First a little background on "dynoing": Horsepower ("hp") and torque (sometimes referred to as "tq") values are numbers that all car enthusiasts want to know about their cars and other peoples' cars. These numbers are what define the car's performance abilities, both in stock and modified form. Car manufacturers will always diplay the performance figures for their cars because they know that (if nothing else) a car buyer will know what more or less horsepower means.

What most people do not know is that there are two different ways of measuring hp and torque, one is "at the crank", and the other is "at the wheels". "At the crank" is engine hp/torque that the engine makes on its on without having to propel the weight of the car, which is what almost all manufacturers post. Obviously, hp/torque is lost when you factor in the car's weight and other variables, or what is known as "drivetrain loss". Drivetrain loss is the loss of hp/torque after it goes through the drivetrain components, and this usually amounts to a 15-20% loss in "at the crank" hp/torque.

However, most dynamometers will measure "at the wheels" hp/torque because it is the true value of how much power the engine and car as a whole are making. If you are planning to modify your car to yield horsepower gains, having a baseline dyno done is strongly suggested so a benchmark to work by is available.

the basics

This car was first dynoed at Waterfest '01 on Podium Performance Product's DYNOmite dynamometer on 22/7/01. However, further studies and information show that the results received from their equipment was flawed due to computer error. the car was then redynoed on Upper Limit Performance's DynoJet dynamometer on 27/8/01 after having been chipped by UPsolute.

Dynoing a car is most certainly a new, exciting and completely different experience.

dos and don'ts

The first thing that happens at a dyno is the car in question is rolled on to the dynamometer and then strapped in so that the car does not go flying off. The dyno computer is then attached to the engine, which is done by tapping into the spark plug wires, and electrically grounding the car. The first run done is used to properly center the car's wheels on the rollers, this is usually performed with the car rolling at around 10 mph before the actual, counted runs begin.

The rules for the counted runs are as follows:

1. Turn off all traction control systems
2. Never dump your clutch
3. Never step on the brakes (unless the operator tells you to)
4. Never move the steering wheel, but hold it in place when doing the runs

results (22/7/01, waterfest 2001)

Modifications:

• Eurosport Accessories Cool Flo intake
• Freedom Design/Sebring exhaust

results (27/8/01, upper limit performance)

Modifications:

• UPsolute chip
• Eurosport Accessories Cool Flo intake
• Freedom Design/Sebring exhaust

anaylsis - a second opinion

After the Waterfest dyno was posted, a person with the username "mattrenn" e-mailed me about corrections he had to offer. Here is part of his e-mail, again, this is in reference to the Waterfest dyno results, which are believed to be incorrect:

Anyway on to your dyno test. At the Crank the VR6 is rated at 174 hp and 181 ft-lbs of torque (you already knew that).

Torque is the force the engine puts out. Horsepower is just that, power. Which is force x speed. In other words if you want to convert Horsepower to torque all you need to do is multiply Horsepower by 5253 (comes from the units conversion) then divide by the rpm the engine was turning at that Hp. This is why Hp and Torque are always given with a RPM.

Hp = (torque x rpm) / 5253 or in your case at ~4800 rpm you made ~180ft-lbs of torque (your max torque), so you were making:

Hp = (180 x 4800) / 5253 = 159 hp. At that RPM. Which is pretty close to your dyno graph. So I'd say the dyno was accurate.

Also your reading your chart wrong, don't feel bad I did the same thing at first too. You have to read max Hp. Then go down on the chart to the RPM line. Then read the RPM at that point. So you are actually making max 176-178 hp at ~5700 rpm. Your Hp line is Hp vs time, not Hp vs RPM as typically shown.

Basically without forced induction the only way to increase max torque is by increasing compression (more pressure), or going bigger displacement (more air). Basically adding a chip helps to raise compression (hence with a chip, usually requires 93 octane gas). So I'm surprised by your torque gain (Do you have a chip?). Stock torque at the wheels is like 160-165 ft-lbs, or so I've heard. Don't have dyno data to prove.

But since you increased the 'breathing' of your engine with the intake and exhaust your are now flowing more air in and out of the engine. Basically your making it pump air better. This effect typically doesn't help a whole lot at lower rpm, where the VR6 makes max torque. The engine just doesn't use a lot of air. However at the higher rpms 5000+, you are moving a lot more air. So the effect your intake and exhaust has is greater.

Now at higher rpm your hp number benefits because hp is torque times rpm, divided by 5253. So the higher your rpm, typically, the higher hp you get. So with your mods your torque is not falling off as rapidly at the higher rpms than stock. So you multiply your rpm (6300, big number) by a slightly higher torque number. This produces the substantial gain in your hp numbers.