Landracing Forum
Tech Information => Technical Discussion => Topic started by: robfrey on December 20, 2009, 02:48:32 PM
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Has anyone here built a traction control system that simply turns on a switch if the rear tire speed exceeds the front tire speed by a certain percentage? Davis is really proud of their system (over 4k). Seems like a lot of money for such a simple function. I am thinking on building our own but I was just wondering if there is anyone on the board that has done the yet and if it worked?
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The Edelbrock quick data has the switch capability comparing two functions I think :?
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Ah, you make it sound so simple. Detecting the difference of rotation front to back, no problem.
Reacting to that event fast enough to do something. Big dollars.
No amount of money will keep you from blowing the rear tires off with way too much horsepower for what the surface will hold.
The initial design has to be within the realm of pretty close for electronics to have a chance.
Then you have to look at the reaction time of the mechanics involved. You have to kill horsepower instantly. Almost impossible. And you have to do it hundreds of times per second to keep up with it.
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and there is a pretty fast car that knows now not to do it with IGN. retard
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Why not ign retard?
I know that you can't completely lean on it as you will burn up the ex valves but if you just bump it every once in while? We will need a dash warning light to know that it is activating so we can adjust the boost controller for the next attempt. Computation speed is not problem. Old assy code will run plenty fast enough.
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Aparently there was afterburn(ING)er effect that became an affect of the exhaust system--- and from what little bit I read and heard and deduced it made a pretty good blow torch :-o
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If you do ignition retard on a turbo motor the exhaust heat goes to "melt the exhaust valves" hot pretty fast! That is actually one way of eliminating turbo lag, when you step on the gas the ignition goes big retard for a few milliseconds and the exhaust heat goes skyward and the turbo spools up real fast. Can't do it long as I said before the exhaust valves will exit thru the turbo in liquid form.
If you do some sort of traction control, it has to be a combination of several systems, one that can be fairly instant, like applying the brakes,(the top fuel guys did this before NHRA outlawed using the onboard computer to interface with the car controls, they actually had a seperate set of calipers that were only for keeping the wheels from spinning.) one that at the same time kills power, ign. retard(not good for above reasons) or maybe killing some of the cylinders, or backing off of the throttle etc. It can get pretty complicated pretty fast maybe a well educated right foot on the driver is the best start.
Rex
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It can get pretty complicated pretty fast maybe a well educated right foot on the driver is the best start.
No question that the right foot is the cheapest method.
I feel that the record holders will all be using traction control. I don't see that many vehicles that can afford to give up the acceleration or stability that traction control allows.
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One of the simple and least expensive traction controls is limiting how fast the engine revs,the 101/2 in. tire drag racers
were able to go over 200mph for the first time using this system.
JL222
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The rev feature mentioned above is available in some of MSD'S digital 7 ignitions available at Summit Racing and others.
JL222
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One of the simple and least expensive traction controls is limiting how fast the engine revs,the 101/2 in. tire drag racers
were able to go over 200mph for the first time using this system.
JL222
I don't think anybody is still using the MSD "dots" program in the 10.5 classes. My spies tell me that most of the good working cars were using something other in Orlando this year.
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The rep at Davis wants us to hook up to the ign retard of our MSD digital.
I would rather it would just start pulling cylinders.
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Rob, when did the pro 5.0 cars first go 200? I'm sure it wasn't this year. :cheers:
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No, not this year for sure. I'm just saying that it looks like the trend is that they are getting away from using that feature MSD has in their digital 7 for whatever reason. I didn't get a reason why.
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Has anyone made a simple series of dash lights that would sequentially turn on as traction was broken. I.E. 3% 5% 7% over etc?
Sort of like a manual traction controller for long wheelbase car with the driver in the front.
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Gale Banks made just such a system for Al Teague. Adjustable up to 17% slip.
DW
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We had a single-step indicator on one of the bikes -- when drive wheel speed exceeded non-drive wheel speed (okay, rpm) by a settable percentage - a light would illuminate on the dash. We labeled it "Warning" -- could have said "Lift, idiot!". But it did what it was supposed to do.
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Slim, Who made that system? Is it still available?
I think I can build something like this but I don't want to reinvent the wheel if I don't have to.
