Dyno Difference

ninetyfiveGT said:

Hey guys. I just have a quick question. What's the difference between a Mustang Dyno and a Dynojet? Why are all the numbers I see coming off of a Dynojet bigger than those off the Mustang Dyno?

Hopefully someone can set me straight here.
Thanks,
Chris

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Because the Mustang Dyno's dyno 10%-15% less
than a Dynojet! That's just the way it is.

Dynojet of course!

Darkhorse845 said:

Dynojet of course!

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I would say the opposite/

Mustang Dyno. More real world. Bragging numbers from a dynojet only. Do your tuning on a mustang.

tuning on a mustang dyno and power dynos on a dynojet. a mustang dyno will apply a load that closely simulates the actual load that the vehicle sees on the road

GTPhreak said:

tuning on a mustang dyno and power dynos on a dynojet. a mustang dyno will apply a load that closely simulates the actual load that the vehicle sees on the road

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VERY TRUE! If you want to dyno your car and get the best tune for performance and have the most accurate info then the Mustang Dyno is the way to go. If you just want to dyno your car to get higher #'s so you can brag to everyone then the Dynojet dyno is the way to go. All serious racers only use dynos that simulate load on thier cars. Do seach on internet and you will find out the facts.If a car is dynoed on a Mustang Dyno and it made 400 RWHP, then if you put the same car on a Dynojet Dyno it will show RWHP to be around 425to 460. This is because Dynojet Dynos do not simulate load.

Problem is, Dynojets are far more prevalent than the Mustang dynos.

Dynojet is actually an accelerometer whereby it uses a 3000-3200 pound drum that is used to create an inertia load on the vehicle being tested. The vehicle's horsepower (HP) and torque try to overcome the weight/inertia of the drum to accelerate it. As a result the software and electronics try to measure the horsepower and torque that the vehicle is developing to overcome the drum's weight and inertia. The resulting horsepower and torque will be higher than a true loading dyno because once the drum starts rolling not as much power is needed to keep it going. Example -- When pushing a car on a flat road, once the car starts moving not as much power (effort) is needed to keep it going. The software does not ask for vehicle weight or anything like horsepower needed to maintain 50 MPH (a number that is actually put out by E.P.A. and N.H.T.S.A.).

The Mustang dyno is a true loading dyno, because it uses an inertia weight as well as an eddy current motor that is attached to the rollers. This eddy current motor creates a drag on the shaft by way of electricity that causes a magnetic field to try and overcome the torque going through the roller shafts. This current is controlled by software that is always trying to simulate load as if the car is driving in real world conditions. The real benefit from the loading dyno is the ability to maintain a load that allows a tuner to properly go through a fuel map or ignition map and tune the chip for optimum horsepower and torque. It has the ability to also simulate the IM240 emissions test as required in some states. It can check 1/4 mile times as well as times for 0-60 MPH and 0-100 MPH. It can also be used for road testing and simulation for drivability problems. As a result of the loading capability, the dyno numbers from a mustang dyno will come out lower than the inertia (dynojet) dyno.
There this is why.

I understand and agree that loading an engine is better, but I don't know enough about the computer program that "loads" the car. Different cars have different wind resistance factors, etc. How does a person know that the computer has matched his correctly? Or are all cars treated the same - one size fits all? Is the cal factor chosen from a menu for different cars?