John's Kenne Bell Supercharged GT500 with 3inch pulley KB

[Justin@VMP]

John brought his car over yesterday for a dynotune. He has done few other mods on top of the standard KB kit, longtube headers and high flow cats, and he wanted to make sure the car was dialed in just right. With very little cool down it made 646rwhp/636rwtq with a very rich a/f. We could probably have made a little more power with a long cooldown. I got down to business tuning and tweaking it. The KB tune is designed to work with a multitude of pulley sizes from 3.25" to 2.5", so they throw a ton of fuel at it. John never plans to run smaller than a 3" pulley and did not like the fuel pump duty cycle being nearly 95%, so we backed down fuel pressure which also helped it stabilize and got the pump duty cycle down to 85%. The KB tune runs a lot of spark and a very rich a/f, obviously it works, but not everyone likes to tune GT500s this way. I put in my standard spark curve which is much more conservative but still makes good power on 93 octane, you never know what you are going to get from the gas pump. I tuned the a/f to be a flat 11.5-11.7 at wide open throttle. After a 20 minute cooldown we ended up with 672rwhp/649rwtq. I also remove the top speed limiter. Boost did not change, the first run just had a spike at the end.

http://www.vmptuning.com/dynographs/johnwittkb.jpg

KB Tune
http://www.vmptuning.com/dynographs/johnkbtune.jpg

VMP Tune
http://www.vmptuning.com/dynographs/johnmytune.jpg

[padrat]

Hey Justin. The Shelby runs great after the tune.
Took it to Orlando speedworld (AKA Orlando spinworld) last wed night and granny shifted it to a 11.22 @ 127. Not to bad considering the 1.7 short time. Previous best was 11.5 @ 125.

[Justin@VMP]

good to hear