header wrap/ shilds help against hot running engine ?

[frank_ster]

first off its a buick swap into a subaru legacy so its a tight fit.

today was pretty warm and sitting in traffic my engine is running up to 210 deg.
and i have my own custom fabbed headers and cross under pipe.
and i would like to have the coolant temperature a lot more steady where the thermostat opens at 180, and fans come on at 190.

currently if i turn on the ac the coolant temp would rise and rise.

so if i wrapped my headers and cross under pipe would that make a difference. i know there is a lot of heat radiated from the pipes but how much i can't quantify that.

the radiator i have is from a subaru wrx its over 1" thick and i have 3 slim fans, they are not the highest flow but they seem to push a decent amount of air.

Also i have a 12" tall 24" wide intercooler in front of that its some what blocking or restricting flow. so the other idea i have is to put a water to air intercooler and another thinner less flow restricting rad to cool the intercooler water.

when i drive on the highway it cools down only a tiny bit. down to about 195 with the fans on.

what i do notice is if i do a lot of engine braking ie deccel fuel cut where there is zero fuel going into the engine the temps drop about 5-10 deg in about 45 seconds. is this because the headders cool off quickly ? or just the intake air pressure drop causing some internal cooling ?

 

[earlbrown]

If underhood radiant heat is the culprit, I'd ceramic coat the exhaust. That way the turbo get's access to the heat and you won't have a big wick under the hood waiting to burn the car down.

 

[kidglok]

ceramic coat the exhaust and a turbo diaper

 

[frank_ster]

^ i was thinking about ceramic coating .. how much does that usually cost for a custom application ? its my daily driver so i rather not have it down for more than a day or two.

i have powercoating kit ,, can ceramic coatings be powder coated or done your self ?

 

[aminga]

Ceramic goes on as a liquid and you'd need a blast cabinet with AlOx media to clean them

 

[frank_ster]

^ i have a blast cabinet .. do you have a link with more information ?

 

[frank_ster]

and my headers are stainless pipes but with steel flanges.

 

[aminga]

^ i have a blast cabinet .. do you have a link with more information ?

I read over on the columbia coatings forums. It's not hard you just have to be careful, keep it clean and follow the directions. There are some coatings that cure in place without heating.

 

[aminga]

But more the point. In a properly functioning cooling system underhood temps should be irrelevant.

 

[frank_ster]

^ yes i know .. but i have very little room. if i had a 3" thick rad and some amazing fans it would not be a issue. but i dont have room for that.

on a stock buick fwd 3.8 the engine has heat shields they would take like almost 30 min to warm up before the fans would cycle. mine is hot in 6-8 min!

so is that the only difference ? the heat shields ? or is something else in play ?

 

[frank_ster]

well i ordered some aluminum oxide media and 8 oz of black high temp ceramic coating. will post pics..

 

[frank_ster]

but again has anyone said hey wow the engine is running much cooler after installing some sort of heat management ?

otherwise i'm gonna pull the front mount intercooler and do the water to air system

 

[earlbrown]

I've never monitored underhood temps but I can see my 02 was a chitload more active when I added ceramic to my headers and crossover

 

[kidglok]

My underhood temps feel a lot cooler with ceramic coating and a turbo diaper.

How much? I dunno, but I no longer sweat while standing over the engine bay


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[frank_ster]

but not noticable coolant temps being lower?

 

[earlbrown]

only if your underhood temps are causing the elevated cooling temp. If it's a flow problem or a sizing problem, all the exhaust coatings in the world wont fix that.

 

[frank_ster]

^ its hard to say .. since this rad cools a 2.5 turbo 4 cylinder with zero issues before.
i know its not the same thing but how much heat could a 3.8 possibly make even at idle. over a 2.5 turbo.

 

[ek02]

GN's have a big crossflow radiator, and that gives a clue as to how much heat a 3.8 can make. Electric fans will not cool a small radiator as well as a stainless flex fan will in my experience with V6 engine swaps. Aluminum cores with 2 rows of 1" tubes and a lot of fins per inch really work better than a 3 row copper core. Be Cool radiator fixed me up with a custom radiator for a 4.1 in a Toyota that really works. It was not cheap though.

 

[TURBOPOWERED68]

try a 160* thermostat.
also at what temp. do your fans come on?

 

[frank_ster]

i have gone with no thermostat same deal. the fans come on at 195 , but i can force them on but it doesn't help.
the subaru radiator has a high fin density. i wish i could put a stainless flex fan but there is no room and it would actually be on the crank pulley to be somewhat in the middle of the rad. i was thinking of going with a be cool or giffen radiator but then everythin would have to move forward even more and the intercooler would have to come out.

but the original question is will wrapping the headders make a difference and the consensus here is no. i will go ahead and do it to lower underhood temperatures. and see if it helps.
but looks like i will have to go with plan B water / air intercooler and if thats not enough an even bigger rad.

i was also thinking of putting the tans cooler ( currently part of the rad like a gm ) somewhere else on the car ie in the rear above a muffler with a fan. and an engine oil cooler on the other side in the rear. do this to spread the heat around.