standard S2 Gtech run

[1975DCS]

However accurate (or not) the G-Tech is - it is a good tool for guaging RELATIVE performance improvements before and after modifications - absolute figures are less important for that. As long as it repeatedly gives you approx the same answer at the same engine trim and ambient conditions.

Yes I would see as the main purpose and benefit of this device! For that I would want one too...

[Audi_CQ]

I assume this device works a bit like this: you put in the weight of the car and by monitoring the G-force (and speed) on your car it will calculate (with known data) what kind of hp equals what kind G-force. If I am wrong please feel free to correct me.

Spot On

With this quote "Results are @wheels with no correction for drivetrain/wheels/wind resistance losses." you are already saying the answer. It cannot see the difference between 4wd and 2wd, so power @wheels will be unreliable data. Also power at wheels is not to be influenced by wind resistance but speed is!

It doesn't matter if it's 2 or 4wd. Power @wheels is the same and is NOT ureliable
Calculating/estimating/guessing flywheel hp is unreliable

HP at wheels not influenced by wind resistance, but for a g-tech it matters. If trying to guestimate flywheel power it's something to have in mind.

An ex. : Testing with g-tech at top speed(if restricteed by wind resistance and not rpm) will get you 0 hp @wheels........

Cheers,
Roger

[GandalfS6]

In principle there is little difference between a dyno (where you measure how the rollers are accelerated) and a Gtech (where the car itself is accelerated). The major difference is wind resistance. If you know the frontal area of the car and its drag coefficient, you can calculate the effect of wind resistance.

My car does not really like dynos as they normally can not simulate the right airflow - my car is stronger top end when measured with a Gtech as you don't have to simulate airflow - it is the real airflow.