Technical power limitations on standard gearbox

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Technical power limitations on standard gearbox

500oc

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the big smoke
ive done a lot of reading up on the A500 and it seams there are problems with the gearbox and how much power it can take.

are these urban myths or is there any truth in the above statement?
 
All drivetrain components are rated in torque not bhp, the common factor for gearbox is 2.5-3times oem torque value. This is to ensure against destruction from standing starts, fast gearchanges etc where the instantaneous torque factor is higher.

This means you can run more power as standard but as soon as you use that power for faster gear changes standing starts etc this is when it will break.

This also accounts for driveshafts, hubs, anything where you get that initial shunt of torque when engauging the power. The person running close to 300bhp has had major driveshaft issues & according to the regs the Trofeo cars must change the hubs every 600klms!!!though a lot of that is down to failures with the extra grip & therefore forces extracted on the hubs.

It has been said a few times that the 5 speed gearbox is on the cusp of it's limits in terms of torque hence why the Trofeo cars use the stronger 6 speed box from the Punto as TBH the Trofeo cars don't need 6ratios as many drivers commented on the ratios being too closely stacked.

As with any upgrade to a car it can expose weaknesses elsewhere.
 
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The first generation Trofeo cars used the standard box but this was swapped for the second year (this year) due to a number of failures and difficulties experienced through the first racing season.

The hubs tend to suffer more from cornering forces due to the high grip tyres than power delivery - this is nothing unusual in motorsport where hub upgrades are one of the trickier aspects of upgrading a road car to motorsport standard.

Driveshafts are pretty easy to get replaced and upgraded. We had problems on my Seicento a few years back that resulted in them being replaced with some basic upgrade versions from an local supplier. The Dallara was also upgraded at the same time, from the same supplier - it cost about four times as much for those as for the Sei - I think it was about £600 for the Dallara and £180 for the Sei.
 
Trofeo gears are beefy gears!

Forgot to mention that the gearset in the Dallara was also changed - it worked out at about £300 per pair of gears - a good reason for keeping the gear ratio count down! These aren't even dogtooth gears - just regular helical with syncromesh all beefed up to take the strain. Some of the older cars had to find extra space for the beefier gears by shaving the size of the reverse gear down to the point where you couldn't actually use it other than demonstrating you had a reverse gear by selecting it and gently moving the car a few inches....
 
Yeah sounds about right.

It's also a GM box. Same as used on the Vectra VXR or diesel, one of the two.
 
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