Troubleshooting my Last HPDE - LotusTalk - The Lotus Cars Community
 
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post #1 of 14 (permalink) Old 11-13-2017, 07:28 AM Thread Starter
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Troubleshooting my Last HPDE

Last event of the season, it was 32 degrees most of the day, with about an hour where it go up to 40
People on here were right that R888Rs are not at their best in those temps, but they're still way better than even the best rainy day.

What I couldn't figure out is some inconsistencies I was running into while on the track. Inconsistencies in grip, both while cornering and braking.


Couple items, I never felt ABS engage and so it's either very smooth to engage, or I wasn't braking hard enough, but I doubt that, as the data logger was pegged in most corners (It has a max of 1.1G) so I was driving hard enough likely to engage ABS. I even had a couple offs because I couldn't scrub enough speed.

This particular instance I made it a lot worse by freaking out when the car wouldn't come down from speed and then turned in early too:


And this one was exacerbated by the fact that it's off camber. The instructor told me to drove over the crest of the off camber left hander, almost to the edge of the track and then turn in super late, basically drive straight across the back of the apex, but I couldn't slow down fast enough and got 2 wheels off, and spun (gracefully I might add):


But I never felt the ABS come on, and I was on the pedal hard, hard to the point where I knew any steering input would not be a good idea. I never locked the tires up, and as far as I'm aware the car has operational ABS.

The other thing I never felt engage around the corners was traction control. I kept it on due to the temps and the car was very lively. I had the rear end move considerably mid corner at least a dozen times. The only time I felt the TC was powering out of some corners.
So is the TC system on these cars just very simplistic, meant to stop wheel spin say under slippery conditions and that's it? Or does it help correct in a spin as well?

I blocked off both oil coolers, and it didn't seem to matter. I could still touch the oil lines in the front of the car with my bare hands right after coming off track.
But maybe I blocked the brakes too and the pads were fading.
They're CL RC5+ pads front and rear.
This track isn't high speed as you can see, but I do have a Rev400


Still learning this platform,yesterday it was a handful but it was extremely rewarding.
I didn't give 1 point by all day, and the car performed great, it's really still way faster than I am.
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post #2 of 14 (permalink) Old 11-13-2017, 07:40 AM
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1. Why aren't you guys wearing communicators?
2. It looks like apart from going too fast you were mixing inputs quite a bit in the first spin, if you had kept braking straight, or just turned in it might have been OK? You were definitely going too fast though.

Overall, you would know if the ABS or TC comes on it is not subtle. If you never engaged either even once, then I would say its not working. go out on the road and just slam the brakes at 30 mph and find out? Or launch the car? With your HP the TC will come on for sure every launch.

2007 Exige S with almost every track mod...
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post #3 of 14 (permalink) Old 11-13-2017, 07:49 AM
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ABS is very noticeable when it comes in, so despite what it felt like, you still had to have had some braking left on the table. I can't listen to the video right now; were the tires ever chirping under braking? I find (with my different tires) that I can get the tires to chirp before ABS comes in. ABS is also heavily dependent on rate of application (jabbing vs. gradual), the wheel mass, rolling diameter, pad compound, temps, etc, so everyone's mileage varies pretty wildly. Technically there is some venting between the oil coolers and the front brakes, but it does not look to be much more than just a way to get the oil cooler air out. I doubt blocking them will induce fade any different than being open. I have only run mountain roads with mine blocked and did not notice any fade, but on a 70F day at the Tail of the Dragon, my oil will overheat when the coolers are blocked.

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post #4 of 14 (permalink) Old 11-13-2017, 07:53 AM Thread Starter
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Originally Posted by kfennell View Post
1. Why aren't you guys wearing communicators?
2. It looks like apart from going too fast you were mixing inputs quite a bit in the first spin, if you had kept braking straight, or just turned in it might have been OK? You were definitely going too fast though.

Overall, you would know if the ABS or TC comes on it is not subtle. If you never engaged either even once, then I would say its not working. go out on the road and just slam the brakes at 30 mph and find out? Or launch the car? With your HP the TC will come on for sure every launch.
Thank you, like I mentioned the first off was partly due to my reaction to not being able to stop, I turn in way early and then I wrestle with the consequences, giving too much of all inputs likely.

The TC I felt several times coming out of corners and I've felt it on the street. You can even hear it from the track side videos as it cuts ignition timing, but I didn't know if there was more to the TC system, like any sort of anti skid system because I certainly felt no corrections happening mid corner by the car, to keep the back end from coming around.

The ABS is a mystery to me. I guess I'll just have to go out and stomp on the brakes...
Could i Have been dealing with ice mode, because the pedal was firm and I was on it, the car was stopping just not with enough bite. I could understand if the tires didn't have the grip due to the cold and the abs was engaging but I didn't feel it in the pedal, hear it pulsing or anything. Some ABS systems are more intrusive than others, so I figured I might be missing something.
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post #5 of 14 (permalink) Old 11-13-2017, 08:03 AM
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REV400 doesn't work well with TC, turn it off and dial back the driving until you get used to the car.

The first corner, a LITTLE too fast coming in but if you trailed it better you would've been fine.

If the pedal was truly firm then yes, that does sound like ice mode. Lift, reapply, repeat until the car reacts appropriately. Happened to me yesterday at Sonoma coming into the carousel (turn 6) - pretty bad place to have it happen, but once you're used to the feeling the reaction becomes more natural.
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post #6 of 14 (permalink) Old 11-13-2017, 08:08 AM
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In my car I feel like I have experienced two distinct ABS interventions.

First is what I would call normal, when braking hard I sometimes feel a vibration in the pedal. I have experienced this in other cars as well when ABS is active. If you were very excited or on a rough surface this might not seem noticeable.

