I have seen Dyno charts on some sites here and there, i have a question about what it shows...what does it show. lol. I mean does it show the engine's torque and horsepower in a specific gear, such as third or 4th? Or does it show an overall rating of torque. Or does RPM's in the case of dyno mean how fast the wheels are spinning the the cylinder of the dyno,and really has little or nothing to do with the rpm's on the tachometer of a vehicle. I would really appreciate anyone who knows anything about what im posting about, thanks. If the last scenario is the true scenario of rpms, i will have other questions that will help me and probably a whole bunch of others who have little understanding of Dyno.

 

The typical dyno sheet shows info gathered during one acceleration run in one gear.Depending on the system it can show a/f ratio,air temps ,water temps,egt,nox,etc...Its a controlled simulation of a car being accelerated.Hondas are typically tested in fourth gear.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Condor018 &raquo;</TD></TR><TR><TD CLASS="quote">I have seen Dyno charts on some sites here and there, i have a question about what it shows...what does it show. lol. I mean does it show the engine's torque and horsepower in a specific gear, such as third or 4th? Or does it show an overall rating of torque. Or does RPM's in the case of dyno mean how fast the wheels are spinning the the cylinder of the dyno,and really has little or nothing to do with the rpm's on the tachometer of a vehicle. I would really appreciate anyone who knows anything about what im posting about, thanks. If the last scenario is the true scenario of rpms, i will have other questions that will help me and probably a whole bunch of others who have little understanding of Dyno. </TD></TR></TABLE>

As far as I understand (never having used a dyno), specifically, most dynos measure simply how fast a big drum gets accelerated. From this it can figure out the engine's torque and horsepower throughout the entire rev range. Obviously this big drum will get accelerated faster in 1st gear than in 5th, but ideally the computer also knows (or measures...not sure on this one) how fast the engine is spinning and therefore, after the calculations are complete, the data should be similar: a pretty accurate graph of the engine's torque and power throughout its rpm range. The data shouldn't differ much in the different gears, except inertial effects will show slightly lower numbers in the lower gears, and perhaps the transmission has a different efficiency depending on gear, but I'm not sure how much of an effect these have.

 

Thanks for responding, im gonna read a little more into this. before I post again.