Tralfaz
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| posted on 16/9/06 at 09:32 PM |
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Degrees of body roll per G (Seven Type)
Hello all,
Anyone have any information on the degrees of body (chassis) roll per G of any seven type cars?
FWIW I am figuring on 3 degrees or less(hopefully more like 2), but I was curious about others.
Thanks
Brian
[Edited on 16/9/06 by Tralfaz]
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zetec7
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| posted on 17/9/06 at 06:02 AM |
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I'm afraid that there will be no two Locosts alike for degrees body roll per G of lateral acceleration...it all depends on the individual setup.
Some cars (eg. Lotus and Caterham, as well as a few kit manufacturers) are equipped with anti-sway bars, which will reduce body roll dramatically.
I suspect most are not so-equipped, though, as it takes a fair bit of lateral G's to get much roll ouit of a car this light. We're
leaving room for anti-sway bars if we need them, but we're going to set up the suspension without first. We can always add 'em in later
if we wish...
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Tralfaz
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| posted on 17/9/06 at 01:45 PM |
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Agreed.
I was curious if anyone had any data sets of manufactured or perhaps other well developed cars to use as a reference to aid in the development of
mine.
Right now I am working thru Roll Center and Camber change in roll. I have come up with a desirable setup which is good up to about 3 degrees of roll
before losing ideal camber geometry. If I adjust for camber much past this point rollcenter movement suffers notably.
Best Regards,
Brian
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marksimon
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| posted on 23/9/06 at 11:12 PM |
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I'll answer as I have the info to hand for one I measured:
For a ~ 2000 Caterham Seven Supersport Widetrack the quasi-static total roll per g ( body to ground ) is about 3 degrees, with a linear region up to
about 0.9 g. The measurements showed that the tyres account for about 0.6 degrees per g of the 3 degrees.
I recall a Peugeot 106 GTi I had came out about 2.5 degrees per g total roll. Ferraris and BMWs tend to have 'high' quasi-static total
roll per g, generally in the region of 4 to 6 degrees per g.
In my experience, it is not worth targeting roll per g to any particular figure on Lotus Seven type cars; unless you are racing your car, particularly
on twisty hillclimb or sprint type circuits. The reason is that these cars have very low roll inertias, and thus roll is not often an issue.
Suspension bounce and pitch modes are much more important for road driving in these light cars, particularly here in the UK.
Hope the above helps and that you continue to enjoy setting up the suspension.
Mark
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Tralfaz
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| posted on 24/9/06 at 12:36 AM |
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Great Mark,
Thanks so much.
I was trying to ascertain some real world data to help establish some parameters for modelling my Suspension on the computer.
Trying to shrink the number of infinite possibilities 
Best Regards,
Brian
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cymtriks
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| posted on 25/9/06 at 08:06 PM |
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quote:
Originally posted by marksimon
I'll answer as I have the info to hand for one I measured:
For a ~ 2000 Caterham Seven Supersport Widetrack the quasi-static total roll per g ( body to ground ) is about 3 degrees, with a linear region up to
about 0.9 g. The measurements showed that the tyres account for about 0.6 degrees per g of the 3 degrees.
I recall a Peugeot 106 GTi I had came out about 2.5 degrees per g total roll. Ferraris and BMWs tend to have 'high' quasi-static total
roll per g, generally in the region of 4 to 6 degrees per g.
In my experience, it is not worth targeting roll per g to any particular figure on Lotus Seven type cars; unless you are racing your car, particularly
on twisty hillclimb or sprint type circuits. The reason is that these cars have very low roll inertias, and thus roll is not often an issue.
Suspension bounce and pitch modes are much more important for road driving in these light cars, particularly here in the UK.
Hope the above helps and that you continue to enjoy setting up the suspension.
Mark
Those values seem a bit high.
For a Seven I'd expect about 2 to 3 degrees per g.
I'd also expect the same for a Supercar. I'm sure I read an article on the development of the Testarossa and Ferrari F40 which gave 3 and
2.5 degrees respectively.
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cymtriks
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| posted on 25/9/06 at 08:19 PM |
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quote:
Originally posted by Tralfaz
I was curious if anyone had any data sets of manufactured or perhaps other well developed cars to use as a reference to aid in the development of
mine.
Right now I am working thru Roll Center and Camber change in roll. I have come up with a desirable setup which is good up to about 3 degrees of roll
before losing ideal camber geometry. If I adjust for camber much past this point rollcenter movement suffers notably.
Best Regards,
Brian
1st generation MX5 had 4.9 degrees per g. The front roll centre was 61mm, the rear 120mm. Camber gain was 0.91 degrees per inch at the front and 0.58
at the rear. The scrub radius is zero.
The Elise roll centres are 30mm/75mm front/rear. The camber gain is 0.31/0.45 degrees per inch front/rear. The effecive swing axle length is about
180inches/110inches front/rear
The Deon Caterham RCs are 60mm/120mm front rear
The new Caterham CSR has RCs at 30mm/65mm front/rear
You claim to have a geometry that's ideal????
Please tell us what "ideal" is!
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