Johneturbo
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| posted on 9/5/09 at 07:28 PM |
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Wrong spring poundage?
Gday all
Been doing some headscratching today over my cars handling.
ie it doesn't give me confidence of anything that isn't billiard table smooth!
well anyway was looking over the front and noticed the offside was more compressed than nearside (about 2cm) this is an inboard set up and the
pushrods are both the same length
now the springs are the same length and so are the dampers first thing i checked once i noticed it.
i've attached some pics
is it just a case of the springs being different poundage they are both marked as 175lb
 
Description
 
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[Edited on 9/5/09 by Johneturbo]
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mr henderson
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| posted on 9/5/09 at 07:45 PM |
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Might have been done as part of a corner-weighting exercise. Check out the recent "suspension set-up" thread
John
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Johneturbo
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| posted on 9/5/09 at 07:52 PM |
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Ok i built the car, i've only had it laser tracked so far.
the first pic is with the platforms wound all the way down, strange how the offside is more compressed
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philw
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| posted on 9/5/09 at 08:01 PM |
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These are protech arn't they, i had the same with mine the internal valving was slightly different, as i live near to them i took the shocks
down there and they did it while i waited excellent service.
Must try harder
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philw
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| posted on 9/5/09 at 08:04 PM |
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Forgot to say, whip your springs off and compress the push rod into the damper by hand and feel if they are similar.
Must try harder
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Agriv8
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| posted on 9/5/09 at 08:40 PM |
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could it have wound itself down ?
regards
Agriv8
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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stuart_g
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| posted on 9/5/09 at 08:59 PM |
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Hi Jon,
I still stand by the 150lb springs I still have fitted and what you fitted to your first car. They totally transformed my car as the front suspension
actually moves now where as before it was solid even when I stood on the chassis and jumped up and down. I now have the rebound adjuster set two
clicks in from fully wound out.
When I put mine together I wound the sping adjusters up the shock the same amount and set the ride height with the pushrod lengths. My shocks ended up
like yours but the other way round, my passenger side is slightly more compressed than the drivers side even with me in it.
By the looks of your pictures it definately isn't right you have hardly any movement especially in the drivers side before it will bottom out.
I would get the springs changed for 150lb as you did on your first car and while the shocks are off do a compression comparison test between the two.
Also too much toe in all round the car will make the steering very nervous on a light BEC being used for the road where the camber is always changing.
I know I said it to you before but speak to Andy at AB performance, I know it is a bit of a treck from you but it will be worth it.
Cheers
Stu.
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Johneturbo
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| posted on 9/5/09 at 09:46 PM |
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ok thanks for the ideas guys
philw, yep they are protech i'll check how they feel once i've removed the springs
Agriv8 in the first pic both springs platforms were wound all the way down, but to get them looking the same( same compression of the damper)
i've had to wind up the drivers side to get it looking the same.
Stu, i'm tempted to take it to AB and see what he thinks of the setup, something isn't right i'm just not sure what yet.
also stu when you had yours corner weighted how much difference was there on the platforms per side
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Chippy
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| posted on 9/5/09 at 10:07 PM |
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You might like to check that the back springs are adjusted equally, if one is higher than the other, it could make the fronts look like yours. Just a
thought! Cheers Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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Johneturbo
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| posted on 10/5/09 at 01:52 PM |
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quote:
Originally posted by Chippy
You might like to check that the back springs are adjusted equally, if one is higher than the other, it could make the fronts look like yours. Just a
thought! Cheers Ray
funny you should say that, i've had to wind up the passenger side platform to get them even at the back.
drivers side
 
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passenger side
 
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Andy D
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| posted on 10/5/09 at 06:44 PM |
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Could you have a front spring on the rear and a rear on the front??
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procomp
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| posted on 11/5/09 at 07:18 AM |
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Hi
If you have had the alignment and geometry setup done then it sounds like it needs the corner weights setting. Also a car that sits level at rest with
no one in it will not be right when driver is on board.
The balance ( valving ) of the dampers will not affect the ride height of the car at all. It only affects the control of the spring once in motion.
Although it is fair to say that many MNR owners have changed springs and have had dampers balanced to aid ride quality.
Cheers Matt
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Johneturbo
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| posted on 11/5/09 at 02:17 PM |
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quote:
Originally posted by Andy D
Could you have a front spring on the rear and a rear on the front??
nope first thing i checked 
procomp, so would you say that its ok to have such a variation with the spring platforms
or is that down to the springs not being equal poundage
[Edited on 11/5/09 by Johneturbo]
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procomp
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| posted on 11/5/09 at 04:40 PM |
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Hi
It's quite common to have one of the rear springs wound up more than the other if corner weighted with driver only in the car. However the
fronts would normally be within a few MM of each other.
Certainly on your fronts you have got to wind the spring platforms up to gain enough travel for bump. But what adjustments are on the push rods.
Highly unlikely that the platforms wound themselves down as they are not easy to move with the weight on them. ( although i do offer a locking collar
for customers who do wish to have one for peace of mind )
Best to count the number of coils on the springs and measure the wire diameter to easily check if they are matching on either side front and rear. If
correct best to get the car setup on ride height and corner weighted. As mentioned Earlier valving could do with checking on the fronts especially as
the inboard dampers are very direct acting meaning that they need to be matched very closely. Something that MNR will not have checked.
Cheers Matt
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Johneturbo
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| posted on 11/5/09 at 05:05 PM |
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Hi Matt
i appreciate the advice
with the front platforms, i wound down the passenger side to get them equal
if i wind up the passenger side then that damper sits higher as in the first pic.
what i need to do is wind them both up a lot more, but then the front ride height is to high, so maybe i need shorter push rods as they are both fully
wound in.
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stuart_g
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| posted on 11/5/09 at 05:55 PM |
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quote:
Originally posted by Johneturbo
Stu, i'm tempted to take it to AB and see what he thinks of the setup, something isn't right i'm just not sure what yet.
also stu when you had yours corner weighted how much difference was there on the platforms per side
I have measured from the bottom of the spring platforms to the bottom of the thread on the front shocks and they are both 33mm. The pushrod lengths
are probably different to achieve the same ride height both sides, can measure if you want, they are definately not fully wound in (shortest). When my
car was corner weighted nothing needed adjusting hence the same measurement.
Here are a couple of pics that show how my passenger side is slightly more compressed than the drivers side, the opposite to yours. The second pic
shows the amount of movement before the shock will bottom out.
 
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Johneturbo
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| posted on 11/5/09 at 06:02 PM |
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thanks for the pic stu,
looks like you do still have enough damper travel. i'm gona swap the front springs around and see if i get the same result.
re ride height, if i wind both platforms down the car sites at about 90mm( i thought it would be a lot lower) the rear is about 125mm so i don't
want to go any heigher than 100mm
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stuart_g
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| posted on 11/5/09 at 06:08 PM |
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I wouldn't go any higher than 100mm at the front, it is plenty high enough. You should get 100mm with the bottom wishbones parrallel to the
ground measured just in front of the wishbone.
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