I stumbled across this site:
www.enginebasics.comand this article on traction control:
www.enginebasics.com/Advanced%20Engine%20Tuning/Traction%20Control.htmlSome hi-lights:
At this point I just thought the car was going to lead to my early death, and to be honest wasn’t as much fun to drive as some lesser horse power cars, because I had to always be VERY CONCENTRATED on my driving.
A buddy of mine picked up a 700+ WHP car that he said was VERY easy to drive. He went even so far as to say he would even let his wife drive the car if the traction control was set on the “wife” setting he called it. I had to know more.
He introduced me to the Racelogic Traction control. A unit that can be fitted to most modern day EFI cars. He daily drives this monster car and I still remember the day he came over with a light dusting of snow on the ground and told me I had to drive the car to really fall in love with the racelogic box. Well, once I did I had to have one. Flat footing a 700+ HP car in the snow is a HOOT! The drivability in even the slickest climate was just unreal.
Safety aside, the performance is unreal. I can see why traction control was so big in Formula One ( F1) racing. These guys are supposedly the best drivers in the world and they have traction control on there cars. No matter how good of a driver you think you are, a traction control set-up will only make you better. Personally it has made my car incredibly fast in corners and in straights. The traction control can modulate the power so well that no human could react that fast to what’s going on.
PLEASE DO NOT CONFUSE THE RACELOGIC TRACTION CONTROL with an OEM traction control on a car. While some of the sports cars like the Nissan R35 GTR and the Chevrolet Corvette are coming from the factory with very nice OEM TC units, they still cannot be tuned or dialed in to be just as good once the owner starts to modify the cars engine and tire sizes.
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That's the type of performance I'm hoping for with my FAST XFI traction control feature.
Inputs, Racelogic:
> The racelogic box wires in to the cars factory ABS wheel sensors, or if
> your car didn’t come equipped with ABS, can be wired to 4 wheel speed
> sensors that can be purchased separately.
Ouptuts, Racelogic:
> The other major wiring is cutting into the factory fuel injector wiring.
> This wiring is not taped into, but instead cut fully so that the Racelogic
> traction control box can fully intercept and modify the signal from the
> factory ECU to the fuel injectors.
(both quotes from page referenced above)
Inputs, FAST XFI:
> wheel speed through the use of a driveshaft collar or your vehicle speed
> sensor – if equipped with an electronic transmission
www.dragzine.com/tech-stories/ignition-electronics-efi/inside-fasts-xfi-2-0-hardware-and-software-tuning-features/Outputs, FAST XFI:
> ...is implemented through either timing or the rev limiter. “The timing
> anticipates wheel spin and if it sees that, it’ll start pulling timing out to
> try and stop it,” explained Winstead. “If you actually exceed the
> driveshaft curve, it’ll start cutting cylinders. And the further you exceed
> it, the more cylinders it’ll cut, until the point that it’ll actually shut the
> engine off if you far exceed the driveshaft curve from tire spin.”
both quotes from
www.dragzine.com/tech-stories/ignition-electronics-efi/inside-fasts-xfi-2-0-hardware-and-software-tuning-features/Racelogic has a sensor on each wheel, while FAST has one sensor for the driveshaft.
Racelogic cuts cylinders, while FAST cuts timing, then cylinders.
It appears that FAST XFI traction control is designed for drag racing:
> Say you’re going to be doing some heads-up or bracket racing and the
> track is real greasy...
www.dragzine.com/tech-stories/ignition-electronics-efi/inside-fasts-xfi-2-0-hardware-and-software-tuning-features/because I found little about it being used on the autocross.
There are no user-adjustable controls while driving.
While racelogic seems to be designed for all-purpose driving:
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Slip levels are adjustable in 1% increments from 0% up to 25%, and launch control comes as standard. Cut level thresholds, rev limits, wheel sizes and RPM operating levels can all be altered in real-time
The Standard Traction Control system has six degrees of operation, which equate to degree of oversteer in RWD application and degree of understeer in a FWD application. The Six levels are 0% wheel slippage (Wet conditions), 5% (Dry), 10%, 15%, 20% and off.
Setting a RWD vehicle to 5% in the dry will deter the rear end losing traction and a tail slide occurring. 5% in a FWD car will deter excessive understeer.
If the weather conditions deteriorate whilst the car is in use the system can be adjusted whilst in motion down to the wet setting and 0% wheel slippage, making the car much safer to drive in adverse conditions.
The throttle can be fully depressed without over-revving the engine. The car is put into gear, the throttle floored, and then the clutch is engaged, whilst the launch control system controls the wheelspin and revs for the perfect start.
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www.racelogic.co.uk/index.php/en/other-products/traction-control?start=5This post points out that racelogic requires high-impedence (factory style) injectors:
> If you have an ECU that uses low impedence (high current) injectors,
> the RaceLogic setup will NOT work.
www.ffcars.com/forums/17-factory-five-roadsters/286188-traction-control.html#post2615489and this is documented in the racelogic manual:
> 1.4.6 Injector Resistance
> Ensure that the injectors are not of a resistance lower than 4 ohms as
> the traction control cannot cope with the amount of current driving
> such injectors.
