Alright, I'll see about snapping some pics. As an FYI, I have a modified version of the Paul G./Vishnu rear diffuser. I would call it a good starting point, but there are some things that could be done to improve it if you're designing one from scratch.

l8r)

 

mines not a ALMS diffuser. Its a custom prototype dry carbon diffuser from the Oreca race team in France. it is similar to the picture of sierra's rear diffuser, but wider and longer.

 

good luck with the build ryan.

 

9.5 degrees is the ideal angle for the diffuser, and the verticals on the "side" of the tunnel need to be as low as possible.

 

I thought I read somewhere recently that you can actually make the angle even steeper the closer you get to the back of the diffuser? Might be from reading I was doing on sports racers...so not sure if that would still apply to a car with a high roof/low back (trunk).

Dave

 

What R&D is this statement based on, and for what application? The current "double-decker" rear diffusers on F1 cars would seem to be more steeply inclined than 9.5*, for example.

Sorry, not trying to sound like a jerk, but I am inherently suspicious of generalized statements like this. I have been doing a bit of research for production sedan aerodynamics, and I have yet to see a single example of a track oriented aero package that has been built without artificially imposed restrictions (the likes of the Enzo, Veryon, etc. excepted) - especially when it comes to a rear diffuser.

Building an aero package for TA allows a unique opportunity to explore all possibilities. Maybe building a rear diffuse that is adjustable in multiple ways (strake height, vertical adjustment) would be the best way to go. That way the diffuser can be adjusted for different tracks. I would suspect, that if you got the underbody aero to work well enough, you could pretty much eliminate the rear wing altogether (assuming you had an adjustable front splitter and rear diffuser).

l8r)

 

Awesome guys all the input is appreciated! I have yet to look into the specifics of the diffuser but from what I have read a functual diffuser with splitter can eliminate the need for a wing. But I have only seen such examples on aerodynamically correct cars.

I don't know the overall differance it would make on a 4 door sedan!

 

Ryan - have you decided what size of tire you're going to run?

Unless the Redline rules change - I assume you'll run the max 275? NT01's?

For NASA, I heard Hoosier was going to renew their contingency...

 

It will be a 275, but the tire itself is still up in the air?????? hmmmmmm

 

Started a new thread about diffusers so we don't screw up yours.

Looking to start and finish this weekend because my wife is out of town and I can stay up late and listen to butt-rock in the garage and pound Dew-skis

 

Haha....... Dew-skis!!! Alright buddy, I will be checking / copying the diffuser build!

 

quick update.... 2 doors down, 2 to go!

Then its on to removal of misc metal brackets that have no place in a race car...

 

I can't believe you gave an abortion to a car you still owe money on....LOL that is fricken nuts!

I'm not so sure E85 would work out for me..... How many laps at BHFs do you think you would get on a tank???? Now calculate consumption with the FP RED!!!

I really do love my 110 leaded this year I've been running it 24/7. Does anyone know if the FP RED upgrade requires additional cooling?

 

I'm thinking of going E85 next year too. It's just so much cheaper than 100/104 that I sometimes run - especially if I have to buy it at the track for $8-9 / gallon. I also hear it runs cooler.

A downside to E85 is definitely the consumption as you stated. I've heard 30% more. So instead of getting 4-6mpg; think 3-4mpg....ouch. Now that's burning through a lotta fuel.

 

I've thought about making the switch to E85, but when I can still get 100 octane at relatively reasonable prices (between $5-6/gal), I have a hard time justifying the expense of the conversion.

l8r)