Steering Universal Joint

[Blake8828]

Hi guys,
My biggest complaint with my 3.0R-B is the steering feel, or lack of steering feel....
I've installed hard control arm and steering rack bushes.
New tie rod ends.
Wheel alignment.
Flushed power steering fluid.

I noticed the steering column U joint has a rubber damper which seems to have a bit of play in it, I see the STI WRX
U joint doesn't have this. I am wondering if these parts are interchangeable or if anyone has swapped/upgraded their
U joint to improve steering feel?

Any help would be great, thanks!

[HardwareBoB]

If your car is an 07-09, it has a 3.3 turn steering rack. You can replace it with an MY15 STi steering rack - instructions are on legacygt.com.

It's not a cheap exercise, but it will absolutely transform the steering.

From what I have read, changing the rubber damper out for a straight section will do basically nothing.

[Blake8828]

Thanks for the reply,
unfortunately it's an MY06...
So is the lack of steering feel more due to the steering rack in these cars?

Cheers

[HardwareBoB]

MY06 is 3.0 turns lock to lock - Sti is 2.4

http://legacygt.com/forums/showthread.p ... 34351.html

I don't have too much trouble with mine, but the STi steering rack would certainly liven it up.

[bigBADbenny]

It apparent that steering feel can be increased in a few different ways:
Suspension geometry: eg: camber, caster, Ackerman angle, kingpin inclination, scrub radius etc.
Rim spec and tyre choice has to be a big factor...
Alignment: especially toe. See above.
Steering speed/resistance...
Nvh/bushing/bracing related...

You start off with the light and numb feeling stock setup, and end up hopefully with a setup not too harsh, heavy and tyre shredding


Rack ratio:
It's 2.3/13:1 (VA, JDM GD & GR, S402, etc) vs 2.7/15:1 (prefl gt/adm wrx/sti afaik) vs 3.1 turn/17:1 ratio postFL.
But what's in a point one of a turn anyway...

The GRB STi rack is also a direct fit but both STi will require the inner tie rods to be swapped out for lib itr's as GRB STi onward is wide track.

Ime the guibo-less STi uni does add some fingertip feel to the steering. I'd say it's akin to doing rack bushings: minor.

A small steering wheel increases turning effort marginally.

Apparently a restrictor can be added to the power steering lines to decrease assistance.
Or eg underdrive PS pulley.

I'd consider rigid collar too.

Caster adding LCA bushes and camber/caster tops add weight to the steering off-center and increase centering.
I think that's your biggest chance to add feel.

But it will be at the expense of running larger diameter tyres.
Eg 235 40 r18 on 18x8.5 +35 being close to rubbing the liner.

If lowered the RCA kit is a must to negate bump steer.

I used to pine for feel when totally stock but no longer with these mods:
365mm PROVA D steering wheel, STi uni, AVO caster LCA's, Shockworks, light rims, great tyres and some front and rear bracing. From memory my alignment is fairly conservative as regards toe...
Still have to fit the STi rack and WL rack bushes but already my steering is quite heavy off-center and plenty communicative

I'd recommend also doing some research around the S and TS models where STi utilised flexible draw bars and braces to limiting stretching chassis forces without the harshness of rigid bracing.
So successful that the 2.7 turn 15:1 ratio rack was deemed sufficient for the S206 model.
Combined with great shocks and rigi cola, it's said to be sublime.

[Blake8828]

Thanks for all the Info!

Seems there is a lot more to it than I first thought....

[BillyCorgi]

Extract from USDM MY09 Factory Service Manual
http://imgur.com/dKY7tj9
For what it is worth, the 2.5GT-B and 3.0R have a 2.8 Turn Lock-to-Lock steering rack, however both have a larger turning radius and shorter wheel angles at full lock to match.
So is the 2.8T L-to-L rack any quicker?

Wikipedia define steering ratio as
Steering ratio
From Wikipedia, the free encyclopedia

Steering ratio refers to the ratio between the turn of the steering wheel (in degrees) or handlebars and the turn of the wheels (in degrees).[1]

The steering ratio is the ratio of the number of degrees of turn of the steering wheel to the number of degrees the wheel(s) turn as a result. In motorcycles and bicycles, the steering ratio is always 1:1, because the steering wheel is fixed to the front wheel. A steering ratio of x:y means that a turn of the steering wheel x degree(s) causes the wheel(s) to turn y degree(s). In most passenger cars, the ratio is between 12:1 and 20:1. For example, if one complete turn of the steering wheel, 360 degrees, causes the wheels to turn 24 degrees, the ratio is then 360:24 = 15:1.

A higher steering ratio means that the steering wheel is turned more to get the wheels turning, but it will be easier to turn the steering wheel. A lower steering ratio means that the steering wheel is turned less to get the wheels turning, but it will be harder to turn the steering wheel. Larger and heavier vehicles will often have a higher steering ratio, which will make the steering wheel easier to turn. If a truck had a low steering ratio, it would be very hard to turn the steering wheel. In normal and lighter cars, the wheels are easier to turn, so the steering ratio doesn't have to be as high. In race cars the ratio is very low, because the vehicle must respond a lot more quickly than in normal cars. The steering wheel is therefore harder to turn.

Using the data from the FSM and the Wikipedia definition, the steering ratio for the two racks, using the average of the achieved inner and outer angle, at full lock are
http://imgur.com/y43eVNT
15.75 for the 2.8 turn rack and 16.32 for the 3.2 turn rack.

I have no idea if this has been done right?

[bigBADbenny]

To further confuse matters some Subies have a variable ratio rack quoted around 19:1.

Personally I think there's better clarity to halve the turns: so full lock from center is one and a bit for a JDM STi rack, but eg just over one and a half turns for a postFL. A big jump.