Quick Steering rack question

[predator]

Hi all

I was wondering what difference there is to the way a car handles based on it's steering rack ratios?

The various Impreza models listed below all have different figures (Based on ver 8 & 9):

WRX = 16.5:1

STI = 15.2:1

STI V-Limited = 13.0:1

Sti Rally Car - 11.0:1

I assume that the lower the number the better the handling performance of the car?

I read that a lower ratio would reduce the amount of turns on the steering wheel before you got to full lock?

Google doesn't seem to have the clear answers here so any help is good.

Thanks

[nztintin]

i have just put a quick rack in my foz, yet to test it fully but it does reduce turns lock to lock, and makes steering more heavy (unless that was something else i've done at the same time)

only benifit is not having to change hand positions on the steering wheel AFAIK

[BC5RA]

Handling performance is not the domain of the steering rack.

A quick rack will result in more positive steering feel, as well as more responsive to steering inputs.

First quick rack was found in the RS type RA which had a 2.6 (13:1) lock to lock.

[Optical]

Ive just gone from 13:1 ( with 2.6 turns lock to lock) to 11:1 (2.2 turns)

Steering is much heavier and I cant do U-turns on normal roads anymore. So if that is a concern, dont bother swapping

Ive got a spare 13:1 / 2.6 turn quick rack spare if anyone wants one

[Guest keltik]

Call me an idiot for asking, but how has it affected doing u-turns?

[Optical]

the max wheel angle has decreased

[Guest boostcut]

do you think if you had more lock it would be the same as before? because a quick rack should have the same lock the only real difference is in the pinion which is bigger to effectively speed up the time it takes to move along the rack.

[Guest boostin]

Yeah I would have thought it would have been a larger gear ratio for the pinion to wind the rack across quicker, not a shorter lock.

[Optical]

it's both

i dont know why, but it is...

more lock would be nicer, but not the same as before. wheel angle has definitely increased in relation to steering wheel angle which is all i was hoping for. Mean I dont have to take my hands off the wheel to smash hairpins now

[Optical]

dont be retarded

[Guest boostcut]

try theese,

http://www.trademe.co.nz/Trade-Me-Motors/Car-parts-accessories/Performance/Suspension-braces/auction-229343709.htm

i had so much lock in my cefiro it ripped the drivers side guard clean off

[Optical]

haha, i think you have mistaken me for another reubenh.

Once you have experience with R RA and spec c racks come back and talk to me

[BC5RA]

I don't suffer any loss in steering lock.

I can't see how you would, only the speed in between the two points increases.

[Guest boostcut]

i dont particularly want to talk to you i just wanted to help. i dont understand the comment about rueben but sounds like your a racist. is it because im black???

[Optical]

 BC5RA said:

I don't suffer any loss in steering lock.

Between which racks?

Probably something to do with a GD rack in a GC

[Guest boostcut]

a gd is like 100 mm wider in the wheel track if im not mistaken. and i believe the hub is where the length is made up. this will be why you have a sht lock.

[Optical]

 boostcut said:

a gd is like 100 mm wider in the wheel track if im not mistaken. and i believe the hub is where the length is made up. this will be why you have a sht lock.

you are mistaken on both counts.

The reduced lock is not a problem, it's just less. That's all im saying

[BC5RA]

Well i am talking almost two decades in technology past.

After driving my Gen 1 RS type R which had a standard 3.25 and into my current RS RA (2.6) I didn't notice a larger turning circle, but then i wasn't exactly testing the theory.

But now you've got me thinking, will test it when I go out.

[Guest boostcut]

can you tell me then??? because im getting told im wrong but no info to back it up....

[Optical]

why should I educate the dumb?

For the sake of a good discussion:

Lateral arms are the same width except for the spec'c's which are 10mm wider. Also the spec c arms have a 25mm longer rear pin so the wheel sits further forward to give more caster.

To accomodate the extra pin length the subframe is different n the c's. Otherwise GC and GD suspension components have the same width and length apart from some small shaping differences to give slightly different caster.

The steering rack mounts are the same between GC and GD up to 2005. So the steering racks bolt up to the subframe, but have a different spline on the steering column so some custom adaption is required.

GD's have wider rims from factory which gives wider track width. Hubs are slightly different to give the GD's more postive camber due to frame widths, but the offset is identical.

That's what I know anyway from the stuff ive played with. Anyway, might start googling 'sti turning circle' as i want some turning circle numbers now