The DC2 Castor Thread

[tinkerbell]

Are the benefits of that small amount of caster dramatic? lol

well, you wouldn't know would you?

but i can say this:

i did feel the improvement in the handling from the swap, particulary on initial turn-in.

i did not feel the *dramatic* changes to bump steer that you insist exist.

so just so we can be clear about the "extent" of the changes that exist, i will measure the bump steer next week whilst fitting a set of JIC adjustable camber arms... i will also see whether the JIC arms have exact alignment with the OEM arms...

[milkman]

Thanks for the replies guys! Interesting indeed..

Well Mr. Heasemans failed to mention the trade-offs that may result (there always is isn't there?).

Never heard of bump steer until you guys mentioned it.

http://www.longacreracing.com/articles/art.asp?ARTID=13

Interesting... reading that article I can see why dramatic changes can cause bump steer.

Can someone elaborate on the UCA swap?

maybe milkman can talk to heasmans about the UCA swap - as both ways of changing castor on DC2 lead to increased bumpsteer...

I'll pick his brain when I get my alignment done there in a fortnight or so.

[tinkerbell]

Can someone elaborate on the UCA swap?

just swap the upper arms, you have to remove a few nuts and bolts:

I'll pick his brain when I get my alignment done there in a fortnight or so.

pls do

[freakygeek]

Thanks for the link milkman....

E. How Much Bump Steer?
Ideally you should run as little bump steer as possible. Most of the tracks we see today are old and bumpy. Bump steer on these rough surfaces causes the car to be unpredictable.
Some bump out can make the car more stable on corner entry. Bump in is almost always undesirable.
Some people use small amounts of bump out to create entry stability and an Ackerman type effect in the center of the turn where as the bump setting causes the LF to turn a bit farther than the RF as the RF compresses and the LF extends.
My recommendation is to run .005 to .015 thousands of bump out but never allow the tires to bump in.

[tinkerbell]

you getting worried my measurements are gunna show it is not as "dramatic" as you have been made to believe?

getting in early with quotes about how much bump *should* be... clever

[freakygeek]

you getting worried my measurements are gunna show it is not as "dramatic" as you have been made to believe?

getting in early with quotes about how much bump *should* be... clever

No bump-in under compression is desirable. Period.

Why are you so intent on proving something which others have already proven with measurements? 6mm of toe change is dramatic for 2" of suspension travel.

[tinkerbell]

cam, you seen to be missing the glaringly obvious point of my position:

*if* my car does have 6mm toe change at 2 inch compression, why is it so unnoticeable (i.e. not dramatic) on the road and on the race circuit?

and why did Eugene report that after he did it, that the positive improvement was noticable? yet did not report any noticable negatives? (and we know how objective he is)

[tinkerbell]

of course, it could mean i am a ham fisted lout who lacks a profound connection to my own car...

[tinkerbell]

Quoted from http://honda-tech.com/zerothread?id=2333432

thanks for the link Cam, finally read it all...

from the guy who actually took the measurements:

You won't feel it from the drivers seat unless you have an incredibly sensitive butt-o-meter.

i guess that settles it; the reason i havent noticed it, is that it is probably not noticable to the driver...

i'll still measure it, and then install my JIC arms the right way around (measuring to see if they are same as the OEM ones) and see how it feels on the resurfaced OPH (despite the fact that the worst effects of bumpsteer are apparently most felt whilst going straight and braking hard)...

[freakygeek]

(despite the fact that the worst effects of bumpsteer are apparently most felt whilst going straight and braking hard)...

In your case you will have more toe-in under braking on the front axle, therefore most likely more stability, at the expense of turn-in whilst trail braking....

[fatboyz39]

hetic thread.

We are still running non-swapped arms. We get 1.5' degree castor each side.

[tinkerbell]

In your case you will have more toe-in under braking on the front axle, therefore most likely more stability, at the expense of turn-in whilst trail braking....

to what extent do you think running 670 lbs/in front springs will impact on this?

[freakygeek]

to what extent do you think running 670 lbs/in front springs will impact on this?

Obviously there will be less deflection than with stock R 245lbs/in springs... therefore less toe change.

I'm sorry Dave, you just can't convince me that this modification is a good thing... but you should let me drive your car sometime anyway...

[tinkerbell]

so less toe change would mean i notice the dramatic bumpsteer less?

yes Cam, i do need someone (insightful) to drive my car... i have done so much modificatiosn to it i forget what it is "supposed" to feel like...

[freakygeek]

so less toe change would mean i notice the dramatic bumpsteer less?

yes Cam, i do need someone (insightful) to drive my car... i have done so much modificatiosn to it i forget what it is "supposed" to feel like...

Yes, absolutely there will be less bumpsteer with less suspension deflection due to the far increased spring rate...

I'd be interested to see how your car feels though.