Roush OEM calibration is designed to deliver approximately 489 hp / 590nm at wheels ( 575hp/ 680nm at crank). I did not even bother with it and went straight ahead with VMP Tuning's genious Justin Starkey's performance tune.
The car put down 562hp / 648 nm at wheels ( 661hp/762nm at crank), about 86hp and 82nm more power than Roush OEM calibration. All this with only using the 85mm stock pulley that makes about 8-8.5psi boost. The 2013 GT500 has 661hp / 849nm torque. The car has same hp level as the 2013 GT500 despite the missing torque that GT500 has due to it's bigger displacement. The difference is 87nm but it'd be interesting to see how both cars would perform at a drag race.
We spent significant timin in datalogging, AFR, ignition timing, battery/alternator voltage. As in the graph below, the AFR measured at the exhausts were dead spot on 11-11.2 until 7200rpm. Although it climbed from 11.0 to 11.4 between 6800-7100, it was still in safe zone. Assuming that tail pipe sniffer reads about 2% leaner than actual AFR, these numbers would be 10.8-11.2 before the CATs which is absolutely safe. The alternator voltage was also steady at 14.2-14.4 volts meaning fuel pumps were getting steady supply of power with no indication of running out of duty cycle.
I have the green light from Justin to try the smaller 82mm pulley which is supposed to increase the boost by 1psi to about 9-9.5, using closed airbox.
The pulley is expected to safely add another 20-30 hp and 30-35nm torque at the wheels which should bring the final numbers to 690hp/800nm at crank.
The next step is the 79mm pulley which adds another 0.5psi to make it around 10 psi in total. Now i am a little skeptical about going that low but it is always the best to go step by step with proper datalogging. The 79mm will put the injectors at their limit and I assume the car wont be safe to run above 7000rpm with stock injectors. The installed fuel pump voltage booster might definitely help to keep AFR steady but I dont think 79mm is a good option without larger injectors. Upgrade to 79mm should definitely put the power levels to around 705hp / 815nm. Which is way more than any street car can use without proper, sticky, drag radials.
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