ESS4.6is - Give us some more info on your SC. Is it a recent install? How many miles have you put on it? Who did the install? Any other work done (i.e. engine and tranny software, brakes, etc.). Any change to gas mileage? Sorry to ask all the questions, but you're the only guy on here running the ESS kit.

The install was not recent I had it done in 2003 with about 3000km on my 4.6is. It was a standard ESS kit wiht 6psi of boost (full details on the stock kit is at esstuning.com) I drove it until 30,000km with minimal problems. I did have some O2 sensor issues and failing injectors that seemed most prevalent with cold weather. I was pretty content with the power until about 6 months ago when one of friends got a cayenne turbo S and another friend got a trailbazer SS with a supercharger. I could not stay with them at all. So I went to a performance shop and we firstly went with larger injectors, had some porting work done and forged parts installed as well as a custom cam to lower the compression ratio. The pulley was then changed about 4 days ago and a new 6 rib belt was installed to prevent slippage. Tuning for the beast was a lot of work, as my mechanic spent 3 days straight perfecting it. Transmission has different fluid in it, some servos but basically stock. Brakes are stock (for now). As for gas milage, with the ESS kit I was seeing about 11mpg, which is quite bad. So far with this new tune and increased boost I am seeing around the same at 11mpg.

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2007 Jeep SRT-8 (going to be supercharged)
2007 Trailblazer SS
2003 X5 4.6is ESS supercharged
2004 Silverado SS supercharged
2005 Escalade supercharged
2003 Corvette ZO6 supercharged
1999 Mercedes S600