My simulation software has over 300 variables, so this can only be an approximation.
Gearbox and final drive ratios can make a big difference if they don't allow the engine to be kept in the power band at all times (this is VERY important).
I have assumed a static coefficient of friction of 1, as this is what a reasonable road tyre will achieve on a good surface. Actual date is very difficult, if not impossible, to get from tyre manufacturers.
Data supplied:
Weight 1200kg
RWD
Other assumptions:
50/50 weight distibution
245mm wide rear tyres
25sq foot frontal area
Drag coefficient of .36
5" ground clearance
Gear ratios of 1.908, 1.525, 1.282, 1.085, 0.922, 0.786 (mine)
Final drive 3.85 (mine)
Max BHP at 6250 with gearchange at 6500
Max lb/ft at 5200
Redline 7500
Turbocharged
Runs at 300ft altitude (Santa Pod) under English weather conditions (dry but humid)
In order to achieve a 10 second 1/4 mile run (as stated in the thread title) you will need around 750bhp and 650ft/lbs (10.98 at 137mph) in a car weighing this much.
I stress, before I get taken apart with real data, that this is very rough as too many variables are unknown. For example, raising the tyre friction from 1 to 1.25 (about the best you will get with road tyres on a sticky track) ET drops to 10.72. Lose 240lbs and you are into the low 10s (10.48/140).
In order to achieve sub-10 second runs in a car this heavy, as asked in the post
, you will need a big hike in power, up to the order of 1100bhp and 1000lb/ft.
There is also a fair amount of wheelspin in the lower gears, so some sort of launch control would see an improvement.
The prgramme tends to be a little pessimistic, so you should be able to improve on these figures.
Gear ratios are important. I have used mine here, but these have been optimised for my power data so will not be ideal for a different car.
In order to get a more accurate result, all of the variables need to be known, but this gives you an idea of what is required.
If anyone is interested and can supply comprehensive car data I will run the program for you. I will need as a minimum:
Displacement and location of engine
RWD, FWD or AWD
NA, super or turbocharged (1 or 2)
Horsepower at RPM
Torque at RPM
Redline
Compression ratio
Gearbox type and ratios
Final drive ratio
Kerb weight
Weight on front wheels
Wheelbase
Tyre section width
Driven wheel(s) diameter(s)
Tyre profile
Tyre make and model
Coefficient of drag (not too important)
Frontal area
Overall height
Overall width
Ground clearance
Weight of driver - be honest
Weight of fuel when doing run
If you have a power readout that would be useful
This is in no way a comprehensive list but will get us in the right ball park. If you already have some runs under your belt it will be interesting to see how close I can get
I have tested it using magazine data for various standard cars and it is pretty accurate. I ran it using the Elan data when the car last worked as was within .16 of a second. The difference could have been due to me not having a clue how to launch
