Traction and Launch Control
I was headed down the Race Logic path up until the point they stopped manufacturing. Plan B was the Holly Dominator ECU with Holly/Davis traction control. However, after I did a little research I discovered that their approach is to compare crankshaft acceleration to a configured threshold. From their site:
"Basically, 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."
So it's an open-loop system and it doesn't have a clue what any of the wheels are actually doing. In the end it's the wheels that matter. Modern ECUs have a lot of processing power and software guys are extremely good at algorithms (yeah, I'm a software guy). Since we're talking about a rear wheel drive SL-C the front wheels provide very good road speed and the rears provide drive speed. So Davis system looks at RPM whereas all of the others that I'm aware of look at all four wheel speeds (and perhaps RPM).
Traction control sits somewhere between improving your lap times to saving your bacon. RPM provides a good idea of what the wheels might actually be doing and Davis Technologies has obviously been very successful with drag racing and truck pulls. However, when it's my bacon in the seat I want those decisions made by a closed system with all of the relevant data.
My plan C is a MoTec system. Hopefully plan D is not needed!
Wheel Speed Sensors
The biggest challenge with installing...
a reluctor wheel cast in the inboard side of the front spindle?
Mesa, good point . I should have mentioned that. According to pnut he can see a reluctor inside of his hub (mine has a metal dust cover, so I can't tell). In any event, the location of pnuts' reluctor would require the upright to be machined. The MoTeC sensor has a threaded 3/8" body and, IMO, would compromise the upright. If the reluctor were located between the upright and wheel flange or if the upright could be machined without compromising it, that would likely be the easiest option.
a reluctor wheel castIn any event, the location of pnuts' reluctor would require the upright to be machined. The MoTeC sensor has a threaded 3/8" body and, IMO, would compromise the upright. If the reluctor were located between the upright and wheel flange or if the upright could be machined without compromising it, that would likely be the easiest option.
I know that I could count wheel studs, but there are only five which is below the minimum recommended by MoTeC and the flange on my wheel hubs have three large holes that I think would interfere with the sensor. I considered using the bolts on the Brembo hat, but there are only 10 which is a fraction of most OEM reluctors, not to mention that those bolts are really close to the rotor cooling vanes which are going to get hot.
I’ve been looking for a reluctor that could be mounted to the round hub flag via spacers/standoffs. It may need to be made from two parts because a single-piece one would need to slip past the rectangular flange that mounts to the upright and I’d estimate that it would need to have an ID of ~4.5”. I could design my own, but I wanted to see if anyone had solved this problem already or had any ideas of an off of the shelf one. The reluctors below have integral standoffs. However all of the ones that I’ve seen spec what cars they fit, but don’t provide and dimensions.
HS230 MoTeC Hall Effect Sensor $171.00
HS230 Hall Effect Sensor
- Body Thread: 3/8-24"
- Input Voltage: +4.5 TO 24 VDC
- Output: Open Collector NPN with internal 4.7KΩ Pull-Up
- Frequency Range: 0-12 kHz
- Airgap: 0.030" - 0.060"
- Operating Temperature: -20° to 140°C
- Vibration: 15G, 10-2000 Hz
- Internal reverse polarity protection
- DTM4S Termination
- Top rectangle: 4.0"
- Flange Thickness: 0.32"
- Hat Thickness: 0.35"
- Flange Diameter: 5.5"
- Reluctor Ring Jig
- Custom rings in UK
- Some Specs
- Solid big rings
- Volvo 90mm (3.54") ID link
- Imprezza 100mm(3.9") ID
- 160mm (6.299") ID, no mounting points? link
- 6.77" no legs link
- Hub: http://www.zip-corvette.com/blog/corvette-parts/corvette-timken-wheel-bearinghub-assemblies-for-c4-c5/