Thứ Ba, 3 tháng 1, 2017

autocross and dccd part 1

solo2sti 04-21-2004 03:57 PM

autocross and dccd
I have autocrossed for years and have driven rear engine rear drive, front drive, rear drive and now have this new awd. My question is how to best utilize the dccd settings for autocross? What's going to make the car rotate the best?
jmott 04-21-2004 04:18 PM

Re: autocross and dccd
[QUOTE][i]Originally posted by solo2sti [/i]
[B]I have autocrossed for years and have driven rear engine rear drive, front drive, rear drive and now have this new awd. My question is how to best utilize the dccd settings for autocross? What's going to make the car rotate the best? [/B][/QUOTE]

shouldn't the question be, which setting gets the car around the track fastest? That may not be the same as which one power oversteers the easiest.

some guys did a rather detailed writeup on extensive experimentation they did, and they concluded that the 'auto' mode was fastest.
wm07 04-21-2004 04:42 PM

I still think it depends on your driving style, so everybody would have different suspension settings for their car, same thing would apply to DCCD settings... But I am only a autox noob, what do I know? :rolleyes:
Watkinsm3 04-21-2004 05:12 PM

What I've found so far is that it is VERY tough to tune the car for an entire autox course using manual. Bear in mind I've only been to one event where the temp was about 60. Controling the level of lock allowed me to fine tune the car for one corner but this tended to sacrafice another corner. Sending alot power to the rear would allow excellent exit from one corner but cause the car to be too loose coming out of another corner. Surprisingly AUTO (so far ;)) has proved to be very effective in maintaining the balance of the car. Allowing throttle steering when needed but, most importantly, putting most of the power down coming out of the corner without alot of post-apex oversteer. Alot of lock to tune for one corner results in understeer in another... too open to tune for the other corners and you're too loose somewhere else.

My thoughts on this may change as temperatures increase going into the season (allowing for a more consistent rear biased setting). I'm also very tentative to admit that a computer control on a car can make better choices than me.

AUTO does have the advantage of dynamic change which is something I'd never attempt on course manually.

My vote, right now, goes with AUTO

We'll see how my theories stack up in DC I guess... :)

-Matt
jmott 04-21-2004 06:56 PM

[QUOTE][i]Originally posted by wm07 [/i]
[B]I still think it depends on your driving style, so everybody would have different suspension settings for their car, same thing would apply to DCCD settings... But I am only a autox noob, what do I know? :rolleyes: [/B][/QUOTE]


theres not really too many styles of driving that fall into the really quick category.
skuttledude 04-21-2004 07:11 PM

I vote AUTO.

I like sterring with the rear and found that in full rear lock, its just too loose. However if there is a very warm day with lots of traction, I'll try putting it into rear lock.

So far I've used AUTO, especially when it was much colder. I also found that the AUTO position for me gave me good traction coming out of tight corners.

I'll know more this weekend on a long open track.

Rally On,,


Davis
afpdl 04-21-2004 07:18 PM

Auto throws the diff into open as you enter the turn and then locks it up on corner exit. It rotates the car quite a bit in that mode but locks the diff up so you can pull out of the turn. But since the only thing I have ever really driven at autoxs are awd cars Im currently slower in auto mode then in manual with alot of diff lock.
GT2RS 04-21-2004 07:55 PM

I stay with Auto as well...because i feel most turns in an autocross course are too varied to be set on a fixed single setting.
trojan9x 04-22-2004 08:54 AM

I think it all depends on what you are used to driving. If you are used to driving a RWD car, then the manual setting might be to your liking. It's all about experimentation and seat time in the car. I'm sure you'll find what works best for YOU.
DrBiggly 04-22-2004 10:43 AM

[QUOTE][i]Originally posted by jmott[/i]
[B] theres not really too many styles of driving that fall into the really quick category. [/B][/QUOTE]

I agree!

I've tried auto and manual modes and wasn't a fan of the manual. I don't like to relinquish control of any facet of a vehicle's operation if I do not have to, however a computer most certainly can make better decisions on how to control the diff than I can.
jmott 04-22-2004 10:54 AM

[QUOTE][i]Originally posted by trojan9x [/i]
[B]I think it all depends on what you are used to driving. If you are used to driving a RWD car, then the manual setting might be to your liking. It's all about experimentation and seat time in the car. I'm sure you'll find what works best for YOU. [/B][/QUOTE]

Yeah but this isn't fashion or something, there is an objective fastest way around the course.

