EOS diffuser fins...nyone???
Thread Starter
Burning Brakes
Joined: Jul 2009
Posts: 863
Likes: 362
From: Maumelle AR
EOS diffuser fins...nyone???
Has anyone tried the EOS Diffuser Fins sold on Ebay and other sites? They appear to be knockoffs of the ACS Diffuser fins, with a slightly less sophisticated mounting setup. They are about 1/2 the cost of the ACS brand. The ACS versions are numbered, and you know which fin goes where, but the EOS that I bought simply have two that are #1 and two that are #2 stamped. The fins are not all the same length and have what appears a very slight bevel. Hand trial fitting makes it difficult to figure out which goes where?? There is an included drilling template, that shows where they should be, .. but not WHICH ones go where ? ... 
Drifting
Joined: Jul 2002
Posts: 1,973
Likes: 152
From: Somewhere in Dallas TX
Has anyone tried the EOS Diffuser Fins sold on Ebay and other sites? They appear to be knockoffs of the ACS Diffuser fins, with a slightly less sophisticated mounting setup. They are about 1/2 the cost of the ACS brand. The ACS versions are numbered, and you know which fin goes where, but the EOS that I bought simply have two that are #1 and two that are #2 stamped. The fins are not all the same length and have what appears a very slight bevel. Hand trial fitting makes it difficult to figure out which goes where?? There is an included drilling template, that shows where they should be, .. but not WHICH ones go where ? ...
Lol @ using my car photo.
Hope it gets figured out. Maybe do some double sided tape and see how it looks first. Also, probably the ones labeled 1 are for the outer sides and 2 for the inner?
Thread Starter
Burning Brakes
Joined: Jul 2009
Posts: 863
Likes: 362
From: Maumelle AR
I lifted that pic from the ACS website. I also noticed the knockoff brands are using this same photo on Ebay. Trust me though, .. your badass Z is selling EVERY ONE of these that sell!!! ... Awesome View
Last edited by Stew24; May 25, 2018 at 01:31 AM.
Le Mans Master
Joined: Oct 2009
Posts: 7,397
Likes: 124
From: Frisco TX
I have the ACS ones and i can tell you the inners are the same and the outers are the same.
I will check in the morning which ones are inner versus outer (longer or shorter).
The fitment is good enough but not perfect. There are some tiny gaps.
I will check in the morning which ones are inner versus outer (longer or shorter).
The fitment is good enough but not perfect. There are some tiny gaps.
Instructor
Joined: Jan 2016
Posts: 197
Likes: 44
The fitment for the ACS one has gaps? I'd expect that one to have no gaps at all
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Thread Starter
Burning Brakes
Joined: Jul 2009
Posts: 863
Likes: 362
From: Maumelle AR
I didn't think I would be able to use mine on initial inspection. They have bevels to the mounting surfaces, which will cant the fins either one direction or the other. In other words, they will either lean to the left, or lean to the right? Also, I don't remember either of them being longer or shorter? I wrote EOS asking for some clarification on this, and they simply wrote back that they are all the same! Well, that's some BS, ... they are NOT all the same. After more inspection, it appears they are to be grouped together with both 1's on one side and both 2's on the other side. Which goes to driver's side or passenger's side to be determined.
Le Mans Master
Joined: Oct 2009
Posts: 7,397
Likes: 124
From: Frisco TX
I didn't think I would be able to use mine on initial inspection. They have bevels to the mounting surfaces, which will cant the fins either one direction or the other. In other words, they will either lean to the left, or lean to the right? Also, I don't remember either of them being longer or shorter? I wrote EOS asking for some clarification on this, and they simply wrote back that they are all the same! Well, that's some BS, ... they are NOT all the same. After more inspection, it appears they are to be grouped together with both 1's on one side and both 2's on the other side. Which goes to driver's side or passenger's side to be determined.
Looking at your pics there....
I would say image #2 is for the LEFT SIDE
And image #3 is for the RIGHT SIDE
Those mounting surfaces are EXACTLY like the ACS ones.
Instructor
Joined: Feb 2016
Posts: 158
Likes: 38
From: Georgetown, ON Canada EH !
I didn't think I would be able to use mine on initial inspection. They have bevels to the mounting surfaces, which will cant the fins either one direction or the other. In other words, they will either lean to the left, or lean to the right? Also, I don't remember either of them being longer or shorter? I wrote EOS asking for some clarification on this, and they simply wrote back that they are all the same! Well, that's some BS, ... they are NOT all the same. After more inspection, it appears they are to be grouped together with both 1's on one side and both 2's on the other side. Which goes to driver's side or passenger's side to be determined.
Just installed a set of these...the ones marked No. 1 fit the passenger side, and No. 2 on driver's side.
Instructor
Joined: Feb 2016
Posts: 158
Likes: 38
From: Georgetown, ON Canada EH !
Thread Starter
Burning Brakes
Joined: Jul 2009
Posts: 863
Likes: 362
From: Maumelle AR
Thread Starter
Burning Brakes
Joined: Jul 2009
Posts: 863
Likes: 362
From: Maumelle AR
Instructor
Joined: Feb 2016
Posts: 158
Likes: 38
From: Georgetown, ON Canada EH !
I'll try and get some decent pics tomorrow. Unfortunately I just had by driveway resurfaced so I won't be able to get the car out of the garage for a couple of days.
I think the diffusers look great on the car. Installing by removing the lower fasteners and reaching up to attach the upper diffuser fasteners on the driver's side is a bit of a chore due to all the parts up in there. I ended up using hex headed fasteners rather the the supplied phillips head screws on the upper holes (so you can use a wrench).
Also, because you have to flex the panel to reach up, the holes need to be drilled a bit larger or slotted in order to get things lined up.
The fit is not 100% flush in a couple of spots but you'd have to get to within inches of the diffuser to notice.
If I were to do it again I would remove the lower bumper fascia and install the diffusers.
Instructor
Joined: Feb 2016
Posts: 158
Likes: 38
From: Georgetown, ON Canada EH !
I forgot to mention....since I drilled the holes oversize I used washers on the back end with the fasterners.
Here's a few pics....not great but you'll get the idea.
Before anyone comments on the dirty pipes....haven't cleaned them since a got the car March, 2016. That's over 2 years and 20,000 miles of exhaust. Opted for that rather than painting them black.