kikiturbo

Actually I am not contradicting you, the way mitsu system works is a bit different to what people expect.. it looks like the system is not about optimising ultimate traction, but rather works during requested direction (yaw) change. So steady state at set steering will bring open diffs, change in steering angle will bring about diff lock.

I am looking to post some logs and you will see what I mean.

we logged solenoid current with evoscan, and other thinhs, such as speed, G lateral and accel/decel, brake switch state, steering angle and steering speed. It is the steering speed input that usually brings the largest change in solenoid current.

LetsGetThisDone

iTrader: (1)

In theory, stead state/steering/speed you want open diffs so you're not dragging or pushing any one tire. Letting them all rotate freely at the speed they need to given corner radius would allow optimal grip.

kyoo

iTrader: (29)

^ steady state equal some amt of throttle? if so i'd think you'd want a little bit of torque to the outside wheels?

kikiturbo

yes, and you get more tq to the outside at higher speed/throttle.. I will post the log tonight..

psushoe

iTrader: (8)

...if you have ayc. Usdm ct9a's can't do that.

kyoo

iTrader: (29)

isn't that exactly what clutch lsds do?

LetsGetThisDone

iTrader: (1)

No, AYC actually has left/right torque vectoring. A clutch LSD just progressively locks the axles together as torque input goes up.

kyoo

iTrader: (29)

not talking about torque vectoring specifically - i'm talking about sending torque to the outside rear wheel, which is what a clutch lsd does. sends torque to the wheel that has more grip, which is the outside wheel. it may not be electronically controlled, but the net result of "attempting" to bind together two wheels going different speeds with different loads is that - if it's not that, something else is causing my rear outside wheel to propel the car forward - as evo x owners riding in my car have noted

kikiturbo

locking the rear diff just makes the inside and outside rear tire try to equallise their speed. Normally that would induce understeer unless you seriously unload the rear inside tire, which is something you usually do with a stiff rear ARB

kikiturbo

sure, I was just commenting on what I noticed while testing..

Bee-Raddd

unfortunately ER cant help me since i have AYC. Been talking to a couple guys in the UK and they offer the service. lost 5th gear dog ring this weekend racing so repairing that before next round in 2 weeks then ill pull trigger on a tuned ayc diff ecu and see what differences we get!

kyoo

iTrader: (29)

depends on the diff. correct me if I'm wrong here, clutch diffs Rey to equalize torque as opposed to a speed sensitive diff. both rear wheels receive the same amount of power, but the inside rear travels less and the outside rear wheel receives the extra torque.

while this is moot/not really about steady state cornering with little throttle, if what you were saying we're true lsds would only ever create understeer until literally tires broke traction

kikiturbo

clutch diffs will try to equalise speeds between the wheels.. it will transmit more torque to the wheel with more traction, and that depends on tires and suspension setup. Hence, it will induce initial understeer however, it doesnt mean you can not get optimal performance with suspension adjustment. There have been lots of succesful race cars running fully locked rear diffs (like porsche gr C cars and even subaru impreza WRC)..

I have a nice PDF on the subject.. should look for it..

dave_evolvix

iTrader: (1)

Quick question... I know ACD Tunes are popular for AutoX, and it would seem that English Racing is the new favorite pre-set tune. What about the Time Attack and Road Race crowd? Worthwhile upgrade?

kyoo

iTrader: (29)

please do.

at the risk of derailing the thread, i'm curious what the difference is in the definition then between torque-sensitive limited slips, like clutch types, and speed sensitive diffs. what you seem to be describing is a speed sensitive differential, rather than a torque sensitive differential, but the clutch is the latter.

ultimately though, the end result is i'm getting more torque to the outside rear wheel, and it doesn't require the inside wheel spinning or up in the air to do it, works for me.

i will say that, just with a rear lsd, especially with one that is 1.5 way that is acting some on decel, the car will understeer, at least off power - BUT, that the ACD tune (only the one I got from English Racing) has eliminated entry understeer while allowing the rear diff to function properly on power. I'm really happy with the setup.

re: for on track - i think it was designed really with track driving as its basis. Autox settings/more "aggressive" settings on ER's ACD tune just make the car looser on turn in. would check with ER or whomever as far as how they tune for track.