If you are concerned with safety, have you added a _*safety loop on the
front portion of the drive shaft.
*_
Rarely discussed, cheap, but better than pole vaulting the car on the
drive shaft.
Larry
drmayf wrote:
> Sandy Ganz wrote:
>
>> Anyone running 1350's U-Joints/yokes? (stock is 1310's I think). I
>> have a set
>> of 1350 yokes and wonder if anyone has gone to the trouble?
>>
>> Sandy
>> _______________________________________________
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>>
>>
>>
>>
>
> Sandy, all.... why the concern for a the ujoints? Unless you add a
> lot of weight to the rear of the tiger, the road/tire grip is the
> traction fuze. Do some math and it wont take long to figure out that
> the coefficient of friction with the road surface is sufficiently low
> that it wont really take much to loose traction. I know most of you
> are uunder the assumed knowledge that those big ol ires add grip.
> Alas, they do not! So even in first gear at peak torque say 450 ft
> lbs.... the low gear fives another multiplication of what? 2.4 or so
> (what ever your first gear tranny ratio is) times that and then once
> again when it goes trhough the diff ring and pinion. so 450 x 2.4 x
> 3.0 = 3240 ft lbs (NOT lbs - ft, lol) at the combined axles. Divide by
> two and that goes to each tire. Or about 1620 ft lbs. Now divide that
> by the tire rolling radius in FT and you get the available force. Or
> if the tire is a 24" dia (makes math easier) then radius is 1 ft, so
> force is 1620 lbs. BUT, the car weighs about 2400 lbs give or take.
> And the corner weights are close to being the same so each rear wheel
> carries about 600 lbs. Even if you could get the coefficient of
> friction to 1 (drag racers get more) on your street tires the most
> available force that could be used is 600 pounds of driving force. It
> is easy to break the tires loose. Wokring backwards from the max
> force that can be applied at the road tire interface then you'll find
> that the drive shaft only transmits about 600 x 2 / 3.0 = 400 ft
> lbs. Is a 1310 big enough? Yeah. Add to that the increased size of
> the 1350 means a larger yoke on each end of the drive shaft and a
> larger shaft diameter you have increased inertia to deal with as
> well. There is one other consideration to think about as well and
> that is load reversals when doing spirited driving around a track. In
> that case, you are on and off the gas pedal a lot. Each time that
> happens there is a jerk load associated with gear shifting. I see it
> all the time on the salt. Cars that go up in speed ie first to 2nd
> have a lot of inertia and that drives the shaft at car speed via the
> diff gearing. The small interval when you are off the gas and mashing
> the clutch allows th ewdrive shaft to reach the same proportional
> speed as the rear tires. So when you let the clutch out there is a
> jerk load because the engine is turning slower The drive shaft has to
> bring the engine rpm up to the speed that the car is going. If that
> makes sense.
>
> In any case, make sure you really need the extra strength.
>
>
> i just got out of bed a few moments ago so if the typing is crappy
> blame the lack of coffee, lol....
>
> mayf
>
>
>
>
> YMMV
>
> Mayf
> _______________________________________________
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