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AYC Brake Off vs On for Track Racing

16K views 112 replies 33 participants last post by  Motorsports Performance G 
#1 ·
Hey guys I'm new to track racing and just wanted to hear your opinions on running the car with AYC Brake off vs on. My friends that race SCCA auto-x and NASA tt have taught me the car with the brake off so I can learn to control the car without as many aides as possible. They got me hooked into track racing and HPDE last year so I've run all 5 events with the brake off now.
I've heard the argument that the car is faster with the ayc brake on and that it's better to race the car that way since it'll be faster but since I'm still learning I've been enjoying learning car with the brake off.
Just wanted to hear the thoughts of track rats here and how they run their cars for NASA tt or time attack.
I tried to search for this thread but wasn't able to find one in the first 2 pages. I apologize if this is a topic beat to the ground already.
 
#8 ·
Think of HPDEs as a means to improve your driver skill while having a great time and going faster as just a by-product of that skill. Don't focus on going faster. Eventually, you will start noticing the car braking etc against your wishes. You've already been to 5 events, you should start noticing things you never did before after about 5~10 more events depending on your adaptability. To achieve this, just go "off/off" on the ASC switch. I recommend beginners to use full ASC ON if its only their first or second time on the track, then gradually move to OFF/ON and then to full OFF/OFF.
 
#14 ·
Good explination. Kept all on my first two track days. By my third track day the throttle cutoff was getting obnoxious and almost dangerious so I went off/on. Last year I expermented with trail braking and your description above explains why if felt odd. Will try off/off next week.
 
#9 ·
AYC will always be on. Off removes the throttle cut. Off/Off removes the individual wheel braking. I believe Off works well for auto x, atleast that how I felt. Auto X tends to have sharp turns though. Full track I would think off/off would work better.
 
#10 ·
At low speeds with lots of steering input, the OE maps for the AYC actually have more power being sent to the inside wheel. (I've heard theories on why it is set this way, including the idea that it is designed to prevent folks from clipping a curb with the inside rear wheel, but I have no inside information as to the actual reason.) With the AYC rear-wheel braking aid still on, the brakes are applied to the outside rear wheel in a sharp turn at low speed. In my opinion and experience, you don't want any of this when autocrossing. I would at least turn off the single-wheel braking. If the class in which you run allows, I would seriously consider having both the ACD and AYC reprogrammed.
 
#12 · (Edited)
I was wondering this same thing but more so what modes work better with different weather conditions. I know I read some older threads where members were saying best setting for the track is off/off and gravel mode, but no one has expanded into discussing different modes and how they work in different weather.

Particularly on a really rainy day, I'm wondering what would be the best mode. I know when I try with off/off and gravel mode, the car slides and loses control easier, tarmac definitely holds more grip I noticed even with off/off and wet roads, although I'm sure my shitty stock tires play a big role as well.
 
#16 ·
My friends had me learn the car from day 1 with off/off and in tarmac and I've enjoyed learning the car this way. The evo does slide a lot more and the steering inputs have to be a lot more smooth as well as the braking and accelerating to keep the car from being upset, but I've grown in both areas as I've tried to push the car harder and harder.
I used to autox a lot and I tried one event with the ayc brake on and I didn't like how it felt when steering. It felt unnatural so I raced the rest of the season with it off/off.
It's nice to see most guys on the forums here agree off/off is best. I was just surprised when I met guys at the track try to convince me that off was a better option and I only did one season last year so before this season began I just wanted to see some other opinions. Thanks for all your responses!
 
#17 ·
The car doesn't fight throttle inputs in the off/on mode. It individually applies the brakes to specific wheels and sends power to others to force the vehicle to PIVOT about its center, forcing the vehicle to turn in better. This is on the opposite end of the pivot spectrum normally occupied by forced oversteer to "point in/rotate".

From experience, it's more difficult to understeer while on off/on mode, and i can get on the power sooner and harder with MUCH less oversteer. I'm still experimenting with left foot braking and am convinced that off/on mode with a trained left foot braking technique will be vastly superior to the typical off/off forced oversteer "rotate" mentality that so many people have on these forums.

Side note, i havn't done enough experimenting with gravel/tarmac/snow to see which gives me faster exit speeds, but dicking around on wet pavement, i've noticed that gravel and snow causes me to understeer easier and earlier on turn in. I've since upgraded tires & changed alignment to zero toe, so this needs much more validation to say anything of value.

as far as driver training goes, i agree that off/off forces you to develop skill and pay attention to vehicle limits more. But it is of my personal opinion that i am still faster around the track in off/on mode.
 
#18 · (Edited)
The reason that Gravel and Snow cause more understeer (on pavement) at turn-in is that the center is still partially locked.

The two main differences between modes are level of maximum lock and how quickly the center opens when you lift, brake and/or turn. Since Gravel and Snow open more slowly than Tarmac (i.e., stay locked longer), the odds of the center still being partially locked at turn-in are higher in these modes, and a locked center is not what you want at turn-in on pavement.

edit: I am here ignoring the AYC because the question I'm responding to concerns turn-in and I'm assuming that the driver will not be at 25%+ throttle at turn-in
 
#21 ·
This is interesting because McCoy indicated the opposite on numerous occasions, that in his team's extensive Time Attack experience gravel mode made the car more oversteer than in Tarmac mode..
 
#20 ·
I'm repeating myself here but Tarmac Gravel & Snow also affects AYC. Tarmac being highest amount and Snow being the least.
 
