Lotus Elan

Spax Adjustables Ride Ht

PostPost by: khamai » Thu Mar 11, 2004 4:58 pm

Has anyone had any experience with mounting Spax adjustable (AS version - adjustable spring perch) mounted with stock springs (16" free length 75lb/in) on the front a found the ride height to be about 2-3" higher than stock.
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PostPost by: john.p.clegg » Thu Mar 11, 2004 5:02 pm

i don't think the dampers will affect the ride height,more likely to be the springs of a wrong poundage or length?
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PostPost by: john.p.clegg » Thu Mar 11, 2004 5:04 pm

P.S.
that is if you have set the perches at their lowest
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PostPost by: Unibrain » Thu Mar 11, 2004 5:41 pm

I'm using the same spring/shock combo and find the ride a bit high. See
<a href='http://www.unibrain.org/motorsports/elan/gallery/restoration/DSCN1101' target='_blank'>this picture</a> to see what I mean. The adjusters are within an inch of the lowest setting and the ride is still 1-2" high. I'm waiting to get the car on the road and things to settle a bit before doing the final height adjustment.
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PostPost by: khamai » Thu Mar 11, 2004 7:16 pm

Right... I should explain further. I have the perch at its lowest level. I've compared the fitted length of the spring with my other Elan (with stock suspension) and they are within 1/2 inch on one another. That 1/2 inch only explains about 3/4 inch of the 2-3 inch difference.

One thing I noticed was that at the top of the stock Armstrong damper the mount is right on top of the perch, whereas on the Spax there is a shaft of about 1 inch between the top of the perch and the mount. The bottom perch is in pretty much the same location on both. This extra inch on the Spax would add about 1 1/2 inch in ride height. In my case add another 1/2 inch from the differenc fitted spring length to the 1 inch shaft on the Spax and I get 1 1/2 in of added length between the top mount and the bottom mount of the damper. This would equate to about 2 1/2 inches in ride height.

I'm getting the impression that others running Spax with stock springs are seeing the same thing. I'd like to avoid getting shorter springs, but I don't think I have a choice. RD has 100lb/in springs with a 12 inch free length. These would take out about 2 inches in the fitted length of the spring (perch to perch) and would lower the car about 3 inches.
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PostPost by: type26owner » Thu Mar 11, 2004 7:53 pm

Kiyoshi,
Shortening the springs is easily done. It takes about an hour a piece. Can be done with a cutting torch and a disc sander or preferably a belt sander. Ran across a website awhile back that showned how to do it but I've lost the link. Doing so will increase the spring rate to the point you'd be better off just replacing them with the 100lb/inch type.

I had the Spax steel washers which retain the upper rubber cushion on the bottom side fail by cracking and folding back into a conical shape. Both sides had failed in the same way at the same time. The threaded portion of the shaft then has more vertical travel available so it pokes throught the fiberglass. I should be greatful the holes are smallish and appear to be original to the car. If the washers are only about .06" thick then be wary. Made my own which are .125" and have not had a similiar failure.
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PostPost by: khamai » Thu Mar 11, 2004 9:16 pm

Keith,

Thanks for confirming my decision, which was to call Ray @ RD and have ship a set of 12" - 100lb springs. I've gone down the path of cutting springs on various cars in the past and have yet to really get a satisfactory result. Spring changes typically end up putting a smile on my face.

Great tip on the washers. I'll change them when I do the disassembly to change springs.
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PostPost by: type26owner » Thu Mar 11, 2004 10:56 pm

Kiyoshi,
Even with the new springs check the squareness of the ends. These springs tend to pooch out sideways and can really bind up on the shock body. I had to regrind the flats on the ends of mine to get them true and square to reduce the binding after a month's usage. Still needed greasing to get it to handle okay and quiet the squealing. Have thought about making canvas covers held on with velcro to keep them clean but haven't done it yet. I didn't buy my springs from that vendor so hopefully you'll be better off.;)
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PostPost by: khamai » Fri Mar 12, 2004 3:12 am

I always check that. But, thanks for the reminder. Especially prone on softer springs that are old (spring sag). The original Armstrongs are typically fitted with a plastic sleeve over the shock body. I've been looking into finding some oversized shrink tubing to do the same.

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PostPost by: Rob_LaMoreaux » Fri Mar 12, 2004 1:02 pm

I had this problem when I put the Spax adjustables on my car and after some calculation I went with 14 inch stock rate (75lb/inch) springs. These actually settle a little lower than I like even though they looked a bit high when the car was first put back on its wheels.

If I did it again I would go with 15 inch 75lb/inch springs.

I do have some 12 inch 115 lb/inch springs I may put on the car some day but I worry that they may be too stiff to be comfortable on the road so I have hesitated to put them on.

Remember that there is about a 2 to 1 ratio of shock to wheel movement, so 1 inch of the shock movement is about 2 inches of the wheel movement.

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PostPost by: khamai » Fri Mar 12, 2004 4:10 pm

I think I once calculated the damper mechanical advantage around 1.8:1. Thus, as you pointed out 1" change in fitted length of the spring is about 1.8" of ride height change. This is the number I've been using, but I should go back and find my measurements to confirm instead of using old memories.
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PostPost by: berni29 » Sat Mar 13, 2004 8:14 pm

Jim

That Elan is beautiful. So is the garage. Is that Bahama yellow? I am going to do my +2 in that colour. I doubt very much if the finish is going to be of the same quality though.

Happy motoring

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PostPost by: elancoupe » Sun Mar 14, 2004 2:32 am

I use the adjustable Spax on the front of mine, and had the same problem, ride height too high on the lowest setting. I talked to John Kouba about it, and he provided me with shorter springs of the virtually the same rate, in chrome silicon steel. Ride height is now where I want it.
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PostPost by: TomR » Mon Mar 15, 2004 8:30 pm

For what it is worth, I am using AVO adjustable perch shocks on my S4SE and determined that I could fit a 11" spring without compressing with the perch at the lowest point. I went to Renton Coil Spring to get 115 lb/in, 11" long, 1.875" ID titanium springs for $150 ea. Apparently they stock them for some snowmobile application. Not cheap, but easy to assemble and very pretty. I end up with the perch in the middle of the adjustment range at perhaps 1/2" below stock height.

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PostPost by: Unibrain » Tue Mar 16, 2004 1:28 am

Berni,

The color is as close to Lotus Yellow as I could get. I had a sample shipped from England and matched by the shop that did the paint. As for the garage, if you saw the other side you would not call it beautiful.

- Jim
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