Rear diffuserfin repair


B. West

GT Owner
Dec 17, 2012
356
Irvine, CA
Rear diffuser fin repair

Ok.....I know this has come up on other threads but I wanted to give you a first hand experience. When I purchased my FGT, the previous owner had backed into a curb and damaged the rear fins. The center left fin was the most damaged and most noticeable (sorry no photo). I lived with it but it bothered me every time I looked at my car. I thought the fins were fiberglass so I sought out a mobile fiber glass repair person but no luck. I eventually purchased a new rear diffuser and had that one installed when I had my new exhaust installed. The day after the installation of my exhaust, I drove to the post office (1.3 miles away) to listen to the exhaust. I backed in to the space and was so enamored by the sound of the exhaust, I didn't pull the parking brake up enough. As i sat there preparing to exit the vehicle, I didn't realize the car had rolled back slightly and into the curb. Dang it....now my new diffuser was scratched. I visited one of my dealers and the body shop manager said the fins are molded plastic and an easy repair. I took the old diffuser in first. It took a couple of days to repair but I have to tell you, the results are better than new. The repaired fins are perfect and looked better than the new diffuser on my car before I damaged it. I changed out the diffusers (put the repaired old one back on) and took the new diffuser to get repaired. I have posted photos of the repaired original diffuser (left and right side) and photos of the damaged new diffuser. I will post photos of the repaired new diffuser when I get it back tomorrow or Monday.
 

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Empty Pockets

ex-GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Oct 18, 2006
1,361
Washington State
'Repairs look darned good - read that "perfect" - to me!!! :thumbsup:thumbsup
 

shelbyelite

PERMANENTLY BANNED
May 10, 2007
1
The OEM fins are definitely fiberglass. If they are molded plastic on your car, then they have been swapped out with the Stillen replacement fins at some point in time
 

B. West

GT Owner
Dec 17, 2012
356
Irvine, CA
I think you are mistaken Shelby. I know for a fact that this is the OEM diffuser. I will post photos of my repaired "new" damaged diffuser which is 3 miles new out of the box. Either way, I am more than happy with the repair. I will find out for certain if it is molded plastic or fiberglass but this guy has been in the business for decades and I'm pretty sure he knows what he is talking about.
The OEM fins are definitely fiberglass. If they are molded plastic on your car, then they have been swapped out with the Stillen replacement fins at some point in time
 

shelbyelite

PERMANENTLY BANNED
May 10, 2007
1
Let's see, I have only bought and sold over 500 Ford GTs as my daily business for the past 8 years. I can tell you with 100% certainty that the OEM diffusers are FIBERGLASS. Stillen sells plastic replacements, but the OEM diffusers are most definitely fiberglass. I have replaced and repaired enough of them in my day to know this. I can also tell you that the OEM diffusers are not sold separately from the belly pans. If you have a set of diffusers that are from ford that you purchased separate from the belly pan, please give me that part number.

Not trying to be rude, but this is not a topic I am guessing on :)

Oh, and regardless what the material on yours are, they look great and like new now :thumbsup
 
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B. West

GT Owner
Dec 17, 2012
356
Irvine, CA
Let's see, I have only bought and sold over 500 Ford GTs as my daily business for the past 8 years. I can tell you with 100% certainty that the OEM diffusers are FIBERGLASS. Stillen sells plastic replacements, but the OEM diffusers are most definitely fiberglass. I have replaced and repaired enough of them in my day to know this. I can also tell you that the OEM diffusers are not sold separately from the belly pans. If you have a set of diffusers that are from ford that you purchased separate from the belly pan, please give me that part number.

Not trying to be rude, but this is not a topic I am guessing on :)

Oh, and regardless what the material on yours are, they look great and like new now :thumbsup
Shelby, with all due respect, no one is doubting your FGT accumen. Im only trying to share a positive experience and what was communicated to me. Why don't we say that we are both right and the bady shop manager is wrong?? Maybe he thinks it is plastic and the body man is using fiberglass?? I will find out. And yes, either way, they look great. I will find out for certain though for everyone's benefit.
 

shelbyelite

PERMANENTLY BANNED
May 10, 2007
1
Agreed Mr. West :)
And wasn't trying to hijack your thread. Your fins do look great!
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,194
OEM's are fiberglass and Stillen's are rubber.... and Mr. West, I agree.... who cares what the shop thought they were, they did a great job on the repair. Thanks for sharing!!! Do you think they'd be game to take on a diffuser with much greater damage??
 

