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I am working on a new car for stock class solo.

I found an interesting damper that I want to use. Fully extended length is longer by about .5 of an inch from stocker so I am good there(+ or - an inch ok). Fully compressed length is a little under .5 of an inch less than stocker. I am worried that I might "bottom" out the shock and cause damage to it's internals.

Shock rules state that I cannot use "offset" bushings but on this car, the shock is a stand alone part. Spring and bumpstop are completely separate from the shock. I think I should be able to use offset bushings(.25" on each one)  to match the stock dimensions. There will be no performance advantage to doing this vs a coil over type system which would lower the car if you used offset bushings.

What I want to do is to "shorten" the eyelet to eyelet distance to match the stock dampers so I know I won't bottom the shock out. I don't know if it would be possible to actually bottom the shock out but I'd hate to wreck a couple of expensive dampers when such an easy fix is there and would cause no performance advantage on this type of suspension system.

Time for a letter?

FM

 

If the "interesting damper" and stock bump stop causes damper damage how is any change to save said damper not a performance advantage

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Mark Hirt
2007 MX-5 MS-R
Bowman Race Kart - rented
Webmaster Chicago Region SCCA

I don't think that was the intent of the rule.  I believe the intent is to allow for a sligltly larger range than stock OEM measurements.

Remember, in this application, the bumpstop and spring perch are not located on the shock. They are located about 8 inches away from the damper.

I am not trying to shorten the effective length of the new damper from the stock dimensions. I am trying to match the stock dimensions(eyelet to eyelet).

Technically, I think I could have a welder completely weld up the whole area of the eyelets then drill them out with the offset then use spherical bearings for the "bushing" that are not offset and would be legal but all that work seems pretty silly when I can do the same thing with an offset bushing.

FM

Why not just put an additional bump stop on the shock itself, thereby limiting the travel to same as stock?

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Robert Puertas
www.EvoSchool.com

there should be any number of ways to correct the situation within the parameters of the allowances, but since you haven't been specific about what you're using or doing it can''t really be determined yet

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"Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car.
Horsepower is how fast you hit the wall, torque is how far you take the wall with you." --Anonymous

The car is a GM "twist beam" rear axle. Both the stock damper and the one I want to use have an eyelet to eyelet mounting. The both have the same stroke.

I tried to find a good picture of the system showing that the shocks are separate from the spring/bumpstop system but I couldn't find any.

I would not be able to "add" a bumpstop since that would be the same as adding more spring. You can substitute bumpstops for the purpose of replacing shocks but since the stock bumpstop is in a different location from the shock, I don't think I would be able to get away with that.

The aftermarket damper might work fine since OEM usually put a little extra room in designs and probably didn't want the stock shocks bottoming out internally either. Doing the offset bushings will make sure I match the stock dimensions so I would feel more comfortable about avoiding bottoming with the new ones.

FM

Why not remove the rear springs and cycle the suspension through its range of movement and find out if there will be a problem first, before trying to solve a problem that may not exist on your Cobalt SS turbo?

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David Avard
89 Honda Civic Si black (STS)
07 Mazda 3s (HS?)

lol, way to spoil the pussyfooting Davard

 

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"Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car.
Horsepower is how fast you hit the wall, torque is how far you take the wall with you." --Anonymous

Huh? What Cobalt SS turbo? Why would I want to race one of those heavy FWD cars that probably can't even beat a GS MiniS?
Cmon now...

FM

260hp, 260 ft.lbs, launch control, no-lift shifting, a real LSD, 18 x 8" wheels, and "the best handling FWD" according to R&T.  Yeah, sounds like it would suck for autocross, especially Pro Solos.  Why would anyone drive a "Slobalt."

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David Avard
89 Honda Civic Si black (STS)
07 Mazda 3s (HS?)

Mike,

My personal opinion is that in this case you could offset the center of the bushing up or down along the axis of the shock (not side to side but that's not what you want to do).  You would then use the new center of the bushing for determining legality in terms of spring seat position and overall extended length.

It would probably be tidiest if you made a metal sleeve that fit into the shock eye, with a hole in it to place your bushing where you want it. Weld or bolt that to the shock eye so that it can't rotate and effectively becomes part of the shock.

Can you get the shaft shortened? 

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John S.
S2000 #42as