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neither do I but thanks to Ben from the Xtreme saturn board, we were introduced
to a software dyno. This is a downloadable program that can be used on your
computer to interpret a tach signal in the form of power and torque. How? Well
basically a "real" dyno measures the speed that your wheels turn, and accelerate
through a certain gear in certain conditions under load. How can a software
program do the same thing? Well by using a tach signal from the ignition coil,
a signal determining the engine rpm is delievered. The rpm by the gear ratio
and final drive can give you wheel speed, just as a dyno does. The software
dyno calculates how fast your wheel speed increases in a certain gear and in
certain conditions. You, the user, enters the gear ratios, the frontal area,
outside conditions, car weight, and a host of other information, and the
software dyno uses this to create a hp and torque curve according to your engine
performance. The idea is simple and effective. So where does the rpm input
come from and how does it get to the dyno? You build a voltage driver, which
uses the input from the tach signal and goes through a series of resistors and
potentiometers which turns it into a readable signal by the computer as sound.
A recording program such as Goldwave records this sound when you "make a run" by
starting at a low rpm in the gear and accelerating to redline under throttle.
Then you load the recording onto the software dyno and it interprets the
recording signal into a dyno graph by a series of calculations using the
provided information. Ingenious! Anyways, enough talk here are the dyno
sheets. The "Bolt-On DOHC" is the 1993 Saturn, before the turbo. The intakes
were tested on a stock 1995 SL2.
