Quaife?, Where the best prices are? Options

[ArtechnikA]

QUOTE (BigD9146gt @ Feb 25 2005, 11:56 AM)

The Quaife locks between 15% and 80% depending on the amount of change between the wheel that is losing grip/spinning and the wheel that has hook-up. Your statement, if i'm reading it correctly, is what a non-limited slip does.

you are correct in that with a torque-biasing diff, when a wheel has ZERO grip, it will spin; in this reqime, it acts just like an open diff.

similarly, the torque-biasing diff works only under drive - not overrun (braking.

[brant]

QUOTE (KenH @ Feb 25 2005, 09:25 AM)

The general rule is 40% for AX & 80% for Track. Mine is set for 80% and works well on the track but I have not run an AX with it yet. I do not believe HP would be a determining factor when choosing a ZF or TB diff. Others will need to comment on that. Those I have talked to preffer the ZF for track use because it is "always" working - accelearation, braking, rear wheel lift. Rear wheel lift is probably a bigger problem when AXing. Not sure I understand your comment "how much resistance would each wheel need to provide in order to have the diff functioning". The ZF is always functional, acceleration and deacceleration. It uses a "plate/disk" system that senses drive shaft input and wheel load to manage the "slip". I would try and talk to as many "drivers" as possible. It is expense to have a new differential "fitted". There is a possiblity the Quaife my not work all the time - but the ZF will always work. Ken

Ken,

my comment about "how much pressure" was aimed specifically at the comment about a TB not functioning when a wheel was lifted. To rephrase, I was asking if a TB would work when say a wheel is unweighted some, but still had 100lbs.. (or 200lbs, or x lbs) of weight on it.

each of us has to make our own decisions and findings.
I usually take advice from my the local guru who has been giving me good advice for 15years. my guy, AJ installed my locked diff (not really a spool, just a welded diff) and has never given me bad advice.

I believe that the HP threshold is based somewhat on smoothness. I'm theorizing here, but would guess he was trying to explain to me that a high HP car can still be faster on a track by improving traction and giving up smoothness... Where a lower HP application is faster on the track by highlighting the smoothness from a TB diff and has limited gains in traction due to the ability of a race tire in a dry situation to put down a good amount of torque.

So What I was asking is in reference to the comment that
"a TB diff does not work when one wheel is unloaded"

do you know if that is true only when fully unloaded or still true if just partially unloaded?

I trust my guy and will put together next years box with a TB, but still love to learn.

[brant]

QUOTE (ArtechnikA @ Feb 25 2005, 09:27 AM)

this kinda goes with the "225HP" threshold - that seems a plausible number for the point at which a sticky race tire can be broken loose letting the clutchpack work better. i think that number is probably lower in limited-traction conditions, such as a rallye car's loose gravel or the glare ice i faced this morning just trying to move my car into a parking space. Mark Donohue was a big fan of the spool and a very smooth driver. one drawback to the spool is that the "friction circle" technique tends to promote understeer, because the braking-while-turning and the accellerating-while-turning forces with equal drive to the back wheels tend to make the car go straight. only if you can consistently develop adequate slip angles with the drive wheels can the car be pursuaded to turn. (hence the change in driving styles you observed.)

Rich,

thanks for your time, and thanks for writting all of this out!

I was very clearly told when I went with the locked diff that I would:
a) need to re-learn the driving and
(IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif) reminded that in (low traction) rain or sand, things would get scarry fast.

I had to re-learn to deal with the understeer. Kinda like the 911 guys have Known for years. Its truly a "dirt-track" style to get the car to rotate. You literally force the rear into a slide until you are pointing the direction you want, and then apply power to go straight.

for that reason, I'm guessing that the whole differential debate is based upon some cars/some levels of HP/and some driving styles are better off with one type over the other.

I think that you can still be smooth with a locked diff/spool, but its a whole different type of smooth which involves constant "smooth" drifting and dancing on the traction limit.

[KenH]

http://www.quaifeamerica.com/

They should be able to answer questions about the TB's operating range.

The understeer was not that great on mine. 2223# car, 225# rear springs, stock rear swaybar, 22mm front torsion bars, 22mm front sway bar set 1-1/2".

Still "tweeking".

Ken

[brant]

I've been told, that the understeer is not bad with the TB...
Its good that you confirm that.

Its on the locked diffs that the understeer is significant.
The rear remains locked at all times (like an 80%ZF except more so)

I anticipate that a TB diff will let me go back to a much smoother and less "dirt track-ish" driving style...

Thus the exact reason the TB is supposed to be smoother and possibly quicker (according to some)

I've made up my mind long ago.. my wallet just won't let me play yet.