Resolved [RESOLVED] How does AWD work? [Merged 9-7] torque split division slip drive

[turboawd1992]

Just always wondered, does anyone know how much power a 1g AWD sends to the front/ rear wheels?

 

[boostin91]

I don't quite think you guys get it, but there is no preset at all on an awd witha viscous coupler. Maybe a wiseman should step in and explain this.

 

[Boost Junkie]

Its 50/50.

The VCE locks it into 4wd. There will be NO "slipping" so if you make a sharp corner tires will bounce becuase they are all forced to spin at the exact same speed. If you drop (remove) the transfer case and drive shaft the car is then FWD. Normal driving and dynoing is fine, don't go launching it or doing burnouts though.

 

[TheTSiGuy]

Hmm, i wasnt sliding or slipping in the rain really with my talon, but when i went to take off at high rpms and attempt to launch it in the rain, its rear end started to ever so slightly come out, but then it straightened out...is it supposed to do that?

 

[TalonRacer18]

Wish it was like the skyline . full power to the rear, and sensors on all 4 corners sampling at like 1000/sec, when slippage occurs it sends power to the front.

 

[steve]

Originally posted by Ktreece777
So does anyone actually know if its 60/40 or 50/50 or ?

Like Defiant, CowPimp, and Boost Junkie said, it's 50/50 as long as all wheels have grip. Once a wheel is slipping the power transfer is controlled by the action of the viscous coupler in the center diff and optionally the viscous coupler in the rear diff.

The book boostin91 was talking about is the 1G technical manual. I haven't seen the DSM version on the net, it's part of what you get on the manual CD or you can read the 3000GT/Stelth version at http://www.stealth316.com/2-stim.htm the AWD works the same way.

If someone has the DSM link post it. (https://www.dsmtuners.com/threads/1g-dsm-1990-technical-information-manual.517385/)

 

[Defiant]

Alright, goddamn it. Maybe THIS will convince you

 

[Defiant]

SEE?

 

[shadrach]

Search on here AND DSMTalk. This topic has been covered many times in the past, almost as much as the vented BOV debate...

Read this:
http://home.comcast.net/~eliot_www/awd.html

Then this:
http://auto.howstuffworks.com/differential7.htm (damn, i love this website)

Then you'll understand a lot more about AWD systems in general. (Warning, not ALL the manufacturer specific details are correct/up2date in that link, but the general idea is explained well.)

The point these guys are trying to make is the Viscous Coupler is simply a friction/clutch system surrounded in fluid, similar to a torque convertor. The the rate of rotation of the front half and rear half start to change (due to tires slip on one side) then the resultant heating of the fluid causes it to transfer power away from the slipping, and over side to the other side.

 

[bigfoot]

If you want a 35/65 F/R split get a Cusco center diff. I know a rallycross DSM that uses an EVO drivetrain, they use clutches just like the Skyline setup. You can also use the Torsen style Quaife center diff. If I had the cash to build a trans I'd get a Cusco.

 

[Defiant]

Originally posted by shadrach

The point these guys are trying to make is the Viscous Coupler is simply a friction/clutch system surrounded in fluid, similar to a torque convertor.

Well, only kind-of. A torque convertor actually recirculates its oil in order to multiply the connection. A VC only has very closely-spaced discs in a dense silicone fluid. Once the input and output have a speed difference, the fluid expands so that the coupling seizes. No recirculation or variance in power in vs. power out occurs.

 

[14.5 drift]

The other day I started a thread asking if my gsx had an lsd any where in it, and I was told that it was all open diff. In this thread it sounds as if my car has a center and rear vlsd. Wich is it?

 

[steve]

Originally posted by steve
the 1G technical manual. I haven't seen the DSM version on the net, it's part of what you get on the manual CD

If someone has the DSM link post it.

To follow up on my own post, it's at http://www.twingles.com/manualcd/dsmgift/

Long gone - Now we have https://www.dsmtuners.com/threads/1g-dsm-1990-technical-information-manual.517385/

It should be required reading.

Steve

 

[titogs95]

I am sorry for bring this from the death!!
But I was searching and I want to be sure that also the 2 Gen it is also 50/50 torque splits!

Also is it true that smoe AWD 2G doesn't come with LSD (It was an option only?)

I am really sorry i am here to learn though!

TIA

Tito

 

[steve]

I was searching and I want to be sure that also the 2 Gen it is also 50/50 torque splits! Also is it true that some AWD 2G didn't come with LSD (It was an option only?)

Yes, 2G's work the same way as the 1G's.
I can't say for sure on the option status with 2G's. I didn't watch that closely when they were in production. I was happy with my 1G and didn't see a reason to replace it.

Steve

 

[TOPSECRET]

My friend has a 91 talon with abs and he has the rear limited slip. My 6/8/91, 92 also has abs and rear limited slip I don't have any paperwork showing what was available option wise though. It's wierd that you could get a talon with abs and lsd but not a gsx. Is the lsd in our cars clutch type or viscous?

 

[Defiant]

It's 50/50 until a wheel slips, at which point the whole system goes solid.

 

[wicketdreams]

can someone explain to me the advantage/disadvantage to runnin a 50/50 front/rear torque split on a AWD street car.

 

[Fitz7099]

Benefits of Welded Center Differential

1) It will not break if done properly
2) The tranny becomes 4WD, the front and rear differentials will always turn at the same rate
3) Great for drifting in the snow and on dirt roads

Drawbacks of Welded Center Differential:

1) It can produce severe oversteer in any situation
2) Tight turns and Parallel parking is really hard on the drivetrain and the tires will be squealing
3) The center diff is no longer the weakest link, it's a $150 item to repair where the next weakest link is the transfer case ($600 used), rear differential ($500-$750 used) or cv shafts ($100 each). The tranny itself should handle the extra load since the front differential is pretty much bulletproof.

Taken from: http://www.ecanfix.com/~mdhamilton/centerdiff.html

 

[Quasimondo]

Pricing is a bit off for the transfer case (I picked mine up for $150) and rear diff ($200 w/ axles), but everything else is true. Unless you're going in a straight line, and a straight line only, you're better off leaving the center diff as is.

 

[JayRolla]

Isnt the AWD already 50 front 50 rear. Im pretty sure it is.

 

[Syndicate13]

Isnt the AWD already 50 front 50 rear. Im pretty sure it is.

The torque split is variable based on available traction. Under normal conditions it is 50/50, I think he's talking about making it permanent. FWIW I ran a welded diff for a time and I hated it, I'm so much happier with my 4 spider.

 

[stevieraywolf]

Front and Rear diffs can be geared differently, and can lock at different speeds, too. Don't know about these things, but most trucks with part-time are geared differently.

 

[slipstream808]

Sweet zombie thread it's back from the dead!!

That's some interesting info I didn't know right there.

 

[99gst_racer]

Front and Rear diffs can be geared differently, and can lock at different speeds, too. Don't know about these things, but most trucks with part-time are geared differently.

You're referring to the ring and pinion gears, not the differential's planetary gears.

 

[stevieraywolf]

Actually, I'm referring to a part-time system. They have different driveshafts. If the Front Wheel Shaft is smaller in circumference than the Rear Wheel Shaft, they will have more power. (Technically speaking, it will spin faster, but the LSD will convert that speed into raw power, keeping the tires from spinning and holding down torque while skyrocketing horsepower through the axel, allowing the tires to grip better. This is why part-time 4 wheel drive is almost always associated with low traction situations, such as mudding, climbing hills, or going straight up sand dunes.)

Actually, I'm not sure if that last one's possible.... I'll be right back....