How to calculate performance impprovements?
I'm trying to find a reliable way of calculating performance improvements, or maybe even just changing plugs & HT leads, that is cheap and that I can do myself.
I started with post on Home Dyno and after reading links in White Knight's reply on that wondered if there was a simpler method that doesn't require anything more than stopwatch and basic arithmetic.
The dyno figures aren't really that important. I just want to be able to measure changes to see what does and doesn't work and how it compares with base and other improvements.
Would this work?
Get my 5sp manual 3.9mpi rolling and stabilise at, say, 20kmh and check rpm, then accelerate on WOT to, say, 100kmh and check rpm and elapsed time from 20 to 100? Or maybe do it on rpm from around 20mph rolling start to about 4,500 - 5000 and check elapsed time? Do say three runs and take average. Do all future runs on exactly same bit of road in similar weather conditions. Then compare times over base and improvement and calculate percentage difference?
I'm suggesting rolling start and staying in one gear because it doesn't involve any gear changes and eliminates driver variables and gives constant test process.
I realise it's nowhere as precise as a dyno, but it seems like it should give fairly reliable comparisons for my car.