Insulating turbo/exhaust

Tim C · 15-11-09, 05:47 PM

I've seen the exhaust downpipes insulated before, but I haven't seen anyone go as far as the hot side of the turbo. The kit pictured below was on the car featured on the 900BHP quattro thread
http://www.classic-audi.co.uk/forum/...ghlight=900bhp

It claims to "virtually eliminate turbo lag"!

What's the theory behind that then?
I can see it reducing under bonnet temperatures but can there be any other real gains?

spaarky · 21-11-09, 03:05 AM

have looked at similar in other applications (non-turbo) - not sure in this specific application, but in general, the theory appears to be that wrapping the hot bits retains the heat within the hot bits, which increases gas velocity & thus gas flow. presumably that's why they claim to reduce turbo lag i.e. increased gas velocity should mean that the turbo is spooling up faster in all conditions than a similar 'non-wrapped' turbo/manifold so there's less of a lag before the turbo comes on. dunno if it's true or works, but it should have the by-product of reducing under bonnet temps.

caution though, since a) it's usually expensive and b) in some cases, the way in which you wrap the hot bits can force the heat back into the heads, turbo or other components, which are usually designed to rely on the heat dissipating into the atmosphere i.e. depending on which bits & how you wrap them up, you may find more power but also find much higher head, turbo etc temps which affects longevity. I've wrapped NA exhaust manifolds for more power in the past, and it does seem to work according to the theory but you have to be careful & think about the specific application.

most useful advice I've come across was in relation to exhaust manifold wrap - don't wrap right up to the exhaust port, but leave a gap of a few inches since otherwise the heat that would otherwise be vented to the atmosphere will be retained in the pipe and sink to the head, making the head run much hotter. leaving a bit of a gap allows the head temp at the port to dissipate, so head runs at normal temp, but you get the benefit of the wrap keeping the heat in the rest of the pipe to increase velocity & aid gasflow & scavenging etc.

in general, it's an area with lotsa differing opinions. personally, I can see it would help in theory, as long as you're careful & make sure you don't heat the heads or turbo too much. if you want to use it on your turbo & you got a turbo temp gauge, give it a go & monitor the temps. or find someone with a similar application who has used it with no ill effects. I'd be v wary of just buying some & wrapping it all up - you may find a power improvement at the cost of seriously impaired turbo, head, manifold life

Tim C · 21-11-09, 05:52 PM

Thanks for that Spaarky, sounds like good advice.

We're in the process of fabricating a tubular exhaust manifold, along the lines of the works one.
The Emerald ECU we have on the car runs with an exhaust gas temperature sensor.
I think we'll use it for a while, then wrap the downpipe and see if there is any appreciable increase in EGT as well as performance. Then think about the turbo and perhaps part of the manifold.
Every little bit helps

Gaz · 28-11-09, 01:44 AM

Quote:

Originally Posted by Tim C

Thanks for that Spaarky, sounds like good advice.

We're in the process of fabricating a tubular exhaust manifold, along the lines of the works one.
The Emerald ECU we have on the car runs with an exhaust gas temperature sensor.
I think we'll use it for a while, then wrap the downpipe and see if there is any appreciable increase in EGT as well as performance. Then think about the turbo and perhaps part of the manifold.
Every little bit helps

can anyone recommend a good brand of heat wrap for the down pipe?

spaarky · 04-12-09, 10:03 PM

lots of availability, but quality & price varies, tho never usually cheap - always seem to need much more than you have - usual motorsport people, Merlin etc & also kit car suppliers etc too - I got some from Car Builder Solutions in Kent which came with stainless clips etc. have been told that one of the cheapest is :

http://www.agriemach.com/default.php?cPath=0_7_42

amanda · 04-12-09, 10:13 PM

Demon tweeks do some as well

www.demontweeks.co.uk

21-11-09, 05:52 PM	#3
Tim C Senior Member Classic Audi Club Member Join Date: Aug 2009 Location: Poole, Dorset, England Posts: 1,729	Thanks for that Spaarky, sounds like good advice. We're in the process of fabricating a tubular exhaust manifold, along the lines of the works one. The Emerald ECU we have on the car runs with an exhaust gas temperature sensor. I think we'll use it for a while, then wrap the downpipe and see if there is any appreciable increase in EGT as well as performance. Then think about the turbo and perhaps part of the manifold. Every little bit helps __________________ quattro RR - crystal silver quattro WR - 1981 Lombard RAC rally recreation (50% share) Nissan Navara - tow car / service vehicle for above A4 2.0T quattro s-line special edition - wife's http://www.flickr.com/photos/37654549@N06/sets/

04-12-09, 10:13 PM	#6
amanda quattro hussie!! Classic Audi Club Member Join Date: Jul 2007 Location: doin' it on all fours!! Posts: 5,993	Demon tweeks do some as well www.demontweeks.co.uk __________________ Mystic blue m3 ghay hairdresser mobile 4 sheds 1 shopping trolley Gti RS6 ...my baby

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21-11-09, 03:05 AM	#2
spaarky Grown up member Join Date: Oct 2008 Posts: 124	have looked at similar in other applications (non-turbo) - not sure in this specific application, but in general, the theory appears to be that wrapping the hot bits retains the heat within the hot bits, which increases gas velocity & thus gas flow. presumably that's why they claim to reduce turbo lag i.e. increased gas velocity should mean that the turbo is spooling up faster in all conditions than a similar 'non-wrapped' turbo/manifold so there's less of a lag before the turbo comes on. dunno if it's true or works, but it should have the by-product of reducing under bonnet temps. caution though, since a) it's usually expensive and b) in some cases, the way in which you wrap the hot bits can force the heat back into the heads, turbo or other components, which are usually designed to rely on the heat dissipating into the atmosphere i.e. depending on which bits & how you wrap them up, you may find more power but also find much higher head, turbo etc temps which affects longevity. I've wrapped NA exhaust manifolds for more power in the past, and it does seem to work according to the theory but you have to be careful & think about the specific application. most useful advice I've come across was in relation to exhaust manifold wrap - don't wrap right up to the exhaust port, but leave a gap of a few inches since otherwise the heat that would otherwise be vented to the atmosphere will be retained in the pipe and sink to the head, making the head run much hotter. leaving a bit of a gap allows the head temp at the port to dissipate, so head runs at normal temp, but you get the benefit of the wrap keeping the heat in the rest of the pipe to increase velocity & aid gasflow & scavenging etc. in general, it's an area with lotsa differing opinions. personally, I can see it would help in theory, as long as you're careful & make sure you don't heat the heads or turbo too much. if you want to use it on your turbo & you got a turbo temp gauge, give it a go & monitor the temps. or find someone with a similar application who has used it with no ill effects. I'd be v wary of just buying some & wrapping it all up - you may find a power improvement at the cost of seriously impaired turbo, head, manifold life

04-12-09, 10:03 PM	#5
spaarky Grown up member Join Date: Oct 2008 Posts: 124	lots of availability, but quality & price varies, tho never usually cheap - always seem to need much more than you have - usual motorsport people, Merlin etc & also kit car suppliers etc too - I got some from Car Builder Solutions in Kent which came with stainless clips etc. have been told that one of the cheapest is : http://www.agriemach.com/default.php?cPath=0_7_42