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It was just using one of the functions on the MoTeC. Front and rear wheel-speed sensors input to the unit and preset it to the desired difference rate. Probably lots of other machines will do it -- and lots cheaper than a MoTeC.
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hay Slim, traction control are the orange mile markers? happy new year. did I tell you its going to be almost 80 here today :-P
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It was just using one of the functions on the MoTeC. Front and rear wheel-speed sensors input to the unit and preset it to the desired difference rate. Probably lots of other machines will do it -- and lots cheaper than a MoTeC.
I'd still use the MoTeC though. If this is a high power turbo motor, an ECU is a given. So it costs little more to use the appropriate MoTeC and get all of their functionality and quality. I know more about ECU's than LSR, and most of the rest are simply junk when the boost gets turned up and we start needing more functions.
Good ECU's limit power by cutting out injection pulses cyclicly through all of the cylinders, essentially turning off cylinders to limit power. This method lowers the EGT, since no un-burned fuel is going into the exhaust.
To do this without an ECU, I'd hook up a twin engine aircraft tach to front and rear wheel RPM and run my right foot off of the split. Of course, this means we're somewhat eyes down instead of on the horizon. My sources on the salt all tell me that there is always some wheel spin and 5 to 9% is common with 10% or more indicating traction problems.
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Blue
We ran the Goodyear wide tire [2222 type] tire for 13 years but not every year and it still had small bumps on tires and bought new tires because of age.
We found that are tires were growing an inch and a half at 275mph exit speed because our tach didn't register enough rpm to go that fast.
JL222
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If you can find a Range Rover to pull parts from, they have a computerized traction control already set up for a forced air induction (sport models) that monitors and adjust the wheels at a rate of 200 times per second. They're also designed already to work with anything. Engine from England or Germany, Transmission from India, AWD transfer case from USA, German or Italian suspension, etc..
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ummmm Blue.... if your so called "good" ECU cuts pulse width, yes you would effectively limit power..... by going lean and holing a fricken piston... The best way is to pop a blow off valve on a blown motor so you can still stay spooled up... the second best way is to kill ignition... the last thing you want to do is stop feeding fuel to a hot motor that still has spark....
Kent
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It was just using one of the functions on the MoTeC. Front and rear wheel-speed sensors input to the unit and preset it to the desired difference rate. Probably lots of other machines will do it -- and lots cheaper than a MoTeC.
I'd still use the MoTeC though. If this is a high power turbo motor, an ECU is a given. So it costs little more to use the appropriate MoTeC and get all of their functionality and quality. I know more about ECU's than LSR, and most of the rest are simply junk when the boost gets turned up and we start needing more functions.
Good ECU's limit power by cutting out injection pulses cyclicly through all of the cylinders, essentially turning off cylinders to limit power. This method lowers the EGT, since no un-burned fuel is going into the exhaust.
To do this without an ECU, I'd hook up a twin engine aircraft tach to front and rear wheel RPM and run my right foot off of the split. Of course, this means we're somewhat eyes down instead of on the horizon. My sources on the salt all tell me that there is always some wheel spin and 5 to 9% is common with 10% or more indicating traction problems.
Normally I try to stay away from the "Big Theory" posts you make, but... wow. This one is way off.
First, what qualifies an ECU as "junk" ? I've spent a lot of time on a test bench with different ECUs and all of them will work fine for what anyone here wants/needs to do. A friend in a NASCAR engine building shop has been testing at a much higher level of detail than my work a few years back, and what he's finding is that the most popular domestic systems are actually the ones with the most problems... that's neither here nor there.
Some other corrections:
-Fuel cut is NOT how traction control is implemented in a Motec system, at least not if you expect the engine to live. It's ridiculous to think that cancellation of an injection event will allow instantaneous "zero" fuel into a given cylinder, unless you are running a Direct Injection setup - in which case, you are not using Motec (or any other commercially available ECU). Nice in theory, absolutely impossible in practice.
