Yes or No to rear diffuser.

[Anaxilus]

Originally Posted by sw20kosh

Thought I'd join the diffuser party and share my DIY that I've had on the car for over a year. It was a difflow diffuser for an elise/exige that I retrofitted. Making a new exhaust design was certainly fun!

That is very nice! If you ever come up w/ a retrofit kit or parts list feel free to share.

[Frostyman]

Originally Posted by TeamZleep

It's actually sitting in my garage, missing 2 of the insert fins. That and the center exhaust are just sitting there... If nobody wants them, they're getting cut up and tossed, and I'd hate to do that.

Got pics of the dual outlet, what's chilling in the garage? PM a price.

[Wonderbar]

Originally Posted by TeamZleep

Also, I can't really vouch for the accuracy of the mpg display, but I have noticed this:

These are all my averages, reset before I leave each way.. about 5-7 miles city driving/25-30 miles highway combined on my drive to work one way.

Muffler delete: 27.5 avg.
Muffler delete with the diffuser I just took off: 29mpg avg.
Apexi. N1 with the diffuser in the pictures: 34.7-36.4 avg. mpg.

My driving style doesn't change. I zip around in the city areas, then do 5-10mph over the speed limit with cruise control set. Speeds on the highway are 55-70. I usually do 65-75. I've been logging this new setup since Sunday.

I really think it has to do with the change in area coverage/and angle of the flat portion of the diffuser/number of fins. I think the old setup had too much going on.

Some of my pacnw guys have sent me text photos of 38+ mpg on the dash.

Your theory about angles and such is correct to the extent that the lower the angle the less downforce created but higher drag reduction and vice versa (to a limit of about 14 degrees.) Eco-modders will build diffusers for drag reduction and try to keep them close to 0 degrees, not generating downforce but reducing the drag drastically. I've thought about doing it on my kid-hauler

[TeamZleep]

Originally Posted by Wonderbar

Some of my pacnw guys have sent me text photos of 38+ mpg on the dash.

Your theory about angles and such is correct to the extent that the lower the angle the less downforce created but higher drag reduction and vice versa (to a limit of about 14 degrees.) Eco-modders will build diffusers for drag reduction and try to keep them close to 0 degrees, not generating downforce but reducing the drag drastically. I've thought about doing it on my kid-hauler

I spent a LOT of time reading through your wind testing thread, that on top of the exhaust made me decide to change it up. I can't believe the milage/stability difference in just changing the angles/fins.

[bkblitzed]

I would love to fab up an exhaust design where its in the middle and above my bumper.

[wholeeoh]

personally i think aftermarket companies are seriously slacking on rear diffusers.

[Wonderbar]

Originally Posted by wholeeoh

personally i think aftermarket companies are seriously slacking on rear diffusers.

Agreed! That's why I built my own. People are form > function and that's the target market. That's why there are not as many functional pieces as we'd like.

[bkblitzed]

Originally Posted by Wonderbar

Agreed! That's why I built my own. People are form > function and that's the target market. That's why there are not as many functional pieces as we'd like.

have you thought about a front splitter?

[Wonderbar]

Originally Posted by bkblitzed

have you thought about a front splitter?

Working on it. Just slow going for me lately.

[bkblitzed]

Originally Posted by Wonderbar

Working on it. Just slow going for me lately.

sweet, i guess ill hold off on the apr splitter than.

[FRSfan111]

I'm tuning the apr splitter with DWLabs diffusor and it definitely flows well having both.

[TeamZleep]

:P

[bkblitzed]

Originally Posted by FRSfan111

I'm tuning the apr splitter with DWLabs diffusor and it definitely flows well having both.

is the apr aluminum?

[FRSfan111]

No it's CF so I ordered the black diffusor. So it matches better. However I though about doing that "hydro dip" stuff (where u can make an item look cf) on the diffusor. But it looks clean as is, so no need.