Thanks for your explaination here about what is truly a confusing
subject (not to mention least understood)
I tip my hat to you for taking the time to go into detail as to how
it works and the physics involved
DOUG
>Thanks for your explaination here about what is truly a confusing
>subject (not to mention least understood)
>I tip my hat to you for taking the time to go into detail as to how
>it works and the physics involved
Thanks, Doug. Hope I made sense. When you get into it, you realize the
difficulty GPL's developers must have had in determining the setup interface,
and how it relates to the underlying physics. For instance, once you set ride
height, it remains set even if you go back and change spring rates. In
reality, spring rates determine sag, or negative travel, and would require a
subsequent readjustment of ride height. No worries about this in GPL. I'd
love to get a look at the guts of this game.
Cheers,
Steve B.
Quoted text (12 lines)
> >Thanks for your explaination here about what is truly a confusing > >subject (not to mention least understood) > >I tip my hat to you for taking the time to go into detail as to how > >it works and the physics involved > Thanks, Doug. Hope I made sense. When you get into it, you realize the > difficulty GPL's developers must have had in determining the setup interface, > and how it relates to the underlying physics. For instance, once you set ride > height, it remains set even if you go back and change spring rates. In > reality, spring rates determine sag, or negative travel, and would require a > subsequent readjustment of ride height. No worries about this in GPL. I'd > love to get a look at the guts of this game.Good question. Not an easy one to answer, though. GPL (the Lotus, anyway) has
at least 5 inches of positive wheel (not shock) travel (see my post on low
riding and bump rubbing). Even at max ride height and spring rate , there are
a few inches of sag, or negative travel left in the suspension. Go flying over
a hill and you'll see it extend. At ride heights below 5 inches, you have to
either stiffen spring rates and/or fit longer bump ***s (supplemental ***
springs, actually - they're not "stops") to keep from bottoming. How much of
each depends on the track and your preferences as to ride/handling qualities.
Since we don't know the suspension geometry, we don't know how much shock shaft
we're working with; thus the quandry. I'd say if you run the full 2.5 inches
of bump ***s, they'll come into play pretty early, but gradually so, in the
travel, allowing you to run softer springs for a more progressive rate.
Opinions, anyone?
Steve B.
Recently, I changed my setup at Spa from a ride height of 1 to 1.25 and the difference
was dramatic as you travelled down the start/finish straight ie the car was bouncing much
less and was far more controlable at 1.25. This tends to indicate to me that the car is
riding on the bump ***s at the minimum ride height. This is also suggested by Doug
Arnao in his interview with Randy Magruder at Digisports. However, as you all probably
know, it is possible to have ride height set to 1.00 and bump ***s to 2.50 so once
again I am at a loss. I might go and see if I can see a difference in handling between
bumps of 1.00 and 2.50 at very low ride heights. Or maybe I'll just go and read the manual
right thru this time :)
--
Byron Forbes
Captain of Team Lightning Bolt
http://members.tripod.com/~HOSHUMUNGUS
and
[link lost in import: /~godsoe/bolt/home.htm]
Quoted text (19 lines)
> >How exactly does one determine how much suspension > >travel is available before hitting the bump ***s? > Good question. Not an easy one to answer, though. GPL (the Lotus, anyway) has > at least 5 inches of positive wheel (not shock) travel (see my post on low > riding and bump rubbing). Even at max ride height and spring rate , there are > a few inches of sag, or negative travel left in the suspension. Go flying over > a hill and you'll see it extend. At ride heights below 5 inches, you have to > either stiffen spring rates and/or fit longer bump ***s (supplemental *** > springs, actually - they're not "stops") to keep from bottoming. How much of > each depends on the track and your preferences as to ride/handling qualities. > Since we don't know the suspension geometry, we don't know how much shock shaft > we're working with; thus the quandry. I'd say if you run the full 2.5 inches > of bump ***s, they'll come into play pretty early, but gradually so, in the > travel, allowing you to run softer springs for a more progressive rate. > Opinions, anyone? > Steve B.<Recently, I changed my setup at Spa from a ride height of 1 to 1.25 and the
difference was dramatic as you travelled down the start/finish straight ie the
car was bouncing much less and was far more controlable at 1.25. This tends to
indicate to me that the car is riding on the bump ***s at the Minimum ride
height.>
You are on the br's at 1 inch ride height, and also at 1.25 inches; they're
just not compressed as far, giving a lower initial spring rate and more
compliance. You could accomplish a similar result by leaving the ride height
low and reducing the spring rates, while keeping or even lengthening the br's.
(assuming they're not maxed already) While that bump just out of La Source
argues for more than minimal ride height, Eau Rouge is the crunch point at Spa.
Your speed through there will determine max spring/br requirements for the
track.
< I might go and see if I can see a difference in handling between bumps of
1.00 and 2.50 at very low ride heights.>
And you'll find it. The more you rely on longer br's vs. stiffer springs for
a given ride height, the more progressive your effective spring rate will be,
as it's a combination of both the steel and *** "springs".
< Or maybe I'll just go and read the manual right thru this time :)>
Read the manual? Heaven forbid! It's against the universal "guy" code! It's
not in there anyway :-). Extended high-speed dips like Eau Rouge require a
high maximum applied spring rate, either through stiffer coil rates , longer
br's, or greater ride height, while quicker jolts might be dealt with through
higher bump damping, which is more time-sensitive. Unfortunately, there is no
single best answer for everyone. GPL is quite realistic in that EVERY setup is
a compromise. You always want more, but end up settling for what you can live
with. Therein lies the art, no?
Steve B.
Steve Blankenship
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