Though, if you are just out to have fun crank it up to max rear wheel bias and doritooo the heck out of it. :)
Patrick L 04-22-2004 10:56 AM

It's best to leave it in Auto. It does all the work for you. I have talk to a few long time autocrosses like Chris Fleming who have driven the STI and they have told me that it's best to leave it in Auto.
del105 04-22-2004 11:00 AM

Auto all the way, I've run the same course back to back testing a couple different settings and the Auto setting seemed to average about .5-.8 sec faster on that course.
trojan9x 04-22-2004 12:14 PM

I don't know what provoked that comment, but I was in no way implying that he should set it to full rear and drift his way around the track. I was simply stating that if he is used to RWD cars and the way that they drive, that setting might feel natural for him. Like I said, everyone has different driving styles and with experimentation and seat time, he will figure out what is best suited to his driving style.

[QUOTE][i]Originally posted by jmott [/i]
[B]Yeah but this isn't fashion or something, there is an objective fastest way around the course.
[/B][/QUOTE]
del105 04-22-2004 01:16 PM

There is no full rear. 35 65 is full open
afpdl 04-22-2004 01:41 PM

[QUOTE][i]Originally posted by del105[/i]
[B] There is no full rear. 35 65 is full open [/B][/QUOTE]

I think he just meant put the wheel to full rear.
jmott 04-22-2004 02:22 PM

Ive never really heard of this driving style thing. Not among the quick guys anyway. All the really fast guys seem to have the same style.


[QUOTE][i]Originally posted by trojan9x [/i]
[B]I don't know what provoked that comment, but I was in no way implying that he should set it to full rear and drift his way around the track. I was simply stating that if he is used to RWD cars and the way that they drive, that setting might feel natural for him. Like I said, everyone has different driving styles and with experimentation and seat time, he will figure out what is best suited to his driving style. [/B][/QUOTE]
wm07 04-22-2004 03:19 PM

[QUOTE][i]Originally posted by jmott [/i]
[B]Ive never really heard of this driving style thing. Not among the quick guys anyway. All the really fast guys seem to have the same style. [/B][/QUOTE]

Does it mean all the fast guys' car have the same setup? same spring rate? same swaybars? same wheel and tires combo? if that is true, then what is "THE" setup? *can't wait to go out and buy the same setup*
FSelekler 04-22-2004 03:39 PM

We have driven it in "auto" mode last year in AS, but now we changed the chassis significantly going into ESP this year, where the auto mode is hindering us at this time, or it just seems that way.

We do not get enough rear rotation at corner exits and the worst part is we can feel the changes dynamically in the diffs. The problem is chassis predictability.

I co-drive with a local champion and since his better than I, we setup the car for his preferences. He is, and I am too, for predictibility rather than maximizing DCCD setting for a given situation, which is nearly impossible in autox. Hence the first event we went in last weekend, we tried both OPEN and AUTO, we both posted better times in OPEN so far.

He placed 2nd in ESP behind the 2002 National Champ, I placed 8th due to a darn cone (4th with raw times). We still need some improvements in the configuration of the chassis; however, I think we will be sticking to OPEN at this time.
Watkinsm3 04-22-2004 04:01 PM

FSelekler,

Ambient temperature was?
FSelekler 04-22-2004 04:08 PM

Right around 80 deg, with Toyo RA-1, using 38.5 front, 51 rear pressures.
trojan9x 04-22-2004 04:13 PM

jmott

anyone that knows me or has seen me race knows that I'm no slouch behind the wheel and I was not describing any particular driving style at all. :confused:

I agree also that car setup will play a huge role in the setting that you choose. Whomever may find that they may take their first run on Auto and find that the coarse is really tight and the car isn't rotating good enough and maybe their next run choose to put more bias towards the rear.

Every coarse is different and the settings you choose will be hugely influenced on that.

