I finished installing my Whipple supercharger about a month ago but due to waiting for other parts to show up (mostly Kooks headers & H pipe) and waiting for the snow to melt I just today got to test drive it. I must say I'm in love but I have some questions.
First, the boost/vacuum gauge. At an idle and putting around the gauge reads around 22 of vacuum. Is this correct? I have never driven a boosted vehicle so I have no idea what it should read. When I jump on it I hear a beautiful whine and the gauge jumps to about 10lbs of boost. This I am sure is correct I just am not sure of the vacuum reading.
Second, when I come to a stop from any speed and put the clutch in the idle seems to hang around 1300-1500 for about 5 seconds or more before it slowly drops to 800-900 where it should be. Is this what your car does? I hate how it doesn't drop to 800-900 right away. It reminds me of when I tried the BBK throttle body. When I installed it I had a very similar problem with the throttle body so I took it off and went back to stock.
I purchases my Whipple kit from Lethal Performance and it came with a custom SCT tune from Dave Lund. I am not sure if a custom tune from my local tune shop can fix this or if it's something due to a vacuum leak. I am not convinced it's a vacuum leak because the idle does eventually drop to 800-900 and idles fine once there. I would think if it was a vacuum leak it would never drop to 800-900 rpm.
Maybe I should change the throttle body to a accufab or ford racing one before I get it dyno/tuned? I did use throttle body cleaner my stock unit when I was installing the supercharger to try and clean it up some.
Any input would be much appreciated