11.2 at 129mph



Went to the track yesterday and ran the car on street tires. Its my first time out in the car and I have only had it a few days so launching it is not my forte. It was hooooot out so I threw 5 gallons of 101 in it just to protect the motor from detonation. My car is not tuned for the higher octane so I doubt I picked any power up. It was bouncing between 84-87*(according to dragtimes. My ambient temp was reading 88-90) out and we were there from 12-5pm. Track prep seemed pretty decent. I know the car has a lot more in it and I am confident on street tires with the right temps I can knock out a 10.5 on street tires. I was launching at about 3700 rpms. Probably could have done a 4000 rpm launch and gotten it to stick. Thanks to Fartpipe for pointing out I am an idiot for launching the car all day in Sport mode. I followed his advice and through it in touring and knocked the air pressure down to 21psi and was able to go from 11.4 all day to 11.2 at 129. I was also having a bad time with the 1-2 shift because I was getting some pretty decent wheel hop. Also I had half a tank of gas at the beginning of the day and at 4:50pm when I popped off my 11.2 I was down to a 1/4 tank. So ideally if I was down to the light and everything yanked out of my car for weight savings I potentially had a 10 second run in that heat. Also that was a hot lap run as in I literally rolled right back through no stopping and still popped off that time. To me that is very impressive because my coolant temps and oil were both at about 210-215 and it still pulled that time.



So here is the down side. As we are leaving the track I blew past some of the Vengeance guys and noticed I was blowing lots of smoke at high rpm. I attributed it to unburnt fuel. I drove easy for a bit on the way home and then stopped and filled her up once she got low enough. Started beating on it again on the highway while I was driving and the smoke was very faint now. However, I noticed the exhaust note changed. I instantly knew I melted a cat. Pulled over and checked the exhaust pipes and sure enough there were platinum flakes. Also could hear the cats rattling. By the time I got home they were rattling something fierce and you could hear that gurgle that if I am correct Quickwag had complained of when his cats let go. To me it seems as if the cats on these cars which are shared with the Z06 were not designed for a boosted application will fail due to high boost or repeated abuse. Also the fact that I run a safe tune which means it runs rich, but not as rich as the factory tune will help eat the cats up quickly. The 101 octane was unleaded so it definitely wasn't that, I know that it burns hotter so that may have helped to contribute to the failure, but I am 99% sure its the high boost and high heat nature of a boosted car.
Also noticed on the way home my oil and coolant temps with the A/C on were hovering around 217 and off at 207. Granted I was reading 90-93 ambient temps and have never driven the car in that high of heat. I usually hover around 192 coolant and 198-202 oil.


