348 Any early 348 owners willing to trade/upgrade to 355 rear lower forks?

I believe those were done with a corresponding upper mount being lowered 2-3mm.

I could be wrong but not sure the effect of those without the top also. Maybe Mitch will know.

Definitely considered doing this a while back, the challenge versions are available still, but the top mount is an open question.

 

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Raising the chassis mounting point on the lower A-Arm reduces the level length on the instant center* of the A-Arm geometry which softens up the rear end (when the spring rate remains the same). This should reduce oversteer (static) and allow the car to roll into corners faster allowing the astute driver to roll on the gas sooner.

If I remember correctly, the later 348s lowered the chassis mounting point of the upper A-Arm to (also) reduce the length of the instant center and raise the roll axis inclination (softening the rear as above, but also raising the rear roll axis by a lot more than (~2× more) the modification being proposed here).

But all my work is based on F355 with only a brief excursion into 348 chassis geometry--so take this with a grain of salt.

(*) because the upper A-Arm points downward from the hub to the chassis, whereas the lower A-Arm is rather horizontal.

 

Mitch in you experience, why do you think Ferrari chose to revert to the 348 lower fork for the Fiorano handling package?

 

To compensate for some change in suspension geometry and mechanics.
It could compensate for lowering of the ride height.
It could compensate for stiffer front versus rear springs.
It could compensate for stiffer anti-roll bars.
Or a mixture of all three.

You see, its a game of all ends towards the middle (good handling) Springs, Shocks, Tires, Alignment, and Suspension Geometry are all playing their own little parts.

 

I agree.

I have purchased the forks, seeing as I have significantly stiffer springs, FHP anti roll bar and a lowered ride height. I'll post my findings once I install.

 

Interesting all that, i follow.
My forks will be install next year.
I can't help now but score all your advises.
Thanks

 

Ride height is measured with the car
a) on a flat, level surface, with drivers weight in drivers seat, ½ tank of gas, and tires at operating pressures ~38-40 PSI (not cold pressures 32 PSI)
b) from the road surface to the center of the lower rear bolt on the chassis side of the A-Arm pivot point.

If you switch the lower bracket, you will have lost a direct measurement point. I suggest you measure before and measure after so that you get the ride height properly set. You should probably also measure the road surface to the lower part of the sub-frame.
Then after the change, raising the rear ride height adds oversteer (or subtracts understeer) 1.6× as fast as lowering the front does the same thing.

 

I don't know. My F355 WSM shows a figure using the upward bracket, and I assume that that is the one you want to measure.

 

LOL The old Carrol Shelby trick on the mounts

 

Who did the plating? I need to do some hardware. Having hard time finding local that will do small batch of car parts.