Ok I'm using an accelerometer in my car to calculate the approximate power output of my car and accurately record the forces acting on te vehicle in 16 directions. Only problem is to calculate the power I need to know the approximate losses in the drive train.

So my question is, has anyone driving an awd (TL if there is any difference) had a dyno test done and recorded their drivetrain losses in a percentage? Stockish if possible too

thanks

Ok I'm using an accelerometer in my car to calculate the approximate power output of my car and accurately record the forces acting on te vehicle in 16 directions. Only problem is to calculate the power I need to know the approximate losses in the drive train.

So my question is, has anyone driving an awd (TL if there is any difference) had a dyno test done and recorded their drivetrain losses in a percentage? Stockish if possible too

thanks

From my SKR tune, it was between 35 and 40 %.

Alright thanks, I figured somewhere around there

From my SKR tune, it was between 35 and 40 %.

:stoopid: :(

I took my car out for a little spin this afternoon after everything was calibrated and set up, and I was actually quite surprised by the results. I put in the weight of my vehicle and me ( as well as about 20kg for the useless collection of junk that seems so build up in my boot) estimated at around 35% drivetrain losses and then opened it up a little once I got onto the highway, only took it up to ~110km/h before anyone has a go at me. Surprising part was the results- it calculated my engine kw to be 156 which is pretty accurate IMO. Especially over such a short acceleration band.

Now that I know it's all working well I will set it up to measure kwatw, which could be a little harder with the awd than it would for a 2wd, but I'll figure it out.

I took my car out for a little spin this afternoon after everything was calibrated and set up, and I was actually quite surprised by the results. I put in the weight of my vehicle and me ( as well as about 20kg for the useless collection of junk that seems so build up in my boot) estimated at around 35% drivetrain losses and then opened it up a little once I got onto the highway, only took it up to ~110km/h before anyone has a go at me. Surprising part was the results- it calculated my engine kw to be 156 which is pretty accurate IMO. Especially over such a short acceleration band.

Now that I know it's all working well I will set it up to measure kwatw, which could be a little harder with the awd than it would for a 2wd, but I'll figure it out.

Shouldn't it be easier??
Given it's calculating the power based on the forward momentum of the car, it can only calculate the power at the wheels (driving power), and then use the drivetrain loss to 'derive' the power at the fly?

Yes, it's easier to measure kwatw than engine. I was mainly using engine kw (which are easy enough to find out) to check everything is calibrated.

To work out kwatw with an accelerometer you need to gave it set up with the weight of the car as you do the test. Once the mass is in and the accelerometer is mounted, calibrated and zeroed all that needs to be done is to do the test run (must be straight and level) to start the test you will need to slowly feed in power to get moving then gradually accelerate to full power. If you just drop your foot off the line you will get a spike on the g-meter which could ruin your results.

Anyway once you do your run the accelerometer will record the g forces and speed during the run and using the mass of the car can simply calculate power. Power=mass x acceleration. For engine kw you'll just need to know your drivetrain loss

I would love to have/use a G-Tech or one of these apps on my phone. (need to upgrade phone first though).
Something that records maximum G-Force, as well as something that calculates power and times 0-100kph, etc would be fantastic for tuning.
Put on a new exhaust, go do a power run.

Get different tyres or suspension setup, than go measure lateral g-forces for maximum cornering grip.

Could come in very handy, especially if trying out custom mods like playing with intakes or suspension tweaks.