EXHAUST INSULATION.

[dwaite]

Hi all.
A quick question.
Has anyone used insulation wrap around the manifolds, and if so does it reduce the engine bay temperature and increase engine running ?

Regards.

Dean.

[LeeBee]

I have Thermotec on mine, it does keep it a little cooler but that's about it

Cheers

LeeBee

[johno]

I've just bought some from Demon Tweeks and will be fitting it on Christmas day / boxing day.

I know that sounds rather sad but when you work for a brewery trying to deliver in London you don't get much time off at this time of year.

My hope is that it will protect the copmonents around the manifolds and reduce genral heat in the engine bay. The claims of reduced fuel consumption and increased power I have taken with a pinch of salt, I'll let you know my feeling after Xmas.

Cheers

Mark

[markbigears]

so how does the car look mark? looking good?

[mhibbins]

I don't understand the theory of this stuff. You surely aren't contributing to the general cooling of the engine as a good clean cooling setup is easily good enough to keep the engine cool. Aren't you, by insulating the manifold reducing the heat escaping from the engine and therefore actually making this type of cooling worse? What else needs protecting from heat in the engine bay?

Also, aren't you just going to transfer the heat further along the exhaust to just under the gearbox, for example?

I'm not trying to be negative, I'm genuinely interested in the theory.

--
Mark

[johno]

The car looks far far better than it did. The blue roof suits the car much better and is the original spec as released from the factory.

The car mats are superb, and to have a seat that is properly sprung is superb. Funnily enough the new seat is far re,oved from what I'm used to as the old seat had ripped and the foam was knackered just resting on the fibreglass.

I am very happy with the finished results and when we organise another 'S' meet you can get a look.

Cheers

Mark

[Greenv8s]

quote:
I don't understand the theory of this stuff. You surely aren't contributing to the general cooling of the engine as a good clean cooling setup is easily good enough to keep the engine cool. Aren't you, by insulating the manifold reducing the heat escaping from the engine and therefore actually making this type of cooling worse? What else needs protecting from heat in the engine bay?

Also, aren't you just going to transfer the heat further along the exhaust to just under the gearbox, for example?

I'm not trying to be negative, I'm genuinely interested in the theory.

--
Mark

It definitely reduces the under bonnet temperatures, this reduces the thermal stress on everything and also helps the engine run cooler (it is surrounded by cool air instead of hot air). It moves the heat out of the 'closed box' of the engine bay into the area under the car, which (a) has nothing heat-sensitive in it and (b) has a massive air blast cooling it. Disadvantage is it makes the engine quite a bit quieter.

Cheers,

Peter Humphries (and a green V8S)

[mhibbins]

Oh I see, thanks for that

How far back would you take the insulation material?

--
Mark

[LeeBee]

As far as your wallet goes!

Cheers

LeeBee

[simon lawrence]

Try www.thinkauto.com They are much cheaper than many other places, and the service is very good.

[johno]

Wrapped the manifolds yesterday and drove down from Norfolk to Bow this morning. It has changed the level of engine noise. I also think it has changed the character of the engine. Whether that is due to a performance change I don't know and won't be able to prove or disprove as I haven't got before and after figures.

It definitely seems that is was worth while though. I would suggest if anyone is doing it that they get 50 foot of 2 inch Thermotec. It has covered mine from the port flanges down to the top of the collector. But make sure you get the length measured right otherwise you could screw it up completely.

The way I worked the wrapping was to cut lengths for the front 2 pipes and wrap from the front upto the port flanges and then fixing it with the snap strap at the ports so I knew they were covered and the start was overwrapped with the wrap starting from the collector and finishing at the rear port again with a snap strap.

Beware of when you fire it up for the first time, is does really smoke and stink ! Make sure you take it out of the garage to do it.

For the guys who have done it already, did you use the spray on Hi Heat covering aswell ? I'm considering finishing of with this, but just wanted know any details.

Cheers

Mark

[LeeBee]

I used some normal black exhaust spray on mine (it was cheaper around £8 for a big can) and it worked well.Johno I have just found an old email from you, it went into a outlook express folder that I don't check! sorry I will email you shortly (not ignoring you!!!).As I said I didn't notice a performance difference in mine but then I don't use the car do I!!!!!!!!

Cheers

LeeBee

[jaydee]

Classic&Sportscar's Alistair Clements runs a Tasmin 2.8i. A recent running report included details of the exhaust setting fire to the floor of the car... Surely insulating the manifold increases the risk of this ?
Also the thermal stress, instead of being taken up by a relatively simple bent tube manifold, will be presumably tranfered to the cats and silencer ?
Can't, obviously, comment on Tivs specifically but I wanted to do this when I had the Elan in an effort to reduce the hot plastic smell and was widely advised that it was not sensible on plastic cars...
I'm not convinced that there is particularly strong airflow over the exhaust in any car-if there was would the (fairly involved) heat shielding around the cats be necessary ?
Def. a case of looking before you leap IMHO...

[johno]

In the case of Alistairs Tasmin, I think the article details that the exhaust was running too close to the floor pan to start with and needed some attention. I believe this was a problem with Tasmins and a wrap such as Thermotec would in fact help in this situation if applied to that part of the exhaust.

The insulation on my manifolds only goes as far as the collectors at the front of the engine and then the rest of the system is uninsulated and open to the fresh air below the chassis in a strong air current.

I feel it has definitely reduced the under bonnet temp and quitened the running. The areas around the manifolds were definitely cooler than previously.

By insulating the manifolds you are maintaining the gases at a higher temp to increase their velocity away from the block. I would imagine that by the time they have reached coleector and passed to any inline silencer/cat etc they will have cooled to within tolerable operating temps.

My exhaust is fairly styraight thru and what little silencing there is quite a way back. Thermotec themselves advertise products for wrapping Cats and Silencers in aswell.

Cheers

Mark

[jaydee]

P'raps wrapping the manifold down to the collector then insulating the floor pan above the rest of the exhaust would be the best way to go ? I can't imagine insulating your silencers is a good idea if you've got the whole of the rest of the system insulated-after all the heat's got to be dissipated somewhere !
"I would imagine that by the time they have reached coleector and passed to any inline silencer/cat etc they will have cooled to within tolerable operating temps."
Probably the case but its got to be worth checking _before_ trying it ! (Relatively) Simple approach to checking the cat temps-run the car until it's hot then take a spot temperature reading just 'upstream' of the cats (not of the cats themselves-they're very well insulated.)
If you can safely use exhaust insulation it should have very real benefits-particularly if it helps to reduce the temperature of the air entering the engine, after all 10C less=3bhp more as well as the exhaust velocity benefits johno mentions.

[johno]

The exhaust wrap on my car has changed the exhaust note and created even more snaps, cracks and pops

[dejay]

After visiting Prodrive earlier this year, It showed that rally teams put alot of emphasis on reducing heat.
They put a protective coating all the way from the manifold to the tailpipe to keep the heat in the exhaust. Not only does this keep the engine cooler increasing bhp (10c = approx 3-4bhp) but it keeps backpressure in the exhaust which also increase bhp!