4wd system on legnum vr4

[WireD]

Hi!
i dont know if this is the right place to put this Q, and i dont know if i ask the Q correctly, but here goes...

What is the fwd/rwd split on the 4wd system on the legnum?

the mazda 323 GT-R has something like 53% rear/47% front.

The old Celica GT4 has 50/50 drive...

the legnum? :D

thnx in advance.

Øyvind

[Kieran]

It's 50-50 I think, but the AYC system makes it feel more like a 60-40 rear bias at times when you're driving - it certainly feels like it'll break off into oversteer rather than understeer - you do have to be doing something silly for that to happen though!/help

[dickytim]

it is a viscous coupling in the transfer case so and I have heard 50/50, but I would argue a point that it is more the suspension set up that the AYC that gives the car a tendency towards oversteer that understeer, also the way it is driven.

[WireD]

The reason for the Q is VERY simple, m8s!

THIS:

http://i21.photobucket.com/albums/b295/Grim678910/Snow1.jpg

http://i21.photobucket.com/albums/b295/Grim678910/snow2.jpg

Imagine the fun we have here....? :D:D:D :evilgrin:

[thecustomer]

the split is 50:50 under normal loads, shifting to 40:60 front:rear when accelerating/going hard

Which for some is a normal load

:2thumbsup

Will

[Nick VR4]

The reason for the Q is VERY simple, m8s!

THIS:

http://i21.photobucket.com/albums/b295/Grim678910/Snow1.jpg

http://i21.photobucket.com/albums/b295/Grim678910/snow2.jpg

Imagine the fun we have here....? :D:D:D :evilgrin:


Wow what a great place :2thumbsup :2thumbsup :2thumbsup :2thumbsup

[WildCards]

I've managed to swing the rear end out and havs a very sideways moment. A little scary, but it sorted itself out with enough opposite lock and throttle feather.

[Kieran]

I've managed to swing the rear end out and havs a very sideways moment. A little scary, but it sorted itself out with enough opposite lock and throttle feather.

I just leave the TCL on! I turned it off once on a quiet road and deliberately provoked it just to see what would happen.... I about sh@t myself!!/help /Steeringw :toilet:

Thank heavens for AYC!!:embarasse

[WildCards]

The TLC comes off mostly, due to the car feeling loads quicker. It does give a few 'I need to check my pants' moments though.

Might need some new tyres soon though, so hopefully i'll be seeing less AYC lights on my way to work aswell

[Nick Mann]

the split is 50:50 under normal loads, shifting to 40:60 front:rear when accelerating/going hard

Which for some is a normal load

:2thumbsup

Will


This is a version I have not heard before! I have never yet seen any evidence to support a theory on torque split. Do you know of any?

[Kenneth]

This is a version I have not heard before! I have never yet seen any evidence to support a theory on torque split. Do you know of any?

It is the theory that I heard. 40/60 F/R under acceleration.

/edit: although some google searching seems to point otherwise

[Kenneth]

Only real reference to 60/40 I could find is for weight distrobution F/R and that was for the evo

[bradc]

I remember someone on here saying that it did tend to give more power to the rear under hard acceleration, but I've never seen any numbers.

I also remember a dyno graph that measured front/rear power independantly, I think the rear had about 15% more power. I'll get the graph up later on tonight when i'm at home

[thecustomer]

This is a version I have not heard before! I have never yet seen any evidence to support a theory on torque split. Do you know of any?

Let me see if I can track down the source
Don't think it's the kind of thing you'd imagine
:thinking:

Will

9am update
ok, haven't found the piece on f/r power split yet -though bradc's chart below looks pretty convincing
I have found this (http://dwolsten.tripod.com/articles/mitsu1.htm) which would appear to be definitive on the AYC/ASC setup:


reprinted from Automotive Engineering, September 1996

Mitsubishi combines active yaw control and active stability control

Mitsubishi chose to apply its active yaw control system (AYC) to a high-performance, all-wheel-drive model in the forthcoming Galant mid-size sedan replacement. The AYC is combined with the active stability control system (ASC) that employs braking force as a stabilizing factor.

