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Understeer .2RS

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Old 02-25-2019, 08:30 PM
  #16  
orthojoe
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Originally Posted by -eztrader-
Do those pressures increase rate of tire wear?
I would think that it should decrease the rate of tire wear. My experience has been that the more you try to bleed air after every session, the worse things get with times, handling, and wear. Set it cold. Bleed once after the first session. Done. You'll find the car to be much more consistent
Old 02-25-2019, 08:52 PM
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TRAKCAR
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I need to drive an .2RS at Sebring again.

The one I drove had insane front grip, way too bound up.
After taking take out rake and adding front bar it was drivable.
It was fast, as front grip cars are, but I feel for the average weekend drover it was much to hard to squeeze the last second out of it.

Opposite of .1RS where we always have been looking for front grip..
Old 02-25-2019, 08:55 PM
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Originally Posted by orthojoe
I would think that it should decrease the rate of tire wear. My experience has been that the more you try to bleed air after every session, the worse things get with times, handling, and wear. Set it cold. Bleed once after the first session. Done. You'll find the car to be much more consistent
Correct.
Dunlops, right?
It doesn’t keep me from bleeding, overdriving and destroying tires tho.
I can’t wait to put Dunlops on, bleed and forget the rest of the day.
Although, we may not completely be able to because Florida heat and humidity add a lot of PSI after noon.
i have a couple track days with the Michelin truck at the track, but as soon as those are behind me, I’ll try them.

The Michelin’s can only be made to work by going slower.
Old 02-25-2019, 09:37 PM
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Originally Posted by TRAKCAR
I need to drive an .2RS at Sebring again.

The one I drove had insane front grip, way too bound up.
After taking take out rake and adding front bar it was drivable.
It was fast, as front grip cars are, but I feel for the average weekend drover it was much to hard to squeeze the last second out of it.

Opposite of .1RS where we always have been looking for front grip..
Didn't that 991.2 GT3 RS have non-stock front springs that were softer than the stock 991.2 GT3 RS springs? Different springs than the stock ones would move the balance everywhere depending on the spring rates used. Most people run the stock shocks and springs, very few upgrade the shocks and/or the springs.

Old 02-25-2019, 09:42 PM
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TRAKCAR
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Yes, softer front and rear.
Thanks for that, I should have mentioned and that’s why I need to drive one again..
My car had .2RS spring rates and it had plenty of fro t grip.

But completely different cars, diff, RWS, sway bars, even steering is more direct (smaller wheel, or differet ratio?)
I think the .2RS will be perfect on 19” but will need softer springs otherwise.

We shall find out :-)
Old 02-25-2019, 09:48 PM
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I haven't run on the Dunlops, but I would just move the rear bar to Full Stiff... other than that... it really should drive nicely for you in the stock settings.

Best Regards,
Dave
Old 02-25-2019, 10:30 PM
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orthojoe
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Originally Posted by TRAKCAR


Correct.
Dunlops, right?
It doesn’t keep me from bleeding, overdriving and destroying tires tho.
I can’t wait to put Dunlops on, bleed and forget the rest of the day.
Although, we may not completely be able to because Florida heat and humidity add a lot of PSI after noon.
i have a couple track days with the Michelin truck at the track, but as soon as those are behind me, I’ll try them.

The Michelin’s can only be made to work by going slower.
Yup. Dunlops. Hopefully I'll finally get a chance to run a 3rd day on the tires this friday
Old 02-26-2019, 09:34 AM
  #23  
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What does 2mm toe in on rear translate to for degrees? I see a lot of posts of .15 or .20 degrees rear toe...what is that in millimeters?

on my .2GT3 I’m running zero toe front...2mm inward per side on rear...bars front and rear in stock middle position...car lowered slightly from stock...-2 camber all 4 corners on MPSC2. I ran 1st time this weekend at Sebring....just like I did on the .2 Carrera GTS I kept the tires hot at around 33/34 front and 35-36 rear and no roll over of sidewall and wear right down to the Michelin Man mark of the edge of tire tread.
Old 02-26-2019, 10:26 AM
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Originally Posted by mdrums
What does 2mm toe in on rear translate to for degrees? I see a lot of posts of .15 or .20 degrees rear toe...what is that in millimeters?

on my .2GT3 I’m running zero toe front...2mm inward per side on rear...bars front and rear in stock middle position...car lowered slightly from stock...-2 camber all 4 corners on MPSC2. I ran 1st time this weekend at Sebring....just like I did on the .2 Carrera GTS I kept the tires hot at around 33/34 front and 35-36 rear and no roll over of sidewall and wear right down to the Michelin Man mark of the edge of tire tread.
Any reason for zero toe up front? Wouldn't just a smidge help?
Old 02-26-2019, 12:26 PM
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2mm rear toe per corner (4mm total) is about the same as 5/32", and that translates to 0.17 degrees per corner in the GT3 and 0.16 degrees in the RS (because of the RS extra 1" on wheel, and larger diameter tires).

Rear bar in my .1 GT3 RS and .2 GT3 RS came at full stiff, front bar in the middle.
Old 02-26-2019, 01:38 PM
  #26  
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Originally Posted by -eztrader-
.2RS - totally stock - Dunlops. First half of sessions were ok- but 2nd half seemed to get worse. Tried lowering pressures to 28f 32r hot - and still did it.

Any ideas?
I changed my Dunlops to Cup2's and they solved this problem - this was also with the Manthey Racing geo setup and the Cup2's made the difference. It's not cheap to change when you don't really need to, but I feel it was worth it. Rather than complete understeer though, I would class it as a lack of feel, just when you need it most...
Old 02-26-2019, 04:47 PM
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Seth Thomas
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Originally Posted by -eztrader-
Cota this weekend. Seemed to be worse on the right turns. 2 / 6 / 8 / 13 / 16/ 18

Turn in and Apex seemed the worse portions
Did the understeer happen when you were adding any bit of throttle in those turns?

Turns 2 and 18 are both high speed turns where we are typically trying to be on constant or full throttle. Adding rear bar for this type turn might help here. If rear is full stiff then you might need to raise the rear ride height slightly. The alternate effect caused by raising the rear is it can change the car to more of an oversteer car in turn 10.

Turns 6/8/13/16: Decreasing radius turns and most cars understeer through these turns with the way it is shaped. At what point in the turn did start to understeer and what were you doing with your right foot when the understeer started?

Note the key question with all of these are what were you doing with your right foot when the understeer starts and when it is at its worst?

Before making any changes to the suspension of the car it is important to think about what you were doing in the car. Could it have been something you were doing to create the understeer and not the car or suspension setup itself. I watch a lot of videos of drivers at tracks where they are complaining of understeer. 90% of those videos I watch the driver is inducing a lot of the understeer.

Last edited by Seth Thomas; 02-26-2019 at 07:52 PM.
Old 02-26-2019, 04:49 PM
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^^^ eztrader, pay attention here
Old 03-01-2019, 12:07 AM
  #29  
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Originally Posted by krell
Any reason for zero toe up front? Wouldn't just a smidge help?
like toe out? How much and why? Thanks! Mike
Old 03-01-2019, 12:08 AM
  #30  
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Originally Posted by A/S
2mm rear toe per corner (4mm total) is about the same as 5/32", and that translates to 0.17 degrees per corner in the GT3 and 0.16 degrees in the RS (because of the RS extra 1" on wheel, and larger diameter tires).

Rear bar in my .1 GT3 RS and .2 GT3 RS came at full stiff, front bar in the middle.
Thanks! Then I’m in the ball park I think.


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