The other experience has been the dreaded "ice mode" which is quite obvious as the pedal effort stiffens up dramatically. The car will still stop but I have to really lay into the brake pedal, whereas usually the first inch of pedal travel in my car feels soft. If you don't want to increase the pedal effort, you can pump the pedal and reset the ice mode. It can be a real pucker moment if you are waiting for that last moment to go for the brakes, trying not to leave a fraction of a second on the course, and get surprised by ice mode with no time left to pump the pedal. I have been in some autocross situations where after a couple of runs I know where the ice mode will hit and depending on the layout I may focus on being smooth to the pedal or just know it's going to happen and roll with it.

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post #7 of 14 (permalink) Old 11-13-2017, 08:17 AM Thread Starter
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BTW just for some comparison, some better laps towards the end of the day. These were the same session though as the spin, so while I was driving a better line, and much more in control. I still spun it, which is that inconsistency I'm talking about. The track actually felt decent (relative) this session, even though the sun was setting and it was getting colder:

Don't mind the music, I was having a bit of fun:


And here's the spin from outside, you can see I just run out of track on the right hand side. That corner is off camber though, so when I tried to turn in at the very last, as to not go off track it put the rear tires on the grass:
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post #8 of 14 (permalink) Old 11-13-2017, 08:37 AM
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Quote:
Originally Posted by Ls1Rx7 View Post
Thank you, like I mentioned the first off was partly due to my reaction to not being able to stop, I turn in way early and then I wrestle with the consequences, giving too much of all inputs likely.

The TC I felt several times coming out of corners and I've felt it on the street. You can even hear it from the track side videos as it cuts ignition timing, but I didn't know if there was more to the TC system, like any sort of anti skid system because I certainly felt no corrections happening mid corner by the car, to keep the back end from coming around.

The ABS is a mystery to me. I guess I'll just have to go out and stomp on the brakes...
Could i Have been dealing with ice mode, because the pedal was firm and I was on it, the car was stopping just not with enough bite. I could understand if the tires didn't have the grip due to the cold and the abs was engaging but I didn't feel it in the pedal, hear it pulsing or anything. Some ABS systems are more intrusive than others, so I figured I might be missing something.
Ice mode isn't really a second operating mode but the extreme case of normal mode, so it gets its own name for convenience. If your brakes are properly bred, the pedal feel is pretty nicely firm anyways, so that's not a symptom unless the firmness changed rapidly on you. My experiences with 'ice mode' was after noticeable pulsing of normal ABS. AS systems look at two things - slip and slip rate. Most people ignore that last one. ABS will kick in if the wheels are spinning, say, 80% as fast as the car, but it'll also kick in if they are heading towards that quickly and not there yet. This is where pad bite, rolling inertia, and grip play a roll.

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post #9 of 14 (permalink) Old 11-13-2017, 10:10 AM
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Quote:
Originally Posted by Ls1Rx7 View Post
Thank you, like I mentioned the first off was partly due to my reaction to not being able to stop, I turn in way early and then I wrestle with the consequences, giving too much of all inputs likely.

The TC I felt several times coming out of corners and I've felt it on the street. You can even hear it from the track side videos as it cuts ignition timing, but I didn't know if there was more to the TC system, like any sort of anti skid system because I certainly felt no corrections happening mid corner by the car, to keep the back end from coming around.

The ABS is a mystery to me. I guess I'll just have to go out and stomp on the brakes...
Could i Have been dealing with ice mode, because the pedal was firm and I was on it, the car was stopping just not with enough bite. I could understand if the tires didn't have the grip due to the cold and the abs was engaging but I didn't feel it in the pedal, hear it pulsing or anything. Some ABS systems are more intrusive than others, so I figured I might be missing something.
Ah, no there is no stability control at all, its just basically the on off switch you have felt.

I didn't ever run the ABS that long, but I always remember the pedal pushing back at me when I felt it.

2007 Exige S with almost every track mod...
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post #10 of 14 (permalink) Old 11-13-2017, 10:19 AM
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As you suggest, the TC isn't a sophisticated anti-skid system, it's just a power-limiter. It seems mostly intended to limit corner exit power over-steer. Anti-skid systems can use individual brake application to help catch a spin, but that's not the case here.

HTH, -Ed

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post #11 of 14 (permalink) Old 11-13-2017, 02:25 PM
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Originally Posted by Ls1Rx7 View Post
But maybe I blocked the brakes too and the pads were fading.
They're CL RC5+ pads front and rear.
I've been using the RC5+ pads for a few years now. I'd be amazed if you can get them hot enough to cause fade.
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post #12 of 14 (permalink) Old 11-13-2017, 05:50 PM
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At 32-40*F I can't believe your braking would be limited by anything other than tire grip. The question is, what was going on with your ABS? FWIW, I find that there's less pedal vibration with ABS on my Exige than on any other cars I've owned. It's also quieter. If it weren't for ice mode, I'd be a fan.

-Ed

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Last edited by AustinP; 11-13-2017 at 06:54 PM.
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post #13 of 14 (permalink) Old 11-13-2017, 08:13 PM
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Good to see you got out.

Ed is right, tire grip is your biggest problem when it's that cold. Log some warm season track days to build a proper comparison set, then troubleshoot and modify components accordingly.
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post #14 of 14 (permalink) Old 11-14-2017, 05:02 AM
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This has been mentioned before in brake bleeding threads - an easy way to activate ABS (or in your case, verify it’s working) is to find a paved section of road with some sand on the paved shoulder. Put one side of the vehicle in the sand and then brake to activate ABS. With sand under the front tire, it won’t take much to activate the ABS. You don’t need a lot of speed - it seems like I did this at 30 mph or so. I’ve found it easy to do with no risk of control loss since the other side of the vehicle is on dry pavement.

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