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Whats the difference....

Want to know what to brakes/springs to buy?
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Dan
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Whats the difference....

Postby Dan » Wed Jan 02, 2008 11:48 am

Is adjusting the dampening an adjusting the spring rate the same thing? If not how would you adjust the spring rate as i think this is what my coilovers need, a bit more length for the suspension to travel

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endapender
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Postby endapender » Wed Jan 02, 2008 11:59 am

No. The spring rate is set during manufacturing. Usually measured in kg/mm. If a spring is rated a 5kg pre mm means that it takes 5kg of weight to move the spring 1mm. 10kg/mm means that 10kg is needed to move the spring 1mm. Generally the bigger the spring rate the stiffer the spring thus a stiffer ride.
The damping adjustment is in the damper and changes the valveing in the damper so that if you set the damper to soft the valve opening is bigger which means that if you push the rod down all the way it will return to te top quickly. If you adjust the damper to to hard the rod will return slower to the top.

If your car is hard on the road usually different springs with a softer spring rate will make it softer on the road. The problem this brings is that the car can get more bouncy on the road but this can be helped with damper adjustment so make the car comfy and still hard enough for good handling

What prioblems are you having with your suspension Dan

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Dan
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Postby Dan » Wed Jan 02, 2008 12:19 pm

cant really take any weight in the back without bottoming out so im thinking either the springs are too soft and cant take the weight of any passengers or dampening is too soft

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Postby endapender » Wed Jan 02, 2008 12:34 pm

its prob your spring rate too soft Dan. Did you get any specs with the coilovers as th what the spring rate of them.

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Postby Mr. Tezza » Wed Jan 02, 2008 1:18 pm

isn't adjusting the springrate moving the bolt at the bottom of the spring... i cud be wrong just guessing
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Postby mAltezza » Wed Jan 02, 2008 1:31 pm

iv got the same problem dan, iv even tried those stupid splitfire rubber spring ajusters, but no luck think it made it worse if anything,
Its the springs that are too soft, the bottoming out noise when you have passengers, is the spring the is fully closed, if u see what i mean,
Iv been after a cure for this for a while now but theres nothing, unless you can get other springs that will fit your coilovers,
If you can get some i'll want some too,
Finally dyno'd 163.7 Bhp @ the wheels @ Thor Racing

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Postby CDA Ben » Wed Jan 02, 2008 8:00 pm

If it's the D2 coilovers, then you can try tightening the springs to increase spring rate, and lengthening the whole strut (done by the adjust right at the bottom). This may solve the problem with bottoming out, although you could just as easily screw up the handling of the car. Make sure you note exactly what settings all the adjustments were before you start playing around, because if you forget, then good luck to playing around trying to get the old settings back as it's a never-ending forward backward process of trial and error.

Alternatively, the shock might be leaking and you can bottom out more easily if that happens. Unlikely for the shock to fail completely as you'ld definitely notice that.

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Postby KaTaLy5t » Wed Jan 02, 2008 8:04 pm

I have the same problem with my TOMS coilovers Dan. I don't know if I can adjust the dampening. If I put any weight in the back I scrape on speed ramps and bumps and I can't drive that fast on a country road!

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Postby Dan » Wed Jan 02, 2008 8:14 pm

CDA Ben wrote:If it's the D2 coilovers, then you can try tightening the springs to increase spring rate, and lengthening the whole strut (done by the adjust right at the bottom). This may solve the problem with bottoming out, although you could just as easily screw up the handling of the car. Make sure you note exactly what settings all the adjustments were before you start playing around, because if you forget, then good luck to playing around trying to get the old settings back as it's a never-ending forward backward process of trial and error.

Alternatively, the shock might be leaking and you can bottom out more easily if that happens. Unlikely for the shock to fail completely as you'ld definitely notice that.


Cheers Ben, but doesnt lengthening the whole strut raise the height of the car? Shocks aren't leaking but 3 of them were, and have been repaired since. Is there anything else that can fail on the coilovers to cause this bottoming out, there is 2 adjusting rings at the top. What are these for?

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Postby Dan » Wed Jan 02, 2008 8:28 pm

KaTaLy5t wrote:I have the same problem with my TOMS coilovers Dan. I don't know if I can adjust the dampening. If I put any weight in the back I scrape on speed ramps and bumps and I can't drive that fast on a country road!


All coilovers as far as i know have some sort of dampening adjustment, usually has a thing on the top mount that lets you adjust dampening. Well i tightened up the dampening on the rear and seems to be a bit better

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Postby KaTaLy5t » Wed Jan 02, 2008 8:37 pm

Must have a look at mine. Might make it a bit more bumpy but it beats the crap out of scraping the bottom!

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Postby CDA Ben » Thu Jan 03, 2008 12:03 am

Not all coilovers have damping adjustment. A lot of the Cusco coilovers don't have adjustable damping. And adjusting the damping won't solve the bottoming out problem by very much.

The good coilover models have independent height and damping adjustment. Damping through the knobs on top. Height through adjusting the lower bracket.

Image

Some don't have a lower bracket and only have the one immediately below the spring. This means that you can still adjust height, but if you do, you'll be changing the spring rate as well.

@Dan, that's why if you don't want to affect the height, you can compress the spring (ie. increase the spring rate) by adjusting the bracket immediately below the spring. Then lengthen the whole strut by winding down the lower bracket.

The adjustment rings on top.....I've never played with them before. As far as I know, they do nothing. For the D2s, it's the bracket immediately below your spring, and the whole aluminium bracket that you adjust.

There shouldn't be anything else that can fail easily on coilovers. Shocks are the main thing as they have the most movement of all the parts.

The BMW used to have that problem as well, and we just raised the back a bit more. Looked a bit more aggressive as well with the slightly leaning forward look.

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Postby Dan » Thu Jan 03, 2008 12:57 am

Thanks for the info ben, The only adjustments ive done with these D2's is moving the bottom ring highlighted in black for height adjustment. So is it the ring ive highlighted in red near the top that i need to adjust to compress the spring? So if im understanding you correctly, do i need to compress the spring and lengthen the shock to retain current ride height and solve bottoming out issue?I thought compressing the spring is bad for the springs ?
I'll be out at CDA tomorrow so maybe i can have a chat with you if your there

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Postby Noel » Thu Jan 03, 2008 10:31 am

From that pic Dan it looks like there isn't any thread left to compress with... :?

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Postby CDA Ben » Thu Jan 03, 2008 8:07 pm

Dan, that is correct. Generally it's not recommended to compress/uncompress the springs by adjusting the red one. But if the initial settings are not right, then you might as well go ahead and adjust it. And bottoming out shocks is much worse anyway as they'll fail faster. I won't be at the shop, Nick will be there though.

And ya, there doesn't look like there is any more thread to compress.


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