Under-damped front dampers (already filled with ep80/90)

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Andy P
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Under-damped front dampers (already filled with ep80/90)

Post by Andy P » 05 May 2009 11:32 am

Well, I've finally driven my Valvo and its great except the front suspension. I'm running cut down rear MR2 springs in the front and the dampers are filled with ep80/90. I made sure they were fully drained and then filled with the correct amount of oil and first impressions I thought they'd work great as it takes a lot of effort to pull the shaft out. The problem is, after my quick test drive the front is very bouncy. The springs feel ok for the height i'm running (ie very low) and I'd rather not replace them with softer springs because I'm pretty sure I'll bottom out.

What are my options? I was thinking of draining and refilling with even heavier oil although I'm not sure what. I've had a quick search and I've found some 120w silicone damper oil (the problem being its only sold in 57ml's because its designed for an RC car!)

I do have a set of suspension off my S40 that I could play with but I'm not entirely sure how'd I'd go about replacing the damper on the front of the 340 as its one piece with the strut - or am i completely wrong?

Anyone got a spare pair of front struts localish? Ultimately I'd quite like to make a set of adjustable coilovers.

All help / comments greatly appreciated.

Cheers!

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xtrmjks
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Re: Under-damped front dampers (already filled with ep80/90)

Post by xtrmjks » 05 May 2009 04:01 pm

I think Your problem is cut springs, I run my coilovers with EP80/90 and 300lbs springs.
works well!! As for cut springs, they no longer are progressive..
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Andy P
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Re: Under-damped front dampers (already filled with ep80/90)

Post by Andy P » 05 May 2009 04:56 pm

I'm not entirely convinced... The springs are very stiff I admit - there is little sag when the car is lowered off the jack..

I guess you could be right - if the springs were longer but gained stiffness via preloading (obviously I have none - sping is about half the length of the damper!)

I think the problem is.... I need to be a man and make some coilovers lol :lol:

Andy

kaos
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Re: Under-damped front dampers (already filled with ep80/90)

Post by kaos » 05 May 2009 06:55 pm

parts are cheap to make coil overs. rally design i think it is. you weld on a threaded tube, add the spring etc
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WooDooUK
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Re: Under-damped front dampers (already filled with ep80/90)

Post by WooDooUK » 05 May 2009 09:10 pm

How long have they been on the car? when i did mine i wasn't to happy with them but i left them (because im lazy:) ) they bled themselves and got much better. might be worth giving it a while and chance to bleed.

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Re: Under-damped front dampers (already filled with ep80/90)

Post by classicswede » 06 May 2009 10:41 am

kaos wrote:parts are cheap to make coil overs. rally design i think it is. you weld on a threaded tube, add the spring etc

Those kits do not fit as the 340 strut is to thick
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Re: Under-damped front dampers (already filled with ep80/90)

Post by classicswede » 06 May 2009 10:45 am

If your dampers are already worn no matter what oil you put in that are going to be cack.

Is the problem on the bump or the rebound side of things?
Dai

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Andy P
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Re: Under-damped front dampers (already filled with ep80/90)

Post by Andy P » 06 May 2009 11:40 am

Its the rebound thats the problem (too quick) so the springs bounce the car up.

I'm currently looking into making some height and damping adjustable coilovers. I've found a suitable candidate to modify but I'm not too sure if I should spend £150 on something that I'm going to take an angle grinder to, that may not actually work....

I'll let you know once I've grown some balls :oops:

Oh, and the current dampers are in good condition.

Andy P

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xtrmjks
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Re: Under-damped front dampers (already filled with ep80/90)

Post by xtrmjks » 06 May 2009 03:13 pm

Compbrake do coilover sleeves to 300, using 2,5" spring..
I would try to bleed shox first..
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Andy P
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Re: Under-damped front dampers (already filled with ep80/90)

Post by Andy P » 06 May 2009 03:23 pm

Yup thats where I was going to get the sleeves from however I'm thinking of going a slightly different route. If it works out I'll let you all know how it goes.

If however it all falls flat on its face... you wont be hearing too much from me :? lol

Andy

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Andy P
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Re: Under-damped front dampers (already filled with ep80/90)

Post by Andy P » 07 May 2009 09:42 am

Ok, taken the plunge. Buying a pair of spax height and damping adjustable coilovers (rsx) made for another car which I can hopefully adapt to fit on the 340.

Wish me luck!

Andy P

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xtrmjks
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Re: Under-damped front dampers (already filled with ep80/90)

Post by xtrmjks » 07 May 2009 07:45 pm

Andy P wrote:Ok, taken the plunge. Buying a pair of spax height and damping adjustable coilovers (rsx) made for another car which I can hopefully adapt to fit on the 340.

Wish me luck!

Andy P
For same money, You can have GAZ make You some!!!!
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Andy P
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Re: Under-damped front dampers (already filled with ep80/90)

Post by Andy P » 08 May 2009 11:03 am

Ahh but I guess you're assuming I bought them brand new at full price...

I'm not that rich and/or silly enough to spend that sort of money only to take my trusty grinder to it ;)

Got a front pair second hand for a bargain price.

Andy

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Re: Under-damped front dampers (already filled with ep80/90)

Post by tommysb » 13 Aug 2009 08:32 pm

Can anyone give any feedback on the suitability of the 80/90 oil? I took my front shocks into a garage today, and they laughed when I suggested that's what i wanted!
I'm putting on 200lb springs, and the old oil from the shocks was VERY thin. They suggested a 5/30 oil was as viscous as I would want, and that would be very stiff.
Should I insist on 'stiffer' oil? Or give it a try? I need to make the decision tommorw as I'm putting the struts back on in time for Retro Rides!

Worst comes to the worst, I can take the shocks off and change the oil again. Since 5/30 is quite a lot thicker than what's currently in there, I can't see it being underdamped, personally.

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Re: Under-damped front dampers (already filled with ep80/90)

Post by tommysb » 18 Aug 2009 12:41 pm

For the record,
I went with the 30 oil, 190lb springs, and it seems fine.

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