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extreme heat in engine bay

Old 09-19-07, 10:44 AM
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extreme heat in engine bay

I have a turbo 1st gen with hks stainless tubular manifold and t04e, 3" custom galvanized aluminum downpipe and 3" exhaust out. My manifold is hot, always has been, but after a while on the interstate, the heat begins to get real intense in the engine bay and coolant temps are greatly affected. My question is; heatshield products makes a header wrap that withstands 2k degrees contiunous and up to 3k intermittant. Has anyone used this before, how well does it work and is there possibly something better. The guy I talk to at heatshield products says that I probably have a problem with in the exhaust but I'm not convinced I do. Their is nothing there to create a blockage. The only thing else possible would need to go to a 4", but how much of the heat in the manifold will be reduced. The turbo is still the same size. My ecu is a microtech and afr's are between 12.5 and 13.5 usually. I had them at 14 to 14.5 and was told that was too lean for a rotary. Suggestions please. Thanks
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Old 09-19-07, 11:03 AM
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What are your EGT's, or do you have a way to monitor them? Any idea what the mixture is? If you're running lean the exhaust will be much hotter. I would think by virtue of being a turbo it would be a lot hotter than N/A's, but I just used fiberglass wrap on the headers and fabbed up the stock heat shield to try and keep some of that head away from the carb.

If all else fails, some sort of extractor (either for the radiator or the engine bay) would be a reasonable band-aid.
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Old 09-19-07, 11:59 AM
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Originally Posted by christaylor View Post
What are your EGT's, or do you have a way to monitor them? Any idea what the mixture is? If you're running lean the exhaust will be much hotter. I would think by virtue of being a turbo it would be a lot hotter than N/A's, but I just used fiberglass wrap on the headers and fabbed up the stock heat shield to try and keep some of that head away from the carb.

If all else fails, some sort of extractor (either for the radiator or the engine bay) would be a reasonable band-aid.
There is no way of me telling what the egt's are at the manifold. The egt gauge goes in the downpipe. The downpipe is not the problem.
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Old 09-19-07, 12:43 PM
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13.5 is pretty lean for a rotary also (under boost)

what are you EGTs at the downpipe location?
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Old 09-19-07, 01:33 PM
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Fiberglass header wrap works well for knocking down radiated heat so it would likely help. I've used it on my GT35R 3rd gen and it helps.
I looked at the engine bay pic on your cardomain site and it looks like the stock upper and side radiator ducting is still in place. Are the holes in that for IC and intake tubing sealed up? What about the undertray? Does it go all the way to the opening in the nose? Do you stilll run the stock -SE oil cooler? Helping airflow through that could pay big dividends. Good luck.

Chris
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Old 09-20-07, 07:02 AM
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Make sure your timing is not too far retarded. This can lead to high exhaust temps too...
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Old 09-20-07, 07:50 AM
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Originally Posted by Kentetsu View Post
Make sure your timing is not too far retarded. This can lead to high exhaust temps too...
This is a problem I believe. My microtech says the timing is like 27degrees btdc. I don't think that is right and I've done what the microtech manual says to do on how to set up the base timing but obviously I'm missing something there. It's got something to do with the setup in the microtech that I haven't figured out yet.


As far as opening things up for more air flow. I have completely removed the header panel and drove down the interstate like that and very little difference in cooling. So, I believe the cooling system is working and getting enough air.

I think I may concentrate on the timing issue. The base timing is set but with the timing lock off on the ecu, I need to do something.
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Old 09-20-07, 07:53 AM
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I would agree with most all posted above, for sure you need to know what your egt's are, then tune from there. Look into the jet hot coating or other ceramic coatings for your exhaust. I understand it works much better than wrap.
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Old 09-20-07, 09:02 AM
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Originally Posted by cpa7man View Post
I would agree with most all posted above, for sure you need to know what your egt's are, then tune from there. Look into the jet hot coating or other ceramic coatings for your exhaust. I understand it works much better than wrap.
I've done the jet hot coating and it burned off the manifold. The downpipe is still in good shape although it is discolored.
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Old 09-20-07, 06:59 PM
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Originally Posted by Rotorhead34 View Post
This is a problem I believe. My microtech says the timing is like 27degrees btdc. I don't think that is right and I've done what the microtech manual says to do on how to set up the base timing but obviously I'm missing something there. It's got something to do with the setup in the microtech that I haven't figured out yet.


As far as opening things up for more air flow. I have completely removed the header panel and drove down the interstate like that and very little difference in cooling. So, I believe the cooling system is working and getting enough air.

I think I may concentrate on the timing issue. The base timing is set but with the timing lock off on the ecu, I need to do something.
27* where? at cruise? i drive my car in mid/high vacume with low 40deg of advance (till bout 4500rpm) with low mid and sometimes high 15:1 afr's with

adding the advance drasticly droped egt's and my car also ran cooler
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Old 09-20-07, 07:28 PM
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Originally Posted by cpa7man View Post
Look into the jet hot coating or other ceramic coatings for your exhaust. I understand it works much better than wrap.
This makes no sense to me as an engineer. Compared to insulating wrap ceramic is a great conductor. A good insulator must be thick and contain trapped air. A thin solid insulator would hardly do anything to stop heat. It wouldn't work even if you used a great insulating material like plastic or rubber (if that were possible without it melting).

But there's an easy way to tell. Anyone here with a ceramic coat? Run your engine and get your manifold as hot as you can. Now touch your manifold.
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Old 09-20-07, 07:41 PM
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i have a hpc coated hotside, it was noticbly cooler than before

i also run a fiberglass style wrap which works wonders, i have pulled home at night and beenable to see my downpipe glowing though the wrap, and was still able to touch it, unfortunately i dont know what it is, got it from my dad who works at a synthetics factory, something they made to insulate around jetengines iirc
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Old 09-20-07, 07:57 PM
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I have my manifold ceramic coated from 1revvin7, and its still on, and my exhaust is jet hot coated in their 2000 degree stuff, and It looks the same as when I first got it.
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Old 09-21-07, 03:08 AM
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Use both or all 3 which I might be doing.I have been thinking about heat and fire protection on my project car.Fiberglass wrap,3M blanket,Jet Hot Coatings.

http://www.jscspeed.com/index.html?/univ/thermotec.htm

Jet Hot coatings are proven to reduce surface/radiant tempatures.
I believe in their stuff. My turbo exhaust side,exhaust,intake manifolds,ect almost everything that takes heat or near heat will be coated in my car.Works out because im going for the polished bling factor on my show car.Performance and good looks!

http://www.jet-hot.com/Pages/coatings.html


Also fiberglass wrapping is good but here is something better but pricier, 3M's NEXTEL Thermal Barriers on the underbody above the exhaust for added heat protection to the cabin.These blankets are Ceramic impregnated.

http://www.3m.com/market/industrial/..._barriers.html

http://www.3m.com/market/industrial/...l_Barriers.pdf

http://www.3m.com/market/industrial/...t_bulletin.pdf
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Old 09-21-07, 08:24 PM
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You need the header panel in place along with the undertray or parts that cover these areas. If you don't have the top panel on the air will pass over the top of the radiator not through it. Air takes the path of least resistance. Make sure all pathways for the air to escape around the radiator are sealed. Even small gaps can make a large difference especially on a turbo car.
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Old 09-23-07, 10:43 AM
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Eric,

The ceramic coatings don't radiate the heat off the surface like an uncoated pipe. I am an applicator of Tech Line coatings and have verified a 90% reduction in temp 1 inch from the surface. If ceramics didn't work, they wouldn't use them in the heat shield tiles on the space shuttle.
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