034 RSB, tire pressure, and traction control settings - looking for advice

[spaparizos]

Only way to be 100% certain you are using the proper pressures for the conditions is by using a tire pyrometer. Outside of that, I would say wear observations are likely the next most objective. Optimum hot temps vary by tire, but @Will_'s shared some really good advice as a starting point.

Lap times and feel likely not good indicators unless you are putting down extremely consistent lap times or are a very experienced track driver.

So what to do when pyrometer shows the outside edge too warm and wear is at the tip of the triangle ? Increase pressure? Leave it as is ?

Assume cannot modify camber any further.

 

[JackRabbitSLIM]

I love a good internet argument but most of the tire pressures suggested here probably end up at 40PSI +/- 2 once they're hot, so I'm not sure what the point of it is. I'm not a pyrometer fan either, just saying.

OP, you're going to have wheel spin in a car with no diff, no way around it unless you use XDS. I suggest turning XDS off though because of brake temps. Just drive around the wheel spin. If you are actually a new track driver, it's really good practice for how to balance power on throttle application and it'll help you in corner exit in any car you drive.

Submit to the car gods, get an aftermarket diff (and clutch)...see what you've been missing...

 

[tpellegr]

So what to do when pyrometer shows the outside edge too warm and wear is at the tip of the triangle ? Increase pressure? Leave it as is ?

Assume cannot modify camber any further.

If you increase pressure in that situation, my thought would be that you'd be overinflating the tire to compensate for camber gain in the corners. When only outside or inside temp is affected it is likely not a tire pressure issue but an alignment or suspension issue. In this case, since you said you are at max static camber, I would guess you need to increase roll resistance to reduce camber gain during cornering. You could definitely increase your pressure to reduce wear on the outside of tire but then you'd likely be reducing grip every other place on the track outside of the hardest corners where you were getting the excessive rollover. Like David said, it's tough to lock in a good suspension setup and everything works together so testing is important. Simply finding a tire pressure that optimizes contact patch laterally across the tire's tread is only part of that and I still believe a tire pressure guage, pyrometer, and tire wear are the best tools to try and guage that.

 

[xXDavidCXx]

If you increase pressure in that situation, my thought would be that you'd be overinflating the tire to compensate for camber gain in the corners. When only outside or inside temp is affected it is likely not a tire pressure issue but an alignment or suspension issue. In this case, since you said you are at max static camber, I would guess you need to increase roll resistance to reduce camber gain during cornering. You could definitely increase your pressure to reduce wear on the outside of tire but then you'd likely be reducing grip every other place on the track outside of the hardest corners where you were getting the excessive rollover. Like David said, it's tough to lock in a good suspension setup and everything works together so testing is important. Simply finding a tire pressure that optimizes contact patch laterally across the tire's tread is only part of that and I still believe a tire pressure guage, pyrometer, and tire wear are the best tools to try and guage that.

I mostly agree here, when camber limited and tire wear is not optimal, either accept it, find more camber, reduce body roll to reduce camber loss, or try higher pressures.

 

[jmblur]

Dude, tell me the 100% for sure method by using a pyrometer, and link the results to what exactly the car needs.

I'll wait.....

I've used all these methods, but the only thing that actually helped me get to a solution was analysis and testing.

Not just a pyrometer, because the temps said my tires were too hot in the center, so maybe I should reduce the pressure. So I reduce front pressure and my problem got worse. The issue was actually not enough front camber.

Take in all the data, it will lie to you if you don't have a full understanding why you are getting specific results.

One important distinction here - autocross heats tires differently than track usage. Track use tends to heat the tires from the inside out, as much of the heat comes from brakes radiating heat into the wheel, and from deformation at high speeds.

Autocross tends to heat tires from the outside in - the constant low speed high G deformation generates a lot of heat in the tread. This also means bigger temperature swings, as there's less of a reservoir of heat. It's also why spraying down tires is somewhat effective for autocross, you're cooling the hottest part of the tire directly.

