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?

 

[fmars62]

Ok Im going to try to ask this as best as I can . Anyway, I know every car is different but on some awd cars all the wheels are always spinning but maybe only like 5-10% of the power is going to a wheel or two but when that wheel starts slipping it gets more power. And other awd systems all the wheels have the power evenly distributed. So I am just wondering what the GSX's is like, and I guess the awd Talon TSi too. And also, are you able to change how the power is distributed to each wheel? What setup would be best for what (like drag, rally, etc.? Thanks.

 

[H4G64T]

Supposedly it is 50/50, but in reality it is still front biased due to the nature of physics. It also depends a lot on if you have the viscous LSD. I would say it is closer to true 50/50 without it.

 

[miguelmcv]

If you have a front and rear LSD, all the power will be distributed evenly.

If you don't have LSD in front or back then, the power will be more Uneven.

 

[XTurbodTalonX]

DSM AWD System

Post #8 is rather interesting too...

 

[H4G64T]

If you have a front and rear LSD, all the power will be distributed evenly.

If you don't have LSD in front or back then, the power will be more Uneven.

That is not correct at all. I would kindly ask you to not post things when you really don't have an idea. An LSD redistributes power when it feels a wheel is slipping.

 

[frakkin toaster]

good question op.

i had a 98 gs....im looking to get a 98-99 gsx. ive never had an awd.

what is the 0-60 & 1/4 mi on a stock gst vs gsx?

 

[H4G64T]

The numbers vary slightly by years so for the answer I will use 2GB.

GST 1/4 Mile 15.2
GSX 1/4 Mile 14.7

0-60 GST & GSX 6.3

Actually a GST with an automatic transmission has a 0-60 of 7.3, manual is 6.3.

 

[boosted99_420]

ive heard it was 60/40 but transitions, and ive heard 50/50 but i do know it transistions cometimes ive seen a built GSX launch shoot sideways then shoot strait with out driver doing anything but launch AWD is a very complicated system but worth the extra bit of schooling and work

 

[frakkin toaster]

The numbers vary slightly by years so for the answer I will use 2GB.

GST 1/4 Mile 15.2
GSX 1/4 Mile 14.7

0-60 GST & GSX 6.3

Actually a GST with an automatic transmission has a 0-60 of 7.3, manual is 6.3.

thx for the info man...i really thought the numbers would be a lot different. im guessing the real difference will be on the twisties. the gsx is a lot harder to find im seeing...

ive heard it was 60/40 but transitions, and ive heard 50/50 but i do know it transistions cometimes ive seen a built GSX launch shoot sideways then shoot strait with out driver doing anything but launch AWD is a very complicated system but worth the extra bit of schooling and work

crazy, i have not seen that but i was impressed with a few vids i saw and some impressive numbers.

 

[H4G64T]

Actually besides the twistys, the GSX will outperform in just about everything, especially the 1/4 mile, the GST suffers from some of the worst traction issues out of all performance FWD imports.

 

[my dreamt dsm]

Actually besides the twistys, the GSX will outperform in just about everything, especially the 1/4 mile, the GST suffers from some of the worst traction issues out of all performance FWD imports.

Just pulling your chain ...
I'm not to sure though. My civic and my brother's gsr seems to pull better then my gst launch wise. 2 cent... not all cars are the same so that is also a factor.

 

[H4G64T]

The problem is mostly the weight of the car combined with it's high torque capacity, plus our suspensions aren't to be desired in reality.

 

[slowauto]

my auto gst outperforms most any other manual fwd from a launch though 2nd, im still stock

 

[fmars62]

ok thanks fro alllt he replies guys but when you say 50/50 or 60/40 do you mean 50% in the front and 50% in the back? or is left and right?

 

[H4G64T]

It's front to back.

 

[jtmcinder]

Lots of nonsense in this thread.

The center diff in a DSM is a spider-type, so it's 50/50. Yes, you can get a 35/65 planetary for it, but the stock diff is a spider.

Adding a limited-slip device does not alter the gearing in the diff, so this idea that the VC on the center makes it 60/40 or whatever is nonsense. (If anything, when the VC is active, more torque ends up going to the rear, but not because of the diff.)

Similarly, the idea that "physics" can change the gearing in the diff is nonsense. (Again, when combined with a limited-slip device, the actual distribution of used torque can differ from the gearing of the diff, but this isn't because the diff changed; it's because the torque has other paths to the wheels.)

 

[H4G64T]

I am very disappointed with your response, I have come to know you as someone who logically applies real world data and leaves out theory. Hence why I stated that it is supposedly 50/50, and it is probably true 50/50 when the viscous coupler is disengaged. However as wheels slip the power will be diverted to the non-slipping wheels, therefore anytime that the couple is engaged the front or the rear will be seeing more or less than 50% at the time with a tendency for the front wheels to see less slip in normal driving.

