter than it normally would and the increase in tempreature at the manifold flange is significant. Since the flange is bolted directly to the cylinder head the cylinder head also runs substantially hotter than it would do without the exhausst being wrapped.
In respect to performance - because the cylinder head is hotter the incoming mixture is also heated in the inlet ports and losses density. The valve seats also run hotter than designed and we have to use larger width valve seats if exhaust wrap is being used as the seat is responsible for transferring 75% of the heat away from the valve - unfortunately the larger width seat will not flow as well as a narrower seat so performance is lost again; if the seat isn't wider then it runs hotter and therefore errodes quicker.
We have noticed an average loss of 1-2% in power output with exhaust wrap on an identical vehicle.
When the manifold is ceramic coated on the inside it prevents the heat transferring to the actual manifold so you do not get the heating effect on the cylinder head and the external coating keeps engine bay temps down so the inlet Air temp both inside the engine bay and in the inlet ports of the cylinder head are substantially lower.
HTH
Unfotunately this causes the exhaust system to run much hotter than it normally would and the increase in tempreature at the manifold flange is significant. Since the flange is bolted directly to the cylinder head the cylinder head also runs substantially hotter than it would do without the exhausst being wrapped.
In respect to performance - because the cylinder head is hotter the incoming mixture is also heated in the inlet ports and losses density. The valve seats also run hotter than designed and we have to use larger width valve seats if exhaust wrap is being used as the seat is responsible for transferring 75% of the heat away from the valve - unfortunately the larger width seat will not flow as well as a narrower seat so performance is lost again; if the seat isn't wider then it runs hotter and therefore errodes quicker.
We have noticed an average loss of 1-2% in power output with exhaust wrap on an identical vehicle.
When the manifold is ceramic coated on the inside it prevents the heat transferring to the actual manifold so you do not get the heating effect on the cylinder head and the external coating keeps engine bay temps down so the inlet Air temp both inside the engine bay and in the inlet ports of the cylinder head are substantially lower.
HTH
I would never wrap a manifold itself unless the exhaust is very good quality both in materials and welding otherwise it stands a chance of the extra heat destroying it from the inside out... More an issue on turbo cars but I've seen issues on nobles and had my ultima manifolds rot away under the wrap because they are cheap stainless.
My noble ones ARE wrapped, but they are made of incolnel so can take the heat.
My noble ones ARE wrapped, but they are made of incolnel so can take the heat.
andygtt said:
Must admit never suffered increased head temps from wrapping or drop in performance, or heard of it... Maybe the package was prone to it with poor head cooling
It has been tested on numerous installations and all measure pretty much the same - it makes sense - if you wrap the exhaust to keep heat in, then the exhaust runs at hotter temps. This will radiate heat into anything attached to it and the main contact point is the exhaust flange to cylinder head interface.Peter Burgess also noticed it on MGB he was tuning.
Or on engines like the BMC B-series where inlet and exhaust ports are cheek-by-jowl..?
The manifold on my R1-engined Fury is wrapped - has been ~6years. It certainly does help on underbonnet temps. No problems so far at all, and I do keep an eye on it mindful of some of the issues raised whenever exhasust wrap is discussed.
The manifold on my R1-engined Fury is wrapped - has been ~6years. It certainly does help on underbonnet temps. No problems so far at all, and I do keep an eye on it mindful of some of the issues raised whenever exhasust wrap is discussed.
Upon request from a client a few years ago i very carefully wrapped the header pipes on a race ford 289 V8 in the very enclosed engine bay of a TVR Griffith 200 historic racer, the immediate result was that the manifold suffered stress failures much more frequently due to the extreme heat- those pipes ran bright red under hard power WITHOUT the wrap. Also the cooling system ran hotter due to the inevitable heat soak back into the heads.
I'm sure it can work if the exhaust material is right,and the cooling system is more than adequate, things might be ok. The only value i can see in exhaust wrapping is the reduction of fire risk from an oil leak or line failure, as all the red hot bits are covered, which would suit a turbo car where you have oil feeds and drains fitted to hot exhaust parts! beyond that, not sure at all why one would bother.
I'm sure it can work if the exhaust material is right,and the cooling system is more than adequate, things might be ok. The only value i can see in exhaust wrapping is the reduction of fire risk from an oil leak or line failure, as all the red hot bits are covered, which would suit a turbo car where you have oil feeds and drains fitted to hot exhaust parts! beyond that, not sure at all why one would bother.
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