MPSC Wear Limits?
08-14-2006, 06:39 PM
#31
Nordschleife Master
Originally Posted by Mike K.
I used to really like ( hot) 28f 30 R until I found out it cooks the (R)sidewalls and the tire will blister and go flat. So, try a pound or two and then work with the swaybars.
My guess for the MPSC in the optimal range would be 31-32 HOT starting at about 26-28 cold.
08-14-2006, 06:48 PM
#32
Nordschleife Master
Originally Posted by db_gt3
If I may just chime in for a moment, it has been mine and other fast person's experience that the MPSC will start to lose grip significantly after about ten hotlaps. These are buttonwillow laps; 3 miles per with lots of hard braking, fast corners and not a whole lot of straight (configuration #13 with bus stop). They start to feel "oily" after 10 or so laps. Gotta wait for them to come down in temp and then they are fine.
That being said, I wonder what kind of heat cycle I am putting into these things as they never really cool down. The way we run I never really take more than about a ten or fifteen minute break between sessions (except for lunch). I have felt the tires numerous times right after a sesh and again right before the next, they remain very hot after a short break. Only slightly less hot.
When I stay out too long and get that oily feeling underneath me I am sliding through everything. The tires are so hot I can barely touch them. Then I wait ten to fifteen minutes and they are JUST RIGHT (still very hot). Take them back out and they are once again sticky.
Thoughts?
That being said, I wonder what kind of heat cycle I am putting into these things as they never really cool down. The way we run I never really take more than about a ten or fifteen minute break between sessions (except for lunch). I have felt the tires numerous times right after a sesh and again right before the next, they remain very hot after a short break. Only slightly less hot.
When I stay out too long and get that oily feeling underneath me I am sliding through everything. The tires are so hot I can barely touch them. Then I wait ten to fifteen minutes and they are JUST RIGHT (still very hot). Take them back out and they are once again sticky.
Thoughts?
), I can assure you that MPSCs can and will do just fine even during very long session. I have run them in enduro races (90 mins) in 95+ degree heat with zero issue. I suspect that your pressures need to be lowered a bit. I have seen front pressures range from 31-34 and rear from 34-38 (I run 32/36). If you get them over 38 in the rear, they really do suck.
Originally Posted by LVDell
I spent $75 on a really nice laser aim digital pyrometer at Costco and record my temps and pressures after EVERY session.
My guess for the MPSC in the optimal range would be 31-32 HOT starting at about 26-28 cold.
My guess for the MPSC in the optimal range would be 31-32 HOT starting at about 26-28 cold.
For cold pressures, I have to start around 25 front for 32 hot, and 24 rear for 36 hot.
08-14-2006, 07:16 PM
#33
Nordschleife Master
Originally Posted by 38D
Go get your $75 back. A laser pyrometer does no good for tires. You need to measure them with a probe style, as it is the inside temp that matters. You also need to come in off the track hot, and have someone waiting in the pits.
08-14-2006, 09:23 PM
#36
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Do you guys run the RA-1's at the same pressures?
08-14-2006, 10:29 PM
#37
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Originally Posted by M3Pete
Do you guys run the RA-1's at the same pressures?
08-15-2006, 10:50 AM
#38
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Originally Posted by 38D
As a fast person (), I can assure you that MPSCs can and will do just fine even during very long session. I have run them in enduro races (90 mins) in 95+ degree heat with zero issue. I suspect that your pressures need to be lowered a bit. I have seen front pressures range from 31-34 and rear from 34-38 (I run 32/36). If you get them over 38 in the rear, they really do suck.
), I can assure you that MPSCs can and will do just fine even during very long session. I have run them in enduro races (90 mins) in 95+ degree heat with zero issue. I suspect that your pressures need to be lowered a bit. I have seen front pressures range from 31-34 and rear from 34-38 (I run 32/36). If you get them over 38 in the rear, they really do suck.I run 32-33 front 34-35 rear. Yes the problem is magnified when they get over inflated during a session, but you can't let pressure out while you are driving; the longer I am out, the hotter they get, the more pressure build up. Even when the pressures are dialed in, though, the oily feeling begins at about the 20 minute mark (10 laps). Keep in mind I am talking about 100+ degree ambient temps.
Maybe you're just not that fast?
I will try dropping another pound and see if that helps. I dont want to be rolling the sidewalls, though.
