C COUPE pulley kit - MB Warrenty and Acceleration??

To my knwoledge, no one at any of the MB fora I read has done before and after track tests of the pulley kits. One poster, who also has an Upsolute chip, reports that he is now able to beat 330i's now. Road & Track tested the 330i at 6.5 sec 0-60. R&T's time for the C coupe is 7.6 sec. Another poster reported 0-60 times in the low to mid-6's, but he also has a modified ECU, 3.67 gears and lightweight wheels.<br> <br> One thing to keep in mind is that the coupe has relatively slow 0-60 times because 2nd gear tops out at 52 mph. All other manufactures gear their cars to top out 2nd gear at 62 to 63 to lower their 0-69 times.<br> <br> As for the warranty, the Moss-Magnason (or is that Magnuson-Moss) Act requires that manufacturers prove that the modification caused the failure. However, who do you think is going to have the best legal representation, you or MBUSA?<br> <br> The pulley kit won't change your top speed. It is electronically limited in the ECU to 130 mph. The Vmax limiter can be removed by some chip tuners but the cheapest I've seen is $1500 to have it removed. Without Vmax, the top speed of a stock coupe is 149 mph.

On the A4 you can increase boost with a chip only. Also on Turbo's you can control the amount of boost with a boost controller so when you don't need it you can turn it down. On the Coupe you'll need a pulley to increase boost and the boost is always on and a fixed ratio. Cost can be about the same although some pullies are astronomically priced. Warranttee implications are about the same. You can replace the pulley back to stock and bring it in and they will more than likely never know the difference and repair your car. Doing some quick math, the stock pulley spins the supercharger at about 12,000 rpm. Eaton says 14,000 rpm is their recommended max on the M45. Depending on the brand of pulley they spin the supercharger at 15,000 to 16,600 rpm. The mildest pulley is the Vaeth at 23cm and the most aggressive is the H&S at 25cm with all the others falling in between. The limiting factors in making it bigger is the proximity to the water pump pulley and there's a point of diminihing return where additional RMP cause more drag and heat than power.