RallyCross tough on drivetrains?

In reply to Pete. (l33t FS) :

Yeah, forgot that

TVC is not ATC.  You can turn off the ATC but not the TVC.

Never heard of hitting the brake reducing power, the ATC does when activated.   Of course braking reduces power by increasing the load .  That is why you have to increase the power manually.    Why I never liked it.

The FiST has nice closed throttle oversteer.

TVC= Tourque vectoring control.    Applies brake to inside wheel to reduce undesteer.   Does not slow the car.  Not turned off with ATC

ATC= Advanced traction control. Applies brake to spinning wheel/s. Reduces power.   Can be turned off on the FiST.

Info taken from Ford Fiesta ST supplement.

Basically every new model car will cut power if both accelerator and brake are hit simultaneously to prevent unintended acceleration.  That's what I was referring to.

On the fiesta it allows for about 2-3sec of brake/accel before cutting power. So if you are left foot braking, without lifting accelerator, power will be cut to near zero after 2-3sec from applying the brake.  If you lift accelerator to 0% before 2-3sec the timer resets.

I'll have to try it.

1.5 hrs later.   I learned something new.   Really quick

When I was ice racing , I used a rear hand brake, Ie: parking brake with lock disabled ,when needed.

engiekev said:

Basically every new model car will cut power if both accelerator and brake are hit simultaneously to prevent unintended acceleration.  That's what I was referring to.

On the fiesta it allows for about 2-3sec of brake/accel before cutting power. So if you are left foot braking, without lifting accelerator, power will be cut to near zero after 2-3sec from applying the brake.  If you lift accelerator to 0% before 2-3sec the timer resets.

One should probably not be left foot braking for that long, I wouldn't think.  Heck I can't think of any rallycross situation where you are on the brakes more than a half second, maybe one second tops.  There's never any speed to scrub off.

FWIW, the Bosch Motronic 7.1 in my Volvo will happily let me go WOT on the brakes until the ABS sets a brake rotor overheat code.  At which point I stop.  This takes about ten seconds at 70mph, applying enough brake to keep the car from accelerating.

i think the abs module from the b spec fiesta kit solves the left foot braking issue

In reply to MrChaos :

Hmm...  Would that be considered part of the braking system, or part of the drivetrain controls?

In Prepared brakes are free, but electronic drivetrain controls can be reprogrammed or piggybacked but not replaced.  If that came up to a protest that would be a tricky one because the purpose of the mod is to affect the throttle engagement, which is drivetrain programming.  If the ABS computer affects the throttle output then it is part of the powertrain management.

Disabling the brake light switch is A-OK though.

In reply to Pete. (l33t FS) :

The last really muddy event I found it necessary to left foot brake that long in the Fist to help keep the inside front from spinning, there was a lot of low speed almost hairpin corners that event.  Even with the e-LSD braking it still would spin the inside tire almost immediately with even light throttle. I was on snow tires though and others with rally tires seemed to be doing better.

A friend tol me that tires like Blizzaks tend to load up with mud and then lose traction.

iceracer said:

A friend tol me that tires like Blizzaks tend to load up with mud and then lose traction.

(not sure if you're being facetious, so will assume you're serious) :)

Tell your friend there are a bunch of different Blizzak variants, and that it's an entire line of winter tires, not "a tire," just like there are a bunch of different Potenzas or Wranglers.  Some variants are better than others for different conditions, just like any class of tire. But, seems the most popular snow tires for rallycross are the Altimax Arctic (General) followed by the Firestone Winterforce (which have mush for sidewalls and I woudn't recommend). I don't see many people out there using the various Blizzak models, mostly because they cost more than the Alti and WF, so why would you?

All snow tires load up with mud if you're running in certain types of mud. The siping is counterproductive in mud, in my experience. Plus they generally have rounded shoulders which pretty much suck for turning bite in soft conditions (rally tires and mud tires have vertical/squared shoulders). Snow tires you can cut out every other block to make them a bit better at clearning the tread though. I did that to a pair and it seemed to work ok. 

irish44j (Forum Supporter) said:

iceracer said:

A friend tol me that tires like Blizzaks tend to load up with mud and then lose traction.

