Engine heat affecting clamshell??


bob700

Member
Jul 13, 2007
10
Has anyone noticed how the underside of the clamshell that sits directly over the muffler can develop small cracks from the heat generated by the muffler. I have always been concerned about this area because it fits so very close to the muffler. The heat buildup there can be significant.
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
Has anyone noticed how the underside of the clamshell that sits directly over the muffler can develop small cracks from the heat generated by the muffler. I have always been concerned about this area because it fits so very close to the muffler. The heat buildup there can be significant.

Wasn't a big concern to me. The brick OEM muffler was replaced within 1200 miles with a cat back system. My paint and plastic vents still look great. They were tested in the heat of TX during Rally 4!
 

Black GT

GT Owner
Mark II Lifetime
Jan 2, 2006
771
Get a Heffner cat back
 

DanQ

GT Owner
Aug 18, 2005
336
Lake Zurich, IL
For those keeping the stock exhaust, I wonder if some heat reflecting foil might not be a good thing to add?

https://www.pegasusautoracing.com/productselection.asp?Product=1838
 
H

HHGT

Guest
There was a Heat shield cover made for the GTs about 2 years back. Midnite Blue has one.
 

THamonGT

GT
Mark IV Lifetime
Le Mans 2010 Supporter
Factory Muffler

Here's the best thing to do with the Factory Muffler! Tomy Hamon
 

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Jan A. Byrd

GT Owner
Aug 21, 2006
39
Percy IL
What to sell your rear bumper? J Byrd.
 

bob700

Member
Jul 13, 2007
10
For those keeping the stock exhaust, I wonder if some heat reflecting foil might not be a good thing to add?

https://www.pegasusautoracing.com/productselection.asp?Product=1838

That is what I had done. Some heat insulation material was applied across that area to protect the clamshell. Looks good and was not expensive. That area where the heat has the most effect on the clamshell is also the main support for the clamshell. I want to maintain that area's integrity.
 

THamonGT

GT
Mark IV Lifetime
Le Mans 2010 Supporter
I don't sell any parts I take off my GT. Sorry Tomy
 

Kingman

GT Owner
Mark II Lifetime
Aug 11, 2006
4,072
Surf City, USA
That is what I had done. Some heat insulation material was applied across that area to protect the clamshell. Looks good and was not expensive. That area where the heat has the most effect on the clamshell is also the main support for the clamshell. I want to maintain that area's integrity.

It would be great if you posted some pics of your solution.:thumbsup
 

bob700

Member
Jul 13, 2007
10
Pictures

Here is a pic. Some of the color you see is the resin which in itself acts as a heat barrier also.
 

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Kingman

GT Owner
Mark II Lifetime
Aug 11, 2006
4,072
Surf City, USA
Here is a pic. Some of the color you see is the resin which in itself acts as a heat barrier also.

Thank you for the follow up pic. Did you use the same reflective film from Pegasus?
 

bob700

Member
Jul 13, 2007
10
Thank you for the follow up pic. Did you use the same reflective film from Pegasus?

I do not think so.
 

MR2Race

FGT The Velvet Hammer
Apr 6, 2006
304
Northville Mi.
Do any of the aftermarket mufflers have any insulation material?

Or is the hot gas contained only by a single layer of metal?
(With no insulation material surounding the can portion of the muffler)
 

tmctguer

GT Owner
Jan 11, 2010
129
dana point, CA
Bob700: Thanks for the picture.

I wonder if there is a benefit of putting reflective material over more surface area of the underside of the clamshell (longer lifespan of the clamshell, less long term damage to paint on clamshell,etc.)?

And the opposite -- would there be any detriment to covering more of the clamshell (reflecting too much heat back into the engine compartment, overheating the glass window, etc.)?
 

MR2Race

FGT The Velvet Hammer
Apr 6, 2006
304
Northville Mi.
Anyone ever document what the under hood temps are?

Before and after a modification.

Some method to determine the amount of change?


Hot to the touch is too course an increment. .
 

tmctguer

GT Owner
Jan 11, 2010
129
dana point, CA
I was thinking about doing my own temperature testing. I am trying to figure out how to get a temp probe inside the engine bay that can measure ambient temps.

The things I wanted to test were: A. The "license plate spacer" idea (which sounds good given the huge hole sitting behind the license plate), B. The "muffler cover" developed by a fellow board member who works with thermal material, C. Reflective material placed on the underside of the clamshell.

The key is to replicate testing conditions on each attempt (e.g. Outside temp, length of drive, similar RPM, similar starts/stops, etc). No easy feat but if I can find time to test, and conduct similar test runs, I will post results.
 

fjpikul

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Jan 4, 2006
11,491
Belleville, IL
MAD in NC did this with an infrared measurement device years ago. Look for his old posts.
 

MR2Race

FGT The Velvet Hammer
Apr 6, 2006
304
Northville Mi.
MAD in NC did this with an infrared measurement device years ago. Look for his old posts.

I hope it was not a hand held infrared meter.
 

MR2Race

FGT The Velvet Hammer
Apr 6, 2006
304
Northville Mi.
I was thinking about doing my own temperature testing. I am trying to figure out how to get a temp probe inside the engine bay that can measure ambient temps.

The things I wanted to test were: A. The "license plate spacer" idea (which sounds good given the huge hole sitting behind the license plate), B. The "muffler cover" developed by a fellow board member who works with thermal material, C. Reflective material placed on the underside of the clamshell.

The key is to replicate testing conditions on each attempt (e.g. Outside temp, length of drive, similar RPM, similar starts/stops, etc). No easy feat but if I can find time to test, and conduct similar test runs, I will post results.


I have a few low buck thermocouple readouts I have been using.
For real time measurements.

That along with K-type wire, fused on the end.
Becomes a fine thermocouple for under hood air temp.
As well as a method to measure a surface temp.

Also have a solution for data logging the data if required.