#22 ·
Was McCoy talking about corner-entry or -exit? I was talking about entry, during which you really want the center to be open. My guess is that they were talking about corner-exit, instead, where you want the center locked pretty hard. Also, as mentioned by someone earlier, the modes do affect the AYC, too. As soon as you're back on the gas, the AYC becomes active, so that could be playing a role. (The AYC does nothing when coasting or braking at corner-entry, so I ignored this before because the question was corner-entry push.)
 
#23 ·
McCoy's driving style is probably hard brake to force a slight oversteer into the turn then power out. At least i would assume so if he's in gravel mode. Truthfully, my driving skill needs more refinement before i can start toying with traditional lines and the method mentioned above. Though i will say when i was playing in gravel mode, i noticed i could smash the gas as soon as the front wheels passed apex vs waiting. The front wheels just pull you straight through.

Another thing, i think in tarmac/snow it also changes brake bias. Toying in snow had a very even front/rear brake feeling, though it could be just cause the center diff was solidly locked.

Anyways, back on topic, I will maintain the off/on mode is faster, and would love anyone with real track experience that have extensively tested both to chime in.
 
#25 · (Edited)
Our cars do not have dynamic brake bias. We have a standard, physical prop valve. Therefore, until one of the nannies steps in, the bias remains the same. I don't know if ACD/AYC mode alters the nannies that involve the brakes, but I've never seen anything to suggest that it does.

The S-AWC is cobbled together from parts from various sources. They haven't really been melded in one, common system. That's why I doubt that we'll ever learn that ACD/AYC mode affects the brakes directly.

With that said, remember that one uses a lot less pedal pressure when grip is low. Therefore, one is spending much more time braking at a point below the prop valve's split point. Thus, when braking with low grip, you are probably closer to equal line pressure (front vs rear), in contrast to hard braking on pavement, which will have much higher line pressures to the front.

My new brakes have total piston areas much closer to equal than OE Evo X brakes. I adore it. Given that there's no simple way to disable the ABS, this was the only way that I could come up with to get more rear bias on gravel, dirt, and snow. Still working on a safe way to plumb in a hydraulic hand-brake.

ps. thanks to the above for the kind words ... not that I know what an "RSS feed" is :)

pps. say "hello" to the folks at VCMC for me; tell them it's coming from the guy who made their "Toby Light"
 
#26 ·
Are you on track in the "automatic" mode ? I have about 45k on the SE and I think it has been in the auto mode possibly 4 times ever,(so I can get the cruise control.) And with all the computers on this car doing "stuff" in the different settings For me it has been the best way to turn OFF everything possible,shift by hand. Moving from the Evo 9 to the evo 10 is a big change in how the car "feels". MPG
 
#28 ·
My fastest times have all been set in Auto S-Sport, mostly because there are corners where I have to shift midcorner because of a long exit acceleration zone in a low gear and I can't smoothly reach for the console shifter with my right hand and steer the car smoothly with my left. In Auto, I can keep both hands focused on tracing smooth lines regardless of the shifting requirements.

Also, Auto Sport and Auto S-Sport don't give you the cruise control. Only Auto Normal and Manual Normal do.


Sent from AutoGuide.com Free App
 
#34 ·
Trail-braking in Gravel mode is, to a certain extent, opposites or counter-productive. The goal of trial-braking, as you said, is to have lots of weight shifted forward at turn-in, such that you have above average front grip and below average rear grip. This helps make it easier to get the tail to come around.

In contrast, one of the main attributes of Gravel (as opposed to Tarmac) is that the ACD remains locked longer after you come off the gas and/or steer. The point of Gravel is to help keep the tail straight behind you.

I suggest that you try a few laps in Tarmac, but ease off on the trail-braking (as you won't need as much). Think more in terms of getting back on it sooner, using the ACD and AYC to finish the corner.

Note: this post is half aimed at myself. I used to have a 2G DSM that demanded some pretty serious trail-braking to get into corners. I originally drove the Evo the same way, ending up drifting a few too many times (which was blast, but inappropriate and rather destructive to the tires). It took a while to make the transition to driving the X as an X, instead of a DSM with four doors. But it's much faster once you do so.
 
#35 ·
Trail-braking in Gravel mode is, to a certain extent, opposites or counter-productive. The goal of trial-braking, as you said, is to have lots of weight shifted forward at turn-in, such that you have above average front grip and below average rear grip. This helps make it easier to get the tail to come around.

In contrast, one of the main attributes of Gravel (as opposed to Tarmac) is that the ACD remains locked longer after you come off the gas and/or steer. The point of Gravel is to help keep the tail straight behind you.

I suggest that you try a few laps in Tarmac, but ease off on the trail-braking (as you won't need as much). Think more in terms of getting back on it sooner, using the ACD and AYC to finish the corner.

Note: this post is half aimed at myself. I used to have a 2G DSM that demanded some pretty serious trail-braking to get into corners. I originally drove the Evo the same way, ending up drifting a few too many times (which was blast, but inappropriate and rather destructive to the tires). It took a while to make the transition to driving the X as an X, instead of a DSM with four doors. But it's much faster once you do so.
I have done both with varying degrees of trail braking. Though I only ran one weekend in Gravel, I felt my turn-in was better in Gravel. I don't necessarily want to get into here as this thread is about AYC usage. I will be running in NASA Time Trials this year, so my level of driving might be a bit more extreme than most people in this thread. That is certainly not to toot my own horn (I've still got a long way to go) or to discount anyone's driving skills but is meant as a reference as the dynamics of everything changes at the very knife-edge limit.
 
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