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BMW handling ratio
scoobyis2cool - 22/2/05 at 09:43 PM

I'm hoping someone can help me out here - about a year ago I went to a lecture by a guy from BMW and he was telling us that all BMWs are designed to have a certain ratio/parameter that gave it good handling. It was something like the ratio of wheelbase to track width, or something like that, does anyone know what I'm talking about?

I ask because we're designing the university race car at the moment and we were trying to remember what it was.

Hope someone remembers better than I do!

Pete

clbarclay - 22/2/05 at 09:48 PM

Not sure what ratio BMW use (go and measure a 3 series), the desired ratio depends on the end aplication, 4x4's and drag cars use far different ratios to normal road cars.

flak monkey - 22/2/05 at 09:52 PM

quote:
Originally posted by scoobyis2cool
I ask because we're designing the university race car at the moment and we were trying to remember what it was.

Pete


If thats the formula student car...you are a bit behind on production arent you, if you are still at the design stage?

Sorry cant help with the ratio thing. Tried the magical google? good for all last minute report writing (i mean research) that one...

David

andkilde - 22/2/05 at 09:52 PM

There's a big chart in Stanniforth's Race and Rally Car Sourcebook.

As I recall Karts start around 1.1, the "ideal" or prettiest number is 1.6 and then is stretches on to the 2 plus range when you come to roadgoing saloons and such.

The Terrapin and a number of contemporary formula cars were in the 1.5:1 range.

Cheers, Ted

scoobyis2cool - 22/2/05 at 11:29 PM

quote:
Originally posted by flak monkey

If thats the formula student car...you are a bit behind on production arent you, if you are still at the design stage?

Sorry cant help with the ratio thing. Tried the magical google? good for all last minute report writing (i mean research) that one...

David


If the car was for this year then yeah, we would be miles behind! Luckily it's next year's car so we've only just started the design, getting ideas together etc.

I tried google, but when you put in bmw, handling and ratio, you just get piles of pages about how good bmw handling is or power-to-weight ratios

Thanks for the other suggestions, I'll have to see if our uni library has a copy of the Stanniforth book. Otherwise, measuring a beemer would be easy enough.

Pete

Metal Hippy - 23/2/05 at 12:12 AM

http://www.m535i.org/e28info.html

It's got wheelbase and front and rear tracks on there.

Hope it helps.

I was told by somebody (so don't blame me if the info is crap) that they'd read an article about BMWs and the M535i (the car I linked and coincidentally my donor) was the best handling in a test that was done involving loads of different BMW models.

Again I stress, that info might be shite.

But there you have the dimensions for your perusal.

Rich.

Fred W B - 23/2/05 at 05:55 AM

IMHO, beg borrow or steal a copy of Staniforths Race and Rally Car Source book and read and reread it. You will learn more compitition car common sense than you can get in a weeks surfing

FRED WB

britishtrident - 23/2/05 at 09:05 AM

It goes back to work done by a guy called Maurice Olley (not sure of spelling) at Rolls-Royce and later GM in the 1920s/30s.

liam.mccaffrey - 23/2/05 at 09:22 AM

i was told it 1.6 to one and that is what i designed my middy chassis to i hope its right

britishtrident - 23/2/05 at 02:23 PM

LWB cars are generally less nervous and more predictable than SWB cars -- but LWB cars are less nimble.