RedR1

iTrader: (5)

Does anyone know what other Exhaust will fit in the opening port on the right side? I know the Mazdaspeed exhaust fits (common sense), but would any others fit? Its already a garuntee that the huge cans wont, but would an RB fit with a little modding to the diffuser, or even an N1? Any help would greatly be appreciated.

Chris-

heres a pic of what i mean. . . .

Dan Putnam

Greddy Power SP, Apex-I N1 Dual (not sure on N1 sigle)
both of those fit. I've hand fitted the diffusers on a buddy of mines car and my own. He has the Greddy, and I have the apex-i.
-Dan

Coulthard Fan

That's good to know - I have the dual N1 as well. The thing that kept me from doing this (and a front spoiler too) was concerns about ground clearance on my Koni/Eibach lowered car. Have you guys ripped them off pulling out of Mickey D's or anything?

Scott
(living in the city is great, but the curbs suck)

Roadracing7

iTrader: (2)

I WANT ONE!!!!!!!!! Where do I get a diffuser for my car? I have seen a couple and according to this post title, Mazdaspeed makes one? How much and are they available through mazdacomp? Thanks a lot.

Richard

A-Spec

the Mazdaspeed makes the car look like Gundam hahha
I think if you are going to get a rear diffuser, you should get the RE-amemiya, looks better and I think it functions better also.

Jason

iTrader: (5)

I carry the Mazdaspeed at the rx7store. The RE looks sweet.

Jason
www.rx7store.net

Roadracing7

iTrader: (2)

Jason, I can't find the diffuser on your site. What's the price? Pics?

ShadyMilkman

i'm sure this is a stupid question but what the hell do those things do? i'm guessing it aids in traction some way, but what exactly does it do?

A-Spec

another reason to get it, ppl will ask you what it does and you can act cool and says it makes you go faster...

hmm not sure exactly how it affects the undercar aerodynamics and downforce, maybe some mechanical engineers can share some light?

JoeD

im assuming it reduces lift at the rear end of the car, but only at high speeds, like above 100.

bajaman

On a street car it is simply for show. On race cars like F1 cars, the rear diffuser is an integral part of the aerodynamics, it specifically channels airflow and in some cases the exhaust of the engine is fed into it, with the overall effect that is creates tremendous downforce.
But......only truly tuned, purpose built diffusers are likely to have any effect at all, in my opinion, and only at very high speeds.

It DOES look cool though!

Roadracing7

iTrader: (2)

A diffusor on a street car is nothing but show. The bottom of the car must be low enough and flatbottomed for it to work. There are different types of diffusors. Different heights of the 'tunnels' affect downforce differently. It works on the 787B for example, certain ferraris and most formula car. For example, my 1985 Swift DB-3 Formula 2000 has a rear diffusor that creates additional rear downforce. So I want it straight for aesthetics on my car. Yes, I know my fellow racers will tell me that it's not functional etc, but it looks good to me. L8R

RedR1

iTrader: (5)

RoadRacing 7, a pic of it is attached. The price is only 650 for the pair.

Heres a link to the Mazdaspeed sect:

http://www.rx7store.net/mazdaspeed.htm

Thats the cheapest i have seen anywhere. I'm sure glad i found Jason's site before i decided to go through a "speedshop" here in town.

Dan Putnam, thanx a million!!!

amemiya

am I the only one that acationaly hits over 120 on the highway??

Silex

I just wanted to let everyone know, but normally if you get the MazdaSpeed GTC rear diffuser, it was built only to be compatible with a MazdaSpeed exhaust. So I guess YMMV. Don't know anyone who has it nor if can be used with other applications.

On a lighter note (hhehehe to say the least...) the RE Amemiya rear diffuser (well the new one at least) comes in two flavors One with side skirts, and one without. Aww heck if you guys wanna read up on it go to this site...

http://www.efini.net/diffuser.htm

Ciao...

xravedreamsx

Where could i find the OLD Stlye RE Rear diffuser for purchase could someone please e-mail me at xravedreamsx@yahoo.com thanks.

SpiritR

There is a GB on that diffuser in the other forum

smerkinseven

is the price $650 here for both sides???
http://www.rx7store.net/mazdaspeedparts/sideskirt.jpg

Sprockett

RE Amemiya Rear Diffuser


$975.95

or


$550.95

FourtyOunce

iTrader: (15)

That price quote is a bit dated since that is the old RX7Store site.

SpiritR

Those are rear sidskirts. Not a diffuser.

I think JT is doing a GB on the one in the white pic, Old style. But I think he said he will work with the price

Coulthard Fan

JT can sell it for whatever they want, but for reference I paid approximately 675 for an authentic RE old style rear diffuser one year ago frpm www.corksport.com

SpiritR

Congrats, but my buddy bought a diffuser from JT for $595, so now what? hehe

BrianK

The Lotus Elise rear diffuser offers a bit over 15lbs of downforce at 100mph while creating almost no drag (hence it being there). However, the Elise has a flat aluminum undertray to keep the air under the car flowing smoothly. I doubt that slapping a diffuser on a car that isn't built to have one is worth anything other than impressing your friends. That said, the underbody of an FD isn't that incredibly turbulent, so who knows.



edit: oh, and to answer the orginal question, it works much the same way a wing works - it creates an area of low pressure as the air exiting from the underside of the car expands - thus sucking the back end down. it has zero frontal area and therefore zero drag.

edit#2: Oh wait, that wasn't the original question... well, I'm not going to erase everything now. Good luck finding the correct cat-back!

F=ma

Unless the angle of the diffuser is too steep, ie if the diffuser pulls away from the ground to quickly then the flow will tend to separate, like a wing that's stalling, and it'll create tons of drag.