Does anyone know whether there's any difference with the final drive on the 355 ? I know the US version is with 4.35 but is the Euro version different ? Can we use other model's final drive ? Like 348's for example ? I need a shorter final drive to increase acceleration. thanks
The european final drive ratio is 3.56 :1, which would appear to be the same as the US version (see table below) The 348 final drive ratio is also 3.56 :1, but anyhow would not fit into a F355. What about alternative wheels / tyres ? MW
Thanks for your reply, So the 4.35 final drive is for the Challenge only ? Can you verify that ? Can we just get this gear set for the street version 355 ? much thanks and appreciation from your reply ! Charles
What is your reference for the 4.35:1 final drive ratio? Seems too low for a high-speed (150+ MPH) GT. I know in 308-land this often gets very confused because "final drive" can mean: 1. diff gear ratio only 2. gearbox ratio only (i.e., 5th gear ratio x diff ratio) 3. true overall engine-to-wheels ratio (i.e., transfer gear ratio x 5th gear ratio x diff ratio) Don't know the exact components involved a 355 drivetrain, but I just wanted to warn you that spec translations can get messed-up this way.
Dear MW, I've just checked with my manual and it says this .. mine is a 2.7 Motronic UK Spec. car. 1st = 15:46 = 0.326 = 3.066 2nd = 19:41 = 0.463 = 2.157 3rd = 23:37 = 0.621 = 1.608 4th = 26:33 = 0.787 = 1.269 5th = 29:30 = 0.966 = 1.034 6th = 37:31 = 1.193 = 0.837 RM = 15:42 = 0.357 = 2.8 Final Drive = 16/57 = 3.5625
I have never seen anything that suggests anything different in the gearbox/diff of a 355 challenge compared to a standard 355.
Google Results for: "ferrari 355" final drive displays Final Drive Ratio, 4.35:1 all over the place. Whether that's gospel or not, I don't know. But that's what some are preaching. ___ Search trick: Enclose main search criteria within quotes, other search criteria outside quotes. Hence, the above "ferrari 355" final drive If you wish to exclude a certain term/result, but retain others, then do it like this: "ferrari 355"-final drive In this case, forget about seeing any final drive ratios, but count on seeing drive in addition to "Ferrari 355". But, if you don't want to see final or drive, then do this: "ferrari 355"-final-drive
Whooaahh. The F355 transmission has several more gears these are used to drop axes and turn corners. There is a spur gear that moves power from the cranckshaft concentric axis to the shaft axes (e.g. lower by 3") of the F355 suspension. 25:29 = 1.160 There is a 90 degree bevel gear converting longitudinal rotation into tranverse rotation. 19:20 = 1.052 It is important that this gear be as close to 1:1 as possible for power efficiency reasons. However, it is also important that this gear not be 1:1 for noise reasons as it operates at engine speed rather than road speed (as on most driveline arrangements.) Differential feeder 16:57 = 3.562. This is a straight transfer gear from the output shaft to the differential carriers 4.35 = 3.562 * 1.160 * 1.052
So Mitch, Do you suggest that by physically lowering the car by 3", the final drive ratio will translate to 4.35 ? Can you please say english ? thanks Charles
Charleswan, As far as I can recall the 355 Challange cars had a standard 355 diff ratio of 3.56 :1, so I'd be interested to know where you got 4.35 :1 from. I had a look throught the Challange rules and regulations and found the following references to "gearbox" - it reads :- "The gearbox must remain as originally supplied with the car. (The Swiss version is considered equal to the European version) It is permitted to install a reinforced 3rd & 4th speed selector fork under part no. 167315 in place of the genuine part 157162" I may be wrong - comments welcomed MW
I've got to say that using/comparing these types of numbers all made a lot more sense with a 1:1 top gear transmission bolted directly to the engine crankshaft driving a simple differential . Mitch is giving: transfer gear ratio x bevel gear ratio x differential gear ratio = 4.35:1 and MW just the differential gear set ratio = 3.56:1 and IMO neither is the true "final drive" ratio which would be Mitch's number x the 0.837 6th gear ratio = 3.64:1 Pick any of the three you like
The transmission sits tranversally under the rear axles. The crankshaft axis is 3" higher than the axes of the gear clusters. So one gear is used to drop from the centerline of the crankshaft (and clutch) to the centerline of the gear clusters. A chain could have been used here instead of a gear. The engine and clutch are mounted longitudinally while the gear clusters and output shaft are mounted transversly. A pinion gear is used to make this 90 degree axis change. The heavy parts of the transmission is some 5" lower than in a Viper or Vette. The car was not lowered, but the gear clusters are lower than the centerline of the engine.