body roll

[phyrman]

Here are two pix of cars AutoXing
One is of the Nissan powered Ser5 and the other a Tiger

This shows what is needed to flatten out the cars for AutoXing
and keeping it somewhat comfortable!!!!!

Ideas?

 

[260Alpine]

Larger front sway bar? Nissan is lower? Suspension geometry changes?

 

[RootesRooter]

I wonder what kind of rear suspension the 'Nissan' has?

 

[husky drvr]

Could it be as simple as driving style?

White car appears to braking with almost no steering deflection.

Tiger appears to be accelerating gently on an "off camber" turn. ( measuring off a screen leaves a lot to question but the Tiger seems to have an approximate roll in the pic of 4 degrees - line of tire contact to line of bumper - not all that flat )

Both seem to be concentrating on setting up for the next problem just after exiting the previous problem.

With little evident heavy tire marks on the track, is it possible these pics are during an early practice lap?

 

[Barry]

Here are two pix of cars AutoXing
One is of the Nissan powered Ser5 and the other a Tiger

This shows what is needed to flatten out the cars for AutoXing
and keeping it somewhat comfortable!!!!!

Ideas?

Chassis roll is a function of center-of-gravity height, roll center heights and roll stiffness.

Short of a new suspension system, the roll center heights are what they are (1930's suspension design) and the center-of-gravity can't be lowered much because of suspension compression travel limitations. The only practical solution is to increase the roll stiffness which means stiffer springs and / or stiffer anti-roll bar(s). Stiffer springs are OK for a track car, but not so much for a driver.

 

[jdoclogan]

Having fun with the HLM's high center of gravity and original rear lever Armstrong shocks "roll" at SUNI VII.

 

[bernd_st]

You forgot to mention the rear heaviness & hard acceleration

 

[jdoclogan]

Well, it does have the rare Rootes Factory Baugh Limited Slip Differential option.

 

[phyrman]

Could it be as simple as driving style?

White car appears to braking with almost no steering deflection.

Tiger appears to be accelerating gently on an "off camber" turn. ( measuring off a screen leaves a lot to question but the Tiger seems to have an approximate roll in the pic of 4 degrees - line of tire contact to line of bumper - not all that flat )

Both seem to be concentrating on setting up for the next problem just after exiting the previous problem.

With little evident heavy tire marks on the track, is it possible these pics are during an early practice lap?

The Alpine is finishing a turn. The Tiger is going thru a slight dog leg left to a short straight. It seems to be nosing down on the front right while lifting the left rear

 

[phyrman]

I wonder what kind of rear suspension the 'Nissan' has?

She didn't know! Her dad built it and I didn't get a chance to talk with him. Appears to be a Nissan rear end as well

 

[Barry]

Series Alpines left the factory with a solid rear axle, open driveshaft and longitudinal multi-leaf springs (generally referred to as a "Hotchkiss" suspension system). Changing the brand of the solid rear axle does not change the "kind of rear suspension."

 

[RootesRooter]

Series Alpines left the factory with a solid rear axle, open driveshaft and longitudinal multi-leaf springs (generally referred to as a "Hotchkiss" suspension system). Changing the brand of the solid rear axle does not change the "kind of rear suspension."

When I wrote "...what kind of rear suspension..." I was thinking a bit wider than our stock configuration. The owner has a well thought out Nissan powerplant, putting out gobs of horsepower. Swapping out the stock rear end is mandatory to contain it. The owner might have gone conventional and thrown a Ford 9" into it, but I'll be he at least gave consideration to multi-link or IRS if he wanted to get modern handling to match the power. I have no idea what a Nissan rear end looks like, but I'll bet it doesn't have leaf springs!

As for the two autocrossing cars, a 1" bar up front will produce that kind of lean in most turns. In an Alpine, with otherwise stock rear suspension, you'd want a rear bar as well to avoid huge understeer.