Tarmac-Gravel-Snow Modes

saiko84 · Oct 7, 2009, 06:46 AM

So we all know what these modes are and how and when they are used
That is obvious. I think.
The only thing that isn't that obvious is wet/rainy weather would be classified as "Gravel" mode. At least that is what I read in the manual.
BUT the question to the veterans out there is---

What exactly does it change in the car to help drive in these certain conditions?
Other than change the display saying what mode it is in...
% power distribution of front/rear wheels? Braking sensitivity change? Grapple shoot out the side of the car into building slingshot you around corners? etc.

DetroitRA · Oct 7, 2009, 06:51 AM

Quote:

Originally Posted by saiko84

So we all know what these modes are and how and when they are used
That is obvious. I think.
The only thing that isn't that obvious is wet/rainy weather would be classified as "Gravel" mode. At least that is what I read in the manual.
BUT the question to the veterans out there is---

What exactly does it change in the car to help drive in these certain conditions?
Other than change the display saying what mode it is in...
% power distribution of front/rear wheels? Braking sensitivity change? Grapple shoot out the side of the car into building slingshot you around corners? etc.

This. This is why the Mitsu's AWD platform on the Evos did so well.

DetroitRA · Oct 7, 2009, 06:56 AM

http://www.youtube.com/watch?v=BB_IRFnOf_Q

Ignore the comments, main point of video is that he gives some information on how the ACD works, and then tests out the modes in a small snow test.

havock28 · Oct 7, 2009, 06:56 AM

What mode does the Grapple shoot out in.. would that be gravel or snow?

xi · Oct 7, 2009, 07:12 AM

On the inside cover of the manual, if you read it under UV light, it clearly states that:

Quote:

The Grappling Hook can only be engaged by putting the ACD in "Snow" mode only with the TC-SST in "Sport" mode only.

DetroitRA · Oct 7, 2009, 07:20 AM

Don't forget to turn ASC OFF! Don't want traction control taking over mid corner w/ that grappling hook.

detroit pistins · Oct 7, 2009, 07:29 AM

Quote:

Originally Posted by saiko84

So we all know what these modes are and how and when they are used
That is obvious. I think.
The only thing that isn't that obvious is wet/rainy weather would be classified as "Gravel" mode. At least that is what I read in the manual.
BUT the question to the veterans out there is---

What exactly does it change in the car to help drive in these certain conditions?
Other than change the display saying what mode it is in...
% power distribution of front/rear wheels? Braking sensitivity change? Grapple shoot out the side of the car into building slingshot you around corners? etc.

check out this article!

ACD Article - Answers for everybody!

505RA · Oct 7, 2009, 07:53 AM

just wanted to let you know how the power splits thru the ACD in the 2009 RA

Tarmac - 50/50 (F/R) balance bias, understeer at limits
Gravel - 40/60 (F/R) slight rear bias, little more tail out.
Snow - 30/70 (F/R) heavy rear bias, easy to tail out at the limits.

clifhanger87 · Oct 7, 2009, 08:23 AM

^^ that's not right.
the bias stays at 50:50 no matter what setting it's on. here's a quote from the article linked above:

"Despite popular belief, this switch DOES NOT change the torque split. The differential is geared at 50:50 and cannot be changed by the push of a button. What this switch actually does is quite simple. Each setting determines how long the ACD will delay in freeing the center differential after a steering input is made. In addition, it will determine how much locking force the ACD will exhibit on the clutch pack and center differential."

i'm also pretty sure there's already a thread asking this very question in the RA general

xi · Oct 7, 2009, 08:48 AM

That makes no sense, why would it lean towards rear bias in the snow.
Aside from the fact that it doesn't change the bias, even if it were, it would be backwards.

detroit pistins · Oct 7, 2009, 09:01 AM

Quote:

Originally Posted by xi

That makes no sense, why would it lean towards rear bias in the snow.
Aside from the fact that it doesn't change the bias, even if it were, it would be backwards.

ya i thought it so too!

DetroitRA · Oct 7, 2009, 11:13 AM

You're all crazy, all the ACD does is shoot out a grappling hook. You may not see it, but it's there.

havock28 · Oct 7, 2009, 11:35 AM

i just went for a ride on lunch.. and oh yah.. that grappling hook is nasty.. i felt sorry for the person standing in front of it.. thankfully enough it disengaged and didnt drag him for too long..

GST Motorsports · Oct 7, 2009, 11:38 AM

Quote:

Originally Posted by 505RA

just wanted to let you know how the power splits thru the ACD in the 2009 RA

Tarmac - 50/50 (F/R) balance bias, understeer at limits
Gravel - 40/60 (F/R) slight rear bias, little more tail out.
Snow - 30/70 (F/R) heavy rear bias, easy to tail out at the limits.

Incorrect.

bias is 50/50 all the time, 24/7, 365. Can't change it by software or buttons or anything. It is mechanical 50/50 unless you change the actual diff.

The modes only change the rate of ACD lockup.

saiko84 · Oct 7, 2009, 11:40 AM

Thanks detroit_pistins
That article helps put things in perspective
Now I know why I am pressing these buttons!

...althrough i can't rule out detroitRA's theory of invisible grappling hooks. He may be on to something!