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Discussion Starter · #1 ·
I was noticing on F1 today that from lock to lock they have one full turn on the steering wheel. and a little research later, I found a lot of race cars and have much tighter steering ratios all the was down to 1:1

Our cars have a variable rate steering that start at 17:1 and the after 15 degrees, it starts to gradually go down to 13:1. Making it slower turning when driving on highways, and when you go into twisties and go past the 15 degrees, the turning ratio becomes sharper and the angle of the wheels turn out sharper.

So here is my idea.

I am thinking that 2.5 rotations if you want the can to turn quick. So I was looking at the possibilities of maybe a custom gear on the steering rack, making the turning 1.5 times from lock to lock... currently our rack takes 2.6 turns from lock to lock.

I think this would be Great for AutoX and track as well - as less steering input would be needed to get the car to turn, and less turning would mean more control and less hand movements.

So maybe taking a current variable rack gear we have now and cutting out the middle section to remove one full rotation ( half turn on each side ). If we cut it out of the center of the gear, it would remove most of the 17:1 variable part of the ratio. It would start out in the 15:1 ratio....


Thoughts?

power steering issues, of anything else that you can think of that might make this a good or bad ides?

( this is not meant for cushy street driven only cars.... )
 

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One way to quicken the steering (in general) is to have a pinion made with a larger diameter, and then offset the steering axis to accomodate. I am not familiar with the Porsche steering rack though, and odds are it's more cost and trouble than it's worth.

Another way to quicken the steering (in general) is to shorten the steering arms (at the uprights). However, this too is not for the faint of heart and Ackerman effects (and obviously structure) must be studied.

Obviously, if one quickens the steering ratio significantly, loads go up on the power steering. I would guess it would survive fine in a quick autocross though.

I would not recommend altering the rack or pinion by cutting.

A smaller diameter steering wheel, while not affecting the steering ratio, would reduce the distance hands must travel - and is pretty easy.

I am also not familiar with what options the GT3 RS (racing cars) etc have available. I am told the RSRs use electric power steering, probably sharing little with the street car.

Hope this helps some.
 

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Discussion Starter · #4 ·
-> I Understand it is complicated, a new rack is about $600, then fab costs to make the new rack. Or maybe a larger pinion may be better, as you stated..

-> I do not want to go cutting up that part as that is more physics then I can comprehend!

- > I already have a smaller FVD steering wheel. It does work to quicken the steering a little bit...

Anyone else have any input on this? Advice would be greatly appreciated.
 

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Discussion Starter · #6 · (Edited)
ok today I talked to a engineer and machine shop that works on steering racks for race cars.

Here is what he recommended. Taking the spindle on the front wheels and modifying them and moving the tie rod inward on the spindle, allowing for a quicker turn in. This would be the least expensive and easiest way to make the changes to the steering ratio.
 

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Respectfully...

So your shock/swaybar/alignment setup has screwed up your steering, and you think that the answer is to find someone to build a custom steering rack?:crazy:

You have just confirmed my suspicion that in a past life you were a Medieval Barber. :hilarious:

I enjoy my subscription to FrankinCaymin's "Chronicles of Carnia", but this episode is starting to scare me.:eek:

Be careful, my friend.;)
 

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ok today I talked to a engineer and machine shop that works on steering racks for race cars.

Here is what he recommended. Taking the spindle on the front wheels and modifying them and moving the tie rod inward on the spindle, allowing for a quicker turn in. This would be the least expensive and easiest way to make the changes to the steering ratio.
This is one of the recommendations I made above. But, as above, be careful to determine Ackerman effects, as well as clearances between everything that moves when the suspension travels and the wheels steer. This can probably be done - but be careful before you leap.
 

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Discussion Starter · #9 · (Edited)
HAHAHA Thanks Dave! Yes I have a little too much time and a few too many Dollars :)

the shock/sway/alignment I have now are the best setup I can buy, and on the track, the car is insane! But we do more Auto-X then track, and want to have a nationally competitive car. So anything we can do to knock of seconds if worth a try to us. ( me and my wife )

Hum I might have been a barber :)


Thank you Jeff, I will work with Pros on this one, I am not going to try this one at home .....
 
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