what does it mean "to dyno a car"??

[cccp]

I saw it somewhere, and don't know what it means.. there was also something about a "dyno test"

 

[oubeta]

You place your car on a ramp that has rollers on it that is hooked to a computer and it graphs out your torque curve and real wheel HP

 

[Yarg!]

A dyno is a machine that has a huge fan at the end of it. You strap the car onto it. And it starts up, the huge fan turns and so does the wheels of your car. Then it gives you an accurate "to-the-wheel" horsepower rating (non of that useless flywheel power). To dyno a car means to put ur car on that machine and measure its wheel horsepower.

 

[canadianhitman]

dyno test is where they measure horesepower output at the wheels, at varying RPMs....your car's drive wheels are set onto a sort of rotating drum, which in turn are hooked up to a computer.

Testing on the dyno is done at full throttle. The computer increases the load until it brings the RPM to a lower preset limit to start the test cycle. When the test cycle is started the computer eases the load to allow the RPM to increase. It then takes measurements at preset intervals until it reaches the upper preset RPM limit and then returns the engine to the lower limit. That completes the test cycle.

 

[jackangel]

Dynamometer:

A device used to measure the output characteristics of a car's engine (i.e. torque, hp, rpm).

 

[cccp]

thanks guys, karma for you when I recharge.

 

[IvanOffelitch]

A dyno is a machine that has a huge fan at the end of it. You strap the car onto it. And it starts up, the huge fan turns and so does the wheels of your car. Then it gives you an accurate "to-the-wheel" horsepower rating (non of that useless flywheel power). To dyno a car means to put ur car on that machine and measure its wheel horsepower.

"Useless flywheel horsepower"?

Chassis HP is important, but so is flywheel HP. By comparing both chassis and flywheel HP, you can measure parasitic losses through the drivetrain. I've seen more than 1 car produce awesome engine dyno #'s but mediocre chassis dyno #'s afterwards.

Most serious racers use both.

As a rule of thumb:

Expect 10-15% parasitic loss with manual transmissions, and expect 20-25% parasitic losses with automatics due to torque converter slippage (unless the car is equipped with a lock-up torque converter, or a high efficiency race converter).

Accessory demands (power steering, charging system, etc) contribute to parasitic loss, as do inefficient exhaust systems.

Hope this helps.

 

[ajtomasi]

my trans am was rated at 310hp at the crank but many actually put down 310 to 320 to the rear wheels.

same thing with the dodge srt-4 which is rated at 215 at the crank and actually dynos much more.

car companies under rate cars for many reasons, but mostly for insurance costs.

 

[Tarheel]

Actually any machine that measures torque and rpm and then calculates the hp is a dyno.

You can have a chassis dyno that measures it at the wheels or an engine dyno that only measures it at the crank or flywheel. Both have thier purpose, the engine dyno is usually more repeatable and consistant, while the chassis dyno takes into account the loss of the drivetrain and of course you dont have to remove the engine.

You can also use a dyno for tuning, but you need one with variable load to get the best results.