Which Rack ?

[Darren325is]

Steering rack on my 325i Sport is on its way out and I was thinking about changing it to a quicker ratio.

Which is best and what do I need to buy / modify etc ?

Cheers

[ross_jsy]

Get in touch with DanThe about his power steering lines and spacer kit, very good quality.

For the rack I used a z3 one, but an e46 clubsport rack is now considered the best option. Budget for new track rod ends while you are at it, you need to use e30 ones.

[Brianmoooore]

http://www.e30zone.net/e30zonewiki/inde ... aster_Rack

[Darren325is]

Cheers chaps

[magpie]

an e36 one is the cheapest upgrade option with 3.2 turns v 3.0 turns from a club sport .

you will need to buy a steering linkage conversion kit [two e34 uj's and a splined bar from DanThe] +p/s pipes from DanThe total will come to around £220 for e36 version but it's worth it.

F00k windmilling about

[Darren325is]

Blimey I didn't realise that even a conversion is quite a long rack !
I was thinking more like 2.25 or 2.5 to make it similar to say a group 4 mk2 escort.
This must be possible somehow ????

[Chris_B86]

The Z3 rack is 2.7 turns. I believe you can use a LHD Talbot Sunbeam rack turned upside down, which can give you between 2.25 and 2.4 turns

[gooner1]

The Z3 rack is 2.7 turns. I believe you can use a LHD Talbot Sunbeam rack turned upside down, which can give you between 2.25 and 2.4 turns

Can,t be many of them left, surely?

[Darren325is]

Ok, slightly different question then, what would it be like with no PAS ?
I'm thinking a mk2 escort rack could be fitted which would give me the ratio I'm after. If its too heavy I could always fit an electric PAS motor to it

[Chris_B86]

If it's not a daily drive, no PAS would be fine, you'd probably get more feel too. My dad's old E30 didn't has PAS. No power steering wouldn't be an issue I'd have thought if you were using it on a track, which I assume is why you want such a short ratio.

To use regularly for normal driving with a bit of track/fast road use, the Z3 rack would be more than adequate and still give you a vastly reduced number of turns from standard, plus it's a proven easy conversion, and you still get the pleasure of power steering

[Darren325is]

Mmm maybe a Z3 conversion then cos it is my daily but I want to use it on track days and some night rally events too

[Chris_B86]

Definitely do the Z3 them, plus the fact that it's basically bolt on with the bits from DanThe and still pretty much looks OEM

[Darren325is]

Cheers Chris & everyone

[ajay]

I had one fitted a few years ago, great around town but a bit too twitchy on the motorway for me. I have another available complete with rod ends, not cheap though.

[ross_jsy]

Stop looking at lock to lock as the defining characteristics of the rack, you need to look at the rack ratio. You could put spacers into an e30 rack so it's 1 turn, still the same ratio. Just because a group 4 'scort has a 2.25 turn rack doesn't mean anything, plus even if it's mega quick why would you want that on a road car? There is a reason rally slags get super quick racks compared to road cars.

I have the 2.7 turn z3 rack and I like it, but apparently it's just the same as a 3 turn rack, it just has lock limiters installed. The clubsport one is now the one everyone seems to favour.

There is a guy local to me who modifies Impreza racks to fit e30's. 2.4 turns and more range than BMW racks so they are silly quick.

[Darren325is]

You've lost me. I thought 2. whatever IS the ratio ?

I don't understand how you could have a quicker ratio that wouldn't change the lock to lock count

[Grrrmachine]

Think about how far the front wheels are actually going to turn. If they're both pointing straight ahead, you can't turn them 90 degrees left or right because the wheels would snap off. So some wheels will turn 45 degrees away from straight, some might turn 60 degrees or 30 degrees - these are just examples.

The number you're talking about is how many turns to go from far left to far right, but it DOESN'T you how much it actually turns the wheels left or right.

What ross has said is that the Z3 rack is the same as an E36 rack, but has been limited so it doesn't turn as many degrees left or right. This means that it only takes 2.7 turns from far left to far right, but you haven't actually turned the wheels as much, so a Z3 rack will give you a larger turning circle than a Clubsport rack at full lock, even though it has the same gear ratio inside.

The ratio is therefore how much you have to turn the wheel to get the wheels to move. If you want the wheel to move 45 degrees to the left and you turn the steering wheel 45 degrees, then the ratio is 1:1. That would be verrrrrry twitchy in a car, so the gears inside slow things down to something closer to 15:1, so a 15 degree turn of the steering wheel turns the front wheels 1 degree left or right, and a full turn is 24 degrees left or right.

So how FAST the steering turns, and how FAR are two very different things, and the lock-to-lock number is a combination of the two.

[ross_jsy]

I'm too ill to explain this properly but I'll have a go!

You know how a rack works right? Well the ratio is determined by the pinion size, much like a gear in a gear box. A quick rack will be the equivalent of a high gear. So less input on the wheel means more movement. But just because a rack is say 3 turns compared to 4 turns might not mean it's quicker, it may be the case that they are exactly the same ratio, but the 3 turn rack just has limiting spacers installed.

That's the point I was trying to make about escort racks, without knowing the ratio's they may be no quicker than a 3 turn clubsport rack.

Another way to look at it is the range of the rack. I'm plucking numbers out of thin air here but say 4 turns on an e30 rack gets 100mm of movement at the rack, and the 3 turn rack gets that same 100mm movement with only 3 turns you know it's a faster ratio. But that 2.5 turn rally rack might only get say 85mm movement, they are as near as makes no difference the same ratio.

So before you decide on a rack based entirely on lock to lock numbers you need to find out the ratio. However a clubsport or a z3 rack will be enough for road use with track work. I wouldn't say you need a quicker rack unless you are rallying at a high level.

Sorry if that didn't make sense, have a heinous case of man flu and am rattling this out on an iPhone.

[ross_jsy]

Cheers Grrr, your description makes more sense than mine!

[Darren325is]

Cheers everyone - think I've got it now