Tuning Evo789 ACD
Newbie
Joined: Jun 2009
Posts: 83
Likes: 25
From: QLD, Australia
Wow, she starts to blow my mind when you start adding in the D E and F tables! 
lol
Hey Dave, have you managed to isolate or do you think that triplicates of those D E and F tables align to a Tarmac Gravel and Snow setting?
lolHey Dave, have you managed to isolate or do you think that triplicates of those D E and F tables align to a Tarmac Gravel and Snow setting?
Thread Starter
Evolved Member
Joined: Jun 2008
Posts: 824
Likes: 24
From: Sydney
D-Tables, Speed Delta (+/-) Correction, 3 tables TGC as usual.
E-Tables, Speed Delta (+/-) Lockup Adder, 6 tables, TGC Accel and TGC Decel as usual
F-Tables, Speed Delta (+) Lockup Adder, 3 tables only TGC as usual.
Its seems to look complicated, but when you start to follow the calculation trail, it makes sense, or it does at the moment.
There seem to be time constant filters applied to most if not all steps in the calculation to provide suitable attack and decay ramps and at the end some sort of scaling factor and of course upper and lower limits. And overflow checks which I guess are like internal limits. And test/branch conditions for unknown purposes.
My time on this is drawing to a close, only a few days left before I will be otherwise occupied.
E-Tables, Speed Delta (+/-) Lockup Adder, 6 tables, TGC Accel and TGC Decel as usual
F-Tables, Speed Delta (+) Lockup Adder, 3 tables only TGC as usual.
Its seems to look complicated, but when you start to follow the calculation trail, it makes sense, or it does at the moment.
There seem to be time constant filters applied to most if not all steps in the calculation to provide suitable attack and decay ramps and at the end some sort of scaling factor and of course upper and lower limits. And overflow checks which I guess are like internal limits. And test/branch conditions for unknown purposes.
My time on this is drawing to a close, only a few days left before I will be otherwise occupied.
This is making my brain hurt.
Practical example I'd like to understand: At a track I frequently go to, there's a medium-sized 3rd gear sweeper. Unless I run higher pressures in the rear tires than the fronts, I struggle to get back on the throttle as early as I'd like because the front just pushes. In this situation, would I want the ACD to lock more or less, in order to minimize the push?
Practical example I'd like to understand: At a track I frequently go to, there's a medium-sized 3rd gear sweeper. Unless I run higher pressures in the rear tires than the fronts, I struggle to get back on the throttle as early as I'd like because the front just pushes. In this situation, would I want the ACD to lock more or less, in order to minimize the push?
wow. Thats definitely backwards than what I thought it would be.
If the front tires are currently pushing, wouldnt less lock make them spin more? Ive got in my head that with less lockup, tq will be transferred to the end with the least grip. (thinking like an open diff in a rear end)
Or are you saying that the front tires are loosing traction BECAUSE they are receiving too much tq from the lockup?
If the front tires are currently pushing, wouldnt less lock make them spin more? Ive got in my head that with less lockup, tq will be transferred to the end with the least grip. (thinking like an open diff in a rear end)
Or are you saying that the front tires are loosing traction BECAUSE they are receiving too much tq from the lockup?
Thread Starter
Evolved Member
Joined: Jun 2008
Posts: 824
Likes: 24
From: Sydney
New xmls added to the first post, these have all the latest revisions to descriptions, scaling and additional tables and parameters, including the known Time Constants (there are more to be decoded).
Deffinitions include:
401403
401404
401702
Deffinitions include:
401403
401404
401702
Newbie
Joined: Dec 2013
Posts: 55
Likes: 2
From: Italy
Wonderfull, incredible work Merlin! Thank you very much for do this for all of us ...11
Now seems to be more logical behaviour, I'd like to have a race ciurcuit to test all of those maps
Did you insert current limits too?
Now seems to be more logical behaviour, I'd like to have a race ciurcuit to test all of those maps
Did you insert current limits too?
Last edited by Floppyz; Jan 25, 2014 at 05:21 AM.
wow. Thats definitely backwards than what I thought it would be.
If the front tires are currently pushing, wouldnt less lock make them spin more? Ive got in my head that with less lockup, tq will be transferred to the end with the least grip. (thinking like an open diff in a rear end)
Or are you saying that the front tires are loosing traction BECAUSE they are receiving too much tq from the lockup?
If the front tires are currently pushing, wouldnt less lock make them spin more? Ive got in my head that with less lockup, tq will be transferred to the end with the least grip. (thinking like an open diff in a rear end)
Or are you saying that the front tires are loosing traction BECAUSE they are receiving too much tq from the lockup?
A tuner I know who tunes STi DCCDs basically said the object is to have the c.diff as open as possible, but start applying lock if theres wheel slip. Basically use the lockup for traction.
Evolving Member
Joined: Jan 2010
Posts: 233
Likes: 0
From: Italy
Thread Starter
Evolved Member
Joined: Jun 2008
Posts: 824
Likes: 24
From: Sydney
Current limits? I missed that query, no, not found yet.
I suspect we will find that an ACD Lockup adder total of 255 (or possibly 250) will equal maximum possible current.
The Ralliart K2 gravel rally rom has values that can hit 255 and I think it is a 1-byte parameter so 255 will be the limit. Not quite there yet though.
Has anyone measured the resistance of the proportioning valves?
May have found the 5kph hand brake on = ACD open speed setting.
I suspect we will find that an ACD Lockup adder total of 255 (or possibly 250) will equal maximum possible current.
The Ralliart K2 gravel rally rom has values that can hit 255 and I think it is a 1-byte parameter so 255 will be the limit. Not quite there yet though.
Has anyone measured the resistance of the proportioning valves?
May have found the 5kph hand brake on = ACD open speed setting.
Last edited by merlin.oz; Jan 26, 2014 at 03:25 AM.
Newbie
Joined: May 2009
Posts: 29
Likes: 0
From: California
The progress looks nice. Great work.
Let's remember guys the center diff is an open 50/50 ratio.
An open diff, power can transfer up to 0/100 of the power to the side with less load. (My opinion is the rear because of less weight)
The ACD just limits that, and wants to keep it to a solid 50/50.
If anything the center diff is transfering the power
....the ACD can either Help or Restrict
The XML I was using mainly used delay in degrees (A-map)
And slip in percent (B-map and C-map)
So either my xmls or merlines xml
Higher numbers mean more oversteer
(Well because its open, maybe even longer)
Lower numbers do seem to give under steer
(Because its locking or locking more frequently)
To me merlines xmls look more like time delays (my opinion)
Like the stuff that merline found, I am gonna be playing with it for awhile to see what happens.
Let's remember guys the center diff is an open 50/50 ratio.
An open diff, power can transfer up to 0/100 of the power to the side with less load. (My opinion is the rear because of less weight)
The ACD just limits that, and wants to keep it to a solid 50/50.
If anything the center diff is transfering the power
....the ACD can either Help or Restrict
The XML I was using mainly used delay in degrees (A-map)
And slip in percent (B-map and C-map)
So either my xmls or merlines xml
Higher numbers mean more oversteer
(Well because its open, maybe even longer)
Lower numbers do seem to give under steer
(Because its locking or locking more frequently)
To me merlines xmls look more like time delays (my opinion)
Like the stuff that merline found, I am gonna be playing with it for awhile to see what happens.
Last edited by Malocas; Jan 26, 2014 at 09:24 AM.