Wondering if those of you experienced in dynoing cars could give the Seattle group and any others interested in dynoing their S2000 a heads up on what to look out for.

Are all dynomometers created equal?
Is everyone using 4th gear in the dyno?

The place we're looking at in Seattle is charging ~$75. They provide HP, torque curve, 0-60, 1/4 mile, and top speed results using an enhanced Mustang Dyne System which incorporates the MD7000 control panel with a dyno bed capable of measuring four wheels at once with a maximum speed of 160mph and 750HP at the ground... blah, blah, blah.

 

$75 bucks is a bit steep for a baseline. I arrange group discounts for my buddies all the time and with 20 cars we`ve never paid more than 40 a pop

Ryan

 

I paid right under $100 at dynospot but that included an AF reading. Make sure u get plenty of air and that its not hot. The car gets really funky when it gets hot.

 

I'm not overly familiar with the Mustang dyno, but things to consider are:

1. 3rd or 4th gear shouldn't make a major difference, if any, in power measured. Perhaps 1-2 hp maximum. Just be consistent.

2. Ensure that the dyno operator, or the dyno system, if so equipped, is regularly reading and updating temperature, humidity and barometric pressure. If the system has an altitude correction entry, be sure to ask them what they're using (and then check it later if possible to see if the number is close to reality).

3. Make sure tires are inflated to the proper pressure each time you dyno. Even a few psi differential in tire pressure can cause friction levels to increase (its enough to hurt gas mileage). Try to dyno at your usual pressure. Excessively high pressures can reduce contact patch size and therefore friction, resulting in higher wheel hp readings.

4. Always perform a couple of runs back to back. Usually I throw out the first run as it helps to get engine and fluid temps normalized. In fact, Mingster, Prolene, SoCal28 and myself observed that the F20C actually makes more power on successive runs as engine temps climb and stabilize.

5. Make sure that airflow to the front of the car is consistent. Don't move it around during the test. I also prefer to test with the hood closed to really simulate driving conditions, but, conversely, there isn't a portable fan in existence that can simulate the airflow generated at speed. Thus, whichever way you choose (and hood up is probably safer from a cooling perspective) be consistent.

Oh, and if the cooling fans are running, I'd wait till they turn off before starting your pull. They can cause some airflow idiosyncracies while stationary on the dyno.

UL

 

You da man, UL. Thanks to everyone.

 

Keep in mind that the Mustang dyno is quite a bit different (and more accurate) than the Dynojet:

Dynojet 248C 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 MD250 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. Further information can be seen at www.mustangdyne.com

 

Frayed, back from the dead. How's the M3? Thanks for the education, man.

I guess now I see why the Mustang Dyne place charges more than the other dyno shops in our area.

Gonna link this to the Seattle group.

 

The M3's great, though not as fun as the s2k.

I'm heading to my first track event next weekend, really excited.

On the dyno issue, don't freak if your numbers are lower than those from the dynojet. A properly set up Mustang dyno will give numbers about 10hp lower than a dynojet. Maybe even a bit lower than that.

Have fun! It's worth the few bucks.