5250 High Performance Dyno Shop Blog

cold temperature Dyno numbers. Why they are different?

[fa icon="calendar"] Jan 26, 2017 12:08:43 PM / by Mike Wiener

Dyno Shop DenverDyno Shop Denver | There are many variables that can change the power output of your vehicle.

Some of are easy to account for, others...not so much.

Dyno setup. Depending on how the vehicle is secured to the dyno can change the numbers as much as +-30hp. The tighter the straps securing the vehicle to the dyno, the harder they pull the tires into the rollers. This causes more deflection in the tire which absorbs more power and turns it into heat.

If the dyno has a test bed that can change length to accommodate different vehicles, changing the length can change how the tires contact the rollers, changing the power reading by as much as 30hp.

This type of dyno should have measurements on it to make sure it is properly set up for each vehicle.

Vehicle maintenance issues can change power readings as much as 30hp.

  • If your tire pressures are low, this will rob power and cause a lower reading.
  • If your oil is old, it will actually increase power output vs. new oil.

This is because old oil is often worn out and thinner than when it was new. It may cause a higher reading, but it offers less protection to your motor. Oil soaked wires can lead to electrical issues, like spark blowout. Fix your leaks before you head to the dyno.

Dyno numbers change with the seasons. The colder temperatures of winter often bring boosts in power numbers. This is not always realized on the dyno though.

Want the best numbers? Bring your car during January / February.

Many dyno facilities have poor ventilation, meaning the test cell is often much warmer than it is outside. As the outside temps drop, fuel suppliers switch to a winter blend. This winter blend is of a different mix than summer blend fuel as it has additives to prevent gelling, water separation, and ease cold starts. Warmer air from a warm test cell combined with winter blend fuel leads to lower power numbers.

Onboard vehicle electronics. Almost every modern car has some form of a "power" button. Even a Toyota Camry has a sport mode.

In some cars, the difference between the default eco mode and sport mode can be 100 hp or more.

  • It is the responsibility of the vehicle owner to present the car it the mode desired before the car is put on the dyno.
  • Failure to do so will result in lower numbers and no one wins.

The more performance oriented the vehicle, the more difficult it can be to get it into it's highest performance mode for good consistent results. With so many different vehicles and methods of changing driving modes, it is imperative that the dyno operator discuss with the owner the best settings for good dyno numbers.



Bring your car ready to pull hard, do your homework and know what matters to get a good dyno pull, otherwise you will be let down, we have seen it happen. Our job is to provide a positive and safe dyno experience, anything less just isn’t any fun.

Isn’t it good to know that the numbers you pull will be felt every time you venture (pull hard) to the freeway?

Set up Dyno time

Topics: Dyno Tuning Colorado

Mike Wiener

Written by Mike Wiener