TonyG > New Race Car Build Thread
02-01-2014, 02:33 PM
#886
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Are you just running the tie rods at an angle knowing that you will have some bump steer? Or, did you come up with a different solution?
If I missed some earlier posts where you address the above, I apologize in advance.
Thanks,
Jeff
02-01-2014, 02:48 PM
#887
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Thread Starter
Tony, how did you end up addressing the tie rod angle / bump steer issue? I remember from a while back that it sounded like you were getting rid of those adaptors on each end of the power steering rack.
Are you just running the tie rods at an angle knowing that you will have some bump steer? Or, did you come up with a different solution?
If I missed some earlier posts where you address the above, I apologize in advance.
Thanks,
Jeff
Are you just running the tie rods at an angle knowing that you will have some bump steer? Or, did you come up with a different solution?
If I missed some earlier posts where you address the above, I apologize in advance.
Thanks,
Jeff
So we removed them, and bump steered the tie rods down at the wheel. The angle of the tie rod is not parallel to the control arm. It is a misconception that the tie rod had to be parallel to the control arm on the 996/997 setup because the control arm is not flat at the wheel side. It angels up. So the center line of the control arm at the mounting points is at an angle from the actual control arm (not parallel).That combined with the long control arms (spaced out using factory spacers) resulted in very little bump steer.
TonyG
02-01-2014, 03:07 PM
#888
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Tony, thanks for the additional info. Glad to hear you got rid of the adapters on the steering rack. At some point, I will take a look underneath some stock 996/997s. It sounds like you are saying those cars in stock form do not have a setup where the tie rods are parallel to the control arms. In other words, Porsche somehow figured out the geometry to make this work. Very interesting.
I am struggling with how to solve the bump steer issue on my racecar so this will give me some more things to think about . . .
By the way, your car looks fantastic and I look forward to your updates as you start to dial that thing in and race it in the near future!
Jeff
I am struggling with how to solve the bump steer issue on my racecar so this will give me some more things to think about . . .
By the way, your car looks fantastic and I look forward to your updates as you start to dial that thing in and race it in the near future!
Jeff
02-01-2014, 04:43 PM
#889
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Jeff
Look at the center line of the 996/997 control arm. The line from the center of the inside mount of the control arm to the center line mount for the upright. It's not even close to parallel to the control arm.
What front suspension are you running?
TonyG
Look at the center line of the 996/997 control arm. The line from the center of the inside mount of the control arm to the center line mount for the upright. It's not even close to parallel to the control arm.
What front suspension are you running?
TonyG
02-02-2014, 01:49 PM
#892
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In front, one way I can solve a large number of issues is by properly raising the spindle on the front strut while lowering the steering arms to minimize or eliminate those long tie rod spacer pins (I really don't like those single shear spacer pins). The thing that bothers me about this approach is that the 911 spindles and bearings look to be fairly light duty (they are very similar to the '86 951 front spindles) and I would rather run the 996/997 front spindle/bearing setup because these look much stronger (so I am thinking they probably ARE actually stronger). BUT this would require modifications to my chassis to move the steering rack in front of the front crossmember (you might recall that the steering rack is behind the front crossmember on all "older" 911s). PLUS I will still have to figure out how to solve the bump steer issue if I make the switch. Thus my strong interest in your project . . .
Sorry for the long-winded reply but hopefully it makes some sense.
Jeff
02-02-2014, 03:06 PM
#894
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I just asked Dwain from Vision if he's ever retrofit a 996/997 front upright & control arm to a 70's 911 race car.
Let's see what he has to say....
TonyG
Let's see what he has to say....
TonyG
Tony, my racecar is based on a 1977 911S chassis so it currently has a 935 style suspension. In the rear, I raised the suspension pick-up points by 2 inches by actually raising the entire torsion bar tube by 2 inches in the chassis through cutting and re-welding. I am running coilovers only (no torsion bars) with 930 rear control arms and those 935 style inner control arm mounts that are raised and adjustable. Given what I have done in the rear of the car, I can run a pretty low ride height . . . IF I can work out the front geometry to properly handle the lower ride height.
In front, one way I can solve a large number of issues is by properly raising the spindle on the front strut while lowering the steering arms to minimize or eliminate those long tie rod spacer pins (I really don't like those single shear spacer pins). The thing that bothers me about this approach is that the 911 spindles and bearings look to be fairly light duty (they are very similar to the '86 951 front spindles) and I would rather run the 996/997 front spindle/bearing setup because these look much stronger (so I am thinking they probably ARE actually stronger). BUT this would require modifications to my chassis to move the steering rack in front of the front crossmember (you might recall that the steering rack is behind the front crossmember on all "older" 911s). PLUS I will still have to figure out how to solve the bump steer issue if I make the switch. Thus my strong interest in your project . . .
Sorry for the long-winded reply but hopefully it makes some sense.
Jeff
In front, one way I can solve a large number of issues is by properly raising the spindle on the front strut while lowering the steering arms to minimize or eliminate those long tie rod spacer pins (I really don't like those single shear spacer pins). The thing that bothers me about this approach is that the 911 spindles and bearings look to be fairly light duty (they are very similar to the '86 951 front spindles) and I would rather run the 996/997 front spindle/bearing setup because these look much stronger (so I am thinking they probably ARE actually stronger). BUT this would require modifications to my chassis to move the steering rack in front of the front crossmember (you might recall that the steering rack is behind the front crossmember on all "older" 911s). PLUS I will still have to figure out how to solve the bump steer issue if I make the switch. Thus my strong interest in your project . . .
