I've read a few threads about people putting wrap on their downpipes..........WHY?

What purpose does this serve?

Skoosh.

 

It keeps the heat in your exhaust.
So will lower the underbonnet temps and shlould keep the intercooler temps lower.

Theory also says that due to the exhaust gasses being hotter, it will move faster therefore less back pressure = more power

 

this is new... can sumeone tell me how is it done??

 

Best method,

Take down pipe off,
Pretend it is a broken arm
Now wrap as neatly & tight as possible
Place various clamps, jubilee clips on etc to hold wrap in place
Refit downpipe (the heat wrap won't stay clean!)

Worst method
Do it in situ
Swear, scrape your knuckles
Give up....

 

This may seem like silly question, but wrapping down pipe decreases engine bay temps right.... ok, but also meant to speed up gas flow, theoretically improving performance..... so why not wrap exhaust all the way along to the back box???

Dxx

 

That's correct as did in mine (not fitted yet) and helps reducing overall noise but I guess is the back box that adds more noise rather the downpipe-centre sections.
JIM

 

so where is a good place to buy exhaust wrap then?

 

http://www.proven-products.co.uk/products/cooltek.htm

 

RallyDesign.
JIM

 

Skoosh - I've just ordered some from agriemach

I'm hoping that it comes this week, to fit next weekend -

Mark

 

It also stops the horrible tinnie/ringing noise you get from under the car. Which is most annouying especially when cold.

Best place I found was here at ThinkAuto
http://www.thinkauto.com/acatalog/Pr...white_180.html

And they won't sting you £9 for postage like the CoolTek site.

You will want 10M for the Downpipe and another 10M for the centre section.

Wet it then wrap it. This stops alot of the fibreglass dust and also helps it to shrink when it gets hot.

 

I was beginning to think I was the only one who had that noise - it's very annoying. Thanks for the link.

 

so u mean i have 2 wrap d down pipe, down 2 until jus b4 d back box?... dats a long way m8,n d only effect is to increase powa"?? not d sound r anything rite??
cheers

 

Have you thought about ceramic coating, it looks good works well cleaner but a bit more costly!

 

Does anyone know how much i'd need to wrap an Hks manifold, plus a downpipe ?

 

Personally I wouldn't wrap the exhaust much past the part where the downpipe bends under the car and leaves the engine bay area.

The centre and back don't get anywhere near as hot as the front parts of the exhaust and unless you spray the wrap with high temp paint, you will find that it gets repeatedly soaking wet when it rains and it will steam like you wouldn't believe, EVERY time it gets wet. This constant wetting and drying out will knacker the wrap up in no time.

Also, to wrap the whole exhaust properly with a decent quality wrap would cost an arm and a leg (£100+) and the gains would be negligible.

I'd advise wrapping the downpipe only down to where it disappears under the car only. If you have aftermarket headers and uppipe, it's pretty much essential to wrap these.

The wrap does help to lower UBTs and in theory also speeds up exhaust gases due to retaining kinetic energy in them which is normally lost as heat.

 

Johnny,

for the downpipe you'll need about 1x15' roll of 2" wide.

For the headers, probably a 60' roll of the same.

That's what I used. Make sure you half overlap it.

AND DEFINATELY use that high temp paint on the headers or every time it rains people will be flashing their lights at you, telling you that your radiator has popped as they steam like crazy when wet. I use the stuff rated to 2000 F.

Rich

 

Rich.

Thanks for your advice mate.
Much appreciated.

 

Rapping the exhaust after the turbo will increase gas temp in the system and will INCREASE back pressure NOT reduce it, due to the increased volume created by the increased temp..Boyles Law and all that !

 

Rapping the exhaust after the turbo will increase gas temp in the system and will INCREASE back pressure NOT reduce it, due to the increased volume created by the increased temp..Boyles Law and all that !

 

How do you spell Dyslexic ? Wrap !

 

hmm - not sure I'm with you there - surely it will increase the volume of the gas, - not sure you can directly correlate this with the backpressure - several other factors need to be considered, such as the pressure differential between the front and rear of the exhaust - this will also be increased.

Mark

 

Believe me, it's my job ! you can sit and watch the backpressure increase on the Dyno as the exhaust gas temp. increases. We are currently looking at ways to LOWER the gas temp. to reduce flow noise, and backpressure.

 

P.S. There may be a case for wrapping the headers, (apart from the obvious one of reducing underbonnet temps), because, although the backpressure will increase at the exhaust port due to the higher temp., the increased gas speed created by the higher volume of gas may increase Turbo speed and hence boost,and therefore power, which in turn produces more gas..etc. I don't have any actual proof of this, although there are theoretical formula which would support it..

 

fair enough - given that the underbonnet temps are decreased (particularly on the D/P, being so close to the intercooler), would you think that wrapping the D/P gives an increase or decrease overall ?

Cheers,

Mark

 

On balance I would think that wrapping the downpipe would give a slight improvement in power, but only because of the reduced underbonnet temp. reducing the intercooler temp. If it wasn't for that then the opposite would apply ! again I have no proof of that.
What you should always consider first is safety, the wrap might be needed purely to avoid overheating the bulkhead, and sound deadening material. We once set fire to a Cosworth Granada Scorpio like that..the orange hot downpipes set fire to the sound deadening material INSIDE the car !