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      05-09-2024, 04:49 AM   #1
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Looking for a proper rear diffuser.

Looking for a functional rear diffusers for an e90.

These look like they may actually do something, but who knows???

Fancywide
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Are there any others out there?
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      05-09-2024, 03:11 PM   #2
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I'd love to see some real-world testing of the available diffuser options for the e9x. I don't know if they are helpful or hurtful. I don't know about "proper," but here is another company I found a while back.

Aeroflow Dynamics:
https://www.aeroflowdynamics.com/pro...63c7c331&_ss=c
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      05-09-2024, 08:27 PM   #3
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rear diffusers are useless unless you have a full flat bottom set up.
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      05-12-2024, 02:37 AM   #4
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Quote:
Originally Posted by omgzirra_exe View Post
rear diffusers are useless unless you have a full flat bottom set up.
this. the air is so messed up that by the time it gets to the rear diff/subframe area, that a diffuser back there has little effect. might help keep air out of the back bumper if you have an aftermarket exhaust, but that is about it. airflow isn't just going to start adhering to a smooth surface because it is there. it starts at the front.
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      05-12-2024, 04:23 PM   #5
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Quote:
Originally Posted by omgzirra_exe View Post
rear diffusers are useless unless you have a full flat bottom set up.

This 100%
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      05-15-2024, 03:25 AM   #6
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Great thanks guys. Saved me some money.

Doesn't look too hard to make a full flat bottom though...
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      05-15-2024, 11:04 AM   #7
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Quote:
Originally Posted by 0100 View Post
Doesn't look too hard to make a full flat bottom though...
It doesn't?
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      05-15-2024, 12:01 PM   #8
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Quote:
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It doesn't?
must be an aero genius lol
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      05-18-2024, 02:38 AM   #9
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Maybe it's because I work with sheet metal a lot, but building something like this does not seem hard.

https://pbs.twimg.com/media/C4UP3keWAAIy_ZF.jpg
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      05-18-2024, 11:25 AM   #10
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Quote:
Originally Posted by 0100 View Post
Maybe it's because I work with sheet metal a lot, but building something like this does not seem hard.

https://pbs.twimg.com/media/C4UP3keWAAIy_ZF.jpg
Please keep us posted if so! Managing the exhaust heat will be the biggest obstacle. I know Zebulon made a carbon flat floor and diffuser for one of us. But the heat will be a challenge.
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      05-18-2024, 05:58 PM   #11
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Quote:
Originally Posted by 0100 View Post
Maybe it's because I work with sheet metal a lot, but building something like this does not seem hard.

https://pbs.twimg.com/media/C4UP3keWAAIy_ZF.jpg
if i can make a front splitter i can do a flat bottom, so i understand what you wmean.

the problem with making the flat bottom is making sure the air is doing what you want it to do properly.
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      05-19-2024, 10:48 AM   #12
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Here’s a prefab’ed e92 M3 used by JP Marketing with good results in time trial events.

https://www.jpmarketingllc.com/produ...r-recaro-racer

I’d recommend the use of a diff cooler when using a functional diffuser.
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      Today, 11:27 AM   #13
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Great info guys, glad I started this thread.

That JP diffuser looks like the ticket!!!

Yeah and I didn't even think about exhaust heat....

Definitely not going to be as easy as I first imagined.
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      Today, 11:40 AM   #14
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Quote:
Originally Posted by 0100 View Post
Great info guys, glad I started this thread.

That JP diffuser looks like the ticket!!!

Yeah and I didn't even think about exhaust heat....

Definitely not going to be as easy as I first imagined.
Here’s a must read thread: https://www.1addicts.com/forums/show....php?t=1713247
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