E30 Aerodynamics

[wingnut1961]

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

[team9]

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

[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...

[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

[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.

[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

[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.

[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.

[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.

[nando]

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

[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.

[Jeff2886]

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

[Simple_Smith]

I need to go puke after scrolling through this thread.

Thanks for your input.

[totheredline]

I need to go puke after scrolling through this thread.

[Simple_Smith]

1 YEAR BUMP

Just recently started working on my knockoff Racing Dynamics rear apron for my e30 and started to do some searching around for aero mods as far as rear diffusers, front splitters, side skirts, and under carriage mods.

I'd rather bump this thread because it has some good info in it than start a new thread.

So anyways, I just ordered my HIK Fabrication sever duty skidplate and was planning on making a plywood front splitter that will tie into the skidplate somehow as well as some cheap-ish side skirts (possibly taurus, but hopefully something a bit more squared.) Also possibly cutting the tire well to accommodate a diffuser that will tie into the rear valance.

Pic for suggestions. And to show current state of things..


keep in mind this is my drift/fun/auto-x/cruising/whatever car. Not dedicated to one specific school of thought, just for fun and some degree of function