Tom
TyrannoSullyRex 04-22-2004 04:16 PM

[QUOTE][i]Originally posted by jmott[/i]
[B] Ive never really heard of this driving style thing. Not among the quick guys anyway. All the really fast guys seem to have the same style. [/B][/QUOTE]

That style is what I like to call the howdidtheydothat style. I find myself saying that whenever watching Ramey or Teucci drive.
jmott 04-22-2004 04:18 PM

[QUOTE][i]Originally posted by wm07 [/i]
[B]Does it mean all the fast guys' car have the same setup? same spring rate? same swaybars? same wheel and tires combo? if that is true, then what is "THE" setup? *can't wait to go out and buy the same setup* [/B][/QUOTE]

they usually get pretty close.
and I attribute the differences in setup to be due not to driving style but to the fact that suspension setups are far too complex a problem to optimize perfectly, and that no doubt there are multiple setups that are equally good.

I guess my point here is if you try some setting with the diff, and you don't like it, don't immediately assume it is because you driving style is different and go back to what you are used to. Give it some time and see if your driving style needs adjustment.
Watkinsm3 04-22-2004 05:10 PM

[QUOTE][i]Originally posted by FSelekler[/i]
[B] Right around 80 deg, with Toyo RA-1, using 38.5 front, 51 rear pressures. [/B][/QUOTE]

hmmm.... I havn't had a day up here yet that has reached that temp. I was thinking that as the season progressed it might be effective to send more power to the rears. So far this spring, its been too cold, and I've been unable to put alot of power down ( very loose) with the rear.

Interesting information... Still and ESP car vs my stock prep. thanks for the info.

ALOT of drivers would KILL for the rear stick you're complaining about on corner exit ;)

-Matt
FSelekler 04-22-2004 05:29 PM

[QUOTE][i]Originally posted by Watkinsm3 [/i]
[B]hmmm.... I havn't had a day up here yet that has reached that temp. I was thinking that as the season progressed it might be effective to send more power to the rears. So far this spring, its been too cold, and I've been unable to put alot of power down ( very loose) with the rear.

Interesting information... Still and ESP car vs my stock prep. thanks for the info.

ALOT of drivers would KILL for the rear stick you're complaining about on corner exit ;)

-Matt [/B][/QUOTE]

It is my pleasure.

The car is setup for road courses, hence the rear-end stickiness is great actually, but for autocross it is a different story.

So, we are after a easy-to-switch setup technique to accomplish both :)

Actually, the issue is also a little more complex. Due to our higher-than-normal rear tire pressures and heavy front camber, turn-in was great and we were too loose at the slaloms. At the same time, we understeered in the sweeper exists. Can we get both??? :) we will try for sure.
ANZAC_1915 04-22-2004 06:38 PM

[QUOTE][i]Originally posted by FSelekler [/i]
[B]It is my pleasure.
Actually, the issue is also a little more complex. Due to our higher-than-normal rear tire pressures and heavy front camber, turn-in was great and we were too loose at the slaloms. At the same time, we understeered in the sweeper exists. Can we get both??? :) we will try for sure. [/B][/QUOTE]

Why 51 at the rear? That seems like a bad idea.
afpdl 04-22-2004 06:40 PM

It seems kind of odd that you added power, a suspension, and you are pushing more out of the corners in auto. I had the opposite problem.
afpdl 04-22-2004 06:40 PM

[QUOTE][i]Originally posted by Glenn Wallace[/i]
[B] What pressures were you running F/R? [/B][/QUOTE]

He said he was using 38.5 front, 51 rear pressures earlier.
FSelekler 04-22-2004 10:43 PM

I personally am not found of 51 psi either Glenn. But we maxed out the rear A/R bar, and have only -1 camber in the rear.

Also, Mike, co-driver, is a great left-foot braker; and he seems to be keeping the boot up and have been driving WRX wagon for over a year in which he got last years DS champ locally at what we call "The Council" (quite competitive).

Any how, he still needs seat time in the STi; that is the main issue. I will be changing to stock front A/R bar and increase front camber to -3.5 to -4. Then fix the rear suspension's adjustment knob and set it to 12-13 while keeping the fronts at 10. If all this fails, then we'll increase rear springs to 10kg/mm.

Any suggestions you might have for the DCCD would be much appreciated Glenn.

[i]afpdl -[/i] we have not improved any of the engine components as of yet, waiting on Turboback exhaust and AccessPort.

