crispeed

''Pinion angle has nothing to do with traction''



I always like when people quote equations and formulas from a second hand party.
The 'PR' drag racers/chassis builders have blown most of those equations out the door. High powered short wheel based cars that are getting better 60ft's and travelling down the 1/4 like they are on a rail. When you look at the suspension on those cars and how it reacts/travel etc. it goes against what have been preached here from the begginning. Those cars actually exhibit more an 'IRS' type reaction going against the so called 'antisquat' theory. Not to mention the spring/shock combinations on those cars are also completly different to what is the norm.
You can have different pinion angles with the same intersection points. That's what a fully adjustable suspension is for. Even with the same intersection points just varying pinion angle does effect the 'ET' of the vechicle. It might not be directly linked to traction but it does effect suspension reaction and power transfer to the wheels especially when you're dealing with 'IRS'.
Most of the chassis builders/tuners experiences are based on solid axle applications so when it comes to 'IRS' notting is written in gold as of yet.
From my experince the only limiting factor that an 'IRS vechicle have would be strength. I believe if parts strength was not a factor then traction would be the same or even better than on solid rear axle types.

andrewb70

The reason that E.T. is effected is because altering the pinion angle changes the power delivery to the rear wheels. If a particular rear suspension is such that it allows the pinion angle to change as power is applied, then dialing in extra static down pinion angle will help to ptimally transfer power to the rear wheel, thus improving the E.T. So an improvement in 60 foot times is gained by more power to the rear wheels.

With IRS the pinion angle is even less critical to traction. As long as the working angles are within the recommended limits of the u-jount manufacturer and the output shaft of the transmission is paralell to the pinion shaft, then your good to go.

I am glad to see that you agree that pinion angle has nothing to do with traction.

Andrew

LETHAL RX7

iTrader: (1)

basically anything over 2.5 deg of angle takes 10ft/lbs of TQ per degree thereafter.
Greg