P2K Pro & RS4 Rally Speed?

[chuglobal]

How fast ( mph ) does a stock RS4 Rally go with a P2K Pro with all the default factory components? I've read many people using the RS4 are using the P2K so I'm hoping someone can provide some real specifications. How fast would a Speed Gem 17t single make the RS4 go? Thanks.

[Jason C]

First, you should do your motor a big favor and get a new pinion. The stock 31 tooth is overgearing as shown on the chart at the end of the manual. It will fit and run fine, but you'll be overworking your motor and cause it to wear prematurely. A 28 tooth pinion coupled with the stock 90 tooth spur would be a good all-around combo for a P2K. You may want to go down a tooth for more twisty tracks or up for less twisty ones.

With the 28/90 combo, I average about 20 mph (very rough calculation using distances between driveways and a wristwatch), but I'm sure it is a bit faster than that.

If you like speed but still want to stick with a stock motor, try the Green Machine 3. I have it and it is a good motor, but it puts out less torque than the P2K - a motor better suited to more open tracks.

For your modified motor, I recall there is a 10+ rule for a rough gearing estimate. It goes like this: Say you have a 17t motor (like you speed gem). Add 10 to the number of turns to get the pinion size for the motor. So: 17+10=27t . Keep in mind that this is a rough starting point for your gearing and you should do the math and experiment to see what you like best.

For the 17t, I think your rally would do at least 30 mph or better.