B. West

GT Owner
Dec 17, 2012
356
Irvine, CA
Agreed Mr. West :)
And wasn't trying to hijack your thread. Your fins do look great!

Thanks Shelby :). I will definitely clarify for everyone on the forum.
 

B. West

GT Owner
Dec 17, 2012
356
Irvine, CA
OEM's are fiberglass and Stillen's are rubber.... and Mr. West, I agree.... who cares what the shop thought they were, they did a great job on the repair. Thanks for sharing!!! Do you think they'd be game to take on a diffuser with much greater damage??

Yes, Kendall. I talked with Ryan today to see if he could come down after the Rally. Let's make arrangements to get it to me then or when it is convenient for you.
 

Kingman

GT Owner
Mark II Lifetime
Aug 11, 2006
4,072
Surf City, USA
OEM diffusers are FIBERGLASS. Stillen sells plastic replacements, but the OEM diffusers are most definitely fiberglass.

I don't know why this didn't dawn on me until just now, but most body repair guys refer to fiberglass as plastic......thus a Corvette is referred to as plastic.
 

dmark1

GT Owner
Dec 18, 2010
202
Dallas
Shelby, Stewart Paint and Body ( a noted Dallas high end exotic body shop) just repaired my diffuser for the same reasons as the OP. He stated that it was NOT fiberglass, but rather a carbon based plastic product. These guys are rarely wrong.

Just saying.
 

HPGT

GT Owner
Jul 31, 2012
82
Little Rock, AR
I just looked at my car - it has a few rough edges on the ends. I could see fiberglass threads exposed.
 

shelbyelite

PERMANENTLY BANNED
May 10, 2007
1
I have numerous broken ones sitting on my shelf. Happy to post close up pics for anyone doubting what the material is on the diffusers.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,060
Las Vegas, NV
My broken one is definitely fiberglass. If anyone has a spare I'd be interested... Even then I'll probably pick up a par of the Stillens along with a full set of the new gauges :)
 

B. West

GT Owner
Dec 17, 2012
356
Irvine, CA
My broken one is definitely fiberglass. If anyone has a spare I'd be interested... Even then I'll probably pick up a par of the Stillens along with a full set of the new gauges :)

I will have a spare one when I get my new one back on Mon. I will post photos of the repair.
 

B. West

GT Owner
Dec 17, 2012
356
Irvine, CA
Shelby, Stewart Paint and Body ( a noted Dallas high end exotic body shop) just repaired my diffuser for the same reasons as the OP. He stated that it was NOT fiberglass, but rather a carbon based plastic product. These guys are rarely wrong.

Just saying.

I thought the same thing (fiberglass) and my body shop manager said it looks like fiberglass but is actually molded plastic. Either way, the good news for those with damaged fins is that they can be repaired.
 

Ed Sims

GT Owner
Mark IV Lifetime
Apr 7, 2006
7,853
NorCal
OEM diffuser & front trunk lid are fiberglass. Yes, one can refer to fiberglass as plastic or fiber/plastic composite or fiber/resin composite or etc but it really is simply fiberglass.

Ed
 

MAD IN NC

Proud Owner/ BOD blah bla
Mark IV Lifetime
Feb 14, 2006
4,211
North Carolina
After fixing my diffuser a few times I can attest it is fiberglass material based, could be a different blend but repairs with and like fiberglass practice... I have have experience with plastic cars also:biggrin. Pre 68, the real rough old type "plastic"
 

HPGT

GT Owner
Jul 31, 2012
82
Little Rock, AR
I used to work in a quality control lab inspecting fiberglass products. I am surprised that anyone working in a body shop could not identify fiberglass.