 I'm E here again and welcome to another episode of Cobb U. Now that we've spent all this time and money modifying and tuning our cars, how much power have we actually gained? And how do we measure that power gain safely and in a controlled environment? Welcome to the world of dynamometers, also known as dinos. Dinos come in all sorts of sizes and styles, like in-ground, above-ground, portable, two-wheel drive, all-wheel drive, axle hub, water brake versus eddy current, and inertia versus loading. Dinos are pretty freaking cool and the go-to solution for measuring power gains. But at the end of the day, they're just a tool and they're not perfect, so it's really important that you understand how they work so you can properly interpret the results. We find that many enthusiasts don't quite understand the ins and outs of dinos and often put too much value on the wrong information. So today we're gonna learn how to use a dyno and how to properly read and understand the results to help maximize the potential of your car. At its most basic, a dyno, like this one, can measure the power of your car without actually having to take it out on the road. Now, using a dyno provides a safe, consistent, repeatable environment for you to push your car aggressively. Many of these cars aren't street legal or super high-powered and even the slightest modified daily driver is gonna exceed typical highway speeds on a dyno. As you accelerate, the tires spin the rollers and either a load cell reads the amount of force supplied or a speed sensor measures how quickly you accelerate the rollers. Now, the way a dyno works and reads data will vary, but generally they have similar components. They will have some type of roller for the tires to spin. The exception to this are hub dinos that attach directly to the hub of your car. From there, they will have some sort of brakes to stop the roller. A sensor to read the load on or speed of the roller, a main computer that has the manufacturer's software and a screen to view the results, a fan of some sort to help keep engine and air temps in check, and finally, straps to keep the car from flying off the rollers. If the dyno is being used to tune your car, various sensors will be attached to it like an air fuel meter and a boost sensor. The tuner will then use this information to help him dial in the tune. People tend to think that dyno's actually tune your car when in fact they're just a ruler to measure things. Unlike a ruler though, dyno's don't all measure the same and there's different reasons why. Some reasons are controllable and some aren't. For example, some that are controllable are the dyno's calibration from the manufacturer, how tight the straps are tightened, the type of dyno, how much air is in the tires, and even the driver input. While things like weather, health of your car, and elevation aren't. At the end of the day, if it's not the same car on the same day, on the same dyno with the same fuel and so on and so on, your final numbers are gonna be different. Sometimes those differences are huge and sometimes they're small. To show this, we took our 2007 911 GT3 and did pools on our Cobb dyno and then drove it right away to our friends at Calvo Motorsports and did pools on their dyno. As you can see, same car, same day, and same brand of dyno, but we got varying results. On our dyno jet dyno, the car made an average of 351 horsepower and 276 foot pounds of torque. On Calvo's dyno jet dyno, it made an average of 358 horsepower and 266 foot pounds of torque, showing a small difference of seven horsepower and 10 foot pounds of torque. In comparison, on a Mustang dyno, the same car made an average of 309 horsepower and 244 foot pounds of torque, showing a huge difference. So now let's take a look at how a proper dyno pool is done and how to interpret the data. The car is driven onto the dyno until the tires rest on top of the rollers. The tech will then strap the car down to keep it from sliding off. Once the car is safely strapped down, the driver will get the car and dyno up to the desired gear and engine speed. This is usually in third or fourth gear depending on the transmission. Once they're ready, they will go wide open throttle until they reach the desired RPM. At that point, the brakes on the dyno will be applied and the car will come to a stop. These pools are done a minimum of three times and then averaged for the final result. This is a big part where we find that people don't actually understand what they're looking for and focus on the wrong information. At the end of the day, peak power isn't gonna guarantee that your car is gonna be faster. So stop worrying only about how big the numbers get. Instead, look at the big picture, which is the entire curve. Looking at a sample dyno chart, you will generally find columns to show you the horsepower and torque on the vertical axis and RPM on the horizontal axis. Sometimes other readings are shown like AFR or boost. In this example, the blue line represents a stock pool and the red line is a modified pool of the same car. The first thing to think about when looking at a dyno chart is that you drive your car in all RPM ranges, not just whatever RPM your car happens to make peak power at. Everyone's favorite hobby on the forums and local car meets is to talk about the peak power that their car makes. But that doesn't tell the whole story. What we see when looking at the entire curve is that during the pool, power was increased throughout the entire RPM range. This is what's meant when you hear the term power under the curve. Making a car faster is about optimizing the area of increased power throughout the largest RPM range possible. So if your buddy's car makes the same or even a little more peak power, but yours makes more overall power under the curve, then in most cases, you'll have the faster car. What you can also see in the curve is how smooth or choppy your power is. In this example, you can see that the stock pool at 4,500 RPM has a dip before it increases again. When looking at the same area on the modified pool, you can see that the calibrator has made the necessary adjustments to improve that area. Knowing how much power your car makes is only half the battle. Yes, we wanna know how much horsepower there is and how much torque there is. But when we're modifying our car, we wanna know how much power increased with those modifications. And to do this, we need two things. You need a baseline and then what percentage increased? Can't have one without the other. When modifying your car, you'll wanna get a base number by having it run on a dyno stock. This is gonna give you a figure to compare to later. Can't know how far you've come until you know where you've started. Now what's not important is the figure itself, but how much power you've gained as a percentage. Let's take a look at an example. We'll first get three dyno pools on the car's stock and then three pools after it's modified. If we take the average of the stock and the average of the modified, we can get a percentage difference between the two. This percentage is the amount of power gained through the modification. Now power increase is power increase. So no matter what dyno you go to, if you're comparing a stock pool to a modified pool, you should see the same percent of power increase. Even if you and your buddy get the same stock STI and yours reads 280 horsepower on our dyno and his reads 270 on Calvo's dyno, as long as you guys are doing the same modification and using the same fuel, you should see the same percent of power increase. Given that both of your engines are in good condition. That's gonna do it for this episode. Thanks for joining us and be sure to subscribe to our YouTube channel so you can check out future episodes. I'm Emmy, your host for Cobb U. Remember, check out CobbTuning.com for all your parts and tuning needs. Do you like the storage solutions featured in our studio? Then visit sonictoolsusa.com to get more detailed product information.