Tire pyrometers therefore aren't a great fit for autocross use, because the pattern of temperature in the tire is pretty dependent on the last few maneuvers. It can be useful for determining if camber is sufficient, as inside/outside temps will tell the tale still, but not anywhere near as useful for inflation related temps.

 

[xXDavidCXx]

One important distinction here - autocross heats tires differently than track usage. Track use tends to heat the tires from the inside out, as much of the heat comes from brakes radiating heat into the wheel, and from deformation at high speeds.

Autocross tends to heat tires from the outside in - the constant low speed high G deformation generates a lot of heat in the tread. This also means bigger temperature swings, as there's less of a reservoir of heat. It's also why spraying down tires is somewhat effective for autocross, you're cooling the hottest part of the tire directly.

Tire pyrometers therefore aren't a great fit for autocross use, because the pattern of temperature in the tire is pretty dependent on the last few maneuvers. It can be useful for determining if camber is sufficient, as inside/outside temps will tell the tale still, but not anywhere near as useful for inflation related temps.

This is why I ditched my probe style pyrometer and now use a laser style since I'm more concerned with surface temps, not carcass temps. But, I still use the data with a grain of salt because of course design like jmblur mentions. I'm not making many setup changes because of un-even temps across the tread, except to get more camber to more evenly use the tread, making the temps more useful.

 

[derspi]

Kinda silly to apply what works best in autocross when OP is asking for advice for track days. It simply meaningless info and misleading, at best.

 

[xXDavidCXx]

Kinda silly to apply what works best in autocross when OP is asking for advice for track days. It simply meaningless info and misleading, at best.

The fix to open diff wheel spin (Get a LSD) is the same regardless of racing format.

A lot of the rest of my advice applies to most driving conditions.

How did you contribute to this topic/thread?

 

[victorofhavoc]

Because of the mcstrut front, these cars can be helped with a ton of front bar. It will reduce understeer because you'll have a more effective contact patch.

Also if I may provide a contrasting thought... How much track work have you done? I see a lot of newer people get fast after a few events and suddenly grow some testicular hair for turn in pace. When you cook entry, especially without a diff, you'll be spending the rest of the corner fighting your front contact patch. Maintain more brake for longer into the corner and slowly reduce pressure as you turn in. This "trail braking" will rotate you and make your front contact patch much more effective. You'll also be at a more extreme angle for the apex which will give you much more room to plant your foot hard.

If you have a golf r, gti, ttrs, or rs3 you have a FWD car, and fwd tactics need to be in play. For one, these cars need toe 0 or some toe out all around to get great rotation and a well driven car will have the rear end flinging around like no ones business, but it will be fast.

Ask an instructor to sit with you and coach you through the entire braking zone for a particular (tighter and slower) corner where you've got some runoff.

 

[xXDavidCXx]

Because of the mcstrut front, these cars can be helped with a ton of front bar. It will reduce understeer because you'll have a more effective contact patch.

Really three options
1. Combination of bars and springs
2. Mostly springs
3. Mostly bars

Here is what that would look like on my car.

Front	Opt 1​	Opt 2​	Opt 3​
Spring rate in/lb	​ 400​	​ 850​	​ 250​
Spring WR	​ 249​	​ 530​	​ 156​
Spring WR (body roll)	​ 499​	​ 1061​	​ 312​
Swaybar rate	​ 312 Hotchkis on soft​	​ 160 OEM ​	​ 360 Hotchkis on hard​
Swaybar WR	​ 295​	​ 151​	​ 340​
Spring WR (body roll)	​ 590​	​ 303​	​ 681​
Rear			​
Spring rate in/lb	​ 650​	​ 1200​	​ 575​
Spring WR	​ 203​	​ 376​	​ 180​
Spring WR (body roll)	​ 407​	​ 752​	​ 360​
Swaybar rate	​ 842 O34 on soft​	​ 333 OEM​	​ 912 O34 on hard​
Swaybar WR	​ 139​	​ 55​	​ 151​
Spring WR (body roll)	​ 279​	​ 110​	​ 302​
	​ ​
Front WR/Side	​ 840​	​ 833​	​ 837​
Rear WR/Side	​ 482​	​ 486​	​ 482​
Roll couple % front	​ 0.635​	​ 0.631​	​ 0.635​

