Looking to fit a manual steering rack to my e36 M3
Discussion
I would like to junk the power steering on my e36 M3 and put a manual quick rack on it instead. I am looking to make a little more space between the sump/rack and free up the PAS space to fit a dry sump pump and drive. The car now has an M60 V8 installed ( hence the desired modifications above ) and will only be used on track, any suggestions?
suggestions, yeah, make sure you go to the gym a lot before attempting to drive it !!
heavy car, heavy engine, maybe even soft trackday tyres, lots of camber / castor for handling reasons, and a quick rack so you can catch the oversteer, you're gonna look like an entrant in "worlds strongest man" in short order!!
i don't really see how a manual rack is gonna be any slimmer in the middle were the sump crosses it??
heavy car, heavy engine, maybe even soft trackday tyres, lots of camber / castor for handling reasons, and a quick rack so you can catch the oversteer, you're gonna look like an entrant in "worlds strongest man" in short order!!
i don't really see how a manual rack is gonna be any slimmer in the middle were the sump crosses it??
Max_Torque said:
...i don't really see how a manual rack is gonna be any slimmer in the middle were the sump crosses it??...
Trust me, it is 
I appreciate what you say but I HAVE considered the points that you mention and I really don't see it being that much of a problem. My car is marginally lighter at the front than an M3, the wheels are 8" wide and I will be running no more than 3 degrees negative camber. Add to the equation that I will not be out at any one time for more than 20 minutes driving at, shall we say, a more than average speed and all of a sudden, it sounds almost pleasant don't you think?
I also have an Ultima with 9" wide front wheels and manual steering with 2.2 turn ratio and that is a pussy cat once on the move ( admittedly it has a mid mounted motor and weighs 400 kg's less than the e36 but then again it does have a smaller steering wheel too, which is little help ).
I am not asking how good or bad some may think this modification merely does anybody have any idea of parts adaptability for this application.
GTWayne said:
Max_Torque said:
...i don't really see how a manual rack is gonna be any slimmer in the middle were the sump crosses it??...
Trust me, it is I appreciate what you say but I HAVE considered the points that you mention and I really don't see it being that much of a problem. My car is marginally lighter at the front than an M3, the wheels are 8" wide and I will be running no more than 3 degrees negative camber. Add to the equation that I will not be out at any one time for more than 20 minutes driving at, shall we say, a more than average speed and all of a sudden, it sounds almost pleasant don't you think?
I also have an Ultima with 9" wide front wheels and manual steering with 2.2 turn ratio and that is a pussy cat once on the move ( admittedly it has a mid mounted motor and weighs 400 kg's less than the e36 but then again it does have a smaller steering wheel too, which is little help ).
I am not asking how good or bad some may think this modification merely does anybody have any idea of parts adaptability for this application.
GTWayne said:
flemke said:
...mechanical trail...
Can you elaborate please, I have not heard of this term before: What does it mean and what does it do?In an older car, there would be a kingpin around which the front wheel would rotate when steered. In a newer car, there will be a pair of ball joints, upper and lower, about which the front wheel will rotate. If you draw a line between the centres of the two ball joints (tracing what would be the axis of the kingpin, if there were one), you have the "steering axis". The steering axis normally will lean backwards, so that its upper end is behind its lower end. The angle thus created is "positive caster". Now imagine that you extend this line, the steering axis, down to where it meets the ground. Let's call the point where it meets the ground "X".
Now take the centre of the front "axle", or wheel hub, and drop a line from that centre vertically down to the ground. Call the point where it meets the ground "Y". When the car is stationary, the centre of the tyre contact patch will be at "Y".
Finally, you have to take on faith that, when the car is in motion, the centre of the contact patch migrates backwards from "Y". That new point, which surprisingly remains relatively constant for most tyres on most cars, we'll call "Z".
You always want "X" to be ahead of "Z". This distance is called "trail", and so long as the number is positive, with "X" ahead of "Z", the steering will tend to be self-aligning, so that as you add lock the steering weights up and wants to return to centre.
Although "X" to "Z" is the total trail, from "X" back to "Y" is the mechanical trail. From "Y" back to "Z" is the pneumatic trail.
When people talk about adding caster to a car (that is, changing the angle of the steering axis), what they're mainly after is changing the distance of the mechanical trail, in order to alter the self-aligning torque and thus potentially making the car more stable straight ahead or, conversely, lightening the steering weight.
Does that shed any light?
Another effect of increasing the castor angle is that as more steering lock is applied, the outside wheel will increase negative camber while the inside wheel will decrease it. So don't reduce castor angle simpy to lighten the steering load, as it can have pretty drastic effects on the handling.
The e36 has McPherson struts at the front, so instead of an upper balljoint, take the pivot point at the top of the strut as it.
Also, here's an image to clarify what Flemke said, distance 'n' is the mechanical/castor trail:
The e36 has McPherson struts at the front, so instead of an upper balljoint, take the pivot point at the top of the strut as it.
Also, here's an image to clarify what Flemke said, distance 'n' is the mechanical/castor trail:
, that certainly gives some insight. I have in fact been in talks with a man that can look at all of this in depth for me and upon hind sight, I might go for a Z3 quicker ratio rack and retain the power steering if space for the sump will allow 
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