Castor angle for comp motor front axle

[Spanners Akimbo]

Hi I'm not really sure were this question should go so I'll try here.........................

We're looking at "improving" the front end of our Bowler, by this I mean Buying a quick ratio heavy duty steering box from Tomcat and having the Axle case modded for some addtional castor angle to give better turn in. The question is this: how much castor angle is ideal?

The motor will not be used on the road so some degree of wander is acceptable, but Paul at Tomcat say's that with 12 degrees of castor on their racer things tended to get a little fraught at speed in a straight line, and that bump steer was a bit of a problem.

While we want to improve turn in we still want the motor to be drivable IE not too twitchy!! Have any of you guys had this mod done and if so how much castor have you gone for and what's it like to drive.

Thanks

Greg

[Daan]

On rally cars it is usually around 6-8 degrees, that might be the right bracket for you as well.

Remember though, that the more castor you have, the less ground clearance your draglink has, important for rough terrain.

Daan

[Steve Hiatt]

I have 10 deg on my Range Rover, however it's heavy on the front end with a Chevy in so you would probably be better with 8 deg. It does make a significant difference. We are more handicapped than rally cars with locked centre diffs.

photo by Mark Fell

Driving tip of the day: if you find the front end pushing on in a tight, slippy corner, dip the clutch and let it freewheel until back on course, dump the clutch and throw the back round a bit once you have it under control.

[Henry Webster]

I have 10 deg on my Range Rover, however it's heavy on the front end with a Chevy in so you would probably be better with 8 deg. It does make a significant difference. We are more handicapped than rally cars with locked centre diffs.

Driving tip of the day: if you find the front end pushing on in a tight, slippy corner, dip the clutch and let it freewheel until back on course, dump the clutch and throw the back round a bit once you have it under control.

My front axle is std, but I don't have much problem with turn in, apart from very slippery slow corners. What I do have, though, is a viscous centre diff, which helps significantly with reducing understeer. In fact I hadn't realised quite how much difference it has made until I drove my tow vehicle in the snow recently (locked LT230) it just wanted to go straight on everywhere - quite different to the racer.

I guess the fact that the ride height is standard on the racer helps.

My driving tip of the day is to use a little left foot braking if the car is understeering on faster corners, especially if you've got a little space to play with.

H

[Steve Hiatt]

Any idea how much torque the viscous diff will take?

BTW Henry your Baja link doesn't work, will the entry fee be similar this year?

[Henry Webster]

Any idea how much torque the viscous diff will take?

BTW Henry your Baja link doesn't work, will the entry fee be similar this year?

No, not sure of torque. I know John Cockburn was running one in his Range Rover with the 5 litre griffith engine in it, but I don't know how long it lasted.

Thanks for the tip off about the link - I'll fix it. I don't know about the entry fee - I hope it'll be no more 'cause I'm planning to do it.

H