34 replies to this topic

[MiNiKiN]

Has anybody considered the 1.5mm toe out as a potential influencing factor or the actual guilty culprit?

 

I reckon I have read somewhere (not experienced) that zero toe-in is favourable on an LSD.

[growlerbearnz]

Setting the corner weights has solved much (but not all) of the twitchiness when lifting off! Woohoo! But it's levelled the body out again, which means the driveshafts are back to being at  different angles, which means the torque steer is back. Ugh.

So I've officially gone off the deep end, made a spacer plate for the left side engine mount that tilts the engine by a couple of degrees. The driveshafts are both now at -0.65 degrees. The front wheel camber is at -0.65 degrees. The theory is that since the CV joints aren't operating through an angle, they shouldn't transmit any torque through the steering axis. And if they do (due to suspension deflection, weight transfer, fat bastards in the front seats, etc) the left and right side torque steer should be equal, and should cancel out.

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Unusually for one of my over-complicated ideas, it's worked! The Mini goes in a straight line, even in 1st at 3000rpm (peak torque). Hallelujah! 

(Watch this space for engine bearing failure due to the oil all being at one end... ) 

 

 

Edited by growlerbearnz, 02 June 2021 - 05:57 AM.

[PoolGuy]

Has anybody considered the 1.5mm toe out as a potential influencing factor or the actual guilty culprit?

 

I reckon I have read somewhere (not experienced) that zero toe-in is favourable on an LSD.

That’s one of the reasons that I suggested a more conservative geo setup.

[sonscar]

I would think that ride height and corner weights could be set to have the driveshafts level.What kind of difference in a road car is acceptable?fat driver thin driver ditto passenger 5.5 gallon 7 gallon.full or empty,so many variables.Excessive toe gives quicker turn in so I understand.The car seems too  nervous to enjoy,hope you sort it.Steve..

[Spider]

Has anybody considered the 1.5mm toe out as a potential influencing factor or the actual guilty culprit?

 

I reckon I have read somewhere (not experienced) that zero toe-in is favourable on an LSD.

 

I run with 1/16" Toe on the ATB. Also had the same when I tried the LSD.

At zero or particularly any Toe In on the front make the steering very vague when straight ahead and over steer when cornering and not in a nice way in less than ideal conditions !

[nicklouse]

 

Has anybody considered the 1.5mm toe out as a potential influencing factor or the actual guilty culprit?

 

I reckon I have read somewhere (not experienced) that zero toe-in is favourable on an LSD.

 

I run with 1/16" Toe on the ATB. Also had the same when I tried the LSD.

At zero or particularly any Toe In on the front make the steering very vague when straight ahead and over steer when cornering and not in a nice way in less than ideal conditions !

 

Just to counter this. You also have to consider the way the suspension is mounted and how that effects things. Running fully “Rose” jointed and big fat slicks I run parallel as there is no movement in the tie bars when braking.

[nicklouse]

Setting the corner weights has solved much (but not all) of the twitchiness when lifting off! Woohoo! But it's levelled the body out again, which means the driveshafts are back to being at  different angles, which means the torque steer is back. Ugh.
 

 

Can you please describe what you are calling torque steer.

 

my reason for asking is that often people call something torque steer when it is not and is totally different and has different solutions.

[evoderby]

Setting the corner weights has solved much (but not all) of the twitchiness when lifting off! Woohoo! 
 

<<………>>

Unusually for one of my over-complicated ideas, it's worked! The Mini goes in a straight line, even in 1st at 3000rpm (peak torque). Hallelujah! 

(Watch this space for engine bearing failure due to the oil all being at one end... ) 

 

Great work!

Edited by evoderby, 02 June 2021 - 07:52 PM.

[growlerbearnz]

I would think that ride height and corner weights could be set to have the driveshafts level.

It could, for sure, but I Iike my negative camber. Zero or positive camber does not suit the way I like to drive this car: it has white leather upholstery, which stains easily . Half a degree of negative camber plus 3-ish degrees of caster seems to be doing the trick. 

