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
