355 Fiorano Handling Package Fork for rear suspension lower arm question

They are shimmed to get desired camber either way, so it's not so important where the hole is laterally.

I think the purpose is to keep the lower arm in the same place with the lower ride height, which would increase camber gain under compression if the upper arm mounting were not also adjusted similarly.

 

I discussed this in the FHP thread I started. My guess is it has to do with maintaining a certain suspension geometry front/rear rake when one installs FHP springs. If I recall correctly, it increases the suspension rake while the changes from the outside of the car less noticeable (still normal looking).

I believe increasing the rake provides more front grip/over steer.

 

Challenge cars have standard rear forks. FHP rear forks are unique to FHP cars.

 

And yes, FHP cars run more rear camber than a standard car. There could be a limit to how much negative rear camber a standard car can run.

 

“May” and “must” are 2 different things .


I’ve already checked challenge cars and they have standard forks. The aggressive rear camber is probably coming from adding a bunch of shims. He said “may” because there could be a point too many shims is not ideal posing a safety or effectiveness issue.

FHP cars have 1-2 shims.


This is the reason I believe the FHP rear forks is more about rake adjustments than camber adjustments. Aggressive camber can be had with shims. He also spoke of the importance of torque’ing the nut properly. Too many shims might shorten the shaft/thread length of the fork to catch.

 

“This much camber may necessitate changing the lower control arm mount forks. Always torque lower control arm mount forks properly and replace the nuts with new Nylocks after a few uses. Check lower fork nuts pre/ post track events.”


Adding too many shims may shorten the threads on the fork to catch and torque properly.

 

Its for correcting the geometry with the car now lowered in conjunction with the FHP springs, helps to correct bump steer. It was very noticeable once I installed these that the car had a more planted rear end.

 

For one the springs are significantly stiffer on a challenge car.

Are you sure the EVO kits did not include this item as part of the upgrade?

I can only talk from experience the FHP fork was one of the most noticeable improvements to my F355 probably more so than the FHP steering rack especially when you factor in cost and ease of sourcing and installation.

 

Is it to get the feel back to the 348 feel and handling? Since it’s the fork used on 348s?
Too bad there isn’t a Ferrari development guy on this forum.

 

Evo Challenge cars still run standard rear forks.

 

Ironically, I believe later 348’s have 355 forks.

 

Don’t late very 348s and 355 have the same rear suspension geometry? Upper mount moved 10mm and the bent lower mounts, plus the same rear wheel offsets? All to make the cars easier to drive at the limit?
Challenge cars kept the straight lower arm?