I've got an '02 LS-1 in an RX-7 'vert that was dyno'ed recently. Since I live at about 4500 ft, the raw numbers are a little dissapointing at 339hp and 348 tq. These numbers are uncorrected and I'm wondering if most dyno's correct for standard press and temps. Is there any "standard" way the numbers are done? The car only has a cam and if corrected, it doesn't look so bad (390 hp or so).

 

Yes, a dyno sheet that is not SAE corrected is pretty much worthless for comparison purposes.

 

SAE corrected is the way to go....some like to use uncorrected #'s 'cause they usually are alot higher. My uncorrected #'s were like 18 RWHP higher.

 

In his case, however, his corrected numbers will be higher.

 

Would his corrected numbers basically tell him what he would be running at sea level, as opposed to what he is really getting at 4500 ASL? or have I got it backwards?

 

The way I understand it, the sea level #'s would be higher in my case. I looked up the correction factors on another website and I was supposed to add 15% to get the corrected HP numbers.

 

Yes.

SAE Corrected.

 

power comes from airflow. airflow comes from airmass and rpm. airmass is air density * displacement * volumetric efficiency. air density depends on air pressure and air temperature. thus if you keep rpm, displacement, ve constant, then power depends on air pressure and temp, that's why all standard corrections give you temp and pressure. once you convert your particular results to the standard environment conditions, you can compare power output.

this site gives you a good rundown of how it works, and some calculators so you get an idea how much this stuff changes with temp/altitude
http://wahiduddin.net/calc/density_altitude.htm

 

corrected... well be there when they dyno it.. its easy for a not so honest engine shop to "invent" horsepower when correcting.. for example, if the shop heater just happened to be close to the temp sensor on the chassisdyno.. that would gice a higher ambient, and increase your so called corrected rwhp.. and the tricks go on...

 

dude you were at our dyno day huh! yes the numbers were uncorrected. i was in the red Z06