(not sure if you're being facetious, so will assume you're serious) :)

Tell your friend there are a bunch of different Blizzak variants, and that it's an entire line of winter tires, not "a tire," just like there are a bunch of different Potenzas or Wranglers.  Some variants are better than others for different conditions, just like any class of tire. But, seems the most popular snow tires for rallycross are the Altimax Arctic (General) followed by the Firestone Winterforce (which have mush for sidewalls and I woudn't recommend). I don't see many people out there using the various Blizzak models, mostly because they cost more than the Alti and WF, so why would you?

All snow tires load up with mud if you're running in certain types of mud. The siping is counterproductive in mud, in my experience. Plus they generally have rounded shoulders which pretty much suck for turning bite in soft conditions (rally tires and mud tires have vertical/squared shoulders). Snow tires you can cut out every other block to make them a bit better at clearning the tread though. I did that to a pair and it seemed to work ok. 

Firestone winterforce also changed their design recently.

The fastest of the day at our last muddy event was a Front Wheel Drive car, older civic hatch, with heavily grooved Cooper Weathermaster winter tires.  Those tires already are very "blocky" to begin with compared to any Blizzaks:

Cooper ST2

Blizzak WS80

Kind of off topic with the tire discussion but figured it was still relevant.

OP I would just start driving in events with the tires you have, really any cheap winter tire is great to start with.  Seat time is more important than tire selection when you're in a new car or first starting out.  Any tire you run isn't going to affect drivetrain wear to answer your original question.

Yeah, the winterforces were the best snow tire option for mud use with the super open tread pattern and soft sidewalls. But they've been out of production for like 3-4 years now, not sure if anybody has stock left, and even then they're still four year old tires which isn't great for the compound. I've never run those coopers but I've seen other people have success with them and the tread pattern looks decent. If we'd stayed with it long enough to run through our set of witnerforces we were probably going to give those a try. There's aso a uniroyal option I think that had a better looking tread pattern than most of the current designs, but we couldn't find evidence of anyone running them with success (or at all) and didn't want to take the risk on the compound sucking. Something like the generals or new winterforce are probably the right choice for an all around rallycross/actual street driven winter tire, but they're going to suffer some on looser surfaces. Unfortunately, the things that make tires good on loose surfaces make them suck on the street and on harder rallycross surfaces, so you have to pick which one you care about more.

FWIW, a pair of my Altimaxes I squared the edges with a groover (to use on my front wheels on a RWD car for better turn-in in soft stuff). But the square edges don't hold up long.

Cutting a tire is the fastest way to make it wear out, for some reason the cut edges wear down way faster than moulded ones.

Pete. (l33t FS) said:

Cutting a tire is the fastest way to make it wear out, for some reason the cut edges wear down way faster than moulded ones.

My cut ones are specifically for mud conditions, so they don't really wear down like they would in dry stuff. I rarely use snow tires for anything in rally or rallycross unless the temps are below freezing though. 

In reply to irish44j (Forum Supporter) :

I tried sharpening some worn out old tires, they wore much faster.

I go by "worn out" = the edges are rounded.  That was a habit I got from mountain biking where you could really feel the difference between new, and rounded off.  Maybe it flies in the face of compound being important, but maybe tires that are old enough to get rounded are also heat cycled out?

For mud nothing seems to matter until you have actual paddles for tires, everything packs up and turns into a slick unless you can keep the tire spinning itself clean.  Hell for a rear driver but front drivers just fly when it is muddy...

The FiST is a great car to rallycross we have several in the Central FL region.   Great platform and very quick.   According to Team O'Neill the E diff is actually quite good so I wouldn't be super in a hurry to change it out for a mechanical diff.   Here's a 360 video I took from the passenger seat in one of our local FiSTs.