mrvette

OK, several folks claim the underhood temps are much higher with headers than with say stock cast iron rams horm exhaust....

I can't see it really , as headers would cool much quicker than cast iron, and that hottest part of the cast iron..say the 'collector' would be highest temp, and radiate longer....I know my O2 sensor lit off quicker on that rams horn install than the header collectors...for instance...so much so I run a heated O2 sensor now...

but I feel the heat given off is about the same, and the energy stored heat due to MASS is much greater in the iron system....that I think is worse for the other plastic components...like relays/wiring/and such....

NOW is there any direct evidence of the sustained underhood temperatures with headers of identical style between bare steel and ceramic coated???

GENE

tnt76vette

All I know is that within 10 minutes of shutting off my motor on any length of trip I can HOLD my hand anywhere on my ceramic headers. I wouldn't try that on a bet on anything else. Further, a gallon (or whatever) of gasoline is going to generate a certain number of BTU"S no matter how it is burned and exhausted or whatever....Its just the nature of things......My $.02 :cheers:

71coupe

I agree :yesnod: My headers cool off quickly (even more so now since I got them Jet-Hot coated)
Cast exhaust manifolds stay hot forever. Like a cast iron stove.

What stays hot the longest on my motor is the oil - even after the block has cooled.

427V8

Gene,
I think it's all about surface area.
While the car is running headers would transfer more heat to the engine compartment than ram horns.

But yes I areee. Headers don't have much heat capacity, so they should cool off faster.

But on second thought, do headers actually weigh less than cast iron manifolds? If not then they have basically the same heat capacity, but more surface area, hmmmm

tnt76vette

And I say again gentlemen: BTU's is the issue here......the sooner we rid them from the engine compartment, via the radiator or the exhaust or free wind movement the cooler the engine compartment is going to be. And also "Free Air" Intakes will help the motor receive cooler air but will not make the engine compartment any cooler since the same amount of gas is being burned.....external temperatures being the same of course......

mrvette

Well, I guess really my question revolves around the affect of ceramic coating on engine compartment temps, and therefore pass compartment temps...will it really make any significant differance?? and does anyone have any direct comparison experience on their car?? or a direct compare to say a friend's car vs. theirs....with one of them having ceramic coating and the other NOT???

GENE

flynhi

Ditto 427 - headers have 3 or 4 times the surface area inside the engine bay to radiate heat from. It's the same principal of steam radiators used in older commercial buildings - more surface area means quicker heat dissipation.