Kevin Tetz
October 23, 2013

Will a chassis dyno blow up my engine? Chances are much greater that you'll break something doing a street-tune than strapped to a chassis dyno, even if you're hooked in to the PCM logging with a laptop. The stresses of a hard launch on the street or at the track, followed by three or four gear changes, are far greater than a controlled, single-gear pull at WOT (wide open throttle) on a chassis-dyno. Power pulls are made in a gear that provides a 1:1 ratio between the engine and trans, typically Fourth gear in a T-5, Tremec TKO, or T-56 (or Third gear in a four-speed auto). On a chassis dyno, you can have the opportunity to actually see in action what's going on with every aspect of your vehicle, including wheels, tires, driveshaft, transmission, and all of the information that's coming off the engine sensors into the computer, as well as out the exhaust if you've got a street car and you have to pass emissions. The shock loads of a hard launch as well as going through the gears at WOT are amazing and dangerous if your vehicle is untested; a chassis-dyno allows full power testing with a very controlled and safe environment.

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As with anything, there are some shops that are simply better and have more integrity than others, and with dynamometers becoming more affordable, it's simply easier to "call yourself" a tuner these days. It's up to you to find a tuner that has your best interests at heart, so we wanted to give you several points to consider when qualifying the shop that will flog your project.

8. Rowing up to Fourth gear, a full-throttle pull to 4,500 rpm was recorded and analyzed. Everything looked safe, air/fuel was balanced, but ignition timing was low, netting a conservative 363 rwhp and 490 lb-ft of torque on 93-octane pump gas. After three more 6,600-rpm pulls with a couple more degrees of timing, (19 degrees), the average was a respectable 428 rwhp/481 lb-ft of torque. Standing beside a blown Mustang with headers and a short exhaust is an exhilarating experience! You feel it as much as hear it.

5 Ways to Qualify a Dyno Shop:

1. Appearance

The outward appearance, and especially the shop area of a garage or service center, speaks volumes about the work ethic of a tuner. If things are dirty or cluttered, or if the area looks unsafe and disorganized, this could be a reflection of the employees and more importantly, the owner's quality of work. If they don't think much of their tools and equipment, they might not think much of your vehicle.

2. Customer Service

If someone is rushed, impatient, or even rude to you in person or on the phone, dig a little deeper, but also realize that anyone can have a bad day. Service centers need to understand that you are the customer and they need you to survive, so being dismissive or arrogant does not serve them well. A good customer experience, combined with excellent work and achieved goals creates a repeat customer, and a repeat customer provides the most valuable advertisement on the planet…word-of-mouth.

3. References

If the shop is unwilling to provide a list of past customers for you to call, don't just walk away. Run away! If they're afraid of what someone that has already spent their time and money there is going to tell you, that's a major red flag and is cause for concern. Keep in mind that there is always the potential of an unreasonably disgruntled customer, and that this feedback can often be explained. If you hear negative things, approach the shop owner and listen to his/her side. You may be able to find the truth in the middle, so keep your ears open!

4. Listen!

Is the tuner listening to you? Do they have an interest in what your goals are for your car? If you feel like all you're hearing is bragging about what they got at the wheels of "this car" and "that car" and nothing about how they worked with that customer to achieve his/her goals, this may indicate what we call a "paper tiger" shop. It's not about numbers, even though that's what the Internet forums reinforce. Tuning is about balance and realistic goals for a specific vehicle with specific and unique equipment. Numbers should be incidental, with the primary goal being the optimization of the performance of your vehicle. The best tuners are calibrators that don't have a vested interest in high horsepower bragging rights. Yes it's fun to see a ton of rear wheel power, but sensors, input, and parameters can be adjusted to "report" increases in power with no real changes to anything in the computer or on the engine or chassis. Communication is the key. After all, the dyno operator is going to repeatedly push your vehicle to its maximum output and rpm (with your permission, of course) and you're paying him to do it.

5. Insurance

Ask if the shop has garage keeper's liability. This is expensive, but necessary, coverage for any public service center that protects you and them from an unforeseen catastrophe. You may still be required to insure your vehicle while it's there, so check your personal policy to see what your coverage is. The collector car policy on our subject vehicle covers transport, trailering, liability while at the tuning shop, limited track time, as well as unlimited street mileage. Insurance costs money, not having insurance costs more.