Wirelessly posted

Agree with this as well. In my belief the ideal location for exhaust termination for aerodynamics is on one of the sides up in the body work so that the air coming by will pick it up and take it down the side of the car and away rather than trying to scavenge it with an aero device.

 

^ +1 (agreed)

 

IIRC the idea is that the air going through the fins of the diffuser is high velocity low pressure. Venturi effect blah blah blah lowers pressure under body blah blah. The exhaust there just adds heat and flow through the "venturi" to add velocity. I would think that on decel the flow would just be as normal.


It must have been another book that had the discussion about exhaust flow and diffusers

 

Wirelessly posted

I mean if you were to go out the back of the car this might be your best option but it is in no way optimal... It would basically be like trying to scavenge the air coming off the roof with the rear spoiler which has already been altered than getting fresh high velocity linearly flowing air that was uninterrupted... Side exit is the optimal way to go, this might be second, but don\'t expect to see any measurable difference from just the diffuser by itself in my humble opinion.

 

you guys are talking about blown diffusers? i think this is way over our heads, this is big in F1 right now and even those guys are having issues getting it right. well adrian newey got it right

 

I'm working on an F duct for my Miata.

 

I got you beat with my rubberband actuated kers system

 

I'm putting in pneumatic lifters so I can rev to 18,000.

I like that AWR diffuser due to the curved entry lip. That should help expand the airflow with less turbulence as compared to a sharp entry bend.

 

I can help you remake this one from my car by giving you dimensions but thats all I can do for you.
Let me know if you have any questions

 

post the dimensions,If you need help measuring I can come down to Macon next week and help measure.
(G)

 

This is why the concept was abandoned in F1 in the 90's. The Red Bull car is believed to be using some type of anti-lag to put exhaust gases into the diffuser in off throttle situations.
I always have liked the idea of dumping it above the diffuser to reduce the amount of dead air directly behind the car. Somewhere around the license plate seems like it'd be ideal just looking at but I have never run the data to verify the theory.

 

Somebody make some rear evacuation fans like the 599XX. More downforce + less resulting drag sounds like a win.

 

Go for it. The Gods of speed help those who help themselves.

 

I am away the car until the weekends because of college but dont worry, I should have the time to measure the dimensions this weekend

 

How do you live, I had a car truck and a motorcycle when I was away at school, I just thought one of each would be nesassary but 2 may be overkill for school

 

lol wait you mean two cars? Well I just see one as a daily and one as my racecar. Doesnt sound like overkill to me. I do like my bimmer though. Thats why i've been away from here for some time. Spending too much time on bimmerforums

 

No i meant it would be overkill to have multiples of each but come to think of it I had 2 motor cycles during that time not just one so I guess it was overkill.

 

Interesting. Looks like they're doing boundary layer removal to help the flow stay attached over the diffuser. This could actually be useful if you were having trouble with that.

 

I have a finished mould for a very large diffuser, with a chord or about 600mm. It covers the entire area between the diff and the bumper, and is riveted to the bumper, but only to hold it still not to transfer force, it will need to be bolted to the floor also.

Ill post photos of the mould asap, I just need to pull my finger out and lay some glass over it.

Dann

 

Ok got off my ****,

Heres the mould just about ready for some glass/fibre.

Before anyone points out the lines I drew arent straight, I Know, I only put them on there just now so that everybody can see the general curve.

Its for an NA, it goes from rear subframe to bumper, starts about 5 degrees makes its way to 15 ish. It will be riveted to the bumper but it will have rods mounted through the boot floor to actually support it and some hektik fins. Brah.

its not the exact shape its about 2 inches bigger all around to allow for laying the fibreglass and then to cut it to perfect fit.












http://img819.imageshack.us/g/img0793cu.jpg/

Dann