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-   -   FB leveling, is it necessary??? (https://www.rx7club.com/race-car-tech-103/fb-leveling-necessary-535446/)

Slammed_GSL 04-30-06 07:23 PM

FB leveling, is it necessary???
 
I have installed coilovers and rear Eibach springs with the deadcoils.
I currently have the car setup with with a slight "rake", should it be level?
What is the best setup to have?
This is a DD and a driftcar, oversteer is the game.

Thanks for the feedback fellas.

jgrewe 04-30-06 10:01 PM

You can run it any way you want. I little rake without passengers becomes level with the weight of two people. There may be some small changes in suspension geometry like more caster with less rake but the differences will be small. The rear suspension links will change angles but we aren't talking funnycar rear end height are we? Within a couple of degrees of level I would go by what you like the looks of. If you're drifting you're not looking for the best rear grip, just consistency in how it breaks away.(I don't drift so I'm just guessing on what you want, I want a rear that sticks racing)

Slammed_GSL 04-30-06 10:09 PM

Yep consistency of rear break away is the key. I have new bushings for the rear but have not installed them yet, been waiting to pick some brains on what would be the best setup for the rearend.

Skidtron 05-04-06 05:49 AM

I just started drifting mine a bit and it's stock still but I can already tell the car will need a bit more weight on the front wheels to have good turn in and a healthy bite for kick backs. I autocross as well the car is better at grip then drift stock I can tell you that I'm sure you noticed when yours was stock though. Also I tried a bit of gymkahana at our drift location and the front needs more bite for that too. I do have higher grip front tires than rear just to help but the front will still get into a weird bump hop situation sometimes if the turn in angle is too tight and the rear hasn't slid yet. I was mostly suprised how well it can do braking drifts and how smooth the transition from grip to drift is. I love this old crappy car! I should have bought one years ago.

speedturn 05-04-06 08:27 AM

You really cannot transfer much weight front/rear with slight changes in ride height.

If you want the traction equal for left turns and right turns, then you need to put the car on scales and get the cross weights balanced. You cannot set coil over race springs with just a tape measure, because just 1/8" makes a noticeable difference.

peejay 05-04-06 12:12 PM


Originally Posted by speedturn
You really cannot transfer much weight front/rear with slight changes in ride height.

This is true. Even the most "static" weight transfer from heavy body lean while cornering (think van with no swaybars) is only on the order of 3%, according to Puhn. Wheelbases are generally about twice as long as trackwidth, and "leveling" the car probably alters car rake by only maybe half a degree, so I'd guesstimate that you could affect front/rear weight bias more by hitting the windshield squirters a couple times...

However, you *can* alter the front/rear roll bias with changes in ride height, which affect roll center height and the C.G.'s distance from same. "Level" the car and thinks start to get farked up geometry-wise and it starts handling like ass. Drift guys seem to prefer a heavily understeering chassis for utter predictability (if the tail comes out, it's because you explicitly want it there!) and lowering the rear would be a step in the wrong direction.

DamonB 05-04-06 12:46 PM


Originally Posted by peejay
Drift guys seem to prefer a heavily understeering chassis for utter predictability (if the tail comes out, it's because you explicitly want it there!) and lowering the rear would be a step in the wrong direction.

Actually you transfer more and more weight across the chassis as you raise the the CG higher and higher; this lessens cornering grip. Assuming the car was fairly neutral to start with lowering the rear would in fact promote understeer. Raising the rear would promote oversteer.

peejay 05-05-06 11:45 AM


Originally Posted by DamonB
Actually you transfer more and more weight across the chassis as you raise the the CG higher and higher; this lessens cornering grip. Assuming the car was fairly neutral to start with lowering the rear would in fact promote understeer. Raising the rear would promote oversteer.

In a 1st-gen, the roll center height is fixed relative to the ground. If you lower the car with the same spring rate, the roll stiffness goes up dramatically and oversteer goes *up*. The reverse happens when you raise it up.

That's why performance-oriented lowering springs for 1st-gens don't lower very much, and they keep the spring rates for the rear the same *or softer* and the front rates go up by quite a lot.


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