Stand Alone Traction Control Module
- Thread starter Alky V6
- Start date
In my experience it has not been a maybe.
The driver removes foot from pedal. Now I havent compared driver reaction to traction control reaction but I wouldnt sell the human body short.
Human Benchmark - Reaction Time Test
Come on now. I'm not that naive.
How long does it take for a driveshaft to rotate one quarter turn at 7500 rpm in high gear? That is how fast some TC units take before starting to correct for tire slip.
If human reaction time was enough, then why the huge moves to come out with all the forms of stability control?
How often do you see the tires getting blown away at the track? Is that just a lot of people needing practice on their super human reaction time?
EDIT: What is the reaction time to a stimulus when the person is concentrating on other things? Steering, gear changing, the person in the other lane, tachometer, other gauges, pulling the chute, talking on the cell phone.
Obviously TC will react faster. You didnt think I was trying to say the human reaction is faster?????
However many many passes get away from a driver not lifting. That was the point.Your original thought about TC being used for precisely tuning your chassis is what I was discussing.
As I've said I believe its best used to save a run that may have otherwise been lost, due to constant changing conditions.
I am pretty sure Dusty was only using the Heuristic (or slew control). He can correct me if I'm wrong. Here's some "propaganda" from the XFI manual, take it at face value:
"There are two modes of Intelligent Traction Control that can be used in an XFI. One is called Heuristic Mode, and the other is called PA Mode. Each mode can be used separately or together to reduce or eliminate a loss of traction which can occur due to any number of reasons such as limited tire size, suspension issues, or track conditions. Both modes utilize a speed sensor to monitor driveshaft RPM and are easily set-up using a simple 2D graph. The fact that both modes rely on driveshaft speed instead of other methods that utilize engine speed (RPM) to base their traction control on makes this much easier. The reason for that is you no longer have to ‘chase’ plots on a graph that are constantly affected by other factors such as gear changes, torque converter or clutch slippage, or anything else that can affect engine RPM and the rate at which it changes. Those variances don’t occur with driveshaft speed."
I find the Heuristic (slew rate) mode will work if the car is barely spinning (or low hp) and the PA Mode (connect the dots) works better if traction is worse (or high hp). I have also been testing using an output on the XFI to lower boost in the AMS when traction control is "active".
fastfreddy
Member
- Joined
- May 24, 2003
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
I used the XFI traction control and was happy with it. But these system's don't work like some people think they do. You can't just throw everything at it and expect the car to go faster. My experience was exactly like Lazaris is describing. It will save a pass where the car would have blown the tires off and could be used as a tuning tool as you described earlier. I can see the safety aspect of it but I can hear the rpm difference and feel the acceleration suddenly stop from tire spin. You just know what tire spin feels like after so many passes in the car. The guys smoking the tires for 100 feet before lifting are simply being boneheads.
So I wouldn't call any traction control un-satisfactory. They do what they are intended to do, save a pass. But they do not make a car faster.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
Your right. I never used the latest version of the PA mode.
That's a good point. I was thinking of ignition retard followed by boost lowering in a one after the other routine. The ignition retard would come first and if that wasn't enough then the boost would be lowered.
I couldn't agree more. I think Donny needs to put traction control on his car and then tell us if it works like he expected it to. It's pretty apparent that those of us who are currently using it have diferent expectations/experiences with the systems we are using. Hopefully he goes with the Davis unit. So far, I have heard great things about it and I would like to hear more feedback from someone like Donny who isn't trying to sell me one.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
Some things are in the works. Might be able to test a Davis box by the end of Feb on another car.
I agree. The safety part of it is what I'm mainly looking for. If I get carried away and throw too much at it, I can feel a little bit more secure that it won't launch for the wall.
The scenario I mentioned before of the car that goes down the track before you, misting the track is always on my mind too. Like you stated, it's easy to feel when a car starts to loose traction on a normal track, but when you watch some of these videos of cars that go sideways so fast, it makes me wonder. I've seen fellas at my track, good drivers, that have had things happen that resulted in the car going out of shape so fast. One fella had a radiator hose blow. The car ended up rolling several times down the top end. He wasn't hurt, luckily, and told me after the accident that it happened so fast he didn't have a chance to react at all. He said at one moment everything was fine, he then noticed some moisture on the windshield, and then the next moment he was looking at the track. The car was on its nose.
That might be awhile waiting for feedback from me. I think I'm going to start working on my own system. I'm waiting for the money to upgrade the fuel system, and while I wait for that to materialize I'm going to be awfully bored, so I'm studying up on my electronics to see if I might be able to make something for myself.
My son graduated from Coleman College close to a year ago, and got a good job software programming for a company. Maybe he can give me some pointers on programming a unit. I'm looking forward to it. I think it's going to be a lot of fun.
So if you guys have some good ideas of what routine(s) works best for controlling torque to affect TC, I'm all ears.
Please keep me posted on your findings.
The boost lowering routine is very slow reacting. I use it as a last ditch effort to save a run after timing retard and dropping cylinders. Do you have a blowoff valve?
That was my thinking too. Controlling the boost has to be the slowest way of controlling engine torque.
Yes. I do have a blowoff valve that is semi controlled by the aux channel of the AMS1000. I would suppose that would be a quicker way to control MAP than the wastegate.
Here's what I'm thinking. There have been cases where I've had the proportioning valve set to send a little too much pressure to the rear brakes.
The result was, the rear tires would lock and skip on me. I would have to release the brakes and get back on them a little more carefully. An ABS would have been nice to have right then. With the front tires being so thin compared to the rear, it just seems to make more sense to send more pressure to the rear, compared to the braking bias a normal street car would have. ABS would allow a racer to maximize braking force.
There are some simple rear axle ABS on some trucks that I think would work out perfectly on a spooled rear axle race car to get the most out of the rear meats to help out with braking.
Since the ABS system would be on the car for better braking efficiency, why not incorporate it to help with the job of traction control? It would help solve some of the problems associated with using only engine control to affect torque reduction.
The result was, the rear tires would lock and skip on me. I would have to release the brakes and get back on them a little more carefully. An ABS would have been nice to have right then. With the front tires being so thin compared to the rear, it just seems to make more sense to send more pressure to the rear, compared to the braking bias a normal street car would have. ABS would allow a racer to maximize braking force.
There are some simple rear axle ABS on some trucks that I think would work out perfectly on a spooled rear axle race car to get the most out of the rear meats to help out with braking.
Since the ABS system would be on the car for better braking efficiency, why not incorporate it to help with the job of traction control? It would help solve some of the problems associated with using only engine control to affect torque reduction.
An interesting article I came across during my surfing.
Driving Fast: Driving Techniques and Car Control: Threshold braking – how to get it right
Driving Fast: Driving Techniques and Car Control: Threshold braking – how to get it right
