Here are some graphs from neovb's dyno session.
This is in fourth gear, at 100% and 0% settings.
100% and 0% settings, fifth gear.
100% settings, fourth gear compared to fifth gear.
Note that we use SAE correction, which is going to read a little lower than the STD correction I often see around this forum.
Originally Posted by Ron1n
The car is best tested in 4th, in manual (M4). It provides more control and consistency in the test. Testing in 5th is a waste of time...
To me, every dyno pass we do adds to our store of information. It's never a waste of time.
...not to mention, I question whether or not it skews the #'s.
It does result in different numbers on turbo cars, because the higher wheel load means there's more time for exhaust gas pressure to build in the manifold. All other things equal, you'll see the turbo spool up lower in the RPM range, and you may see higher boost levels at low RPM in the higher gear. The longer pull also will generally result in more heat buildup at the end of the pull, which can mean lower top-end numbers.
But if the car will see high load conditions on the road (and it will) I do like to get some readings from the higher gear.