Ordered Whipple
10-16-2011, 03:29 PM
#192
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Final update for a while:
After several attempts and seemingly always meeting bad luck with test and tune, I FINALLY got some more runs at the track. I went to Pittsburgh Raceway Park this morning and got 5 runs in. The weather was crap in the morning and they had everyone run 1/8 for the first run as the winds were over 40 mph and there was a slight head wind. The winds died down though not much later and we were able to run the full quarter.
Just for a refresher: My 2010 Sierra Denali has the Whipple kit and some custom engine tuning done by myself (mainly MAF calibration), no other mods. I ran at full weight and even with a full tank of gas. From my last visit to the track, I stepped down a pulley size and picked up about 2 psi, added a boost guage and wideband O2, and calibrated the MAF (disabled SD for now).
Launches were about the same as last time. No loading, pretty much off idle and foot to the floor. On my first 1/8 mile run, I accidently left the traction control on and I also hit the fuel cut off at 6,200 rpm. My first 1/4 mile run was actually worse in 1/8 mile and even though I had stepped down the shift points, I still hit the rev limit. After making some adjustments, my second 1/4 mile was the best of the day, so close to 12's but just a 10th or so off. Maybe someone could help with a weather correction? My initial numbers say 12.61 at 109 but that seems EXTREMELY optimistic. Conditions were: 1010 ft. elevation, 54 degress, 60% humidity, 29.72 in/hg pressure. My last 2 runs were pretty close to the same, 13.23 at 105.
I still have a bunch of work to do on the tune and I am going to order bigger injectors soon as I am at 90% injector duty cycle in 4th gear WOT 5,000-6,000 rpm, but I am certainly pleased with the results.
After several attempts and seemingly always meeting bad luck with test and tune, I FINALLY got some more runs at the track. I went to Pittsburgh Raceway Park this morning and got 5 runs in. The weather was crap in the morning and they had everyone run 1/8 for the first run as the winds were over 40 mph and there was a slight head wind. The winds died down though not much later and we were able to run the full quarter.
Just for a refresher: My 2010 Sierra Denali has the Whipple kit and some custom engine tuning done by myself (mainly MAF calibration), no other mods. I ran at full weight and even with a full tank of gas. From my last visit to the track, I stepped down a pulley size and picked up about 2 psi, added a boost guage and wideband O2, and calibrated the MAF (disabled SD for now).
Launches were about the same as last time. No loading, pretty much off idle and foot to the floor. On my first 1/8 mile run, I accidently left the traction control on and I also hit the fuel cut off at 6,200 rpm. My first 1/4 mile run was actually worse in 1/8 mile and even though I had stepped down the shift points, I still hit the rev limit. After making some adjustments, my second 1/4 mile was the best of the day, so close to 12's but just a 10th or so off. Maybe someone could help with a weather correction? My initial numbers say 12.61 at 109 but that seems EXTREMELY optimistic. Conditions were: 1010 ft. elevation, 54 degress, 60% humidity, 29.72 in/hg pressure. My last 2 runs were pretty close to the same, 13.23 at 105.
I still have a bunch of work to do on the tune and I am going to order bigger injectors soon as I am at 90% injector duty cycle in 4th gear WOT 5,000-6,000 rpm, but I am certainly pleased with the results.
Just curious why you are leaving from idle though?
10-16-2011, 06:05 PM
#193
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I guess the only reason is because I had trouble with brake torquing during my last trip. I'm not sure if it was because I left traction control on, tire slip, or belt slip. This time, I wasnt sure how many runs I would get in so I just used the idle launch. My 60's were around 2sec or under so I didn't worry about it. If I had allowed myself some more planning, I would have tried other launch techniques. I'm sure if I were able to brake torque, I probably could have cut a few tenths off my 60'. I logged all of my runs so I have data on my launches. It somewhat appears that I'm spinning just after launch, which is crazy.
08-27-2012, 03:18 PM
#199
I guess the only reason is because I had trouble with brake torquing during my last trip. I'm not sure if it was because I left traction control on, tire slip, or belt slip. This time, I wasnt sure how many runs I would get in so I just used the idle launch. My 60's were around 2sec or under so I didn't worry about it. If I had allowed myself some more planning, I would have tried other launch techniques. I'm sure if I were able to brake torque, I probably could have cut a few tenths off my 60'. I logged all of my runs so I have data on my launches. It somewhat appears that I'm spinning just after launch, which is crazy.