Let me also add a picture for color in the discussion :)

[img]http://members.roadfly.org/flyingtoaster/apr17_3_600.jpg[/img]
afpdl 04-22-2004 10:50 PM

Have you tried running 6-8psi lower in the rear instead of higher?
FSelekler 04-22-2004 10:58 PM

We started from 39f/40r, then ended up with 51 in the rear after trial and error. I'd rather go higher than lower as the lower pressures consumes tires faster, the camber and toe has less effect and pressure changes to rapidly during the run.
turboICE 04-22-2004 11:36 PM

BTW for those of us like me who aren't going to the podium - stay in auto would be my recommendation we have enough behind the wheel improvements to make without trying out manual settings. Just a thought.

It is also comforting for me to know Matt gets around the entire course faster that way.
Watkinsm3 04-23-2004 10:11 AM

[QUOTE][i]Originally posted by FSelekler[/i]
[B] We started from 39f/40r, then ended up with 51 in the rear after trial and error. I'd rather go higher than lower as the lower pressures consumes tires faster, the camber and toe has less effect and pressure changes to rapidly during the run. [/B][/QUOTE]

I don't really notice the excellerated wear... but what I do notice with higher pressures is a less progressive nature as the they start to break away and slide. That's without even mentioning my FWD days in my Integra.


Again, I'm on the stock suspsension (stock EVERYTHING actually)...
I've been actually treating the car like a RWD vehicle in most preparation aspects. Everything has revolved around getting the rear to stick and put down power. 38-42 front and about 35 rear tire pressires... AUTO gives me the stick coming out of the corners and the rotation before that point. I'm still curious to see if this will change based on A) Temperature and B) Surfrace (the concrete of Peru and Topeka). We'll see...

-Matt
FSelekler 04-23-2004 01:42 PM

I have significant room for improvements in my driving as well, no question :) But we have to continue our testing to see if we can compensate the negative effects of my shortcomings with equipment :)

Matt - We are actually treating the car as if it is a front-wheel drive. Even though we put more torque through the rear wheels, the weight is at the front. Not that it is a "rule" (like there are any rules in chassis tuning :)), but as soon as a car's weight distribution goes beyond 59% to the front, it exhibits more front-wheel driven characteristics than rear.

May be your approach will work better though. Best of luck at Peru and Topeka.
afpdl 04-23-2004 04:04 PM

[QUOTE][i]Originally posted by FSelekler[/i]
[B] but as soon as a car's weight distribution goes beyond 59% to the front, it exhibits more front-wheel driven characteristics than rear.
[/B][/QUOTE]

So you would set up a mustang as a FWD car:confused:
FSelekler 04-23-2004 09:56 PM

[QUOTE][i]Originally posted by afpdl [/i]
[B]So you would set up a mustang as a FWD car:confused: [/B][/QUOTE]
LOL, good question, I have never setup one; but no I would not. There are always exceptions :)

Frankly, I did not even know Mustang had that much front weight.
afpdl 04-24-2004 03:13 AM

Well they are not quite 59% front only 57% front;) But they are camber challenged understeery cars stock. Kind of like most cars are now a days:mad:
nathansvt 04-24-2004 02:17 PM

I dont know how this would work in autoX, but I've used it to some success in road course stuff. On dry pavement, I'll keep the DCCD roller all the way in open or one notch forward from that. I leave the rocker in auto. There's one corner that I always have trouble with, being that the car doesnt rotate on entry enough and on exit I can feel the front diff pulling against me. During braking for that one corner, I'll slap the switch off auto and that back to auto when I'm done. While it would be great to have a bunch of presets available (like the UK evo's tarmac, snow, gravel) or a programmable mode, just toggling between auto and open is enough for me for now.
afpdl 04-24-2004 07:08 PM

That is possible to do at an autox but would be a hell of alot harder then it is to do at a road course. It would be easier to just pull the ebrake up one notch to put the diff in full open and then put it back down after the turn.
trojan9x 04-26-2004 09:02 AM

Depending on the coarse, it's hard enough to just keep both hands on the wheel, let alone toggle with the DCCD settings. Yes, I agree a road coarse would be much easier to make that adjustment over an auto-x.

I can almost guarantee that your times will be slower if you play with that setting while in the middle of an auto-x run.

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