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Am I reading the rules right?.....coilovers for my 1972 240Z are still street prepared legal?

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Paint don't make it go any faster.

Yes. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

This idea interests me a lot. If I go to coilovers on my Vette then do I get bumped from AS to BSP or do I take the slippery slide all the way to SM2 or ASP ?

Graham

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http://www.greywinds.com

C4's to BSP, C5's to ASP or SM2 with just coilovers. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Another interesting class question....Aftermarket/custom control arms.

The reason this is a biggie Q is that the s30 Datsun Zs have no way to change suspension geometry. Literally the only thing you can adjust with the factory setup is front wheel toe angle.

Well....Z cars are one ton eggshells. Mine has been hit twice in the past. my other Z car has been hit once. all minor collisions...but devastating to the suspension geometry. I was forced to put camber bushings in the lower front control arms.....just to get rid of the 1.5 degrees positive camber on the right front....and even out the 1 degree of negative camber on the front left. I still cant get them even without them both becomming positive.

The car is not right...and the easiest way to fix this problem is to relocate the lower control arms' mounting bolts and/or elongate the lower crossmember mounting holes and move it over a few/15mm. Here lies my problem....none of this is leagal in BSP class. What can I do to fix it....without going modified. Also if I am going to drill new holes to move the control arms I would like to move them almost an inch up and out...to make them work properly with a coilover system.

The other way I could fix it would involve custom lower control arms $$$.
Ohh and upper camber plates are not even an option unless you move to smaller diameter springs(coilovers)....or make entirely new strut towers to accomodate the movement of stock springs. even then....the sidedraft carbs are too close to the left strut tower to move it much...and the coilover plates still dont give much adjustment over 0.5 degree.

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Paint don't make it go any faster.

Edit: You already answered my camber plate question...

Honestly, I'm thinking you might as well just gut that car, put a cage in it do what you want to it and go straight to mod. Pax will not be your friend, but you don't need to tiptoe around the rule idiosyncracies(sp) that limit you. It's the everpresent dilemma - build a competetive car or build the car you want.

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Tom Freeman
'98 M3/4/5 | '93 Spec3 325i | '12 TSX sport wagon | '03 Tahoe
Team Silver Bullets '91 240SX

well....I could take the car to a frame shop and have it realigned...I have a full size layout of all unibody dimensions...but I have been told that they usually have to cut and weld to get things right and tight. That would likely involve some of the same things I just mentioned...

If the frame shop mvoes things around by drilling and relocating....can I do it and call it a fix....rather than a mod.

simply moving the lower crossmember over 15mm would solve the problem of making the camber even on both sides without going positive.

Ultimately the strut towers are flexed out of position and lower frame rails have been pushed to one side. you cannot fix the lower frame rails without cutting them out....the strut towers will not stay where you bend them unless you cut and weld the top supports.....I would think that the frame shop would likely just move the lower crossmember and call it a day. I can do that in an hour in my garage.

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Paint don't make it go any faster.

I would think that moving parts back to factory position would be legal. It's all about being in OE location. I could be way off base here but I would think if you keep the printout from the frame shop showing that suspension mount points were moved back to OE location and had documentation confirming the OE locations, which your layout should show, then if anyone protested you would be okay. You just have to keep these documents with you.

I'm no rules expert btw, but that's my take on it. Cars that get wrecked must be fixed, and having the frame straightened using common frame shop techniques should not eliminate you from a class.

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'99 Mk IV Jetta VR6 now claimed by the better half.

'90 Miata A-package, Floats like a butterfly and buzzes like a BEE with loudspeakers.

If the factory service manual specifies this as an authorized repair then it would be legal, but re-drilling holes to save a buck or twothousand is not a legal way to fix a car, even if it isn't done for a performance advantage.


It seems to me, if you want to fix the handling on the cheap, then you might just have to accept the prepared/modified class it puts you in, or just keep quiet and don't tell your competitors about the illegal parts that don't help performance.

Honestly though, if the chassis isn't straight, any changes are just a band-aid, so why worry about bleeding edge performance.

I need more details on the front suspension of the Z-car to comment more. I've seen pictures of the strut tops and there is no room for camber plates without getting really fancy or cutting (cutting isn't legal in street prepared or *street* modified-2).

How do the front struts attach to the control arms? Is it like the Celica where the ball joint attaches to the steering knuckle, then the knuckle attaches to the bottom of the strut? If so, there are a fwe options there.

In the Street Mod-2 class you can run longer control arms (or make them adjustable), and get as much camber as you want that way. I'd just run the offset bushings to "fix" the bad side, and run longer control arms to gain the camber. Use Ground Control or similar coilovers (small springs) to get the room for adjustment.

I've done most of these things on my Celica, but I think it has more room to work within the rules.

Scott

steering arms are sandwiched between the bottom of the strut/carrier housing and the lower control arm.
The ball joint housing has 4 ears and is bolted 4 places to the control arm (from the bottom with ball stud poking up through). The "ball stud" is attached to the steering arm...all covered by the bottom of the strut/carrier......... keeps the castle nuts shiny for decades.

The mk1 Z cars have solidly welded strut tubes to the axle carriers. they have solid rods for compression rods in front....no extra length or threading for any caster adjustment.
The rear end is a solid strut and carrier....but with a solid "H" arm with four widely spaced mounting points. 2 inner and 2 outer. rotationally locked/ rubber bushed joints on all four cornersof each H arm. rubber had to shear-twist for the joints to move. This makes urethane bushings a terrible choice....because the factory bushings were preloaded and generated enough force to actually raise or lower the rear end. Urethane or camber bushings are not rotationally locked. They allow the rear end to rebound further and require funky valving to account for the loss of unique spring force provided by the factory sheer bushings.

The mk1 MR2 I had was camber adjustable....as well as toe angle and caster. all 4 wheels as I remember. There was a break between the axle-carrier and the strut tube allowing tilting of the carrier...."camber". All the lower suspension tension/compression rods and rear tie rods were generously threaded on both ends.

as you can see.... the later year cars have a great deal of adjustability.... whereas the early Z cars had no way to fix even minor problems. That is why I have been repeatedly told that they would likely "move" components to account for unibody warpage. There is a great deal of room to move the crossmember and relocate the control arm pivot bolts. They are made like that so you can fix the damn fragile cars.

No wonder the alignment shops all had an easy time getting my beat up-dich runnin-curbed sideways mk1MR2 to factory specs. Ohh and I did NONE of that damage....I trailered that car out of the "Ritz Theater" parking lot and retitled it in my name for 35 dollars. With $1000 spent on springs, struts, bushings, joints, timing belt and radiator...it was right....but UGLY. I tried to sell it @ a few auto crosses last year....I sold it for 700 dollars last winter.
I purchased the 240Z for $900 in march and spent $1500 more getting it right. The Z is soo much more fun to drive and it is winning the meager little BSP class every single time I have raced.

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Paint don't make it go any faster.