Those with a front diffuser, like Seibon, Autoexe, or RE-A
 

Have you noticed a difference in driving at high speeds?

At 130 mph my car, stock with no appearance package, felt like it needed something to help with aero-dynamics... diffusers should help, right?

The autoexe/seibon front looks like it would actually worsen the effect. Care to Share? Sharing is caring.

WTF are you driving 130mph for?

edit: i just noticed you said you get 130mpg.

...still pretty sure he meant mph... i wouldnt know i havent gone that fast

I believe that MM tried that and found that it is not sturdy enough. At 153 MPH the car becomes airborne on a straight line, so be careful going above 120 MPH

Yeah the car didn't feel very stable , per se, at 130, and, although I like the look of the auto-exe diffuser, it just looks aerodynamically like it'd create a dam right here:

http://i35.tinypic.com/255l0yx.jpg

Obviously, if it makes it worse than stock, I don't want it no matter how good it looks.

I'm just asking owners of this diffuser, or the amemiya one, if they can tell a difference for the good or the bad.

Thanks.

For me, the car gets a little loose around 125ish, then once you stay in and get past 135 is hunkers down and stays put. I've had it past those speeds and you run out of RPM before the car goes airborne, LOL

I have the Burnout and at 146mph I felt fine,,, spliters act to split the air before it goes under you car to create a better pressure zone for the it to pass undereath the rest of the car...

My car felt fine at 125. At 135 the front felt light and I backed down. Lowering springs should keep air from building up under the car and causing lift.
I like the Autoexec front defuser. VIS Racing sells a replica that I may get.
http://www.visracing.com/newcatalog/...duct_info.html

uggghh no dodnt get the VIS, horrible product, det it from Siebon, its will still be a replica but its much better in quality.....

burnout front lip. from evo-r. the light feeling from 132 to 138 is gone..

beers :beer:

seriously? i've been in the mid 150's and not in a straight line(not straight for those speeds) and had no issues. My Shinka is slightly more stable above 120 than other models i've driven hard, but still gets a bit uneasy over 135-140.... fwiw as stated i have the Shinka all stock susp.

I've been 138 and never felt that feeling, stock exterior

stock suspension???

that is also a factor..


beers :beer:

yup, that was like a week after I bought the car bone stock

At 125 mph it feels good to me even in a high speed sweeper. The only issues I've had are breaking hard from that speed the back end gets really light (for obvious reasons) and wiggles a little.

Full disclosure: I had the Espelir springs on the car at the time so the car was 1.25" lower. That should make a significant difference at speed.

The burnout lip looks like it would work better, but doesn't look as good :P

Decisions, decisions... -_-

I was not saying that the car was unstable or airborne at speeds under 153 just to be careful. I find that my 8 with RB springs, Koni shocks and RB sways really handles well at sustained high speeds ether in a straight line or cornering. My 8 is very dangerous at speed above 150 mph and at 153 can be moved by a lite gust of wind - I would call that airborne. That is the maximum speed I have seen in my 8 and will admit that there was not very much left in it. I feel that just using one of those bolt on deflectors is not a fix for speed issues but just for looks.

Look at the authentic Burnout Version II it looks much better than the Version I which is what the Evo-R is, it cost alot more too, and took 3 moths to get here, but it was well worth the wait....

Also- pertaining to the high speed discussion I have
Tien Flex's with a 2" drop
AutoExe Undercar bracing
MS Strut Tower Bars
RB Sways, w/ fr end links
The 2" drop really does help........

I think you're officially the fastest 4 port AT rx8...

I agree with that.
Mine feels fine at 125 with the Espelir springs on it.

I know of at least one maybe two 6 port 8s that have gone a little faster but had the same results as far as stability.

Legsport - actually raced in Japan

But to find it for sale. Now THAT's the tricky part.

contact japanparts

i have the yellow konis, tein h springs rb bars and end links. i have a stock front--no appearance kit. No rear spoiler. My car (on the track) does get a little light in the front over 130mph. its a subtle feeling --just does not feel as planted like at 120 and below. the 2009's have more under body paneling and i have been wondering about that.
I just dont want to invest a lot to solve this as the time spent at 130+ is very small. Most times on the track you are not above 100mph.
I have only been on Roebling Road in Savannah since I installed the Pettit system and my debut at Road Atlanta and it's much longer straightaway has me a little concerned. I est at least a 145mph top speed on the back straight. I really dont know if i want to take it that high. You have to brake hard to enter the next turn--a 90 degree one-- and believe me, at 130+ things change.
I am also a little concerned in blowing out the front airdam undertray.
would splitters and or front lip help me noticeably?
follow this thread with interest
olddragger