This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your BMW 3 Series. The book contains 272 pages of full color projects detailing everything from performance mods to timing the camshafts. With more than 650+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any 3 Series owner's collection. The book was released in August 2006, and is available for ordering now. See The Official Book Website for more details.
Forward by Wayne: John has written us an interesting little computer program that allows you to map the drive ratios that you have in your transmission with the final speed of your car.
Hi Dave and Wayne, here is a little program I wrote to do some speed vs rpm calculations after I did a rally a couple of months ago and had trouble with speeds vs rpms, etc. We got lost too, but this won't help that!! Anyways I was waiting until I got a speedo check so I would be able to compare with my program to see if it is accurate and it seems to be. I makes a file called speed.txt that can be used while rallying to get accurate info on your speed settings. Please let me know what you think and if you find any bugs. Note it automatically calcs for 4 or 5 or 6 speed transmissions and for the tire info you can enter tire dia or tire circ or tire revs per mile.
It would be handy to allow someone to see what going to a larger tire would do to their rpm, speed etc. This was a ??? on the 914 area of your bbs and that prompted me to go ahead and finish it up. You sure can put it on the site for people to get and you might want to add the addresses of BFGoodrich and Yokohama as they have the tire info people may need such as tire revs per mile etc.