Caster too low AND too high
 

Hello,

I'm encountering one problem when aligning my MY2000 S2000, for the right wheel the caster is too high and won't go below 7º15', for the left wheel the maximum it reaches is 4º 19'. The guy at the alignment shop doesn't have a clue about what the problem can be.

Some additional information:

- Camber is at -1 on both wheels, even reducing the camber the caster is not affected by much
- I just installed the Spoon rigid collars, with no issues so subframe should be well centered
- I just replaced the suspension bushings (Mugen in the lower arm and Powerflex in the upper one)
- I also installed the Spoon buchings for the steering rack

The car rides straight, I don't understang why one side os off by too much and the other by too little, but the average of both casters is around 6, where both should be but none reaches.
To be honest I'm clueless and I come to you guys for ideas.

I have my car since 2 years now and this is the first alignment I'm doing after the mods I mentioned above, so I don't know whether the car had this problem before. Otherwise it's a very clean S, no track, I bought it all stock and with maintenance at a Honda dealer.

Thank you very much and merry Christmas to you all!!

Don't worry about it,RWD caster is 4-7 & FWD is 1-4 degs
look at mine below, I don't feel any negative effects with mine compared to when I was oem.

Is the subframe shifted?

You sure both caster eccentrics on each arm are working together and not against one another?

One way to know if it's really affecting your ride is by making an aggressive left turn and compare to a right turn turn (i.e. driving down a street then turn left or right at a light), based on your input, the right hand turn should be heavier and the left should turn in faster. If you do a lot of auto crossing you'd want a lower number caster as it allows for faster turn ins, but it makes for a wilder and more 'wobbly' top end driving experience.

I prefer a higher caster number as it gives the steering a heavier feel for my driving style since I don't auto cross and prefer high speed sweepers vs. trying to turn on a dime around a cone in a parking lot at 6 mph. :)

Thanks for answering!

You're fully right, the first time we aligned we found out that the eccentrics were placed the other way around (180º ) and the guy at the shop placed them OK. Despite fixing this the caster spec was not reached.

My logic also tells me the subframe could be moved as one side has too much caster and the other too little, but I don't understand how, I installed rigid collars by droping the subframe on the bolts, installing the collars one by one and then tightening everything back together to service manual torque values. How could I check if it's shifted? Thank you, I appreciate your help.

Are you sure that the arms and spindles are both straight? Has the car been in any collision?

After correcting the eccentrics, is the issue still on both sides or just one?

No collision that I'm aware of, in fact it's a very clean unit.
The arms were removed for installing new bushings and reinstalled according to the service manual, the position of the spindle is not given by the arms?

On both sides but opposite way, on the right side I can't reach less than 7 degrees, on the left side I can't achieve more than 4.20 deg. (Almost 3º difference and Honda specification is 6º)

So I found somehow the problem. I measured the subframe, the lower arm and the kuckle and found absolutely no deviations from the right and the left side, everything looked fine.
After some observation I realised that the Mugen compliance bushings do have a position, given by the two little arrows. I took the lower arms to a shop to install the bushings and they put them on wrong... So I had to remove again the arms, take thrm to the shop and put them right this time.

At the alignment the left wheel had a perfect caster adjustment this time, however the right one was stikk too high. Do you have any ideas? Could the bushing have gotten damagen from the removal and reinstall?

These are my current settings (I also have the Spoon toe arms so I tried to minimize rear toe):

Caster. Left 7° right 8°15'
Front camber -40'
Front toe 0

Rear camber -1°40'
Total rear toe 0°04' per side 0°02'

Sofar I like this setting, however I think it is too tail happy, I should have given just a little bit more toe or put one more washer on the toe arm for dynamic toe correction. In comparison to OEM arms it's much more controllable, less sensitive to bumpy roads and more compliant despite the great oversteer it has now, very different to stock. I still don't known which set up I like the most, I also likr the AP1 character, not forgiving any driving mistake and always willing to precisely rotate.