Sorry for the long-winded reply but hopefully it makes some sense.
Jeff
02-02-2014, 05:56 PM
#895
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The R8 is a V10 with a twin turbo. It's apparently got lots of problems with cooling, intercooling, and a bunch of other things.
Vision didn't do the car. They are going to try to fix it.
TonyG
02-02-2014, 05:59 PM
#896
Rainman
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There was such an R8 (TT, I think it was a v10) at Fontana last time I went to watch the races and the guys had to run without the engine cover for it to stay cool.
02-02-2014, 06:08 PM
#898
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Thread Starter
Vision says they can retro fit a complete 996/997 front suspension (you supply the suspension pieces) with a custom steering shaft with electric power steering, fabricated on a laser frame rack (like they did for my suspension) for about 40 hours. So call it $4500 ish and you supply parts. Perfectly fabricated and race aligned.
Big light weight hubs, big brakes, power steering, much better geometry.
(plus... you get power steering... big improvement)
If you use the GT3 lower control arms, you can easily adjust track width too.
Problem solved :-)
Make the check to Vision Motorsports and put it on a car hauler.
You'll have the car back in 2-3 weeks.
TonyG
Big light weight hubs, big brakes, power steering, much better geometry.
(plus... you get power steering... big improvement)
If you use the GT3 lower control arms, you can easily adjust track width too.
Problem solved :-)
Make the check to Vision Motorsports and put it on a car hauler.
You'll have the car back in 2-3 weeks.
TonyG
Tony, my racecar is based on a 1977 911S chassis so it currently has a 935 style suspension. In the rear, I raised the suspension pick-up points by 2 inches by actually raising the entire torsion bar tube by 2 inches in the chassis through cutting and re-welding. I am running coilovers only (no torsion bars) with 930 rear control arms and those 935 style inner control arm mounts that are raised and adjustable. Given what I have done in the rear of the car, I can run a pretty low ride height . . . IF I can work out the front geometry to properly handle the lower ride height.
In front, one way I can solve a large number of issues is by properly raising the spindle on the front strut while lowering the steering arms to minimize or eliminate those long tie rod spacer pins (I really don't like those single shear spacer pins). The thing that bothers me about this approach is that the 911 spindles and bearings look to be fairly light duty (they are very similar to the '86 951 front spindles) and I would rather run the 996/997 front spindle/bearing setup because these look much stronger (so I am thinking they probably ARE actually stronger). BUT this would require modifications to my chassis to move the steering rack in front of the front crossmember (you might recall that the steering rack is behind the front crossmember on all "older" 911s). PLUS I will still have to figure out how to solve the bump steer issue if I make the switch. Thus my strong interest in your project . . .
Sorry for the long-winded reply but hopefully it makes some sense.
Jeff
In front, one way I can solve a large number of issues is by properly raising the spindle on the front strut while lowering the steering arms to minimize or eliminate those long tie rod spacer pins (I really don't like those single shear spacer pins). The thing that bothers me about this approach is that the 911 spindles and bearings look to be fairly light duty (they are very similar to the '86 951 front spindles) and I would rather run the 996/997 front spindle/bearing setup because these look much stronger (so I am thinking they probably ARE actually stronger). BUT this would require modifications to my chassis to move the steering rack in front of the front crossmember (you might recall that the steering rack is behind the front crossmember on all "older" 911s). PLUS I will still have to figure out how to solve the bump steer issue if I make the switch. Thus my strong interest in your project . . .
Sorry for the long-winded reply but hopefully it makes some sense.
Jeff
02-02-2014, 11:21 PM
#899
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Vision says they can retro fit a complete 996/997 front suspension (you supply the suspension pieces) with a custom steering shaft with electric power steering, fabricated on a laser frame rack (like they did for my suspension) for about 40 hours. So call it $4500 ish and you supply parts. Perfectly fabricated and race aligned.
Big light weight hubs, big brakes, power steering, much better geometry.
(plus... you get power steering... big improvement)
If you use the GT3 lower control arms, you can easily adjust track width too.
Problem solved :-)
Make the check to Vision Motorsports and put it on a car hauler.
You'll have the car back in 2-3 weeks.
TonyG
Big light weight hubs, big brakes, power steering, much better geometry.
(plus... you get power steering... big improvement)
If you use the GT3 lower control arms, you can easily adjust track width too.
Problem solved :-)
Make the check to Vision Motorsports and put it on a car hauler.
You'll have the car back in 2-3 weeks.
TonyG
Best regards,
Jeff
02-03-2014, 12:45 AM
#900
Rennlist Member
Vision says they can retro fit a complete 996/997 front suspension (you supply the suspension pieces) with a custom steering shaft with electric power steering, fabricated on a laser frame rack (like they did for my suspension) for about 40 hours. So call it $4500 ish and you supply parts. Perfectly fabricated and race aligned.
Big light weight hubs, big brakes, power steering, much better geometry.
(plus... you get power steering... big improvement)
If you use the GT3 lower control arms, you can easily adjust track width too.
Problem solved :-)
Make the check to Vision Motorsports and put it on a car hauler.
You'll have the car back in 2-3 weeks.
TonyG
Big light weight hubs, big brakes, power steering, much better geometry.
(plus... you get power steering... big improvement)
If you use the GT3 lower control arms, you can easily adjust track width too.
Problem solved :-)
Make the check to Vision Motorsports and put it on a car hauler.
You'll have the car back in 2-3 weeks.
TonyG