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No, I think you may be right. At least I hope you are. I'm going to model the suspension movement on the computer and see how much the angles would be trying to change at the bushings. I do want some "give" in it, which is why I do want to use some bushings, not just rod ends everywhere. I've driven a fairly light car with hard polyurethane bushings and even that was a little too jarring and rattlely for my liking. If I swing things through about 3" up and down and it only moves .010 or something like that, then even fairly stiff bushings can allow for that.

This is one of the problems with being an engineer, who works with other engineers, in a field where often .0005" is significant; we lose track of the real world.

Rick

Had a dyno day with some pretty cool cars, including the first At-om I've every seen in person. I took this shot to give an idea of size. They aren't as small as I though - comparted to a Mini...

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Hey. No fair Kurt! You've lined up your front wheel with his back wheel to make his look like a limo in comparison to the little mini. The wheel base of the At-om is 92.3" compared with your 80", so that is quite a difference.

I admit this has been difficult for me to visualize. I must stand by my statement that compliant bushings and rod ends are interchangeable, singularly or in pairs.

Yes, two rod ends will limit movement to one plane. However, when one rod end is adjusted to shorten or lengthen the lower control arm on one side, the plane of rotation of the untouched rod end has now changed to match that of the adjusted rod end. A compliant bushings would have "complied"

The upper control arm would need to be adjusted too, to be parallel to the new plane of rotation on the lower control arm, but it will not bind.

If adjusting camber, both rod ends must be adjusted to remain parallel to the other control arms plane of rotation.

FWIW, I would make adjustments at the frame for easier access with the wheels on, moving the arms and the spindles.

I've enjoyed considering this and would like to keep the discussion going.

If you are talking about the pivot axis on the frame for the upper and lower control arms not being parallel, then it would bind.

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Here is some suspension data. This was taken from one particular car, so things could vary from car to car. It is not complete, but the missing pieces can be filled in. For example, if you have the frame laid out and the suspension spindles at the correct track dimension, then your A-arm length will fall out. All "heights" are measured from the ground. Tube diameters include the finish (powdercoating I imagine).

Rick

a engine that i saw used in a mk2 mr2 was the camry/solara v6. not a bad option since i think it was a cable shifted tranny and trd does make a blower for it. i figure if they can fit it in the back of that thing im sure it will fit nicely in the back of yours. check bedell(sp) racing for info. happy hunting.

Interesting thought. It is supposed to be a very light engine (all aluminum). The problem is always finding out just how much these things do weigh. It is a fairly cheap engine (compared with any of the high performance Honda's) but a quick look shows that 90% of them are automatic. Then again, maybe that's something to consider. After all, I'm old and lazy and like driving autos!

Anything basically wrong with considering an automatic in a small, light, home-built middy? Several advantages: no clutch pedal/cable to worry about, and the shifter would be much less critical to rig up.

Anybody else know anything about this engine (the 1MZ-FE is the light weight one)?

Rick

I think this design of the rear control arms is better than the previous version. The idea would be to add a thin-wall bushing of nylon or equivalent between the spindle holes and the bolts. The camber adjustment is done at the frame end of the arms. I'll play with the mounting points on the frame to get the roll centre where I want it.

Rick