Tuning for MBT at WOT without a Dyno - sort of

I used the virtual dyno software, which basically draws an torque/hp plot based on the rate of rpm change vs. time, its all physics after all...

I tried to approach finding MBT at WOT just like you would on a chassis dyno. I started with a 6 degree btdc baseline throughout the whole rev range. I then added 3 degree at a time with each new run until the gains got very small or i ran into detonation. I am very impressed with how it turned out and how the numbers responded to the small changes in ignition timing. (see attached file)

I know the raw numbers may read very small to a lot of you guys but its not about absolute numbers, i just wanted to try the method of finding MBT with alternative ways.

I am sure this method has its limits, i.e. very powerful cars, and you always have to keep in mind to stay safe on the road. I just wanted to share.

Greetings from Germany,

Markus

Thats interesting, the software generated nice curves , it could be more interesting to have back to back comparisions with the same car and the same tune changes on a chassis dyno , I suspect that the dyno is not going to replicate the same load that the car and the road conditions put on the engine while running on the road and it could be a reason for diferents numbers but if the curves have the same trends , both test goes up and down the same way with the tune changes it could be a good tool when there is no dyno in town. Ofcourse is a goog idea to do the road tests on a good OPEN road or better a drag strip or race track for SAFETY and consistent test.

I haven't spent a lot of time using virtual dyno software myself however it does have its place. One of the issues with virtual dyno software is that it's very reliant on the conditions of the test being identical. This means you need to use the same piece of road each time you perform a test, and the results can be affected by gradient, wind and the road surface. If you have no access to a dyno then it's certainly worth trying out provided you are aware of its limitations.