too hot
Thread Starter
Instructor
Joined: Feb 2008
Posts: 211
Likes: 2
too hot
I have had my 70 convertible for eight years. One of the first mods I made was hedders. I have done everything ever posted on this forum trying to make the car cool enough to enjoy with limited results. I am at a point where I am willing to sacrifice whatever performance I may have gained from the hedders and go back to the original exhaust manifold. Can anyone comment on the heat benefit of making this change. My hedders are ceramic coated true dual exhaust. I have no a/c. I am afraid I'll make the change and realize no heat difference.
Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
here what i did to help with excessive heat, i pulled my carpet and installed additional heat insulation under it. and installed these clamp-on insulators on the pipes under the driver/ passenger seats. also installed some additional stick on type insulation on the underside of the the floor board on passenger side. helped alot. and like dochorspower said i installed a manual valve in the heater hose line by the manifold to turn off during the summer.
http://www.jegs.com/i/Thermo+Tec/893/11630/10002/-1
http://www.jegs.com/i/Thermo+Tec/893/14120/10002/-1
http://www.jegs.com/i/JEGS-Performan...70502/10002/-1
http://www.jegs.com/i/Thermo+Tec/893/11630/10002/-1
http://www.jegs.com/i/Thermo+Tec/893/14120/10002/-1
http://www.jegs.com/i/JEGS-Performan...70502/10002/-1
Last edited by speedreed8; May 11, 2013 at 06:11 PM.
Thread Starter
Instructor
Joined: Feb 2008
Posts: 211
Likes: 2
Thanks for the information. The thermal sleeves and the thermal underbody are probably the only thing I have not tried. Still wondering if anyone can quantify the temp difference between the stock exhaust manifold and hedders so I can determine my next step.
Terrorizing Orange Cones
Joined: Oct 2007
Posts: 2,572
Likes: 17
From: Northern CO
These cars have fiberglass firewalls that don't do much to prevent engine heat being transferred into the cabin, regardless of which exhaust system is used.
Besides the OEM splash shields (which offer minimal heat protection, click the link: http://willcoxcorvette.com/product_i...oducts_id=6687), GM designed a "horse-collar" to fit the void between the transmission/bell housing and the transmission tunnel to minimize heat transfer.
Click the link: http://www.zip-corvette.com/ProductD...L2-SR&CTitle=&
Might be something to consider to help keep the heat out. Good luck.
Besides the OEM splash shields (which offer minimal heat protection, click the link: http://willcoxcorvette.com/product_i...oducts_id=6687), GM designed a "horse-collar" to fit the void between the transmission/bell housing and the transmission tunnel to minimize heat transfer.
Click the link: http://www.zip-corvette.com/ProductD...L2-SR&CTitle=&
Might be something to consider to help keep the heat out. Good luck.
Burning Brakes
Joined: Mar 2011
Posts: 969
Likes: 1
From: NJ
You can try the Eastwood internal header coating. Comes in a spray with a long wand and a 360 degree nozzle. Eastwood claims it helps with heat and corrosion. I did spray my headers but have yet to get it back on the roads. I will be able to comment more in a couple of months. I also did apply lizard skin, got a new transmission tunnel insulation piece and the horse collar mentioned above so my claim will not be reflecting the header spray alone....
Le Mans Master
Joined: May 2008
Posts: 9,063
Likes: 2,736
2022 C3 of the Year Finalist - Modified
I am just thinking, could be wrong, but the amount of heat created by the exhaust would not be higher with headers or with stock. The engine creates a certain amount of heat, and the exhaust would not in themselves make it hotter?? I know that cast iron stock manifolds will retain heat longer, and take longer to cool off after shutdown versus headers that will cool of quicker.... engineers, what do you think?
Melting Slicks
Joined: Dec 2008
Posts: 2,070
Likes: 5
From: N.Richland Hills Texas
This was kinda covered in some other posts but I think A/C cars don't need the cut-off valve... It's part of the A/C system.... And with headers and sidepipes my cockpit is at least twenty degrees cooler... The heat is carried away from the body... and firewall ...
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Melting Slicks
Joined: Oct 2006
Posts: 2,938
Likes: 173
From: hebron IL
C3 of Year Finalist (appearance mods) 2019
I have a/c and i needed the cutoff valve. It made a huge difference
Melting Slicks
Joined: Mar 2008
Posts: 2,023
Likes: 6
From: Austin Tx
I am just thinking, could be wrong, but the amount of heat created by the exhaust would not be higher with headers or with stock. The engine creates a certain amount of heat, and the exhaust would not in themselves make it hotter?? I know that cast iron stock manifolds will retain heat longer, and take longer to cool off after shutdown versus headers that will cool of quicker.... engineers, what do you think?
When a material heats up, or cools off more quickly, then it is a better conductor of heat. If headers are a better conductor of heat, then that would mean they are dissipating more thermal energy from the exhaust, to the air in the engine bay, than the stock manifolds. That would result in more heat in the engine bay.