Dyno, do gears effect HP???
02-05-2003, 02:15 PM
#1
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Dyno, do gears effect HP???
Saw a post on a very nice car setup achieving some terrific results.
However the dyno results from 2 runs vary by 42HP at the same boost.
The explanation is that it is because of using 3rd -v- 4th gear for the run.
If this is true, then tire size will effect dyno HP reading also!
So, the following things that seem to effect dyno readings are, 1) type of dyno, 2) the correction factor dialed into the dyno, 3)what the real boost level was, 4)air temp, and now 5) tire size or gear ratio.
If this is the case, the comparability of any of our dyno number is very questionable.
Whats up?????????
However the dyno results from 2 runs vary by 42HP at the same boost.
The explanation is that it is because of using 3rd -v- 4th gear for the run.
If this is true, then tire size will effect dyno HP reading also!
So, the following things that seem to effect dyno readings are, 1) type of dyno, 2) the correction factor dialed into the dyno, 3)what the real boost level was, 4)air temp, and now 5) tire size or gear ratio.
If this is the case, the comparability of any of our dyno number is very questionable.
Whats up?????????
02-05-2003, 02:59 PM
#2
Rennlist Member
yes, 3rd gear is 99.9% of the time your strongest gear. That's why it's the standard gear when running a dyno. One of my hondas I run all my dynos in 2nd gear since it's an automatic and it's the only way I can get some low RPM readings. But as long as you do all your dynos in that gear you'll get a good basis on your improvements.
02-05-2003, 03:04 PM
#4
Rennlist Member
also in a turbo car your Real World HP will always be higher then on a dyno. Because you wont' get suffeciant air flow from that crappy fan most dynos use. Imagine the airflow you get into the engine when going 80 MPH, it's not even close to what you get on the dyno.