Current Setup:
MPSC
Schatz Alignment
Cup Brake Ducts
Brembo Floating Rotors (front)
RS Flywheel/Clutch
Tequipment Roll Bar
GT3 Cloth Seats
Sabelt Harnesses
Center Console Delete
08-15-2006, 11:21 AM
#39
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My friends and I run MPSC's down here in S. FLA. Last year, the Michelin reps were at two back to back events and I worked with them extensively to get my car setup properly with their tires. The pressures they suggest in the literature works like a charm. I start with 25/28 and end up with 32/36. We spent alot of time with pyrometry to get the alignment correct. I drive very hard. I don't notice the tires getting greasy on me unless I overdrive them. Maybe you need better tire management.
08-15-2006, 11:47 AM
#40
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Originally Posted by mitch236
I drive very hard. I don't notice the tires getting greasy on me unless I overdrive them. Maybe you need better tire management.
Current Setup:
MPSC
Schatz Alignment
Cup Brake Ducts
Brembo Floating Rotors (front)
RS Flywheel/Clutch
Tequipment Roll Bar
GT3 Cloth Seats
Sabelt Harnesses
Center Console Delete
08-15-2006, 06:10 PM
#42
Nordschleife Master
Originally Posted by db_gt3
Not for me they wont.
I run 32-33 front 34-35 rear. Yes the problem is magnified when they get over inflated during a session, but you can't let pressure out while you are driving; the longer I am out, the hotter they get, the more pressure build up. Even when the pressures are dialed in, though, the oily feeling begins at about the 20 minute mark (10 laps). Keep in mind I am talking about 100+ degree ambient temps.
I run 32-33 front 34-35 rear. Yes the problem is magnified when they get over inflated during a session, but you can't let pressure out while you are driving; the longer I am out, the hotter they get, the more pressure build up. Even when the pressures are dialed in, though, the oily feeling begins at about the 20 minute mark (10 laps). Keep in mind I am talking about 100+ degree ambient temps.
Originally Posted by db_gt3
Maybe you're just not that fast?
08-15-2006, 06:19 PM
#43
Nordschleife Master
Jim, That is the pressure the Michelin engineer gave me last weekend for my GT3. Michelin supported the Parade in Portland and they had 2 people at all the events. They were at the Friday DE asking and answering questions. 32/36 hot is what they gave me. They also asked me why I ran Hoosiers.
08-15-2006, 06:58 PM
#44
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I ran Nitrogen in the MPSC's for a bit and that worked like a charm. Its a bit tricky trying to figure out where the tire pressures would end up, but I liked 33/36 hot.
08-15-2006, 09:51 PM
#45
Rennlist Member
Originally Posted by db_gt3
Not for me they wont.
I run 32-33 front 34-35 rear. Yes the problem is magnified when they get over inflated during a session, but you can't let pressure out while you are driving; the longer I am out, the hotter they get, the more pressure build up. Even when the pressures are dialed in, though, the oily feeling begins at about the 20 minute mark (10 laps). Keep in mind I am talking about 100+ degree ambient temps.
Maybe you're just not that fast?
I will try dropping another pound and see if that helps. I dont want to be rolling the sidewalls, though.
Current Setup:
MPSC
Schatz Alignment
Cup Brake Ducts
Brembo Floating Rotors (front)
RS Flywheel/Clutch
Tequipment Roll Bar
GT3 Cloth Seats
Sabelt Harnesses
Center Console Delete
I run 32-33 front 34-35 rear. Yes the problem is magnified when they get over inflated during a session, but you can't let pressure out while you are driving; the longer I am out, the hotter they get, the more pressure build up. Even when the pressures are dialed in, though, the oily feeling begins at about the 20 minute mark (10 laps). Keep in mind I am talking about 100+ degree ambient temps.
Maybe you're just not that fast?
I will try dropping another pound and see if that helps. I dont want to be rolling the sidewalls, though.
Current Setup:
MPSC
Schatz Alignment
Cup Brake Ducts
Brembo Floating Rotors (front)
RS Flywheel/Clutch
Tequipment Roll Bar
GT3 Cloth Seats
Sabelt Harnesses
Center Console Delete
I worked with the Michelin engineers at Road America last year and was told I was the only one the entire race weekend that was getting the tires hot enough. Driving style is a huge factor with these tires. You have to get your tire pressures set right for the length of your race. As with 38D, I used the MPSCs for 90 minute enduros (51 laps at a place like Mosport) without issue or loss of grip.
I don't understand your comment "over inflated". If you're hitting 35 hot in the rear, they are not over-inflated. I would argue you could use another pound or two back there, actually, particularly in a high power car like a GT3. What size tire are you running?
What are your tire temps? Are you getting the tires to their optimal operating temperature?