Cota carnage

[Arizona Vipers]

See attached pics
When I was at COTA last month, I could hear the diffuser shaking on the back straight on my last session. Now I know why. LOL.
If you notice on the front of the diffuser (the part facing towards the front of the vehicle), there's only one screw on each side holding it in. There should be two screws on each side, 4 total.
There's only one on the inside of each side, take a look at the outside in the pics and you can see how air gets in there. I'm guessing that's what happened to mine, more and more air got in as the screws got loose all the way down.
I dont know how I"m going to repair the part of the carbon diffuser that got tore off, but for now I'm going to put double sided 3M tape on the inside on both sides, and then gorilla tape over the outside on both sides to keep air from getting in between.
Even on a non-damaged diffuser this would be a good idea for all that track their ACR. Next time you are under there you'll be surprised at the gap. Imagine how much air is making it over the diffuser instead of under.
Hey Doug Shelby, please send me another strake ASAP!

DiffuserCarnage-001.jpg
DiffuserCarnage-002.jpg
DiffuserCarnage-003.jpg
DiffuserCarnage-004.jpg

[ViperGeorge]

I've had some of those screws come out. I got some new ones from the dealer and blue locktited them all. Good idea with the tape on that leading edge. I had the passenger side leading edge come loose. Not sure how it is attached from the factory.

[dewilmoth]

Mine had extensive 3M double side tape from the factory. It was a while ago, but I remember being surprised that the front of the diffuser was basically held on with double stick tape.

[Pappy]

I clean the surface and use new 3M double side tape each time I remove the belly pan to change the rear end grease.

Pappy

[kriskyk]

sorry to see this....but as they say that's racing... hopefully you find an economical solution to repair this

[Arizona Vipers]

I clean the surface and use new 3M double side tape each time I remove the belly pan to change the rear end grease.

Pappy

I will be doing the same as well from now on along with the Gorilla tape over it. BTW I'm taking your wheels/tires down to Wheel Specialists tomorrow to get the tires off, so they'll be there anytime you want them after tomorrow!

- - - Updated - - -

sorry to see this....but as they say that's racing... hopefully you find an economical solution to repair this

Yeah no biggie I'm just grateful the entire diffuser didn't come off at cota. $8K, plus the pieces could have tore my tires apart or killed the guys behind me at 160mph lol

[sadil]

Do you get aggressive with the corners? Those things are so low, I don’t think they would survive the raised red/white rub strips if you had the left side tires beyond the strip during a high downforce turn. Seems like it could take a single instance.

Should just make some spares of those extended sections

[greygt3]

This is a really crappy design. The fact that one of the front corners is held in place by double sided tape is ridiculous. Yes I have replaced my tape on numerous occasions but it always seems to lift after a while. One would have thought a screw on the front edge of each corner would be the very least to attach something this important and expensive.

You must be in your 9L to reach 160, best I've ever seen is 150 between 11 and 12.

[RedTanRT/10]

Yeah no biggie I'm just grateful the entire diffuser didn't come off at cota. $8K, plus the pieces could have tore my tires apart or killed the guys behind me at 160mph lol

AZ, Wow, thanks an $8K part??? I've had to patch my CF diffuser cover in couple of places on my CC as the part, less strakes, is $1,200. Can't imagine having to replace an E's at $8k. I'm sure someone can reproduce those panels for hopefully $1k?

Sounds like tape and locktite can overcome the few factory fasteners. They do get a lot of airflow, Ben had loose bolts on his CC and his got ripped totally right off at Willow springs.

[SSGNRDZ_28]

xtreme and I have the diffuser carbon kits available for about half that. I have long hated the tape solution on the front side of the diffuser and plan on looking into something better if possible.


Glad it wasn’t worse AZ!


Doug

[Arizona Vipers]

This is a really crappy design. The fact that one of the front corners is held in place by double sided tape is ridiculous. Yes I have replaced my tape on numerous occasions but it always seems to lift after a while. One would have thought a screw on the front edge of each corner would be the very least to attach something this important and expensive.

You must be in your 9L to reach 160, best I've ever seen is 150 between 11 and 12.

No, i was in the stock ACR and was hitting about 163. What are your lap times there? I am probably carrying more speed coming out of 11.

[stradman]

Sorry I haven't noticed any tape. Where is this tape you are talking about? Any photos?

[ViperGeorge]

Sorry I haven't noticed any tape. Where is this tape you are talking about? Any photos?

There is double faced tape under the leading edge that holds it to the car. My passenger side let go and was flopping around. Caught it before it broke. Tape over the leading edge would help keep air from pushing underneath and lifting the panel off of the double sided tape.

[stradman]

There is double faced tape under the leading edge that holds it to the car. My passenger side let go and was flopping around. Caught it before it broke. Tape over the leading edge would help keep air from pushing underneath and lifting the panel off of the double sided tape.

Ah Ok. Now I get it. Mmmm. need to look at mine at some point soon then! Cheers

[bluesrt]

hmmmm, ones I have had apart had black tacky strong glue type stuff, its a mother to break it all free

[ViperGeorge]

hmmmm, ones I have had apart had black tacky strong glue type stuff, its a mother to break it all free

Yea, I've assumed it was dark colored double faced tape but it could have been goo.

[SSGNRDZ_28]

Adhesive free solution in progress.

Doug

[ViperGeorge]

Just checked my ACR again in preparation for Hastings later this week. Passenger side leading edge had pulled away again. Cleaned it up and put some 3M double faced tape on it and then used Guerilla Tape over the leading edge. Hopefully the Guerilla Tape will keep it from peeling down from air entering the seam.

[Arizona Vipers]

Adhesive free solution in progress.

Doug

I'm sold already! Put me down for two!

[Arizona Vipers]

Just checked my ACR again in preparation for Hastings later this week. Passenger side leading edge had pulled away again. Cleaned it up and put some 3M double faced tape on it and then used Guerilla Tape over the leading edge. Hopefully the Guerilla Tape will keep it from peeling down from air entering the seam.

Most important thing is just to make sure all those bolts are tight too. Does anyone know the torque specs? For me, I get a lot of rocks in between the diffuser and when I go to tighten those bolts i hear a "crunch". I need to drop it and clean it more often.
The Gorilla tape kicks ass and will do the trick as long as the surface is clean.

[ViperGeorge]

Most important thing is just to make sure all those bolts are tight too. Does anyone know the torque specs? For me, I get a lot of rocks in between the diffuser and when I go to tighten those bolts i hear a "crunch". I need to drop it and clean it more often.
The Gorilla tape kicks ass and will do the trick as long as the surface is clean.

I used blue loctite on all the bolts so hopefully they won't come loose - again. Lost a few of them when they got loose and came out about a month ago.

[ACR Steve]

Paint mark them just like other suspention bolts. East to see if they are loosening when the cars jacked up at an event

[SSGNRDZ_28]

I offer the belly pan bolts in black stainless steel as well if anyone has lost them or wants to replace the OEM bolts.

Doug

[bluesrt]

strange, the part you guys having problems with, the ones I took apart(early 16 acr-e)cars had black goo holding them, and quite tough to remove them

[ViperGeorge]

strange, the part you guys having problems with, the ones I took apart(early 16 acr-e)cars had black goo holding them, and quite tough to remove them

Maybe they changed how they fasten them. Mine seems to have had tape holding it on.