1. Combination of bars and springs (This is my daily setup for autocross)
2. Mostly springs (If I go back to OEM front and rear bars, I have to dramatically increase spring rates to keep the same wheel rate (WR) and keep the same roll couple %)
3. Mostly bars (If I max my current front and rear bar, then I can go down on spring rates to keep the same WR and roll couple %)

#1 is a good balance between relative comfort with the selected spring rates and body roll control,
#2 is tough to live with on the street and my shocks can't dampen the body with such large energy stored in the springs, but provides the most "independent" suspension
#3 is generally more comfortable on the street, but one wheel bumps are harsher and the front may lift a tire on corner exit causing issues with power down for non-PP GTIs, the rear bar won't help much either because of the soft front springs, the rear will be off the ground all the time in corners

 

[victorofhavoc]

Really three options
1. Combination of bars and springs
2. Mostly springs
3. Mostly bars

Here is what that would look like on my car.

Front	Opt 1​	Opt 2​	Opt 3​
Spring rate in/lb	​ 400​	​ 850​	​ 250​
Spring WR	​ 249​	​ 530​	​ 156​
Spring WR (body roll)	​ 499​	​ 1061​	​ 312​
Swaybar rate	​ 312 Hotchkis on soft​	​ 160 OEM ​	​ 360 Hotchkis on hard​
Swaybar WR	​ 295​	​ 151​	​ 340​
Spring WR (body roll)	​ 590​	​ 303​	​ 681​
Rear			​
Spring rate in/lb	​ 650​	​ 1200​	​ 575​
Spring WR	​ 203​	​ 376​	​ 180​
Spring WR (body roll)	​ 407​	​ 752​	​ 360​
Swaybar rate	​ 842 O34 on soft​	​ 333 OEM​	​ 912 O34 on hard​
Swaybar WR	​ 139​	​ 55​	​ 151​
Spring WR (body roll)	​ 279​	​ 110​	​ 302​
	​ ​
Front WR/Side	​ 840​	​ 833​	​ 837​
Rear WR/Side	​ 482​	​ 486​	​ 482​
Roll couple % front	​ 0.635​	​ 0.631​	​ 0.635​

1. Combination of bars and springs (This is my daily setup for autocross)
2. Mostly springs (If I go back to OEM front and rear bars, I have to dramatically increase spring rates to keep the same wheel rate (WR) and keep the same roll couple %)
3. Mostly bars (If I max my current front and rear bar, then I can go down on spring rates to keep the same WR and roll couple %)

#1 is a good balance between relative comfort with the selected spring rates and body roll control,
#2 is tough to live with on the street and my shocks can't dampen the body with such large energy stored in the springs, but provides the most "independent" suspension
#3 is generally more comfortable on the street, but one wheel bumps are harsher and the front may lift a tire on corner exit causing issues with power down for non-PP GTIs, the rear bar won't help much either because of the soft front springs, the rear will be off the ground all the time in corners

All of this is totally true.

Personally I think the front bar is the bang per buck route for a dual purpose car, but you're totally right about one wheel bumps. Manholes are a B word with a lot of bar...

 

[Mini7]

I‘ve learnt some things from the Auto-x guys. They are running events way more often then I am. Making adjustments that work and some that don’t. The two formats are different but most things still applies and is directionally correct. Auto-x is more extreme so I dial the adjustments and alignment settings back as track speeds are much higher. You are looking for neutral balance to slight oversteer for the slow corners. Again this is track dependent and driving style dependent. There are also no rules for HPDE, so many AutoX mods are dictated by the rules. Do your research.

@xXDavidCXx is not giving bad advice. He is one of the few that has taken a very scientific approach to developing his car for AutoX. It all depends on your track goals. Modding for the track is always a compromise for a dual duty car. Make adjustments in small increments until you find the balance that suits your driving style.