PDenbigh Posted January 18, 2006 Share Posted January 18, 2006 I'm looking for facts and opinions on heat management techniques for exhaust systems. I have a turbo car that generates a notable amount of heat among the header, turbo, external wastegate, and 3" downpipe. I have had all of the components Jet Hot coated, and that decreased the levels of under hood heat by a notable amount but after 30 minutes on track it's toasty. I would like to do something additional to the downpipe. It is 3" in diameter and about 2' of it is in the engine bay. As such, it provides a lot of surface area to dissipate heat into the engine bay. My current idea is to wrap it with some header wrap. I have heard that this method causes the metal to deteriorate from the inside out, and other times it just casus cracks. Anyone able to shed some light on this? From experience or otherwise? Thanks a bunch! Quote Link to comment Share on other sites More sharing options...
Tims Posted January 18, 2006 Share Posted January 18, 2006 any wrap will destroy the pipe/tubing even stainless. try a shield or insulate the firewall/floor area instead. simple sheet metal shield works okay, but turbos make heat and lots of it. Quote Link to comment Share on other sites More sharing options...
Greg Collier Posted January 19, 2006 Share Posted January 19, 2006 It's all about air flow... I have a splitter and an aluminum air "foil" at point of entry to direct air up through the radiator, past the tubo, and up through a vent in the top of my hood. I also have two ducts that push air through the engine bay downwards. At 1000 to 1200 degrees you want that heat to escape from all metal, then blow away... Quote Link to comment Share on other sites More sharing options...
Kolia Posted January 19, 2006 Share Posted January 19, 2006 Wrapping can trap humidity and accelerate rusting. It will also increase your EGT and turbo temp. It’s good for HP and reduced lag, but on long term reliability of your turbo, it’s questionable. Some of that heat might make its way back in the engine. (Worst case scenario, lots of “ifs” here…) Like most people said, try and vent that heat out of the engine bay. You might even improve the radiators efficiency at the same time. My 2 cents… Quote Link to comment Share on other sites More sharing options...
alberto_mg Posted January 27, 2006 Share Posted January 27, 2006 tims and collier have some good points. go over the rx7club and check out what us 3rd gen turbo rotary guys go through for better cooling and decreased temps overall. turbo rotaries will generate some very hot exhaust temps - hotter than most turbo piston cars iirc. the header wrap on a downpipe will work wonders at decreasing underhood temps. a lot of us have used it on stainless as well as mild steel downpipes and i have yet to hear of cracking one due to heat or having one rust through. the applications i am referring to are on cars used for HPDE. egts will increase b/c the heat is being kept in the exhaust but i don't see how it would affect the decision. higher egts caused by more heat in the exhaust doesn't mean much. if you don't already have a good, accurate water temp gauge, i suggest you get one and check what water temps you are getting after a session. make sure your radiator is well ducted and your fans are working properly. vented hoods (venting the air out of the bay) sometimes also help when all the other items are addressed. Quote Link to comment Share on other sites More sharing options...
kinkyllama Posted February 12, 2006 Share Posted February 12, 2006 I've been doing a little research on this topic as im in the process of turbo charging my car. Anyways I've found that black velvet works great, it is a paint made by 3m. It's a surface paint that reduces radiant heat by extreme amounts. You paint it on and then bake in your oven (or drive around the block for a min) and you have a totally freakin awesome heat insulator that weighs next to nothing and won't come off unless the top layer of metal is removed. It's a little more expensive than a wrap, but works great. It's also a good idea to do the hot side of the turbo which also limits the heat transfered to the charge air by radiant properties. Quote Link to comment Share on other sites More sharing options...
peerless Posted February 13, 2006 Share Posted February 13, 2006 I was looking for that "black velvet" paint you where talking about and found this nice article I am sure you would all be interested in. Race Car Drivers Beat the Heat http://solutions.3m.com/wps/portal/3M/en_US/Automotive_Aftermarket/Home/Products/Spotlight/Heat/ http://www.mmm.com/market/industrial/ceramics/pdfs/Stock%20Car%20Racing%20Reprint.pdf Black Velvet Coating http://www.marine-paint.com/merchant.mvc?Screen=CTGY&Category_Code=HiTemp Quote Link to comment Share on other sites More sharing options...
Tims Posted February 13, 2006 Share Posted February 13, 2006 the "black velvet" in the link is heat resistant but not any type of insulator as mentioned in the earlier post. I could not find any insulating or heat barrier type paints from 3M. please post a link if possible. Quote Link to comment Share on other sites More sharing options...
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