Autocross- SCCA EV-X Class vs. SS

[remulasce]

The reason I doubt it's the wheel sensors:

I ran hundreds of runs on 265 RE-71's and 265 PS4S's and never had this error before.
I changed to A052's and on the third run had this issue. It now happens every ~10 runs over multiple venues.
I've run 50+ runs on PS4S's since, 4K street miles on the PS4S's, and 300 street miles on the A052's, with no issues.
It only happens in very high power, turning, possibly slightly sliding conditions
It's happened turning left and right

What car and software are you running?

The car's stability control has sanity checks that trigger when inputs are outside its expected normal range. Ie. if a wheel sensor goes bad, it sees 0 speed on a tire as insane, and disables TC and throws errors. Unfortunately there's only a small window where it expects those inputs to be.

Mountain Pass Performance's Party Box has to report fake 'realistic' wheel speeds to defeat TC reliably, but even then sometimes the car will just sort of wake up and notice something isn't right. It sounds like you're hitting something, where it just doesn't its eyes on how hard it's turning, and triggers this failure mode.

 

[gearchruncher]

What car and software are you running?

M3P in track mode with stability control at -10, bias 50/50.
Whatever the pretty recent SW versions are over the last 2 months.

 

[GAGT]

What is everyone running as their wheel config? (I'm set as zero g)

275/35R19 A052's. Published diameter by Yokohama is 26.6"

Why are you running the zero g config if you are using 19's?

The reason I doubt it's the wheel sensors:

I ran hundreds of runs on 265 RE-71's and 265 PS4S's and never had this error before.
I changed to A052's and on the third run had this issue. It now happens every ~10 runs over multiple venues.
I've run 50+ runs on PS4S's since, 4K street miles on the PS4S's, and 300 street miles on the A052's, with no issues.
It only happens in very high power, turning, possibly slightly sliding conditions
It's happened turning left and right

Just to confirm. Ran 265 REs and PS4S without issue. Swap to 275 AO52s and now you have issues. But you HAVE NOT swapped back to PS4S or REs and experienced no cut in power with the same manuevers?

 

[gearchruncher]

Why are you running the zero g config if you are using 19's?

Because the car can't tell what size the wheels are. But it can tell the diameter, and grip. I assumed the Zero G was closest to a sticky 275/35/19 setup.

But Interesting note: I was wrong I was in the Zero G config. I had the car on one of the dark 19" wheel options. I set it to Zero-G before my runs this last weekend, and didn't have a single issue. That's not proof yet (although I never once made it one day without at least one run with an issue before) but I'll keep trying.

To answer your other question, I have switched between the A052's (275/35R19) and the PS4S's (265/35/R19) many times. Never had an issue with the PS4S's. I can't go back to the RE's as I replaced them with the Yoks. I do not switch wheel configs in the UI when I swap, so I've been running the same wheel config for a year now.

 

[superflyrolla]

I noticed Lincoln NE SCCA solo nationals EVX run days was recently announced for Thur/Fri Sept 8/9. It would be cool to meet some of you if anyone is thinking about going. It's the first year with an EV class.

 

[GAGT]

I noticed Lincoln NE SCCA solo nationals EVX run days was recently announced for Thur/Fri Sept 8/9. It would be cool to meet some of you if anyone is thinking about going. It's the first year with an EV class.

You want a tire warmer? I've been running a 350z in STU this year so not sure I'll transition that fast. Plus you'd have to convince my wife to let me go, got a friend's wedding in DC on the 10th.

 

[superflyrolla]

Probably not. I already offered to a friend who's having problems with this street mod Focus RS at the moment.

 

[Rodney!]

Just got SS legal 19" wheels, and 265/35 RT 660's. I hope they fit!

 

[jackmott]

Just got SS legal 19" wheels, and 265/35 RT 660's. I hope they fit!

oh man, if you could only get -2.5 degrees of camber in SS legal form somehow!! Get a few corvette tears.

 

[Rodney!]

oh man, if you could only get -2.5 degrees of camber in SS legal form somehow!! Get a few corvette tears.

I hope this thing doesn't go through tires like the old stock class minis...

 

[jackmott]

I hope this thing doesn't go through tires like the old stock class minis...

you might try the to loosen the strut tops, pry them inwards while re tightening thing

 

[SK360]

Destroyed yet another set of PS4S on just the inside edge. Anyone else running full front camber full time? I'm thinking this looks more like toe wear but we dialed it in for 0 toe on the rack. Wonder if I need to go back to swapping shims :|

 

[Zextraterrestrial]

@SK360 that seems odd. I run full camber all the time and have inner wear but not just the corner like that, much more into the tread.
that's on my 255 Comp2A all season tires on 18" though . 0 toe on rear and maybe <1/4" in total on front. ~3 rear camber >3front

 

[buckets0fun]

@SK360 what are your tire pressures?

How hot did the tires get after your run? You’re running a ~4100lb car on ~2inches of tread (when not cornering), if you drive many miles to your event like this you will see this happen to the tires. Especially if you have tire pressures in the oem recommended range.

 

[SK360]

@SK360 what are your tire pressures?

How hot did the tires get after your run? You’re running a ~4100lb car on ~2inches of tread (when not cornering), if you drive many miles to your event like this you will see this happen to the tires. Especially if you have tire pressures in the oem recommended range.

45. These are street tires not event tires

 

[SK360]

@SK360 that seems odd. I run full camber all the time and have inner wear but not just the corner like that, much more into the tread.
that's on my 255 Comp2A all season tires on 18" though . 0 toe on rear and maybe <1/4" in total on front. ~3 rear camber >3front

Yeah it’s odd, this certainly isn’t “normal” camber wear, I would expect normal tire wear just biased to the inside of the tire. I just ordered 19x9.5 wheels and will go with 265/35/19 DWS06+ for street use, I’m sure they’ll hold up better than the PS4S

 

[dsgerbc]

dialed it in for 0 toe on the rack.

How long ago? Maybe springs settled a bit, lowering a bit, and resulting in some toe-out.
Ever checked it with hand tools? Checking the toe is pretty cheap/easy

 

[SK360]

How long ago? Maybe springs settled a bit, lowering a bit, and resulting in some toe-out.
Ever checked it with hand tools? Checking the toe is pretty cheap/easy

March. Coilovers have been on for 15k miles. Going to get it on another rack

 

[buckets0fun]

45. These are street tires not event tires

Seems pretty reasonable for (what I assume) is the 15k miles you spoke about in the other comment.

May want to rotate the wheels front to back every 5k miles, if you wish to run this much neg camber. Pretty standard for our car to do this with -1.5 camber, zero toe front. It’s a heavy car not “using” the whole tire, accelerated wear is to be assumed.

 

[dsgerbc]

Those running RT660s, what pressures are y'all using?