Coalman

I have always felt that there is just too much variability in the performance of E55's based on anecdotal evidence from the E55's on this forum. For years, I have felt my car was below average, especially after the reflash fiasco a few years back. The K1 mod improved things some. The retune has improved things considerably more. While I know the larger pulley should be the major reason for the improvement, I feel the tune is even more important if your baseline is a poor tune to begin with, which is where I was before I did the K1mod.

I am sure my experience is not unique and that there are many E55 owners out there whose cars are performing well below average because of a bad tune. If you think you are one of them, I would strongly recommend investing in a new tune, even if you don't want to make any other changes. It is a travesty to own one of these beasts at 80% of its potential.

BlkE55K

So what did that baby put down after the pulley and tune?

Coalman

I have never had the car on a dyno. My butt dyno tells me I was probably down at least 50 horsepower from a well tuned stock E55 (I could hardly break the rear tires loose on a hot day). I figure the larger pulley and the more aggressive Kleemann tune has probably added another 30 to 40 horsepower at the crank versus a well tuned E55. So I figure I have gained at least 80 to 90 horsepower from where I started, which is how the car feels every time I step on the accelerator!

TheVazha

The track guys will tell you that dyno numbers mean nothing. I'm not a track guy but I would have to agree with them. As far as "sluggish", I'm with you. It's summer time here and while I can break the tires lose anywhere in first or second gear, I 100% know what you mean. The common theme on this forum is heat soak prevention. If it is one thing that I'm still in awe of its what a bit of heat can do to a once $100K car.