The terminology is all based on a very simple idea. A transversely mounted AWD car is always considered a FWD biased AWD system. Because we don't have electronically controlled clutches in our center differential there is no way to account for the various variables encountered while driving, the VC is really kind of primitive when you think about it.

 

[jtmcinder]

Yes, yes, as I wrote above, the actual torque distribution to the front and rear can differ from the 50/50 gearing of the center diff when any limited-slip device kicks in, whether it be a VC or something else (e.g., a helical or clutch-pack). But that doesn't change the gearing of the diff, itself, and the new distribution of torque is never a fixed value, so it's hugely misleading to start throwing around numbers like 60/40. That's what I was reacting to. I've seen arguments like this devolve to the point of people arguing 60/40 vs 63/37, etc, etc, when it's all nonsense. The diff, itself, is 50/50 and any deviation from this due to the action of a limited-slip device cannot be accurately described by a particular set of numbers as it changes from instant to instant.

 

[jtmcinder]

The terminology is all based on a very simple idea. A transversely mounted AWD car is always considered a FWD biased AWD system. Because we don't have electronically controlled clutches in our center differential there is no way to account for the various variables encountered while driving, the VC is really kind of primitive when you think about it.

Nonsense. Total nonsense.

If you put the Cusco Tarmac diff in a 2G, it's now got a 35/65 (front-to-back) split. It has zero to do with how the engine is oriented. It's due to the gearing in the center diff.

Likewise, the 3000GT, which also has a transverse-mount engine, came stock with a rear-biased, planetary diff. By your logic, the orientation of the engine over-rules this. Bah!

 

[H4G64T]

I see what you are saying now. I forgot this is Tuners and people will differentiate from theory to real world application and make things up. Yes, without argument the gearing is 50/50, it can't be argued lest the person arguing that be slapped in the face with Eagle's brochure about it. For the sake of simplicity, people who do not understand the dynamics of it should just call it 50/50 and move on.

I guess in the end...I am not really sure what the OP is really trying to figure out here.

Nonsense. Total nonsense.

If you put the Cusco Tarmac diff in a 2G, it's now got a 35/65 (front-to-back) split. It has zero to do with how the engine is oriented. It's due to the gearing in the diff.

Likewise, the 3000GT, which also has a transverse-mount engine, came stock with a rear-biased, planetary diff. By you logic, the orientation of the engine over-rules this. Bah!

You are misreading this statement, everything can be altered in one way or the other, I am purely talking about the dynamics of how there are specific points where torque is basically redistributed or applied because of the direction each moving part travels or changes to.

 

[jtmcinder]

I see what you are saying now. I forgot this is Tuners and people will differentiate from theory to real world application and make things up.

[snip]

You are misreading this statement, everything can be altered in one way or the other, I am purely talking about the dynamics of how there are specific points where torque is basically redistributed or applied because of the direction each moving part travels or changes to.

Yes, on Tuners, sometimes people make things up. But they also sometimes resort to producing complete word-salad that has no meaning when they are called it, as you have nicely shown here.

/out

 

[H4G64T]

Well you can have your thoughts on it, but each wheel is not created equal, unfortunately the front diff is seeing things differently than the center diff and the center diff differently from the rear diff.

 

[phunny]

Well you can have your thoughts on it, but each wheel is not created equal, unfortunately the front diff is seeing things differently than the center diff and the center diff differently from the rear diff.

How are you even going to say something like this? You really do just make things up, if the front and rear dif saw things differently it wouldn't be a 50/50.... Just wow.

 

[H4G64T]

You should probably go back to figuring out how to take out bolts.

Drivetrain Power Loss - The 15% "Rule"- Modified Magazine

Differential losses tend to be considerably larger, especially in the case of RWD and AWD vehicles where the torque path is turned 90 degrees as it enters the rear diff and exits it toward the rear wheels. In the case of hypoid-type gearsets (where the gear tooth profile is both curved and oblique) that are commonly used in RWD differentials, losses in the 6 to 10 percent range are the norm, while loss from the driveshaft(s) and prop shaft(s) tend to account for about 0.5 to 1 percent of total loss, depending on how well they're balanced and how many the vehicle is equipped with. In the case of FWD vehicles, the torque path is more direct to the front wheels and the use of efficient helical final drive gears means that drivetrain losses can be as much as 50 percent lower than on RWD and AWD vehicles.

 

[Colt4G63 also]

To answer ther OP: The power is distributed equally to all wheels, but if one rear wheel spins more than the other rear, the rear viscous coupler will create friction, and attempt to equalize output between both rear wheels. Also, in exactly the same way, if the front or rear begins to spin faster than one another, the center viscous coupler will begin to create friction and equalize the speed of both front and rear. The front diff is open, but if one front spins, the front "as a set", would be going faster than the rear, and cause the center viscous coupler to want to make the rears spin as fast as the front. Since that would take more power than the average 200 or so horsepower DSM has, the front stops spinning, and the car just goes.

In laymans terms for the average sheep: The advanced viscous coupler system automatically transfers torque from the wheels that slip, to the wheels that grip.