-There's no "use my right foot" on a turbocharged application in the realm of high specific output. Beyond 35-50% throttle (typically), there is no throttle control of power - you can only close the throttle and lose boost, bigtime. Or, put more simply, there is NOT a linear relationship between power output and throttle position on any of the turbo engines you'll see running at Bonneville! not even close
-traction control has been attempted, and most often, disabled - on the fastest 'liners trying to use it. Even Motec's method is very, very sensitive to tuning. You have to tune it by trial and error on the salt.
-The best setup I've ever used, is one that links wastegate actuation to throttle position. After about 50% throttle I like to use an EMS that couples boost control solenoid position to throttle position, which makes a turbo car act much more like a blower or NA car: this makes power output more linear with throttle position. THere are some really fast guys that figured this out last year, and I've run it on a couple cars. In one instance last year, a 75whp reduction in power resulted in 21mph gain in top speed on the next run (we've logged WHP output at varying loads/rpms so we know how much the change in BCS duty cycle improved the ability to drive the car).
Funny thing is, you CAN do the TPS-BCS linking in an $8000 Motec. But you can also do it on a $230 megasquirt.
-Scott
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One of the simple and least expensive traction controls is limiting how fast the engine revs,the 101/2 in. tire drag racers
were able to go over 200mph for the first time using this system.
JL222
MSD programable digital 7 +
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One of the simple and least expensive traction controls is limiting how fast the engine revs,the 101/2 in. tire drag racers
were able to go over 200mph for the first time using this system.
JL222
IMO, this approach doesn't seem to work well on the salt, especially on forced induction engines. It's very hard on the exhaust valves - it's bad enough on an 8 second pass, but far worse on a 70-90 second pass. Also, nearly all the turbocharged drag racers out there have moved from the timing-based, slew rate controls you mention, to boost control using an AMS-1000 controller...
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One of the simple and least expensive traction controls is limiting how fast the engine revs,the 101/2 in. tire drag racers
were able to go over 200mph for the first time using this system.
JL222
IMO, this approach doesn't seem to work well on the salt, especially on forced induction engines. It's very hard on the exhaust valves - it's bad enough on an 8 second pass, but far worse on a 70-90 second pass. Also, nearly all the turbocharged drag racers out there have moved from the timing-based, slew rate controls you mention, to boost control using an AMS-1000 controller...
Why is it hard on exhaust valves?
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One of the simple and least expensive traction controls is limiting how fast the engine revs,the 101/2 in. tire drag racers
were able to go over 200mph for the first time using this system.
JL222
IMO, this approach doesn't seem to work well on the salt, especially on forced induction engines. It's very hard on the exhaust valves - it's bad enough on an 8 second pass, but far worse on a 70-90 second pass. Also, nearly all the turbocharged drag racers out there have moved from the timing-based, slew rate controls you mention, to boost control using an AMS-1000 controller...
Why is it hard on exhaust valves?
Because the "Slew Rate Control" will retard timing. ON a forced induction motor, this is a poor way to manage power because the combustion charge is burning on it's way out the exhaust valve. The valves can't decide if they want to keep working, or become a puddle of molten metal.
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Are you sure thats the way they do it? I thought they just limited the rpm rate in another way, such as dropping cyls.
JL222
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Are you sure thats the way they do it? I thought they just limited the rpm rate in another way, such as dropping cyls.
JL222
THe ones I used, first retard then drop cylinders which is also not great - it lights raw fuel in the exhaust...
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The best way is to pop a blow off valve on a blown motor so you can still stay spooled up
Kent
What about an electricly operated wastegate valve? Put a momentary pushbutton on the steering wheel within thumbs reach and hold it until the wheels grab again.
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Are you sure thats the way they do it? I thought they just limited the rpm rate in another way, such as dropping cyls.
JL222
THe ones I used, first retard then drop cylinders which is also not great - it lights raw fuel in the exhaust...
If there is no spark, what lights the fuel?
JL222
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Are you sure thats the way they do it? I thought they just limited the rpm rate in another way, such as dropping cyls.
JL222
THe ones I used, first retard then drop cylinders which is also not great - it lights raw fuel in the exhaust...
If there is no spark, what lights the fuel?
JL222
"retard" doesn't mean "no spark"
And if you DO use it to kill spark, the fuel that puddles in the exhaust gets lit on the next cycle, and does nearly the same damage.
