Hey guys I found this interesting site while hunting for parts on the net.
http://www.race-cars.net/calculators/et_calculator.html
Essentially you put your vehicle weight(measured in pounds) and your estimated RWHP and it works out your 1/4 mile time.
This is a great tool if you are looking to improve your racing techniq, as this can give you an idea of whether you are reaching your cars maximum potential.
For those wondering,a pound is equal to 453.6 grams making the calculation 2.204 pounds per kilogram.
Based on my cars weight and RWHP im looking at a low 15 from my new combo once it hits the street.
Hope this can be of use to someone else..