E30 Aerodynamics

[Nesset]

Anyone have a wind tunnel they wana donate to R3V for the day? I would really like to see a STOCK 325is and a M3 in a wind tunnel to see the differences in drag.. I bet we would all be pretty surprised.

[nando]

numbers are published all over the place. they're pretty much the same.

[kingston]

I am interested in the rear aero stuff around the spare tire well and rear bumper. I want to fab something like that for my track car.

[whitebulat22]

Anyone have a wind tunnel they wana donate to R3V for the day? I would really like to see a STOCK 325is and a M3 in a wind tunnel to see the differences in drag.. I bet we would all be pretty surprised.

If not one of these I think just a controlled experiment on a runway or a track straight that can be used repeatedly; such as a pull beginning at 80-90 mph at a defined start and end point, would give us plenty of info to do meaningful (just not exact) calculations with. Beyond M3 vs Mtech2 aeros, this would verify benefits of simple underbody additions. A simple flattened underbody would be able to address very many airflow disruptions.

I really wanna see what huge rear wings do to the drag and high end acceleration on our cars. There'd be more drag obviously but I don't think the effect would be near as drastic as any new car with their smoothly sloped rears.

[MX339]

For those of you who are interested, I'm about 3/4 of the way through this book and I think it would make a great addition to any gearhead library.

It goes through a number of different items (spoilers, wings, diffusers, air dams, etc.) and explains it in pretty simple terms. It was hard to keep reading the book and not just run to the garage and start working on the E30.

Anyways - check it out. It's worth a look.

Competition Aerodynamics: A Practical Handbook
http://www.amazon.com/Competition-Ca.../dp/0857330071

Looks like an updated edition will be coming out in the near future. I'm definitely thinking about buying one. I've got one of the Haynes published books on Engine theory and have really been enjoying it so far.
http://www.amazon.com/Competition-Ca.../dp/1845847768

I am interested in the rear aero stuff around the spare tire well and rear bumper. I want to fab something like that for my track car.

Those are just the standard M3 plastic filler pieces. You'd have the come up with your own pieces and a way to mount them onto the valence.

[Jeff2886]

I've had the book for a while now but it's been sitting on a shelf. I cracked it open to cram for an interview last week hahah. Lots of good info in it. Now the only question is how much can I add without bumping myself up too many SCCA classes lol

[Jeff2886]

If not one of these I think just a controlled experiment on a runway or a track straight that can be used repeatedly; such as a pull beginning at 80-90 mph at a defined start and end point, would give us plenty of info to do meaningful (just not exact) calculations with. Beyond M3 vs Mtech2 aeros, this would verify benefits of simple underbody additions. A simple flattened underbody would be able to address very many airflow disruptions.

I really wanna see what huge rear wings do to the drag and high end acceleration on our cars. There'd be more drag obviously but I don't think the effect would be near as drastic as any new car with their smoothly sloped rears.

A track would be more beneficial because you would be able to see how the added downforce is changing the behavior in the corners. You can compare lap times between setups (assuming you are running consistent times beforehand) to judge the improvement.

[BraveUlysses]

If you guys want to watch, this guy has a really good set of videos on aerodynamics

https://www.youtube.com/watch?v=quDLzxmJl5I

[wingnut1961]

I just got into this E30 and am AX'g it while I sort things out and get my comp license. Interestingly, it came with a large CF GT wing (69 in. wide) that the previous owner used in NASA GTS. It was too wide and mounted too far back for SCCA so I pulled it off the car during my first AX day. After adding the wing back on for the next AX, (narrowed to 61 in. and moved forward 3 in.) I noticed my brake bias was thrown off (locking fronts) after adjusting it to the no-wing position. This was only noticeable at the end of sections with 50-60 mph speeds. Just throwing out that data point...

[team9]

just fyi....your wing is on backwards....

[wingnut1961]

Yeah. PO had it mounted that way. I swapped it around...

[ncrmtrsprtsE30]

I am interested in the rear aero stuff around the spare tire well and rear bumper. I want to fab something like that for my track car.

I cut out my spare tire well and made a custom diffuser out of alumalite that goes from the diff to the back roll panel and from shock to shock, sealing up the whole bottom.


I need to get a better pic of it later... just snapped this one real quick

[MPLFoster]

fucking cool^

[the imitator]

Really like that exhaust look, how it comes straight out of the bodywork makes it look like it was meant that way, not just improvised.

[Wh33lhop]

I cut out my spare tire well and made a custom diffuser out of alumalite that goes from the diff to the back roll panel and from shock to shock, sealing up the whole bottom.
[img]http://i.imgur.com/UxDwwqwl.jpg[img]

I need to get a better pic of it later... just snapped this one real quick

Love the exhaust. Is the bumper ever going back on?