You sound doubtful, this is only MY experience. I'm an amateur! By all means, go out and try it and let me know how it goes. I also tried the manually operated wastegates... they worked next best to the electronic wastegate control. The BOV suggestion above, didn't work because even if the turbo is still spinning, you just lost all your boost. 15psi will be half the engine's power, which is more than the driver probably intended to limit in order to get traction back. My experience there is, on/off/on/off traction/slip/traction/slip behavior. The driver expects power output to be linear with throttle position - it's working for a few of us that way.
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If its done with retard I'am not trying it, but I do have that ignition, I streched enough valves last year but I thought you said retard then dropped cylinders, I thought you meant no spark by dropping cyls.
JL222
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If its done with retard I'am not trying it, but I do have that ignition, I streched enough valves last year but I thought you said retard then dropped cylinders, I thought you meant no spark by dropping cyls.
JL222
The 7 programmables I used, are configurable for either or both.
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My solution is this (so far):
1) Speed based boost controller from Hyper Kontroller (not time based like most other units).
2) FAST XFI boost controller using both the heurstiic and power adder modes. These need to be set so not be used unless you really miss the boost controller programming.
When the boost controller is set correctly, you won't need anything else. That is why I like turbo power. Boost = power not rpm = power.
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I am not sure if the I the SCTA rules are greatly different to the DLRA rules (http://www.dlra.org.au/rulebook.htm),
but.....
3.18 states.... “Entrants using anti-wheel-spin (traction control) devices are subject to a three (3) year suspension from DLRA activities.......”
Most of what is being described here seems to be “anti-wheel-spin (traction control”) other than the warning light which I would think is just traction “monitoring” not “control”.
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I am not sure if the I the SCTA rules are greatly different to the DLRA rules (http://www.dlra.org.au/rulebook.htm),
but.....
3.18 states.... “Entrants using anti-wheel-spin (traction control) devices are subject to a three (3) year suspension from DLRA activities.......”
Most of what is being described here seems to be “anti-wheel-spin (traction control”) other than the warning light which I would think is just traction “monitoring” not “control”.
It is allowed in the streamliner class under SCTA.
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I am not sure if the I the SCTA rules are greatly different to the DLRA rules (http://www.dlra.org.au/rulebook.htm),
but.....
3.18 states.... “Entrants using anti-wheel-spin (traction control) devices are subject to a three (3) year suspension from DLRA activities.......”
Most of what is being described here seems to be “anti-wheel-spin (traction control”) other than the warning light which I would think is just traction “monitoring” not “control”.
My understanding of rules and traction control is a device or controler sensing wheelspin and reacting to stop it.
If you are able to limit the power of the engine to prevent wheelspin is not the same.
JL222
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I developed a device I call the "Slipometer" and used it at the past BUB race. It tells how much the drive wheel is slipping by lighting up sequential green, amber, and red LEDs. It also shows wheel speed and vehicle speed in MPH and KPH. It is still considered to be in development, but it does work as designed. It will work on a bike or a car.
If anyone is interested in buying a Slipometer, I can have copies made.
At this point I am trying to guage the interest in marketing it, so if you are interested, let me know here or by email.
donpearsall@comcast.net
Here is a photo during test and on a run. I have videos of it on the bike but they are terrible quality.
Don
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Traction controll is not mentioned in the SCTA rule book. There was no way to police it so there was no way to regulate it.
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My understanding of rules and traction control is a device or controler sensing wheelspin and reacting to stop it.
If you are able to limit the power of the engine to prevent wheelspin is not the same.
JL222
I would say that is correct if you limit the “speed” it is really just a governor, so set the speed to 300mph put your foot down and hang on.
The only problem is if you get wheel spin at 150mph and they run up to 300 mph before the “governor” kicks in, things could get interesting.
If however there were sensors pick up the wheel spin and react to apply brakes, retard ignition, cut fuel, reduce boost or whatever we are back to traction control.
I do like the concept of Don’s Slipometer (have sent email) as I think this may well be best way round within the spirit & letter of the rules (well, DLRA at least)
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Traction controll is not mentioned in the SCTA rule book. There was no way to police it so there was no way to regulate it.
While I don't have much need for it, it was my understanding traction control was legal in SCTA also.