Whoops!

Forgot, a very important part of the 'diagram'.

The pink line, with arrows, is the travel of the centre on the swivel hub, and remember this is a 2-d view front behind the wheel.



So it can now, more clearly be seen that if the wheels travel is linear (up and down) but the ball joint travel is circular, the wheel must turn and since the ball join is behind the wheel the wheel turn that direction, toe out.

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

So was I on the right track? Gotta love paint diagrams...

I believe this a common mis-conception. Maybe some front wheel drive cars do. However Mini's don't. If this were to occur the steering rack would need to be infront of the wheels.

If the steering rods could self adjust their length whilst the wheel moved up and down then a constant toe could be achieved.

Hmmm....I am studying Mechatronic Engineering, maybe for a 4th year project? ....nah, probably too complicated!

Dam I like this kind of discussion, too bad it's in the wrong threadfor this kind of stuff though.....

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

Spraycanman -

Yes correct track. Suspension stuff is not my thing either, but I have learnt bit on this topic, the toe issue on a Mini.

Since the rack stays constant but the wheel moves up and down the swivel hub must turn in order for everything to exist living in this dimesion, or something like that.

And since the rack and balljoing and steering arm are behind the wheel, the distance to horizontal distance from the ball joint to the car shortens as the wheel goes up, or down therefore the wheel produces toe out during travel.

Also I should ahve done a better paint diagram with a wheel for reference. I understood it in my own head....

Ok, well I think that's about all I know, on this topic, I reckon.

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

haha.. funny enough.. I was pretty serious about doing this whole engine transplant as my 4th year project!!! .. the scope was to do FEA on the frame with fatigue analysis and then do a dynamic analysis of the mini using ADAMS car... as you said.. a tad too complicated for an individual to handle within one year.. especially when my lecturer said since its a personal interest project.. I would have to fund it my-self ( no full time job then!)

Where are you studying by the way??

so you're saying the change in toe angles is mainly due to suspension travel as opposed to suspension member deflection??.. interesting..

^^ You guys are confusing bump steer with torque steer. Minis do have bump steer, but the logic you are using isn't right. It is possible, with the suspension type that a mini has to have the arcs scribed by the motion of the upper and lower links to be sufficiently matched by that scribed by the steering tie rod to have no bump steer. It is also not a given that if you have a bump steer effect that your neutral suspension position is at the peak of the curve such that the bump steer is toe-in in both the bump and droop directions. In any case, bump steer is not your cause of torque steer because any action of the car pitching and raising at the front is symmetrical and opposite at each wheel.

A far greater cause of torque steer is drive axles reaching the outer CVs at different angles to the horizontal. The angle between the axle and the CV in the horizontal plane creates a torque about the vertical axis (ie, the steering axis). If the shaft angles are different, the torque is not equal and opposite and the car pulls to one side. This is not the only torque steer effect but it is by far the greater one if the car is (1) evenly loaded (2) on a flat surface (3) has good alignment (4) equal tyre pressures.

Another major cause of torque steer is the kingpin offset. Minis were originally designed with the king pin axis hitting the ground 1 1/8" inboard of the centreline of the tyre contact patch. That is a large distance. If you now space the wheel out 1" and put wide rubber on with even more offset in the wheel, you can get a very large offset indeed.

Now consider the effect of this offset. As the wheel turns the contact patch moves forward and back, rather than rotating about it's centre. If one tyre has more grip than the other (due to road camber, load etc) then it will pull forward more than the other and the car will steer. The large offset also makes the steering kick-back when one tyre hits a rut or bump. People confuse this for bump steer.

Metro hubs have a more inclined king pin axis (than the mini's 8.5 deg at standard ride height) to reduce the king pin offset and the above effects. The downside to a more inclide kingpin axis are a larger camber change wih steering angle leading to more positive camber on the outside front wheel in tight turns.