> In general terms Racelogic Traction Control is only compatible with
> standard high impedance injectors.
www.racelogic.co.uk/Forum/showthread.php?p=4857And FAST doesn't sell high-impedence injectors with the flow-rate I need:
> High-impedance injector models available up to 60lb/hr for trouble-free
> OEM computer compatibility
>
> Low-impedance* injectors available up to 160 lb/hr for maximum
> performance with aftermarket EFI systems, such as the FAST™ XFI™
> system
www.fuelairspark.com/Products/details/injectors/over.aspBut it seems that racelogic can use high-impedence injectors:
> Actually it can be done - Dan at Advanced Motorsport and Engineering
> supplies such a thing when he fits a TC system to a heavily tuned car
> that is running low impedance injectors.
> Give him a call:
www.advancedme.co.ukwww.racelogic.co.uk/Forum/showpost.php?p=4855&postcount=3And one can buy low-impedence injectors with high flow rates:
> If you wanted to source large capacity low impedance injectors,
> 'Injector Dynamics' produce some good kit
>
www.injectordynamics.com/ www.racelogic.co.uk/Forum/showpost.php?p=4854&postcount=2Injectordynamics has some wild vehicles using their injectors:
> Worlds Fastest Motorcycle, and first to break 300mph barrier with a
> 311.945mph run.
www.injectordynamics.com/coolpics.htmlHere's a guy racing on racelogic:
> I've autocrossed a 1991 240sx with 450whp and a really laggy turbo.
> This car had no Race Logic the 1st time I drove it, and you absolutely
> had to be sure the car was pointed straight ahead before the turbo
> kicked in, or it was pointing the wrong way in no time.
>
> The next time I drove it, it had Race Logic, and it was a totally different
> car. I could basically have the throttle wide open any time I wasn't on
> the brakes, and the Race Logic did the rest. Even in the wet, it was like
> I was a superstar. 180 degree sweeper with my foot to the floor, and
> the back end was stepped out about 12" and just stayed there.
forums.bimmerforums.com/forum/showpost.php?p=23877965&postcount=211> Davis Technologies makes a traction control that just reads the rpm's
> and retards the timing very fast to reduce HP and wheel spin.
www.ffcars.com/forums/17-factory-five-roadsters/286188-traction-control.html#post2614139> ...this Patented system looks for spikes in RPM that are caused by
> wheel slip. If these spikes are large enough, then a correction is made,
> reducing the slip.
www.moretraction.com/howdoesitwork.htmIt seems to me that as an input to determine if there is wheel spin:
- great: wheel sensor on each wheel
- good: driveshaft sensor
- poor: engine RPM
This thread:
www.lateral-g.net/forums/archive/index.php4/t-26665.htmlpoints to this page:
www.racetronics.net/Copy_2_of_Racetronics_Web_Site/Facts.html> NOTE: Being able to detect wheel spin without detecting the speed of
> the car (eather by GPS or a front wheel sensor) is simply ridiculous.
> FACT: To monitor an engine rpm increase and guess that it is caused by
> wheel spin, is very inaccurate.
www.racetronics.net/Copy_2_of_Racetronics_Web_Site/Facts.htmlGPS would seem only possibly useful in a drag-racing situation. And the Davis setup seems just for drag-racing:
> Davis has either open loop (fixed) rate of acceleration or closed loop
> (self learning) where the unit learns the rate of acceleration between
> pulses and can keep the car on the ragged edge of traction. These
> rates are different as the car moves down the track..
www.theturboforums.com/smf/efi-tuning-questions-engine-management-and-other-voodoo/traction-control-units/But I did see a giant ray of hope that the FAST XFI will provide acceptable autocrossing traction control.
Here's a nicely built 427 Cobra replica with it:
www.anitafred.net/Cobra.htm-----
Cobra Roadsters are notorious for having traction problems due to their high torque and light weight (typically about 2300 lbs). The latest FAST XFI computer systems with ETC use a driveshaft speed sensor to detect when the rear wheels of the car are slipping via a sudden jump in driveshaft RPM. In these situations, the EFI computer automatically retards the ignition timing to reduce the motor's torque and stop the rear wheel spin before it gets out of hand.
The Cobra drive train is not a standard one so we had to fabricate a custom driveshaft sensor for the car. Bob Moran at JRM Machine in Hollis, NH started with a standard flying magnet driveshaft sensor and collar and fabricated a new collar for the magnets to fit ERA's driveshaft and differential yoke. You can see the custom flying magnet collar that he made along with the pickup sensor installed on the front yoke of the differential below. This arrangement requires a slightly shortened version of ERA's standard driveshaft.
We are using a driveshaft speed sensor with the XFI to implement electronic traction control as well as to implement recording of vehicle speed, tire slippage and gas mileage.
We are using an accelerometer which is a sensor that allows the FAST XFI computer to measure and record the acceleration/braking, lateral, and vertical G-forces that the car is experiencing. I expect that this will be a useful tuning aid for the electronic traction control and other handling adjustments.
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I'll give him a shout and see how it turned out.