The mechanical component of the AYC system is the torque-transfer differential located at the rear between the wheels incorporated with the final drive/differential unit, and is driven by the propeller shaft from the front-mounted transverse power plant. The torque-transfer differential comprises a planetary gear mechanism that generates two differing rotational speeds which are "fast (13%)" or "slow (13%)"–either relative to the differential case rotational speed; clutch units for left and right turns that transfer torque to either the left or the right wheel.

Five input sources to "read" the driver's intention are steering wheel angle, accelerator stroke, wheel (all four) speeds, longitudinal acceleration, and lateral acceleration. The ECU judges road surface frictional coefficient, actual vehicle behavior, the driver's intention, determines optimum transfer of driving torque between the rear wheels, and signals the hydraulic actuating unit.

Mitsubishi's system differs from Honda's in that it employs an electrically driven hydraulic pump and a magnetic hydraulic valve. Honda adopts a mechanically driven pump from the drive shaft. A senior engineer says that this system is much quicker, works from very low vehicle speeds, and its on-demand characteristics are energy efficient. The system functions in a circle as small as 14 m to, according to the Mitsubishi engineer's estimate, Honda's 30 m.

The AYC's benefits are, again, superior corner tractability, greatly improved cornering behavior, relief from a "held-back" feel during cornering, and traction control capability on split-µm surfaces. Applied to an all-wheel-drive car, the AYC improved accelerative performance on packed-snow, 30-m radius by as much as 30% over a front-wheel-drive model, claims Mitsubishi.

In the forthcoming Galant platform, the AYC will be combined with the active stability control that uses braking force as well as engine torque reduction to slow the vehicle and give a strong yaw moment to regain stability, should the vehicle exceed its cornering limit. The ASC is controlled by the same electronic control unit as the AYC. The combined systems add about 20 kg to the vehicle and a little over 100,000 yen (about $1000) to the price of the mid-size sedan. The AYC alone should be 50-60,000 yen, and there is already a prototype unit for front-wheel-drive application.

Jack Yamaguchi

[bradc]

First of all I can't remember whose dyno this is, it was an English member of the site though.

At the start of the graph there is quite a bit more power to the rear than to the front, then it evens out to about 10% more to the rear until about 5000rpm when the gap starts to get larger again.

[WildCards]

interesting chaps... interesting

[WireD]

hehehe... what have i started...? :D

so, the rear gets more power on boosting?

thats good, cause i wanna play in the snow when i get the VR4 :D

[richy rich]

by the looks of that chart it shows that it is always more to the rear
at all times and the increases and decreases according to revs.

intresting very intresting

[WireD]

suits me and my snow-drifting needs juuust perfectly...! :D:D:D

hehehe.....

[dickytim]

Like any car if you know how to tread it the car will do what you want, I have had my car in servere understeer when I was exploring it's limits, I had to do something stupid to get it there but it can be done. My favourite oversteer tecnhique is the gas, no gas, gas version, works a treat on gravel and grass, I would imaging snow aswell :)

Have fun.

[phosty]

Without clutch packs and electronics between front/back how could variable power splits be achieved?

[DefeXion]

Yopu shouldn't need to do much to get that kicking out in the snow. Just gas off and turn away from the corner, then quickly turn into the corner and gas on when the weight shifts from the inside to the outside. Take some videos when you figure it out :D

I have drifted gravel quite successfully like this, but I don't have ayc I guess. You need a bit of opposite lock if you won't be moving that fast but this is safer because it will shorten your drift and will make your car tend to snap bake to centre as your wheels get their grip again.

To be perfect you want to use all the torque at the wheels to pull you round the corner, like the earths gravity to a sattelite.

[phosty]

Hmmn - I was reading through the info on Stealth316 about the AWD system on the Mitsubishi 3000GT.

http://www.stealth316.com/2-awd.htm - see part 3

Our system is probably very similar - the only differences I can make out is our VCU is in the transfer box not the transaxle, and of course ours have AYC at the back.

Assuming the rest is the same then we have a 50:50 split.