Austarion

i have been telking to many people about irs suspension and when you significantly lower a car as i have done it obviously throws out the factory geometry.

craig with the xerox car explained this but i have studiesd the group a starions and they use rose joints and a heap of other changes that i am not allowed to run under improved production rules.

has anyone done this before? or have any ideas on the best way to lower the pick up point on the the rear hub??

callan_rs2000 wrote:i have been telking to many people about irs suspension and when you significantly lower a car as i have done it obviously throws out the factory geometry.

craig with the xerox car explained this but i have studiesd the group a starions and they use rose joints and a heap of other changes that i am not allowed to run under improved production rules.

has anyone done this before? or have any ideas on the best way to lower the pick up point on the the rear hub??

first do you need to change the angle to get you roll centre back to factory setting
more to the point have you got a problem as it is

from the IPRA section of the good book
9.10 Rear suspension components: Devices for the lateral location of the rear wheels on vehicles with a live axle,
and any associated brackets on the body, are free. Brackets may be welded to the body. All other components
which have any function in the location of the rear wheels must be retained unmodified except for bushings,
which must comply with 9.3 above., Drive flanges, trunnions,hubs, stub axles and wheel bearings are free. It
is permissible to add additional longitudinal rear suspension arms provided that all bushings are elastomeric
and that the mounting points on the body only involve the addition of metal, save for a single hole per arm of

going by this you can change or mod the trunnions

from Wikipedia --- the trunnion is part of the suspension and either allows free movement of the rear wheel hub in relation to the chassis[9] or allows the front wheel hub to rotate with the steering

I dont know the best way to mod this carrier or if you even need to
but the smart move would be to run it by you EO before you change it
and make sure that hes happy with changing the suspention part

cheaterparts wrote:
from the IPRA section of the good book
9.10 Rear suspension components: Devices for the lateral location of the rear wheels on vehicles with a live axle,
and any associated brackets on the body, are free. Brackets may be welded to the body. All other components
which have any function in the location of the rear wheels must be retained unmodified except for bushings,
which must comply with 9.3 above., Drive flanges, trunnions,hubs, stub axles and wheel bearings are free. It
is permissible to add additional longitudinal rear suspension arms provided that all bushings are elastomeric
and that the mounting points on the body only involve the addition of metal, save for a single hole per arm of

I'm not an expert on any of this but a live axle is a solid diff, not IRS (sorry, not trying to be a smart ass Cheater) so the section quoted doesn't apply. It reads to me that panhard arm/watts link systems or means of stopping the diff moving sideways are free.

I just looked up IPRA regs (cos I'm bored and there's nothing on the TV) and found -
8.4 says you can have whatever final drive assembly you want as long as all the mounting points are as per factory (doesn't help you does it?)
and
9.14 says you can move suspension pivot points by 20mm within an existing bracket to aid wheel alignment. Maybe this will help?

cheaterparts wrote:
from the IPRA section of the good book
9.10 Rear suspension components: Devices for the lateral location of the rear wheels on vehicles with a live axle,
and any associated brackets on the body, are free. Brackets may be welded to the body. All other components
which have any function in the location of the rear wheels must be retained unmodified except for bushings,
which must comply with 9.3 above., Drive flanges, trunnions,hubs, stub axles and wheel bearings are free. It
is permissible to add additional longitudinal rear suspension arms provided that all bushings are elastomeric
and that the mounting points on the body only involve the addition of metal, save for a single hole per arm of

Alspos wrote:
I'm not an expert on any of this but a live axle is a solid diff, not IRS (sorry, not trying to be a smart ass Cheater) so the section quoted doesn't apply. It reads to me that panhard arm/watts link systems or means of stopping the diff moving sideways are free.

I just looked up IPRA regs (cos I'm bored and there's nothing on the TV) and found -
8.4 says you can have whatever final drive assembly you want as long as all the mounting points are as per factory (doesn't help you does it?)
and
9.14 says you can move suspension pivot points by 20mm within an existing bracket to aid wheel alignment. Maybe this will help?

rule 9:10 is the only rule that covers the rear suspention
as it states that trunnions are free ( some thing that live axles dont have but IRS do ) I think it would cover it but as I said check with the states Eligibility Officer first
they realy have the last say

i have spoken at length to a few guys who race starions and they all have said if you lower the rear without restoring factory geometry the rear end wants to overtake the front (which i found out last month and bent my starion) they lowered the pick up point on the hub to help cure this

some pics of a group a japanese starion on starquestclub.com show the lowered mounting point

http://www.26liter.us/gallery/thumbnails.php?album=558

Talk to avandull mate, trust me, he has all the info..

Ps we have a guy up here who can make replicas of the "strengthened rear upright", from the stock units, it's not cheap though, but absolutely essential on any track starion that you actually want to have grip in the rear.

I have started stockpiling rear uprights in case it ever happens..

yeah allan and i have been thinking of doing something like this since march after we had a chat to craig at the phillip island meeting

i think we have decided to cut/sacrifice the bottom off one of a spare set of hubs and welding + strengthening it to the hubs on the car - but lower - the improved production rules say 20mm but this may not be enough...

our eligibilitry officer will let just about anything run as long as you arent bending the rules by too much but i would like to run on the mainland in the future....

callan_rs2000 wrote:yeah allan and i have been thinking of doing something like this since march after we had a chat to craig at the phillip island meeting

i think we have decided to cut/sacrifice the bottom off one of a spare set of hubs and welding + strengthening it to the hubs on the car - but lower - the improved production rules say 20mm but this may not be enough...

our eligibilitry officer will let just about anything run as long as you arent bending the rules by too much but i would like to run on the mainland in the future....

check your wording the lower link does not go to a hub - it pivots on the trunnion
and ether way hubs and trunnions are FREE the 20 mm rule does not apply
the 20 mm rule only applies to component that are not free ie - the sub frame

Hey Dave,
if you are serious about having some rear hub modified then put me on your genuine / serious buyers list. I was looking at doing something myself but don't have any measurements of what is likely to work and obviously you've been down that track the the xerox Starion.
cheers
Muz