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Oaklandjester

24 hours of Lemons suspension help

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Greetings, I need some good ideas on setting up the suspension of a 71 for endurance road racing. But first a bit of information

 

The Car current condition

71 Z early

L28 block

5 speed stage

R-180 4:11 open

Unknown lowering springs

Tokiko illuminas

AZ Dave big vented discs WW 1" MC Prop valve

New bearings u joints - new bushings (urethane)

bump steer spacers short steering arms

F 205/50/16 R 225/50/16 Dierzza ZII

ST sway bars F&R

Stock camber castor

new "big dog" frame rails

6 pt roll cage tied in shock towers with cross bay between shock towers.

 

We ran at Sears point 3 days - 24 hours of track time (less pits) car never pushed but we spun a few times - i know i know driver error .. FYI fastest lap 2.09 fasted lap of all cars 2.04 (ok 1 car had a 2:01 on Monday when there were only 60 cars instead of 160.. point is while we are not the best drivers we are competitive..

 

We would like to get any old school el cheepo racing fix advice for the following needs. - with the lemons caveat (need it to work and not cost a boat load - ie no coilovers, no AZ Z track pack, etc creative ideas rewarded..

 

 

Camber - we need negative camber! so far the only idea we are looking at is slotting the top holes at all 4 corners and moving the front holes up and out in the ft cross-member. Any other thoughts?

 

Caster? we got nothing here, any ideas and what will it get us.

 

Lowering. car came with unknown lowering springs looks like about 1 inch. but needs to be lower, lots of room over the tires and car has bump steer spacers... Best so far is advice from Dave Robello, suggested cutting top hats down an inch, (heat up rubber take it out slot metal re install cut down drops car keeps suspension travel... Tried on extra hats destroyed rubber ??? Any other ideas. keep in mind aesthetics are no issue ..

 

Tightening up rear.. negative camber will help -0 camber now.. somebody suggester going to 17 inch rims and bigger wider tires.. thoughts staggered set up no problem, clearance no problem (just cut out any offending metal... _ if so how wide we have a nother l28 block we are building and may get to 225 or so HP..

 

Any ideas are appreciated

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Instead of reusing the old rubber from the hats you could place your modified bits in a Delrin approximation of the original rubber? A mold would be simple enough to make for something like that.

 

Sorry I can't suggest more, though I'm sure someone else will chime in with some vintage racing voodoo!

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DP camber plates from betamotorsports for bolt-in camber plates. Will solve your loose rear and lower car another inch. But you will need to go to 2.5" spring coilover.

 

TTT adjustable TC rods for caster.

 

3.90 Subaru R180 LSD with adapters from johnc at Betamotorsport. Will fix your loose rearend.

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Thank you for your thoughts , I would love to go coil overs but the penalty for doing so would be to great. they love creative fixes but will hit coilovers with a lot of BS lap penalties. We were in class "b" and want to stay there ! The 4:11 gears worked well for sears point andkept us in a good power band . Lemons racing is crowded so rarely are you on a clean line. A LSD unit would cost more than the car did! ( However i will look into one for NASA events.

 

For camber we are going to slot the strut towers( anybody have any pics to share) we were advised to push the front control arm out and up on the front crossmember. (Any pics of thiswouldhelp as well)

 

Any reason I can't swap out a set of 240 front hats for the rears? They look at least an inch narrower???

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Slot the strut towers and move the front LCA mounting point up 3/4" and out 1/2".  You'll have to cut off the inner welded washer on the cross member and then plate the entire inside area with sheet metal of equal thickness as the washer you removed.  Cut, weld, and then drill.   Do not move the mounting points out farther then 1/2" on each side or your tie rod will end up too short to be safe for track use.  Make absolutely sure you retain the same hole alignment as stock.  For you're driving caster should be +4 to +5. equal on both sides.  You can get that by placing hardened washers in front of the forward TC rod bushing big washer.  Use new stock rubber LCA bushings and new rubber TC rod bushings.  What you sacrifice in ultimate handling precision you make up with less driver fatigue and a more forgiving car when a driver screws up.

 

On the rear slot the strut towers and run urethane inner LCA bushings.  Keep the rubber outer LCA bushings.  Run big anti roll bars front and back to control roll and cut another coil out of your lowering springs - only if your struts are shortened.  Add good progressive (not urethane) bump stops and use them as additional springing:  http://performance-suspension.eibach.com/motorsport/products/accessories/bumpstops

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The stock TC rod is almost exactly the right size for running a 5/8" die down it. You could cut it and thread the last couple inches on each end and use a turnbuckle instead of shimming the caster. If you run too much you'll pinch the LCA bushing, but if you're using rubber it probably doesn't matter.

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