David Jenkins
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 posted on 7/10/02 at 07:36 AM |
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Suspension pre-load
Now that my engine is in, and the car's approaching its full weight, I find that I need to put a lot of pre-load on the front shocks to get the ride
height correct (around 1.5", or more).
This seems a lot - or is this what other people have found?
For info, I've got Avo shocks with a top mount that's on the side of the chassis rather than underneath (it is braced!). My springs are 200lb/in,
which may be too light, but I don't want to go too hard - it's a road car, not a racer.
cheers,
David
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bob
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| posted on 7/10/02 at 07:54 AM |
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Hi David
My springs are 325lb on the front using GAZ shocks on the indy,but it is a pinto so HEAVY.
Other pinto indy's i've seen have at least 2" of preload,so if your using a crossflow with lighter springs i suppose theres nothing in it.
Have a look at some archive pics on locostcar club as most are crossflows,i always use pics as a guide its really helped me.
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David Jenkins
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| posted on 7/10/02 at 07:57 AM |
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Bob,
forgot to mention that it's a crossflow, so on the light side!
David
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interestedparty
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| posted on 7/10/02 at 08:03 AM |
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quote:
My springs are 200lb/in, which may be too light, but I don't want to go too hard - it's a road car, not a racer.
Springs are defined by two measurable characteristics, their poundage i.e. how much force in pounds is required to compress them by one inch, and
their unfitted length. As you don't want racer suspension, it sounds like you could do with some springs of the same poundage but maybe an inch
longer. Firms like Demon Tweeks etc should be able to supply.
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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David Jenkins
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| posted on 7/10/02 at 08:38 AM |
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You could be right about spring length - I was wondering whether I needed to increase length, increase poundage, or both! It's also apparent that the
springs aren't under any compression for the first 0.5" of pre-loading thread (they rattle around). I guess this means that an extra inch would be a
good idea (funny - my wife keeps saying that...  )
David
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stephen_gusterson
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| posted on 7/10/02 at 05:36 PM |
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with my v6 i have 350 lb springs and they need a shyte load of preload.
So much so i am gonna make new mounts for the top.
My car being unstandard, with a wider track, means the shockers are more angled - about 50 degrees i think.
If a shocker is angled at 45 degrees it has i think half the load rating for the springs.
So, I wonder David if you have a fairly steep angle?
atb
steve
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interestedparty
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| posted on 7/10/02 at 06:04 PM |
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Regardless of the mounting angle, if the spring is too short then you need a longer one
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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stephen_gusterson
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| posted on 7/10/02 at 07:04 PM |
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yep. thats pretty obvious!
However, there can be a tendency to increase preload in order to adjust the ride height to such an extent that it makes more sense to use a different
mounting point OR a longer shocker.
A damper has no resistance at all - its the spring that does that. So if ther spring rattles loose, then its clearly not fitted properly and even hand
pressure will close up the gap.
atb
steve
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stephen_gusterson
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| posted on 7/10/02 at 07:05 PM |
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quote:
yep. thats pretty obvious!
However, there can be a tendency to increase preload in order to adjust the ride height to such an extent that it makes more sense to use a different
mounting point OR a longer shocker.
A damper has no resistance to compression - its the spring that does that. So if ther spring rattles loose, then its clearly not fitted properly and
even hand pressure will close up the gap.
atb
steve
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interestedparty
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| posted on 7/10/02 at 08:26 PM |
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A set of springs, available in a vast array of lengths and poundages, should cost around £40. As Steve points out, the shock absorber will have no
effect on the ride height, so the best way to deal with ride height problems is to fit the correct springs.
Adjustable spring platforms are best used for setting cornerweights, and should never be adjusted so far up that the suspension travel is reduced.
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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David Jenkins
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| posted on 8/10/02 at 08:43 AM |
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quote:
So, I wonder David if you have a fairly steep angle?
No - in fact, they're more upright than shown in the book (I put the top mounts on the side of the chassis member).
David
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bob
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| posted on 8/10/02 at 03:17 PM |
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David
Have a chat with stevem (steve mullany)
His car is book version and crossflow engined,and he also has springs/dampers in the more upright possition.
I also think they may be spax as well
His car is featured in the 2nd book p186 middle and bottom,also in pics on locost car club
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