 

Can you please describe what you are calling torque steer.

Fair question! The steering wheel tried to turn to the right when using full throttle, strongest in 1st gear at 3000rpm. The strength of the pull on the steering wheel was directly proportional to engine torque (less accelerator, less steering pull). 

I mean, it wasn't trying to rip the steering wheel out of my hands (It's tuned for torque but it's still just a 1330!) but it was quite noticeable, if it pulled that way all the time I'd think the alignment was out.
 

Just to counter this. You also have to consider the way the suspension is mounted and how that effects things. Running fully “Rose” jointed and big fat slicks I run parallel as there is no movement in the tie bars when braking.

Yup! I usually run 1mm toe *out* as my suspension bushes are more constrained* than on a stock setup. I went to 1.5 for testing purposes, that's a standard setting as per the Book of Lies (Haynes).

*Minispares lower arm offset bushes' metal sleeve is *always* a couple of mm too long, the nut stops before the rubber is under any compression. Rubber tie bar bushes squidge sideways under load, easily fixed using a pair of cupped washers.

Edited by growlerbearnz, 03 June 2021 - 05:48 AM.

[nicklouse]

Ok as it is pulling the same way all the time you are correctly describing torque steer. You have also found and are looking to fix the cause of the issue. Driveshaft angles. But I would not bother as you can only fix it (or reduce it) for one instance as some as you go into a corner it is back again.

 

there are equal length driveshaft kits out there which is what I would fit if I was determined to remove straight line torque steer.

 

 

next you say you have toe in? Nope parallel or toe out.

[nicklouse]

Yup! I usually run 1mm toe in as my suspension bushes are more constrained* than on a stock setup. I went to 1.5 for testing purposes, that's a standard setting as per the Book of Lies (Haynes).

Read it again.

[nicklouse]

*Minispares lower arm offset bushes' metal sleeve is *always* a couple of mm too long, the nut stops before the rubber is under any compression. Rubber tie bar bushes squidge sideways under load, easily fixed using a pair of cupped washers.

Interesting that this appears in the quote but not the post?

[growlerbearnz]

...I would not bother as you can only fix it (or reduce it) for one instance as some as you go into a corner it is back again.

Totally, but it's that one instance (accelerating in a straight line) that it bothers me. I expect the steering to load up while cornering (especially with the ATB doing its thing) so a little more or less load isn't an issue. 2nd gear overtaking on a flat road though? the extra pull is disturbing.

Besides, I'm having fun tinkering! It's not a car, it's a hobby. (Repeat until the panic subsides).

Edited by growlerbearnz, 02 June 2021 - 10:34 PM.

[growlerbearnz]

 

next you say you have toe in? Nope parallel or toe out.

Whoops! Brain fart. Corrected. Toe *out*. 

And somehow I double posted. Perhaps more coffee is required. 

Edited by growlerbearnz, 02 June 2021 - 10:25 PM.

[nicklouse]

 

...I would not bother as you can only fix it (or reduce it) for one instance as some as you go into a corner it is back again.

Totally, but it's that one instance (accelerating in a straight line) that it bothers me. I expect the steering to load up while cornering (especially with the ATB doing its thing) so a little more or less load isn't an issue. 2nd gear overtaking on a flat road though? the extra pull is disturbing.

Besides, I'm having fun tinkering! It's not a car, it's a hobby. (Repeat until the panic subsides).

 

Ok  ow I have to drop out as I have never used one of these diffs so can comment more. mine is more of a locking diff until you let off so under hard acceleration I don’t get same effect.  But at least you have correctly IDed the issue and understand what is causing it.

 

final thought. You did set the corner weights with mass in the drivers seat? Or mass in the normal use configuration? If you set it without mass that will almost definitely remove any benefit of doing it in the first place.

 

suspension is a dark hole.