First test and tune of the season tomorrow - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

69to14 · 01-24-2015, 09:00 PM

And also first event in my new 2014 SS. I've been autocrossing MINI's for the last 4 years so this will be somewhat different. I am going to try hard not to melt the tires off but I am expecting a fair amount of both understeer and oversteer. So far I have done nothing to the car except add a catch can. By the next event I hope to at least have the alignment tweaked. But, for tomorrow it's bone stock. I have the Pirelli's and I am thinking about starting out at 46 psi. Any thoughts?

cornerspeed92 · 01-24-2015, 10:10 PM

That seems a little too high on pressure, i dont remember what i ran with my Pirellies, but not that high.

Gen52SS · 01-25-2015, 04:59 AM

Agree pressures too high. It will depend on ambient temp check tire pressures after each run...remember this is a test and tune. On those stock Pirelli's expect the car to push (understeer) like mine did last season until I got the alignment and Hankook RS-3 v2 tires fixed the problem. Seat time...seat time...seat time and driver experience will get you near the top...I assume you are running F Street or CAM-C...have fun good luck.

Stephen12ZL1 · 01-25-2015, 09:02 AM

Most guys start at 37-38psi and adjust from there. 46psi seems too high.

Nor Cal ZL1 · 01-25-2015, 09:56 AM

For tire pressures and alignment you really need to get the tire temperatures. Too much pressure will allow the tire to run cold and have a less than optimal contact area. Whatever pressure is in the tire, not probing the temperature spread is mostly guesswork.

All my set up work begins and ends with tire temps. It is going to tell you about balance of the suspension, alignment, under worked tire/overwworked tire.

Identifing if a tire is overworked is hugely important in road course. People often see and understeering car and want to change suspension components to reduce that. If the tire is too hot and overworked typical adjustments to transfer weight to that tire will make it worse. Adding load to an overworked tire will make even more heat, and if there was money spent of springs and alignments for little to no gain.

Tire temperatures are your eyes for suspension and alignment direction.
I dug up a couple of write ups that are pretty good on the subject.
Enjoy your ride and let us know how it works out.

http://www.elephantracing.com/techtopic/tiretemp.htm

http://949racing.com/using-a-tire-py...49-Racing.aspx

http://www.longacreracing.com/products.aspx?itemid=1721

69to14 · 01-26-2015, 10:51 PM

Thanks for all the input. I realized when I got to the track that 46 would be too high and started with 38 front and 37 rear. The car was pushing but not as bad as I thought it would but I took the first 5 laps with the nannies on. I didn't have a pyrometer with me so I couldn't check the temps but the tires never seemed to get real hot, for what it's worth. It was obvious that the tires were rolling over the edge slightly but the heat had brought the pressure up to 43-44 so I left it alone. The second time out I pressed the traction control button once. That made driving a lot more interesting. Still pushing some but a definite increase in over-steer. I really had to be smooth to keep the back end from trying to pass the front.

All in all it was a good day. I got a feel for what the car would do and finally started finding the bumpers and fenders which was a challenge in itself after 5 years of MINI Coopers. Thanks for the links Nor Cal ZL1, I know what I'll be doing tonight.

01-24-2015, 09:00 PM	#1
69to14 Drives: Yellow 2014 2SS/RS Join Date: Nov 2014 Location: Maui Posts: 10 View My Garage	First test and tune of the season tomorrow And also first event in my new 2014 SS. I've been autocrossing MINI's for the last 4 years so this will be somewhat different. I am going to try hard not to melt the tires off but I am expecting a fair amount of both understeer and oversteer. So far I have done nothing to the car except add a catch can. By the next event I hope to at least have the alignment tweaked. But, for tomorrow it's bone stock. I have the Pirelli's and I am thinking about starting out at 46 psi. Any thoughts?

01-24-2015, 10:10 PM	#2
cornerspeed92 Drives: 2013 1SS 1LE Join Date: Jul 2012 Location: Colorado Posts: 4,188 View My Garage	That seems a little too high on pressure, i dont remember what i ran with my Pirellies, but not that high. __________________

01-25-2015, 09:02 AM	#4
Stephen12ZL1 Drives: '21 ZLE A10 Join Date: May 2012 Location: Mechanicsville, VA Posts: 6,824	Most guys start at 37-38psi and adjust from there. 46psi seems too high. __________________ '21 ZLE A10 Wild Cherry PDR 2:00.78 VIR Full 10.68@131.69 1.68 60' '17 ZL1 A10 Mosaic Black PDR/Nav 2:03.08 VIR Full 11.003@129.2 1.75 (sold) '15 Z/28 #325 Black a/c & stereo. 2:10.1 VIR Full (sold) '12 ZL1 A6 Black 10.52@131 1.55 60' 2:13 VIR Full (sold)

01-25-2015, 04:59 AM	#3
Gen52SS Drives: 2014 Camaro 2SS Join Date: Jan 2014 Location: Seymour, TN Posts: 101 View My Garage	Agree pressures too high. It will depend on ambient temp check tire pressures after each run...remember this is a test and tune. On those stock Pirelli's expect the car to push (understeer) like mine did last season until I got the alignment and Hankook RS-3 v2 tires fixed the problem. Seat time...seat time...seat time and driver experience will get you near the top...I assume you are running F Street or CAM-C...have fun good luck.

01-25-2015, 09:56 AM	#5
Nor Cal ZL1 Drives: 2013 ZL1 M6 Join Date: Oct 2013 Location: Nor Cal Posts: 1,825	For tire pressures and alignment you really need to get the tire temperatures. Too much pressure will allow the tire to run cold and have a less than optimal contact area. Whatever pressure is in the tire, not probing the temperature spread is mostly guesswork. All my set up work begins and ends with tire temps. It is going to tell you about balance of the suspension, alignment, under worked tire/overwworked tire. Identifing if a tire is overworked is hugely important in road course. People often see and understeering car and want to change suspension components to reduce that. If the tire is too hot and overworked typical adjustments to transfer weight to that tire will make it worse. Adding load to an overworked tire will make even more heat, and if there was money spent of springs and alignments for little to no gain. Tire temperatures are your eyes for suspension and alignment direction. I dug up a couple of write ups that are pretty good on the subject. Enjoy your ride and let us know how it works out. http://www.elephantracing.com/techtopic/tiretemp.htm http://949racing.com/using-a-tire-py...49-Racing.aspx http://www.longacreracing.com/products.aspx?itemid=1721

01-26-2015, 10:51 PM	#6
69to14 Drives: Yellow 2014 2SS/RS Join Date: Nov 2014 Location: Maui Posts: 10 View My Garage	Thanks for all the input. I realized when I got to the track that 46 would be too high and started with 38 front and 37 rear. The car was pushing but not as bad as I thought it would but I took the first 5 laps with the nannies on. I didn't have a pyrometer with me so I couldn't check the temps but the tires never seemed to get real hot, for what it's worth. It was obvious that the tires were rolling over the edge slightly but the heat had brought the pressure up to 43-44 so I left it alone. The second time out I pressed the traction control button once. That made driving a lot more interesting. Still pushing some but a definite increase in over-steer. I really had to be smooth to keep the back end from trying to pass the front. All in all it was a good day. I got a feel for what the car would do and finally started finding the bumpers and fenders which was a challenge in itself after 5 years of MINI Coopers. Thanks for the links Nor Cal ZL1, I know what I'll be doing tonight.