Sorry, didn't intend to write a novel length post, just got carried away and couldn't stop my finger from flopping on the keyboard. My apologizes.
James,
I think the consensus is that the raising of the outer tie rod as MMC did on the later M3W's has reduced "most" of the bump steering.
Due to width of the steering rack inner pivots being wider than the inner pivot points of the A-arms, you will still get toe in fluctuation no mater where the outer tie rod is.
In theory, if you drew a line between the ball joint centerlines and the inside pivot centerlines, and at the height of the tie rod, the imaginary length between the two vertical imaginary lines, should equal the length of the tie rod.
I think that if you do a good look, the tie rod is considerably shorter than the theoretical correct length.
What Empire did was to shorten the upper A-arm to a length that better matched the geometry to get the tie rod length to better match the ball joint / inner A-arm pivot point length.
Also with almost equal length A-arms like the M3W has, there is very little camber change on corners.
With the Empire kit and unequal A-arms, you will get a self adjusting tread contact patch with the pavement.
In a hard left turn, the M3W will roll outward compressing the right front suspension/wheel. In the stock M3W, the right front tire will tip outward going more positive in camber relative to the pavement and lose traction.
In an Empire M3W in the same hard left turn, the right front also compresses, but to some degree the shorter upper A-arm does not pivot parallel with the lower and it will tip the upper ball joint inward fast than a long A-arm would. This creates more negative camber and increases the contact patch of the tire with the pavement giving better steering and traction.
Likewise, in the same turn scenario, the left front suspension will rise. In a normal M3W the inside front tire will go more negative and again lessens the contact of the tire to the pavement.
With the Empire M3W in the same hard left turn, the suspension will also rise/extend but the top of the tire will go outward relative to the longer upper A-arm. This helps to increase the tire contact with the pavement. Although the inside tire as we've seen in some of Mark's hard hill climbing turns, it may touch the pavement very little.
So would a "newer" normal M3W perform better than an older without the relocation of the outer tie rod, yes it would. It would also have less bumpsteer or scrubbing as the wheels move up and down in normal driving.
BUT the Empire equipped M3W would just that little bit better all around and a lot better when driven to its limits.
This is just my opinion, I could be wrong. If I am, I just spent very lot of finger taps on the ole keyboard for naught.
I'm really glad to see all the excitement still on this forum. There's a lot of new blood to keep things active. That's also a LOT more positive things to be said about the M3W overall.
Carry on ole chaps... Cheers!
One last comment, I know, won't this guy EVER shut up, but I think this is something that may not have been discussed before about tire wear and steering.
That Ackermann Steering of a M3W.
To those that do not know this, Ackermann steering means that the inside front tire always travels a tighter radius than the outside tire. If they turned equally, one of the tires would be scrubbing sideways around each turn. Now going down the road fairly straight, it doesn't make a lot of difference.
But at slower speeds, like in town or parking lots, it makes a BIG difference to have it correct.
Has anyone ever tried to check to see if the Ackermann geometry is close to or correct on a M3W? Just curious.
Again this is theoretical, but if you were to use your front vertical steering assembly between the ball joints, the centerline of the ball joint vertical and the trailing angle of the steering arm welded to the upright spindle, should intersect with the center of the rear tire. So if you drew a line from the center of the rear tire forward, it should intersect the outer tie rod and then continue forward to come out directly in the vertical centerline of the upper/lower ball joints.
I've read that in racing, some believe more Ackermann or less Ackermann makes a difference. But for standard passenger vehicles, it should be true on.
If this is not entirely correct, your tires will be scrubbing all the time you're not going straight. The sharper your turn, more scrub. This is a possible contributor to tire wear on the M3W's. I could just be full of hot air, which is usually the case.
I think with a little ingenuity one might be able to use a heavier string, chalk line etc, and lay it out on the floor and eye ball the line at the front spindle steering arm area.
Also for those that have nice concrete garages with possibly a nice epoxy finish, when you roll your M3W and move it around with the wheels turned, do the tires squeal while rolling? If they do, this could be an indication of less that true Ackermann steering geometry.
Sorry if I've rambled on way too much. I apologize...
So would a "newer" normal M3W perform better than an older without the relocation of the outer tie rod, yes it would. It would also have less bumpsteer or scrubbing as the wheels move up and down in normal driving.
BUT the Empire equipped M3W would just that little bit better all around and a lot better when driven to its limits.
An excellent, detailed explanation Dan. So the "newer" normal M3W has the same geometry suspension as an older M3W with the "comfort kit" and both of these will perform equally better than the terrible bump steering original set up. As you say, the Empire kit sorts out more of the problems and is another but less noticeable, in normal use, improvement. I can confirm that it is better at the limits. I had a couple of experienced and skilled 3 wheeler drivers try my Empire equipped car on a track at the MTWC training day last weekend and they were impressed by its handling compared to the standard car, particularly that it turned well into corners and didn't need mid corner corrections.
For me, I think I should drive mine for a bit and see how the turn in, ride, stability on the road, stability in corners and tire wear seem. Will also see to what extent I get into any club performance activities. Great to have something like the Empire Kit to dial in the suspension as the need arises.
For me, I think I should drive mine for a bit and see how the turn in, ride, stability on the road, stability in corners and tire wear seem. Will also see to what extent I get into any club performance activities. Great to have something like the Empire Kit to dial in the suspension as the need arises.
James,
Not as important as removing more of the bump steer and wear issues, the Empire kit also allows for caster/camber adjustments which is NOT possible with any stock M3W.
Thought this might be worth mentioning if anyone wants to play with the setup of their M3W.
