Hi guys,

I've been toying with the idea of adding a rear diffuser. Just want to know how effective are they when you you don't have the front under tray + under panels which would direct airflow smoothly to the back of the car? Is it more for looks than actual functionality?

I ask because it seems to me that for such a small amount of coverage (with just the rear diffuser itself), I really don't think it'd have as big an improvement as some people claim it does.

I'm currently looking at APR, Alloy Craft, and Downforce. However, for these products, I have not found actual data / wind tunnel testing data to prove that they work better than without a diffuser.

So for those who has them, what are your experience/thoughts?

 

Its more for looks than functionality.

I call them rock collectors.

 

most certainly rock collectors... the ONLY type of diffuser that is actually really functional is one that is combined with a full undertray. The alloycraft with the undertray if it would ever come out... the pwdjdm doesnt seem popular and is stupid expensive but that is another option.

They may do some small bit difference, but nothing really measurable. Things like the APR are designed to go with their aero package and thats a different story.

 

I have the alloycraft. The craftmanship rivals the best. Looks great too. feels more grounded at highway speeds and up to 120. ive had my s for three months and feel even more confident driving with this addition.
Best bang for the buck and the undertray looks great. Cant wait

 

Thanks for the input. Alooy Craft is the one I'm most interested in. Still I find it hard to justify buying a functionless part. Would you happen to have taken it to the track and see how it improved lap times if any at all?

 

not as of yet. but if i do it will be months from now as im not doing any tracking soon. if you want a little performance buy the diffuser and take your passenger seat out.
then you will lose a few pounds in the s and have a kick ass diffuser in the rear and you can still say its better than before. thats if you still have the seat in your car. jk

 

from the searches i have done

j's=looks
apr=looks
voltex=function
spoon=function
top secret=function

 

I have a spoon diffuser and been tracking it with and without. My times are similar with or without. To me it doesn't have any effect at all. But it sure does look good and yes rock collecter.