adjustable tie-rod ends?

[suicidal2af]

I've searched for a while now, and haven't been able to come up with anything.

Our cars don't exactly have the greatest design when it comes to bump steer. Does anyone make adjustable tie-rod ends for a 2G? I've found them for evo8's, but afaik they aren't interchangable.

/me waits for jtoby

 

[jtmcinder]

I haven't looked. Is it possible to move the rack up a little? As to rod ends, the problem is our stock location is on top of the knuckle. You would have to lower the car a lot before swapping it to being under the knuckle gave a better curve.

- Jtoby

 

[suicidal2af]

I haven't looked. Is it possible to move the rack up a little? As to rod ends, the problem is our stock location is on top of the knuckle. You would have to lower the car a lot before swapping it to being under the knuckle gave a better curve.

- Jtoby

Assuming adjustables on both inner/outer ends, I don't think the car would need to be lowered all that much to achieve a better curve.

Without jacking my car up and looking, I'm 99% positive, the the outer end is on the same vertical plane as the upper and lower balljoint. However, I do not believe that the inner end is on the same plane as the control arm pivots, and I don't think it intersects the instant center.

If we had inner and outer adjustables, you could drop it below the knuckle and still keep the angle correct, and potentially give us better curves.

I dunno, this was just a random thought that occurred to me. It's seen success on cars that are better off than we, and on cars worse off than we...don't see why we couldn't improve on it.

EDIT: The main thing that got me thinking about this is the fact that we could almost eliminate bump in and then run a *tiny* amount of bump out, which unless I'm mistaken will make the car slightly more stable on corner entry(which would be dandy for us FWD guys.)

 

[wret]

Greg, a lowered 2g will toe out under bump. Conventional wisdom is that zero change throughout the travel is ideal. I'm thinking some more about the ideal rear curve for an FWD though.

 

[Todd TCE]

Cool. A real tech savvy thread. No Best tire stuff...

Moving the rack seems the most common method I know of. This is often done with offset busings which shift its mount point. Yup, even lowering won't make it worthwhile to do a complete change of spindle mount on the tie rod ends.

As for the value of 'toe out in bump', I'd say it will offer better turn in but for street use you'll learn to hate the hunting it will provide on the street. Very un nerving and light.

Again, that "what may be best for the track, may not really be what one wants on the street" story line.

 

[suicidal2af]

Cool. A real tech savvy thread. No Best tire stuff...

Moving the rack seems the most common method I know of. This is often done with offset busings which shift its mount point. Yup, even lowering won't make it worthwhile to do a complete change of spindle mount on the tie rod ends.

As for the value of 'toe out in bump', I'd say it will offer better turn in but for street use you'll learn to hate the hunting it will provide on the street. Very un nerving and light.

Again, that "what may be best for the track, may not really be what one wants on the street" story line.

However, when 80% of your driving is on empty backroads, it might not necessarily be such a bad thing.

I've seen quite a few mentions of shifting the rack's mount point -- however, almost all of the 240 and wrx guys run the adjustable tie-rod ends -- since they're readily available, I'd assume.

Anyway, most of this discussion is probably moot if I'm wrong about the locations of said pivots and angle of tie-rod arm. And if I do recall correctly, then it seems to me there might be something to be gained in that area.

I'll take a look at it friday. Got an amazing deal on an AGX/GC setup that I could NOT pass up($200 shipped), so I'm finally installing those. Was a little worried about the AGX's being blown, but they seem to be fine. Now I just need to replace my failing cv axle and *cough* outer tie-rod end.

I'll try to get some pictures and measurements on Friday. Hell, if you want you can swing by for a beer or two Ron

 

[wret]

Now that there's a 2nd guy in Maryland interested in handling, I expect to see more than one DSM at the next autocross at Ripken.

 

[jtmcinder]

If this is going to be car driven on the street, you really don't want it to toe-out in bump. That's the biggest problem with a lowered 2G. Yes, the added toe-out is nice for turn-in, but you only get this when trail-braking. The downside is that it toes-out when you are trying to brake hard in a straight line.

Another issue to keep in mind here is the dynamic toe from the squishy bushings on the compression arms. Under braking, the wheels move back and this adds toe-in. Under power, the wheels pull forward, adding toe-out. If you adjust your driving style to match the car (instead of messing with the car to match your style), this means you should try to avoid trail braking. Use the dynamic toe-in under braking to keep the car stable while braking before the turn, then get on it and use the dynamic toe-out to help you turn.

Having the angle of the tie-rods do one thing (toe-out under braking and toe-in under power) while the compression arm is doing the opposite is just asking for trouble. The odds of them cancelling exactly is about zero. Much more likely is you will end up with a car with extremely non-linear and maybe even non-monotonic behavior.

That's why my gut says we should be raising the rack to get the bump-steer back to near flat and driving the car as it was intended: using the compression-arm bushings for toe.

- Jtoby

 

[suicidal2af]

If this is going to be car driven on the street, you really don't want it to toe-out in bump. That's the biggest problem with a lowered 2G. Yes, the added toe-out is nice for turn-in, but you only get this when trail-braking. The downside is that it toes-out when you are trying to brake hard in a straight line.

Another issue to keep in mind here is the dynamic toe from the squishy bushings on the compression arms. Under braking, the wheels move back and this adds toe-in. Under power, the wheels pull forward, adding toe-out. If you adjust your driving style to match the car (instead of messing with the car to match your style), this means you should try to avoid trail braking. Use the dynamic toe-in under braking to keep the car stable while braking before the turn, then get on it and use the dynamic toe-out to help you turn.

Having the angle of the tie-rods do one thing (toe-out under braking and toe-in under power) while the compression arm is doing the opposite is just asking for trouble. The odds of them cancelling exactly is about zero. Much more likely is you will end up with a car with extremely non-linear and maybe even non-monotonic behavior.

That's why my gut says we should be raising the rack to get the bump-steer back to near flat and driving the car as it was intended: using the compression-arm bushings for toe.

- Jtoby

Wasn't so much aware of those issues. The only concern I'd have, shooting blindly, is that it may not be possible to raise the rack and have the tie rod angle correct, and the potential to shift the inner end out of plane with the control arm pivots. If it's not pointed straight at the instant center, we could just be making things worse. Again, until I actually get under and do some measuring, I'm shooting in the dark here. Maybe Todd could shine some light in here? Sorry if I took out anyone's eyes.

Now that there's a 2nd guy in Maryland interested in handling, I expect to see more than one DSM at the next autocross at Ripken.

I've wanted to go multiple times now...problem I keep running into are retail hours and my current(soon to be former) job scheduling a full month in advance. Oh well, the 30th is my last day at cingular. Hopefully vzw is better about scheduling.

Dunno where in PA you are, jtoby, but you're more than welcome to come drink some beer too