I have recently heard several people refer to dyno numbers lately, either low or high, by saying (Company name here)'s Dynojet always reads lower than others. Or (Company name here)'s Dynojet reads higher than others. Is this true? Is it possible that different Dynojets read differently, or do some operators "manipulate" the dyno results for one reason or another? I thought all Dynojets corrected themselves to a "standard", so a Dynojet in one area would read the same as Dynojets in other areas, correct? TIA, Shawn

 

Dynojets all correct to current weather conditions, but the tolerances of them, or the efficiency of them are probably a bit different. I would imagine an older dyno with 1000s of runs on it would be a bit looser in the bearings to turn. This is why you should always use the exact same dynojet to measure before/after changes when you add parts to the car. The Dynojet is just a tuning tool, not really something to use to compare with other dynos across the country.

I've ran my Formula on three different Dynojets in the Houston area, and the power was always the same. I think some people just like saying that "X" shop has a higher reading dyno because they are jealous of the numbers of someone else. I've also witnessed three "dyno challenges" where someone claimed a particular shop had a higher reading dyno than his shop, and that person was asked to come dyno on it in front of witnesses, and his car actually dynoed lower LOL. Funny.

Tony

 

DynoJet are pretty consistant. My car has been on two differnet ones and the difference was less than 1 rwhp.

While DynoJet can correct for most weather conditions I don't think it can correct for humidity.

 

Thats what I thought, I've just been deluged wioth people telling me that, so-and-so's dyno reads lower than other dynos, don't worry, its normal.

 

just do the smart and fair thing....
go to several dyno's (when you have a good stopping point for a while on your car)... then average the #'s... if you have 5 runs.. and they are 300,305,302,307,305...then that means you got 303.8......the average of all of them!!! cant go wrong with that theory...that would give the best representation for the average weather conditions also....

 

I think 99 blackbird is right,a properly ran dynojet will be within 1-4 hp from the other. it is always a good idea to stay with the same dyno for your mods so you can get an accurate before and after without any question

 

We have one of those low Hp dyno jets
new 2 years ago who knows I would like to know or someone list all the ways people think they can trick the dyno

 

Here's a few ways I know to skew a DynoJet result. I don't think the dyno is tricked just the result tampered with...sometimes by the operator...

DynoJets with the older DOS based software can have the manual data entry for weather conditions. Examples barometric pressure I don't know if the newer windows based ones can have that done or not.

Selecting software verison. Some of the early verisons of software have bugs. Depending on the bug the result can be skewed. Local DynoJet discovered the torque was really very high one day on all A4 cars, they were averaging 25 to 45rwtq higher than expected and higher than prior dyno's. Turned out an old version of software got loaded.

Move the temp measuring probe near the exhaust and raise the reading for the air temp. By using a false higher temp the DynoJet will invoke a correction factor and skew the numbers higher.

Operator doesn't strap the car down perfectly straight or varies the tightness of the straps.

etc

 

My dyno experience with DynoJet is my SAE numbers are lower than Standard uncorrected numbers. Im talking on a 80+* day with high humidity and low barometric pressure. How can this be? If correction doesnt help on days like this than i dont get what correction factor and SAE numbers are for?

 

Anyone want to comment on this? TIA