gasman,
As far as i know most people here have a scangauge like device which doesn't typically have datalogging capability. I happen to have made my own scangauge like device and i have specifically put datalogging in the design. It shows me what condition my largest fuel usage occurs in and where my best or easiest gains can be found.
My system will log speed and injector on time for every second.
I like your idea, I had a similar idea which is why I put datalogging in but I have tried to evaluate mods with this data however it is not as straight forward as we would like. Calculating fuel usage change of a particular modification from these datasets has the same pitfalls as calculating fuel usage from an MPG read out from one of the gauges.
I have tried to measure fuel usage difference for several mods 3 times and every time there is a problem which makes the data unreliable. Any of the following variables influence fuel usage
- change in road gradient
- wind
- rain
- other cars (even very distant cars)
- starting and stopping location
- How the cruise control is working
for large impact on fuel efficiency these variables get washed out but you have to have more than around 3% efficiency change before this happens.
if your after more info on testing, metroMPG has done a whole lot of tests and generated and posted a lot of valuable data on modifications (with his method of testing and experience testing i trust the data he generates without question). There is also a thread somewhere about the best way to test.
Either way if your still after instantaneous data sets im happy to post up whatever you want. I can post highway driving, a set of my drive to work and back or anything else that I regularly do.
I did put a dataset (graph) for a before and after when doing my cold start idle reduction. I mostly put this up to better explain what the mod does and to give some proof for the results. The page it was posted on is here
Cold Start idle reduction - EcoModder
if you want datasets let me know and if i miss you requesting on this thread feel free to PM me as i only check the recent posts so i sometimes miss posts if i am not on for a while