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08-10-2019, 01:02 PM #1
Turbo & Traction Control: Any issues with pulling timing?
As the discussion started up with the new MS3 Pro PNP the mention of traction control grabbed my attention and since I'm running the MS3 Pro (non - PnP) I decided to look into getting it functioning on my setup. The MS3 Pro offers multiple ways to kill power when the TC is activated but is there any issues that I should be worried about if I choose to pull timing?
The car is a 2002 GT, 900hp, TT 2V, 32psi boost, E85 with 4R70 through full length exhaust and the car made the most power with only 14* of timing at WOT. I have the boost dialed in at 32psi at all times.
My concern is whether it is hurting the engine if the timing is pulled enough to get traction? Is there anything I need to worry about?
On a separate note I am still researching the sensors so if anyone can answer the below it would also help:
1. I will use the stock front ABS sensor on the front wheel. Is this a hall effect or VR sensor?
2. Trans is a 4R70 and I want to connect the drive signal to it but not sure what type of sensor it uses or the tooth count it has?
08-11-2019, 10:00 AM #2
Of the different traction control methods, by far the smoothest on the drive train is the progressive timing retard, Kevin. Most all the other approaches beat up the drive train to the a greater or lesser extent. Take a look at this ProEFI Traction control video at the 1:53 second mark where they demo the ProEFI traction control. Click here => ProEFI Traction Control for the video. The alternating tire slip scuff marks and no scuff marks on the pavement along with the on/off quality of engine power management destroys engines and drive train parts from the input shaft on your transmission all the way out to the axle shafts in the rear end. It is identical to the damage a two step does at launch.
That type of approach to wheelsman control is a parts killer. The staccato application and removal of power is devastating. By way of contrast the MS3Pro logic will monitor wheel slippage you have programmed and reduce timing to get below the that slip target you specified, Once below the specified wheel slip target it will gradually increase timing watching the wheel slip percentage to prevent an out of control tire spin situation.
When you use this style of traction control you can take the tire right to the limit of traction without incurring wheel spin above your targeted number. If you watch NHRA Top Fuel on FS1, when the crew chief gets the clutch right the car will do what they call black tracking from the launch almost all the way to the lights. When you are black tracking with a tire you are right at the limits of traction. By achieving this with a smooth roll back of the timing you are smoothly adjusting the engine power to the available traction with out hammering engine or drive train parts to control wheel spin.
Whats even better is that the system is not road condition limited. Irrespective of how good or bad the road surface the triggering event is the tire slip percentage you have specified. Once you reach that threshold the ECU begins to roll back timing to smoothly manage the wheel spin.
With respect to the sensors I am not sure but a call to the FRPP hot line can easily get the information. Rather than using the pickup on the transmission I would use the pickup on the rear wheel. By using the front tire and rear tire you are capturing the data right at the source. When you use the transmission there is the potential to introduce noise into the data attributable to the backlash between the ring and pinion, axles and side gears and anywhere there is a connection in the drive train that has a clearance. In real life the clearance may not really make a difference but as long as we have a wheel speed sensor associates with each wheel why not use them instead of re-inventing what is already there?
08-11-2019, 10:24 AM #3
Thanks for the info, Ed.
Pulling timing certainly seemed like the smoothest method to me compared to cutting spark, I never liked that idea. I read on some forum that when timing is pulled there could be a concern about valves running hot or ?? but the MS has the ability to add fuel to cool them. If pulling timing can cause damage due to heat then adding fuel seems at first like a good method to keep things cool but adding extra fuel also seems dangerous. I know anything can happen but is there a concern from pulling timing that should be addressed?
Currently both ABS sensors are gone and the custom rear axles don't have the ABS ring anymore. I can't remember if these axles were machined for a ring "just in case". I know it was discussed at the time. Using the trans sensor would be easy to wire into (Quick4) but I may be able to design/laser cut a ring for the wheel (or driveshaft - backlash bad) if it minimizes any tuning issues.
I went back to my emails about the axles and we tried to get them machined to maintain the ABS rings but Moser couldn't make them to maintain the rings. Have to think of another method if the trans sensor may not be the best method.
Last edited by KEVINS; 08-11-2019 at 10:59 AM.
08-11-2019, 12:41 PM #4
If you run the engine short of optimum timing it will run hotter. How much is determined largely by the amount of time you choose to operate that way. When we are talking about traction control we are down in the seconds category and operation at reduced timing is likely to have no measurable impact on operating temps. I wouldn't worry too much about the overheating or additional fuel requirements — it is essentially non existant because the time duration is too short to matter.
The lack of ABS ring support on the Moser's raises the difficulty factor by a small amount. You want to try to get the driven wheel speed sensor as close to the driven wheel as possible. The next most attractive location would be on the pinion drive flange by fabbing a ring to either press onto the drive flange OD or sandwich it between the rear u-joint and the drive flange. After that I would go to the electronic speedo output on the transmission. If there is none then there are adapters that fit the mechanical speedo take off that can convert to an electrical signal.
08-11-2019, 05:31 PM #5
Thanks again. I got an email from my tuner and he's used the MS traction control many times so he's familiar with it all. For the rear sensor he's used lug studs before and on his 1100hp vette apparently he uses the CV boot clip as the reluctor with good results..go figure.
08-11-2019, 11:12 PM #6
08-12-2019, 09:48 PM #7
Thinking about this some more... I'm concerned that I may also need to bleed WG dome pressure but not sure at this time how to wire it up since I use Eboost2 for boost control - maybe a separate solenoid....??
Also, I run 14* max timing, 32psi and I'm not sure that the TC can pull enough timing/boost to get the tires to grab, at least w/o hurting the motor (?). On WG springs alone it makes 17.5psi and 840hp so it seems to me that it would have to pull a LOT of timing to get traction... Thoughts?
08-13-2019, 01:22 AM #8
Kevin, the single most important variable in power production (for any given engine configuration) is timing. If you leave the engine with a correct max-power fueling model and begin to pull timing, the only thing that happens is torque goes away. When you are launching it is the torque that gets the show on the road or gets you into trouble spinning the tires. I guarantee you if you pulled the timing back to TDC (0˚ advance) you would see a massive reduction in engine torque — without any damage. The only thing you would have done is make the engine wimpy.
Although you could try to do the same thing with reductions in boost the precision and granularity available in the two different approaches strongly argues for the variable timing approach. It is true that if you daily drove a car with retarded timing you would raise exhaust temps very likely to dangerous levels. On a drag car, that will be running for only a few seconds and of those few seconds perhaps one or two will be associated with reduced timing, you will be hard pressed to see any measurable temp increases especially ones that are capable of damaging engine components. The reduced timing does not last long enough and does not contribute enough heat energy during its short lifespan to make a difference.
BTW when you see ProMods with TH400 3 speeds and converters, the only way they can control the car in first gear is to pull timing. Once launched they roll the timing back in the same way you would with the MS3Pro Traction Control.
Last edited by eschaider; 08-13-2019 at 09:14 AM. Reason: Spelling & Grammar
08-13-2019, 06:50 AM #9
Ok, I'm convinced.. I'll adhere to my own advice and just KISS.