Measuring Performance

In the past I would throw random parts on my car in an attempt to gain better performance. By performance, it can be acceleration, braking, and cornering. Sure the intake seemed like a good idea, and the exhaust sounded cool, I know the turbo worked but didn’t have any hardcore performance data to back up the mods.

The most standard methods of measurement include a butt dyno, a real dyno and quarter mile times.

The butt dyno is far from accurate and can differ greatly between different models. Perceptions can also be skewed by different sounds and different feelings.

A real dyno is not always accessible to everyone and can prove to be quite costly. This is a test that just about every performance minded car should go through eventually. That said, it’s not real feasible to go to the dyno every time you make a simple mod.

The last test mentioned is quarter mile times and trap speed. The speed is quite possibly your best performance indicator.

All of the previous methods are great and very effective, however not practical for the average person. Here are 3 great tools for measuring performance that anyone can do on a daily basis if desired.

Stopwatch: Quite possibly the most overlooked tuning method is a stopwatch. Before installing that next mod, make a couple of base runs and fill out the chart below or a similar chart of your own design. Once you have made the modification make another couple of runs and compare the results. This should let you know just how well that last mod worked. This is also a good method for making adjustments such as fuel enrichment or changing intake lengths.
30-70 MPH Time               Ambient Air Temp
Before                        XX                                               XX
After                           XX                                               XX

A stopwatch is amazingly simple, yet quite effective. This can also be done while driving. Another thing to note is the importance of a rolling start. When starting from a rolling start, the launch factor is taken out of the equation making for some very consistent times. For even more consistency, I recommend accelerating in third gear for the widest acceleration band without speeding. You’ll also need a thermal probe to monitor the outside temperature.

G – meter: I can’t think of the name right now, but it’s a U-shaped style of meter with a ball and some oil in it that tells you how many G’s you are pulling. A similar device that is designed for boats to monitor pitch can be purchased at a Marine retailer. An example of how to use this would be acceleration. You’ll need a passenger for this. Mount the device to the passenger window using a custom made bracket and suction cups. Now from a rolling start, yell “NOW” when you hit 2000, 4000, 6000 RPM so your passenger plots the points on a graph. Make another run yelling “Now” when you pass 1000, 3000, 5000, etc RPM. Once the points are drawn out, you can then connect them. This should give you an idea about your power curve