| Author | Message | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 374 Registered: 11-2002 |
In a word: yes.  | ||
| billy bob (Fatbillybob)
Junior Member Username: Fatbillybob Post Number: 227 Registered: 8-2002 |
Rexrcr, With all the 348/355 similarities, what do you think accounts for the major difference in handling? Do you think it is just the additive effect of all the small details? | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 373 Registered: 11-2002 |
Geometry is same/similar. Many detail differences, though more similarities than differences when you go below the skin. Motion ratios the same. Springs and dampers different, but to me, that's a detail difference, you can bolt that stuff on. Yes, the F355 handles much better, so one can argue that it is a generation above. From the perspective of suspension, it is an evolution of the 348, and the 308 for that matter. The big step is the 360. | ||
| billy bob (Fatbillybob)
Junior Member Username: Fatbillybob Post Number: 226 Registered: 8-2002 |
RExrcr, How do the 348 and 355 chassis compare? Are they even close or is the 355 really a generation above? There are many 355 tweeks like aero undertray and body work but is the chassis very close? | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 367 Registered: 11-2002 |
No, not shorter in the body. That's were the packers come into play. The final "tune" is the packers, after adjusting alignment, ride height, springs, tire pressures, last tool in the box is packers inserted on the shock rod. This adjusts when the shock body contacts the bump rubber, which has a progressive spring rate. This adjusts the front to rear roll-couple distribution. | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 382 Registered: 4-2002 |
It looks to me that if you lower an F355 with stock shocks 35mm in the front and 50 mm in the rear, you will be riding on the bump stops. Are challenge shocks shorter than road shocks? | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 356 Registered: 11-2002 |
Nice Mitch! Now picture the ride heights 35 mm lower in front and 50 mm lower rear. Not really optimized anymore, though the bigger gain is lower CG and reduced Cd. | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 380 Registered: 4-2002 |
And here is a look at the front suspension:  | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 379 Registered: 4-2002 |
F355 rear suspension at factory ride height and alignment  This is as good as I can do at 600*480. | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 378 Registered: 4-2002 |
The following is my (second) attemp at showing the suspension geometry of the F355.  However, this time there is insufficient detail to see anything. I give up | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 377 Registered: 4-2002 |
The following image is my attemp at representing the suspension geometry on the rear of an F355 at factory settings. This image was assembled from a scan from the owners manual. didn't friggen work | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 349 Registered: 11-2002 |
IMHO, if you want to run the SO2's, shave them to 3/32 inch first. Improves the life, response, heat capacity. Why not slicks? | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 348 Registered: 11-2002 |
Different tires, especially street tires, require different alignment and pressures. If you ran factory as-delivered 355Challenge alignment (are you the first owner?) then you're way too high in ride height and the wheels are pointed in different directions. Ferrari knew each race car would receive special attention for pre-race preparation, so they set these specific Challenge-only cars high to drive on and off transporters. You're on a different learning curve with those tires, I cannot make recommendations other than they will require less camber for sure, probably -1o-30' front and -2o-30' rear, but that's an educated guess. | ||
| Jonathan Garrett Donner (Jgd)
New member Username: Jgd Post Number: 7 Registered: 2-2003 |
Thanks Rob! This will be a lot of help getting started The Car is currently set up factory stock. This is our first session in trying to get it set up properly. It currently has Pneumant Street tires on it. Which I ran last weekend at the track at 28 pounds hot front and 30 pounds hot rear. I plan to run Bridgestone S02's as a compromise between street and track tires shortly. Thanks again for your help it is greatly apreciated! | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 345 Registered: 11-2002 |
Ps, the difference is in the details. There is no such thing as improved handling with just a camber castor adjustment. It's a "suspension system". BTW, factory spec castor. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 344 Registered: 11-2002 |
What tires are you running? What are your current set-up specs? Tire pressures, hot/cold? Where do you measure ride heights? The more info you provide the easier it is to set-up via internet. Very basic set-up specs: Camber F: 2o-0' to 2o-30' R: 3o-0' Toe: F 10' out total R 30' - 45' in total (NB: these are degrees and minutes of degrees, not tenths of degrees or fractions of inches.) Ride height: F 92mm to frame aft of front wheel well R 80 mm to frame ahead of rear wheel opening (no undertray) Basically on ride height, you need the rear as low as it will go without causing suspension binding. Front must be low, though use the front as an additional tuning tool, this influences push/loose. Your chassis may measure differently due to confusion over where I measure and where you measure, and crash damage. Make certain to zero the anti-roll bars on the scales. Make certain to keep the chassis level. Cross weight must be within 10 pounds with driver and 1/2 tank fuel. I also recommend locking the rear dampers full stiff and front at 70o off full soft (see the 355 Challenge thread for more info on this) the adjuster only rotates 90o from full soft to full stiff. Full soft is clock wise. Packers are VERY effective for ultimate tuning of roll ballance. I cannot make specific recommendations here, each car and driver is different. Basically, here you tune when and how much the bump rubber comes into the balance equation. Wing at +2o (leading edge down from level) On a unsorted chassis, this could take me six hours with scales and a nice laser alignment rack. Once everything is sorted, though, realignment may only take one hour. Hot tire pressures should be determined by your as*-o-meter, stopwatch, and pyrometer, but usually come in about 30 - 35 psi hot for the Pirelli slicks. Have fun. | ||
| Jonathan Garrett Donner (Jgd)
New member Username: Jgd Post Number: 6 Registered: 2-2003 |
Thanks Everybody. Rob, I have a 97 F355 that I take to track days 2x per month, we are getting it ready to go to Willow Springs next weekend, I am going to Laser align it and would like to set it up to Challenge specs top see if I will get it to handle a little sharper. So I was looking for basic caster/camber specs for Challenge set up. Thanks | ||
| Martin - Cavallino Motors (Miami348ts)
Advanced Member Username: Miami348ts Post Number: 3968 Registered: 5-2001 |
its all there. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 336 Registered: 11-2002 |
Ohh, and: Wheels, tires, offset, wing specs. Skid plates. Nitrogen in tires, tire pressures. Types of tires: slicks, DOT legal, street. Costs to run a car: private and dealter preparation. Isn't Ferrari Chat great??? | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 335 Registered: 11-2002 |
Did you search the archives yet? Just in the last 60 days there have been threads regarding technical specs, handling and chassis set up. Including ride height, camber, caster, toe. How to set corner weights. Shock settings, packers, spring rates. The difference between spring rate and wheel rate. Is your situation not coverered in the past threads? If so, please post more information, like "this is what I run now, but I can't put the power down until the car is almost straight, otherwise it's power oversteer. OR... my car darts right-left under braking and I almost loose it every time..." Happy to help Let me know, I've been setting up Challenge cars and other racing Ferrari's for a long time. Rob | ||
| Jonathan Garrett Donner (Jgd)
New member Username: Jgd Post Number: 5 Registered: 2-2003 |
Does anyone have or know where to get the wheel alignment specs for F355 Challenge car. Thanks in advance |