Rear pinion angle???

[turbov6joe]

I have a TTA that makes ~480 RWHP and need to know what pinion angle you all use that offers the best all around traction on the track without binding the U joints? I launch off of a T brake at ~10-15 psi and use MT street ET's in case you need to know.
I was under the TTA today and noticed that when I installed and set my Spohn adjustable torque arm, I must have had a brain fart and set the negative angle at 1/2º. The destructions that came with the torque arm said to use 2º-3º for a "faster" TTA. Would you all agree with these numbers? I ended up setting mine for 2.5º negative angle to play it safe. I rarely street drive my car and have no need for perfect "on road" longevity, so that's not an issue here. Any opinions will be greatly appreciated. TIA

[TwinTurboIroc]

trial and error man

[Grumpy]

I would put it to whatever the stock set up was... havin a brain fade now... gone 1.3's with a stock set up!!!

[turbov6joe]

Stock angle is/was 0º total and that's about what mine was at untill yesterday. Thing about 0º angle is that when I launch hard off the T brake, the angle ends up in the positive area which is not good for anything let alone ET's. I think the reason these recommend 2º-3º negative for higher HP motors is that the driveline/suspension is under that much more "twist" over that of a stock HP motor....makes a lot of sense to me. Years ago I built a 1978 Ford P/U with 44" mud grips on it. With the motor and the lift, I had to set the pinion angle to extreme negative angle to offset the twist imposed by the motor and the weight of those tires. I would only get about 200 miles to a set of extreme duty U joints beofre they would start making noise of just break...kinda the same idea here. Anyhow, anyone else have an opinion???

[RobCrisafulli]

2 to 3 is fine. You can go as much as 4 if you like. The more pinion angle the slower the car is to pitch rotate. My car used to like 2.5 with the random tech arm.

[turbov6joe]

Ok...thanks Rob. BTW, what are the disadvantages/advantages of a quicker pitch rotation?

[RobCrisafulli]

Basically the more pinion angle the slower the car picks the front up. Picking the front up is good for weight transfer, but slower reaction times and 60 foot. You want the car to transfer weight and move forward.

I recommend writing down the settings and running the car a couple of weekend each tuning the chassis in. Leave the boost alone so you can evaluate the suspension.

Robert

[turbov6joe]

I plan to do just that, thanks for the response.

[Chuck Leeper]

Originally posted by RobCrisafulli
Basically the more pinion angle the slower the car picks the front up. Picking the front up is good for weight transfer, but slower reaction times and 60 foot. You want the car to transfer weight and move forward.
Robert

Robert, would you please explain how the pinion angle setting affects the speed of pitch rotation?? I guess there's something I'm missing in my understanding of suspension operation w/ the various designs out there.

TIA,

[RobCrisafulli]

Chuck,

I would recommend getting the Chassis book by Dave Morgan. I think jegs has it. I think that is the correct name and author. Good book.

Robert

[John Pearcy]

The ideal setting for the TT/A is 2° neg. for drag racing
and 0° for the street. In RSE competition, you change the
setting. When you set your angle to 2°, reset it afterwards
back to 0 and count the turns on the nut to get it there, that way
you can make the changes without the angle finder if needed. The 2° setting that has been discovered to be optimum comes from Joe Cobson. If memory serves, he told me this back when
he was running 9's.