MMD rear diffuser

[rvlyssup]

Damn...that too is exactly what I'm concerned about. The backside being opened looks like it'll create some sort of parachute effect as that entire portion of the diffuser sits lower than the rest of the rear bumper by roughly 1.5 to 2 inches. I've driven mine 2x on the freeway, one @ about 14 miles and the other 130 miles @ 80 to 90 mph with no ill effects. Still i'm curious as to what the long term effects will be. Probably a good idea right now to check for stress cracks @ the rivet mounting points...

Pic of the gap I'm referring to.

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[svtguy]

Did you phone American Muscle about your MMD diffuser? Would be interested in their reply?

 

[JSWM3]

Yep, you're exactly right. It creates an air pocket under there that is severely stressing the plastic. I was the second or third person to install one of these and have put about 800-1000 miles with it on so far. Much of that has been highway mileage which I am almost certain was the culprit. As I mentioned in a previous post I never even exceeded 80mph.

Did you phone American Muscle about your MMD diffuser? Would be interested in their reply?

I haven't had time yet, it happened on my way into work this afternoon. AM has been great customer service wise so far. I need to get in touch with [MENTION=10447]AMAlexLazarus[/MENTION] . He was a great help getting the rest of the mounting hardware out to me. Crossing my fingers that he can help me figure out what to do next.

 

[rvlyssup]

Yep, you're exactly right. It creates an air pocket under there that is severely stressing the plastic. I was the second or third person to install one of these and have put about 800-1000 miles with it on so far. Much of that has been highway mileage which I am almost certain was the culprit. As I mentioned in a previous post I never even exceeded 80mph.


I haven't had time yet, it happened on my way into work this afternoon. AM has been great customer service wise so far. I need to get in touch with [MENTION=10447]AMAlexLazarus[/MENTION] . He was a great help getting the rest of the mounting hardware out to me. Crossing my fingers that he can help me figure out what to do next.

Again, sorry to see & hear about your diffuser. No doubt AM will take care of you. Its not like you did something for it to break off; maybe a redesign of some sort need to happen. Please keep us posted. :cheers: I'm still curious to know how the diffuser handles turbulence when the vehicle is in motion. Would really give us an idea as to what type of forces are encountered causing a portion to shear off like that. :shrug:

Meanwhile, I'll keep an eye out on mine. I don't drive my car that much which sometimes is concerning as I would be last to know that there is an issue with these types of parts.

 

[JSWM3]

Thanks man. I have faith in AM. It's hard to see in the photo but what was so bizarre is how unbelievably clean the break was, to the point that I had to look very very closely at the diffuser to tell which edge had separated from the top and which edge was finished. I've looked it over and over again to see where it could be improved from a mounting standpoint and can't really see any non-permanent option. I feel like it would benefit hugely from an upgrade in the plastic department. It's just way too brittle.

 

[Ultimateone]

Oh wow, I have to to keep an eye on mine, it does feel flimsy as all hell.

 

[SoCalTim]

[MENTION=10447]AMAlexLazarus[/MENTION]

Do you have any info on these diffuser failures?

 

[golfstang]

Call me crazy, redneck, desperate, whatever... should I stuff some socks or something up that gap to block air from entering?

 

[rvlyssup]

Call me crazy, redneck, desperate, whatever... should I stuff some socks or something up that gap to block air from entering?

You'll need all that open area, on both sides, to be blocked off.

In a nutshell, MMD will need to redesign and add an angled / slanted upward lip that fastens to the lower bumper rivet mounting point (on both sides) as you see in my pic above. There will still be a gap in the center portion of the diffuser right below the reverse light but its only about 1/2 inch, if at all any.

 

[golfstang]

So long as the product failure is directly caused by the lack of necessary product integrity, such as the plastic splitting from daily driver use, then the purchaser should be protected under some kind of warranty. While I can't find anything specifically mentioning warranty details of this product, I also cannot find any disclaimers against a warranty.

What I'm getting at is should this failure become a wide spread issue, MMD/AM will almost definitely have our back- both as a customer service move and warranty move.

Let's also remember that it is highly doubtful MMD would release a product with such a drastic engineering fault. This one example may very well be an anomaly.

In fact in makes sense, at least in my head, that a flexible plastic piece would be able to flex when the force of the air pocket builds up- thus preventing failure.

 

[JSWM3]

In fact in makes sense, at least in my head, that a flexible plastic piece would be able to flex when the force of the air pocket builds up- thus preventing failure.

The problem, at least in my case, was that the plastic wasn't compliant enough. I am by no means a plastic or polymer guru, but I can attest that the plastic used for this piece is far too brittle to be subjected to the amount of drag and positive pressure it creates by design. If anything the adhesive should have given way before the plastic did.

 

[rvlyssup]

So long as the product failure is directly caused by the lack of necessary product integrity, such as the plastic splitting from daily driver use, then the purchaser should be protected under some kind of warranty. While I can't find anything specifically mentioning warranty details of this product, I also cannot find any disclaimers against a warranty.

What I'm getting at is should this failure become a wide spread issue, MMD/AM will almost definitely have our back- both as a customer service move and warranty move.

Let's also remember that it is highly doubtful MMD would release a product with such a drastic engineering fault. This one example may very well be an anomaly.

In fact in makes sense, at least in my head, that a flexible plastic piece would be able to flex when the force of the air pocket builds up- thus preventing failure.

Agreed on all points...

If anything the adhesive should have given way before the plastic did.

Did you by any chance replace the grey 3m double sided tape used with a more extreme black 3m versions? I know of at least one person on FB that had the grey 3m separating with the diffuser coming apart on their car about 24-48 hours after install...

 

[Ultimateone]

Agreed on all points...

Did you by any chance replace the grey 3m double sided tape used with a more extreme black 3m versions? I know of at least one person on FB that had the grey 3m separating with the diffuser coming apart on their car about 24-48 hours after install...

Wouldn't matter his actually separated where it bends to adhere to the stock bumper, crazy stuff.

 

[JSWM3]

Agreed on all points...

Did you by any chance replace the grey 3m double sided tape used with a more extreme black 3m versions? I know of at least one person on FB that had the grey 3m separating with the diffuser coming apart on their car about 24-48 hours after install...

Yep. First time installed I used the included grey tape, which promptly melted on a pretty humid 85* day. Second time installing I used the black extreme 3M tape along with a more generous application of the adhesion promoter.

 

[JSWM3]

Wouldn't matter his actually separated where it bends to adhere to the stock bumper, crazy stuff.

Exactly. When I removed the bottom portion it literally peeled away like a page from a notebook. No effort required at all.

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