thepest
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| posted on 2/4/07 at 01:11 PM |
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Spring rates
Dear all,
I have built a book chassis, and I am using it for hillclimb races in malta.
The spring rates I have at the moment are 220lb/mm in front and 180lb/mm in the rear (Shocks from GTS tuning).
The car weighs 560kg, however I find these too stiff for the imperfect roads and occasional potholes we have on our roads here.
What spring rates would you recommend for a softer ride?
At present it just skips on the bumps and the tyres do not contact well when I accelerate out of corners,not to mention my teeth getting chipped...
Anyone with any experince on racing these on rally type surfaces?
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Tralfaz
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| posted on 2/4/07 at 01:15 PM |
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Per MM? I would think they were to stiff!
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Howlor
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| posted on 2/4/07 at 01:18 PM |
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Do you have adjustable dampers as well?
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procomp
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| posted on 2/4/07 at 02:18 PM |
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Hi try contacting FLUKE MOTORSPORT They have a lot of expirience of using a westfield in
these sorts of conditions.
cheers matt
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Rob Palin
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| posted on 2/4/07 at 02:18 PM |
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I think you mean lb/in, not lb/mm? They would indeed be seriously stiff, not to mention a wierd combination of metric & imperial units.
On Locost circuit racers people tend to run 300-550lb/in springs on the front and 120-190lb/in on the rear. It's quite a large range, i know.
The race tracks we use are fairly smooth, in the grand scheme of things, but not super-smooth.
180lb rear springs seems quite aggressive. Maybe swap them for ~150ish and then soften off your dampers? (i run my Avo rear dampers at only 5 clicks
out of 22).
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trialsman
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| posted on 2/4/07 at 03:37 PM |
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Rob. I also have AVO's on my Locost but I do not have any instructions on what the adjuster know does or which way to turn it. Do you know where
I can download something that does? There are no reliable sources for AVO's in the USA, Russ
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procomp
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| posted on 3/4/07 at 06:53 AM |
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Hi please ignore my post above. Not only was in not supposed to be in this section but a totaly different forum altogether. Unless you where thinking
of using a seven for a spot of rallying.
Avo and most other dampers have the adjuster knob working from fully anticlockwise as 0 to fully clockwise as full.
Depending on what valving has been fitted will either give you a raise in bump and rebound (depending on bump/rebound ratio) per click upward or
possibly a fixed bump and only an increase in rebound.
Best bet would be to get them on a damper dyno and see the results as people in your part off the world (assuming usa) are far more serious about
dampers than they are in this country where most people building kitcars never have them checked at all.
cheers matt
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thepest
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| posted on 3/4/07 at 06:53 AM |
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Shocks
Thanks Guys, these are the shocks I am using:
http://www.s123613988.websitehome.co.uk/locost2.htm
It could be that the spring rate is per inch and not mm, I thought that they would always be in mm.
The shocks do not have adjustable damping.
I'll check out protech, thank you
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procomp
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| posted on 3/4/07 at 06:59 AM |
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Hi in simple terms unless they where built exactly for your car/spring rates they are pretty much usless.
cheers matt
PS GTS never supplied good old ron with any dampers for the original race cars in the championship.
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thepest
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| posted on 3/4/07 at 09:11 AM |
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correct rates
So other than trial and error how would I calculate what average spring rate I need?
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procomp
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| posted on 3/4/07 at 01:59 PM |
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Hi depending on the exact setup of the car your fronts are close. But the rears are to hard try 140.
It is a bit of a case of trial and error. Mainly due to different driving styles.
But 200-300 front. And 100-160 rear.
Also the dampers need to be right for the live axle aplication.
cheers matt
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DickieB
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| posted on 4/4/07 at 08:50 PM |
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I agree with Matt from Procomp. 200-220 front, and 120-140 rear. I used to run a roadgoing Westfield which is remarkably similar to a Locost. Also get
your shocks/dampers calibrated. you'd be amazed how many shocks with 22 clicks actucally have a working range of just 3-4 clicks, and you need
to know where that range is, ie do they do nothing until x, and then from x+3 are completely solid? But what if x is 3 or 10 or 17?
Sorry, Maths degree coming in there, but I think it makes sense.
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