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Reducing under bonnet temps - Downpipe wrapping etc- Help please :)

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Old 03 August 2005 | 12:51 AM
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Default Reducing under bonnet temps - Downpipe wrapping etc- Help please :)

Hello All

Currently running a 93 WRX with many many mods.

GEMS ECU
VF34 Turbo
Scoobysport Full De-cat
HKS Intake
HKS FMIC
Uprated Fuel Pump
Ported origional headers
Forge Dump Valve

As have FMIC and diffo turbo, I do not have turbo heatshield fitted and no shielding on Downpipe which can get a bit orange when I am having fun

Looking to lower under bonnet temps. So want advice on :-

Lagging of downpipe - Benefits/Pitfalls?? And what to use etc

Lagging of Turbo exhaust housing - Obivoulsy this will reduce under bonnet temps, but will it cause the turbo to run hotter?

Also I seem to be minus the lower part of O/S exhaust manifold heatshield since last service/repair work so manifold is exposed - Will be going back to ask why not advised of this!! Will this cause any immediate problems? Could this cause cracking of manifold if when the rains return to us?

I see some have lagged the FMIC pipes in engine bay with aluminuised tape, does this really work as this tape seems very thin, albiet manufacturers state it reflects heat up to 1500F. I would of thought you would need a much thicker lagging material than this?

I am also looking into sectioning of bonnet area by air intake so air is drawn in through inner wing and not from Engine bay.

Any info/ideas are appreciated as allways

Cheers
Rob

Last edited by Trebor69; 03 August 2005 at 12:56 AM.
Old 03 August 2005 | 07:12 AM
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Cool

With a FMIC heat management is not so critical as with a TMIC, but to keep everything hot and insulated helps in many ways (and surrounding components, ie Clutch/brake reserviors)
IMHO:
Lagg the down pipe. Fit the turbo shield or fit a turbo insulation bag (very expensive).
The FMIC pipes laged in very shiney alum tape works well as shiney surfaces reflect heat radiation, being thin it does not absorb much energy and a shiney surface will resist heat dissipation (why radiators are black and matt finish).

Challenge is doing it all neatly!
I would get the shield back-on for the manifold too.

Good luck,
Graham.
Old 03 August 2005 | 11:33 AM
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Hello Graham (911)

Thanks for the post, aint been posting on here for a while and you've generaly always been the one first to reply to any of my posts!!

1. cos car has been in garage for what seems an eternity!!! (new radiator, Diff, O/H Gearbox new rear disc n pads etc etc ...) and has come back with some wierd gearbox/diff/transmission noise.. Been back in twice to try n fix it... Very annoying after spending 3 grand + and the heatshield was missing and the pads wernt changed which were nigh on metal.. but hey ho...

2. Up to then car had been great!!

Could you point me in the right direction for some good lagging material etc and exactly what I will need.Would I be right in saying, you fit lagging, tie on with metal ties, then spray it??? Or can you get away with the spraying.

I have seen turbo bags at demon tweeks about 100 quid plus... any other way of doing it, can i just use lagging??

Cheers again
Rob
Old 03 August 2005 | 01:05 PM
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Best lagging material I used was from Agrimech, and you can still get Scoobynet discount if you tell them.
More expensive but better quality IMHO.
Stainless straps (jubilee clips are so ugly) or st steel lock wire is great.
The spray will tend to water proof the wrap to save smaells later on, but on first heat-up it will suffocate you!
I have just the Scooby turbo tin shield on my car, but others (Flat4 and Carl and others) wrapped the hot side of the turbo which a feat in itself...

The turbo bags are a baggy compromise and at that cost a joke. The shield works well and preserves the surrounding area.
I think Agri sell the self adhesive aluminium tape too. the is a special high temperature tape which is the best, really sticks!

hope that helps, sorry about the grief with the car...fully understand, but i do almost everything myself which sometimes is even more annoying!

Graham
Old 03 August 2005 | 01:18 PM
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From: 32 cylinders and many cats
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You can wrap the turbine housing with 1" or 2" wrap - crossing around the up and downpipe to secure. Whether the turbine housing will crack is your risk, IHI housings do crack on some installations.
Old 03 August 2005 | 02:02 PM
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Originally Posted by john banks
You can wrap the turbine housing with 1" or 2" wrap - crossing around the up and downpipe to secure. Whether the turbine housing will crack is your risk, IHI housings do crack on some installations.
This is what I was wondering as to wether wrapping the turbo exhaust housing is a good idea..... So what exactly causes the cracking.. too much retianed heat??

Cheers again for all replies

Rob
Old 03 August 2005 | 02:49 PM
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On VAG motors people seem to be cracking P18 or P20 turbine housings on VF34 transplants. High EGTs, presumably running a bit lean. On a Subaru you might well lose a piston first
Old 03 August 2005 | 03:03 PM
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Originally Posted by john banks
On VAG motors people seem to be cracking P18 or P20 turbine housings on VF34 transplants. High EGTs, presumably running a bit lean. On a Subaru you might well lose a piston first
Well, the car is running fine on mixture running gems ecu and had recent remap. I have an EGT sensor and guage fitted and under normal 80mph crusing runs about 600 ish , round town about 300-400 under hard drving about 700 max... This sound about right..... Would lagging make these temps higher as not disapating heat as much??

Cheers

Rob
Old 03 August 2005 | 03:44 PM
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Those EGTs sound fine, shouldn't be a problem.
Old 03 August 2005 | 06:27 PM
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Is there really a lot to be gained by wrapping the turbo?
The metal shield is quite 'intimate' to the hot side so a good trap of still air is sandwiched under the shield.
Porsche don't wrap turbos, does any production car manufacturer?
Graham.
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