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Author: Subject: Shock mount positioning
cloudy

posted on 16/8/06 at 03:38 PM Reply With Quote
Shock mount positioning

I've come to the point of putting the the top mounts for all the shocks on my scratch build, I've heard various figures like the car should stand at an inch of suspension travel. Are there any rules of thumb or methods I can use to get the correct mounting locations...


I think i'm going to try and aim to have all wishbones level at rest...

James

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nick205

posted on 16/8/06 at 03:49 PM Reply With Quote
Check my post in this thread and get a copy of the book

CLICK HERE

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kb58

posted on 17/8/06 at 12:15 AM Reply With Quote
"In general" at normal ride height with all fluids and driver aboard, you want the shock about half compressed, or maybe a bit less, so 40-50%.

Oh and you should have "about" 3" of *wheel* travel before hitting the bump stop.

All these numbers are subject to great argument, but it's working fine on my car. It very much depends what road surface you drive on and how firm a ride you can stand.





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cloudy

posted on 17/8/06 at 02:08 PM Reply With Quote
thanks kb58, just the info I was after

James





www.warnercars.com

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cloudy

posted on 25/10/06 at 12:57 PM Reply With Quote
Sorry to reopen this one, but what clearance do most sevens have when right down at bump stops on the suspension?

James

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cloudy

posted on 26/10/06 at 04:12 PM Reply With Quote
anyone?
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flak monkey

posted on 26/10/06 at 04:15 PM Reply With Quote
What clearance?

Ground clearance i assume... most have it set between 3" on track and up to 6" for the road at ride height. What that would give at full bump i dont know.

David





Sera

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cloudy

posted on 26/10/06 at 05:33 PM Reply With Quote
sorry. yes its ground clearance on the bump stops i'm after....
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cloudy

posted on 30/10/06 at 10:21 AM Reply With Quote
anyone? even a guesstimate?

Basically i need to know whether i hit the bump stops with the chassis just clearing ground or whether i need to be and inch or two up.....

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cloudy

posted on 31/10/06 at 09:34 AM Reply With Quote
I presume this is harder for people to check than I thought

James

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Marcus

posted on 31/10/06 at 11:58 AM Reply With Quote
On the bumpstops, my sump barely clears the ground.
Guess that means the chassis, at that point, is about 1 1/2" from the floor.





Marcus


Because kits are for girls!!

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cloudy

posted on 31/10/06 at 01:31 PM Reply With Quote
Many thanks Marcus - that's all I needed to know, i'll get those mounts welded in tonight

James

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kb58

posted on 31/10/06 at 02:37 PM Reply With Quote
What you're asking has no black-and-white answer. It all depends on your car's application, what the roads are like in your area, if you have to drive over fallen debris, speed bumps, pot-holes, railroad tracks, driveways...





Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book - http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html

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cloudy

posted on 31/10/06 at 10:04 PM Reply With Quote
OK I've welded them on, it gives about 1" clearance with the bumps fully squashed and 2" as it starts to hit the stops

This gives just over 10cm of suspension travel, with the car resting at about 6cm, leaving 4-5cm of upwards travel.




am I going to get away with this based on the photo + measurements above or do I need longer shocks?


James

[Edited on 31/10/06 by cloudy]

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Uphill Racer

posted on 30/11/06 at 08:23 PM Reply With Quote
Pickup point for coilover on chassis will bend.
NEVER feed loads into the chassis like that.
Wishbone pickup points in tube if not braced (triangulated) will distort chassis.
Sorry for the bad news, but better now while it can be corrected.

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Schrodinger

posted on 1/12/06 at 10:42 AM Reply With Quote
I think you will find that the angle that the shock is at will also give you problems with a falling rate spring IIRC the spring should be as near 90 deg. to the suspension travel as possible and by the looks of yours it's about 45 degrees
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Peteff

posted on 1/12/06 at 11:32 PM Reply With Quote
Weld a bar across your top wishbone and gusset a top bracket wherever you want it on the chassis member then run your shock wherever you want it to make the ride height right. Sorry for the rough drawing but I hope you see what I mean. edit here:- or if your dampers are 12" open 9" closed get some longer ones and I'll take the old ones at a greatly reduced rate.

[Edited on 1/12/06 by Peteff] Rescued attachment suspension.jpg
Rescued attachment suspension.jpg






yours, Pete

I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.

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t.j.

posted on 2/12/06 at 08:53 AM Reply With Quote
Hey,

I'm agree that the chassis will bent at the top mounting pos.

I want to argue that the coil-over in front of the car (most) are also not 90 degr is placed.

If you want to place the coil-over as suggested by pete you have to make a strong wishbone.

I like the idea to keep the coilover as close as possible to the upright.

In this case i would search for longer coilover and made a lot of enforcement on the upper coil-over mounting try to get the forces in the coilover al in line with the forces into the chassis.

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