Traction Control with Limited Slip Diff

[Siestarider]

Thanks McRib, your pioneering saved some of us a lot of useless endeavor. Plus your really cool track build on its own merits.

I have 50,000 lines of tracking data recorded every 0.05 sec Sunday to try and understand how Quaife LSD and TVC are interacting. Spent couple hours last night x-reffing data to track position in turns, main interest is power exit, but wheel speeds and throttle position data are not disclosing brake intervention secrets in any pattern I can see yet.

 

[RAAMaudio]

Posted on another thread but important here as well so....

Since the TVC is for some reason associated with the SRS disabling it may not be a good idea as it might be safer than not running SRS on the track without at least a roll bar, proper race seat, etc....

I am planning to use the Schroth Pro Quick Fit harnesses, race suit and underwear, shoes, socks, low weight very good helmet...I own all that except the harnesses, looking at the pro so I can use a neck support as well.

 

[carramrod]

There must be a way to link Harry's Lap Timer to Accessport log data. If there is, it would be a lot easier to identify the specific turns where TVC is intervening, both where and for how long, whether using LSD or not.

www.racerender.com can take Harry's data, any video, and then your AP logs.

 

[McRib 1s Back]

If it would of worked I would of had one long ago I promise you that, sure wish it was so

I just thought of something, if I provided the wiring schematics of both cars I could compare all the signals and if labeled the same it might be a simple pin change on the connector. Even if not labeled the same I might still be able to figure it out.

Somebody provide the schematics, I will dig in and see what I can find out

Rick
USN Retired
Data System, Fire Control Tech

Hey Rick, on a somewhat related note, I have the Ford factory Wiring Diagram for the FiST. It's very proudly priced (but very good)! I needed it to figure out the TVC "trick" and to sort out very basic ignition problems! The factory fuel pump is in-line with some emissions equipment (and why I had the new low pressure fuel pump wired in directly to the battery via fused link). It's worth buying if you need the information. It was also handy to figure out how much of the factory wiring can be hacked out. The answer is "lots", but beware the CANBUS!

 

[RAAMaudio]

I might have to get a copy

I pulled 20 lbs of wiring, misc brackets, etc out from under the dash on our Scion TC project(265lbs lighter than stock with full interior except carpet where back seat used to be, caged, two race seats and harnesses, foam filled chassis, race/street/audio comp built, 15" sub, won sound quality comps....)

After I was done and carefully went wire by wire the car would not start and other issues and none made any sense at all as most dead end crap or went back and forth across the car for no apparent reason other than generic harness used in other cars and or markets.....it took three long days to get it all sorted out and I have a huge amount of electronics experience on very serious gear.

Nothing I hooked back up had the slightest hint of needing to be there but it worked when back in place.....full factory manual was used.....

I will be careful and test each step of the way if I do any such work on this car!

Thanks
Rick

 

[McRib 1s Back]

Posted on another thread but important here as well so....

Since the TVC is for some reason associated with the SRS disabling it may not be a good idea as it might be safer than not running SRS on the track without at least a roll bar, proper race seat, etc....

I am planning to use the Schroth Pro Quick Fit harnesses, race suit and underwear, shoes, socks, low weight very good helmet...I own all that except the harnesses, looking at the pro so I can use a neck support as well.

Thanks, I agree -- this is an important topic.

Many OEMs put their rotation sensors in the SRS module. In turn, the SRS module is in the safest part of the car, and best place to measure rotation around the y-axis (center and low). This is why it's so common. So, TVC needs this information to make decisions. I have found that a prepped car really messes with the system's ability to make timely decisions. What worked really well on the street and light levels of modifications is simply wonky on a race car!

For a fully prepped car, defeating SRS isn't a problem. This is a very bad idea for a street car, and probably not a good idea for track use if you don't have other racing restraints (I.e., you want airbags in a crash if you don't have a racing seat/harness/cage).

 

[RAAMaudio]

Air bags, the good, the bad and the ugly, saved lots of lives, took a few as well, quite a few serious injuries caused by them

I have removed them from several cars but with this tiny little car I planned to keep them and part of why I did not swap to lighter seats than the Recaro seats. I also calculated that with fixed back seats comfortable enough to use on the street, mounts, sliders, seat heaters and lumbar bladders(last two are very low weight high grade parts I already own) It would only save around 16lbs total compared to the Recaro seats so not worth it and pretty much in the middle of the car, most weight down low, not a big effect on the handling. There were better ways to spend time and funds to make the car faster and far more comfortable with the Recaro seat than fixed back seats on the street, been there and done that to many times

---------

I am quite concerned so a bit of this is talking myself into it being OK to not have a roll bar or better yet a cage but my car is very fast on track, much faster than many lower speed race cars and includes cornering and braking ability as well so I just have to learn to real myself in a bit and not go 100% like I am used to.



I will be about as safe as possible without a roll bar or cage with the mods, safety gear, etc, on the last post a roll bar just did not work out though wish I had one. This rounded, small design and high strength steel likely in the pillars the car is pretty dang strong so should hold up well in most situations so if I ever have a serious off I hope to not land in a bad way.

I would not consider a neck support device if not for using the Schroth harnesses as they are designed to let you submarine in a roll over but not so in a frontal crash.

I will probably get some arm restraints as well as recently about a highly skilled nerosurgen (spelling?) that lost his lucrative career when his hand was crushed in a roll over at an HPDE.

 

[Hijinx]

I'm bumping this thread because it's important for people who are thinking about buying an LSD to understand the nuances of the car.


Sent from my iPhone using Tapatalk

 

[Cligedy]

I added an update to my STX build thread about the TVC intervention after a diff install.

I don't have any data logging on braking/ duty cycle so I can't claim exactly how often the TVC activates with or without the diff. What I did do was record temperatures after autox runs with a IR temp gun. With the diff installed, it is obvious that the brakes are much less active, indicating that my torque biasing diff reduces or eliminates TVC intervention (I expect large reduction, not elimination).

All of these runs are done with all nannies off as much as allowed by the stock FiST, no fuses or sensor removed/ altered. The idea that the airbags need to be disabled to make the car compatible with the diff seem not to be true.

 

[M-Sport fan]

IF the air bags are really/actually tied into the TVC/ESC systems, does that mean that if the air bags were totally disabled by aftermarket seat/steering wheel replacements, that the TVC/ESC systems are ALSO totally/permanently disabled??

 

[Ballzley]

Bumping in for interest

 

[nickstewartroc]

Hey, all. I'm wandering in late on this thread -- I noticed a few references to my car (which is the MotoIQ project car) and thought I'd post to make sure any issues were cleared up.

First, the FRPP ABS Module is not a direct replacement. It is made for the previous generation B Spec racer. It wasn't until I contacted Ford Racing that they yanked the part for our FiST application. It's a project, and I'm done with that part for now...

...because I have figured out how to kill TVC while preserving ABS! It's detailed in my project car thread, but the short version is that you yank both SRS module connectors. It's in the center of the car, under your center console. It's a real pain to get at if your car isn't already gutted. Yanking those connectors will disable your airbags and TVC/ESP. My car is a dedicated track car and doesn't have airbags. I am not recommending this for any street car.

On a final note, there does not appear to be any way to control TVC with the ECU. By design, it's a discrete function.

Sorry to bring up an old thread, would the two connectors be the C310A/B listed in here?: http://www.nicksmustangranch.com/Se...ng_Diagrams/Supplemental Restraint System.htm