So, you want less torque steer:
(1) Get equal drive shaft geometry, usually by having equal length shafts and mounting the diff in the right spot.
(2) Have the lowest king-pin offset you can by not increasing your track width too much, having longer bottom arms and maybe Metro hubs.
(3) Get the castor set correctly both sides. Most cars aren't adjustable and if they are, most aligners don't bother. As Matt Read said in another post, make sure the rack is in the right spot and not bent. Make sure that tha tie rods are the same length from the rack end ball to the tie rod end. (rack dead centre when straight ahead). Make sure the radius rod bushes are the same stiffness both sides.
(4) Set the height of the car correctly both sides
(5) watch out for large camber angles as they make the car more sensitive to variations is road to tyre contact at side. An inclined tyre has a camber thrust that pushes in. This needs to be countered with some toe out. As the car moves over varying surfaces, the camber thrust changes and the car tram-lines left and right. Notice how motorbikes can turn corners even though the handle bars are not turned? Camber thrust.

After all that, the best thing to do is to buy Milliken and Milliken, Race Car Vehicle Dynamics or a similar text, a shed load of coffee and have a quiet read, with a note pad for scribbling.

Wowsers!!!

Its a holiday today and I learnt something!!

The way you explained torque steer makes sense. Other explainations I had heard, didn't seem to me to be quite there.

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-James.

Toyota 4EFTE Powered Minivan.
102 Kw @ The Front Wheels....Oh What a Feeling!

I should note that I wasn't talking about torque steer. I was just talking about toe in out - I just jumped in in the middle of a conversation on torque steer when toe adjustment came up. It's all good conversation though.

Pubudug - What exactly is "suspension member deflection"? I think there's a lot more coming into play than just suspension travel. But in order to understand the overall result each individual 'event' (for lack of a better term) must be analysed on it's own. Then an overal result can be created. So I guess starting with suspension travel and working from there is a good start.

I'm studying at Adelaide Uni. Only in 1st year so haven't learnt anything useful yet!

Where'd you study? - Or currently studying?

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

Sorry, what meant to say was 0.5 degrees over standard i.e. 3.5 degrees total!

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"Not Speeding Officer..........Qualifying"

Pubs, to stop your intercooler piping blowing off all the time, weld a bead around the ends of the pipes....giving the clamps and silicone something to bite up against

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1962 Morris 850.....with a 1310

1998 Toyota starlet.....161.1hp atw

Or use a bead roller to put a bead on the outlets/inlets!!

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"Not Speeding Officer..........Qualifying"

Mr Pubs,
Just to go back a few pages.....
Can you post a couple of pics of your air filter set up? I know its a bit toight in there, but I was wondering what you did.

Also are you running a bov? and what are the engineer's thoughts on the intercooler poking out at the front?

_________________
-James.

Toyota 4EFTE Powered Minivan.
102 Kw @ The Front Wheels....Oh What a Feeling!

Slinky Inc:

I graduated last year.. now working ( not automotive related unfortunately.. they all pay crap wages! )

When I say member deflection, I am talking about movement of suspension parts relative to each other due to defomation in bushes, twisting of subframe, bucking of track rods etc etc. I guess for each car depending on setup it will be different.. I will try it out both ways and see how it goes..

I'll post my intake pics soon.. its right at the front.. dont think it can get much better than having it right at the front

I'm running the stock BOV.. I intend to change it to a A/M one at some stage and have it stuck on the cool side of the piping ( plumb-back ofcourse)

I sent a picture to the engineer and he hasn't said it wasn't allowed.. infact he said it looks good!.. we'll see what Regency fellows say!

ok boys... time for an update

The car passed the track test! yay!... the drive up to Adelaide international raceway was great.. about 40 km drive.. the car handled really well. I got the wheels aligned just the day before.. she handles quite well now.

I tell you though.. the intercooler hanging on the front is not the most ideal thing!... its too much of an attention grabber! .. almost every car that either passes me or stop next to me pokes his head out and has a confused look on their faces. Some boy racers wanted a bit of a play with me as well!.. I was tempted but... i took it easy

The engineer did all the tests. Brakes worked very well and the car passed the lane change test no worries.. the engineer got me to sit in the car when he did the lane change test as well.. I was scared out of my mind.. I never throught we'd make it!

Now I have to wait unitl he writes the engineers report. Meanwhile I have to do up the body work and give it a general prep and then off to Regency for rego!!!

So this project is about done now. boviously the usual mods will follow but I am thinking of bigger and crazier things after some I saw the other cars that were on the track ready to get the engineers stamp of approval.. (which they did!!)

I'll start a new thread for that one..