Essential Mods for a 10 Second Car
"The 10 Second Target"
If you've watched any drag racing or street racing movies then you'll have heard about 10 second cars.
A 10 second car is a car that can do a quarter mile drag race in 10 seconds or less. This is the goal that many set out to achieve when modifying their car.
Although professional drag racing cars can do the quarter mile in less than half that time, 10 seconds remains a reasonable goal for serious car tuners. Having a 10 second car puts you in a rather exclusive set of road legal cars.
What does it take to make a 10 second car? Your skill as a driver will influence your time. Changing gear swiftly and at the optimum point in the power band will have a big effect.
For now, let's focus on the basic tuning requirements to get your car in with a fighting chance of hitting the 10 second goal.
You will likely want to increase your power output, but the smart money goes on increasing the power to weight ratio. A lighter car need less power to reach the magic 10 second goal. So stripping out unnecessary weight combined with power tweaks will give you more bang for your buck.
What power to weight for a 10 second car?
There are a few assumptions made and each of these will have a bearing on the results to a larger or lesser degree.For a 10 second car we recommend the following ratio as a good starting point :-
- 650bhp per 1000kg
- So for a relatively heavy car of around 1600kg, such as a Supra or GT-R, you would need to aim for 750 bhp
- While for a lightweight option, such as an 800kg Lotus 2-Eleven, you would only need around 430 bhp.
Using performance tables and over 10,000 real world data points we can offer this calculator which will show the theoretical best time for your car.
To calculate your VERY approximate 1/4 mile time enter the bhp & weight.
Now we move on to using a fairly sophisticated simulator we get to play with a lot more variables and actually get an ET speed as well.
Now we have a baseline it's time for some more complex calculations. We ran some figures through more sophisticated and complex simulation software, drank lots of coffee and came back a week later to read the results. (It didn't take a week to calculate, but we were distracted by nice shiny cars and engines!)
So using Car weight at 1200kg and assuming its a RWD model as starting points we fed the following into our simulator.
Assumptions made in this next example calculation are:
50/50 weight distribution
245mm wide rear tyres
25 sq 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
Final drive 3.85
Max BHP at 6250 with gearchange at 6500
Max lb/ft at 5200
Runs at 300ft altitude (Santa Pod in the UK) under English weather conditions (dry but humid - yes we know it usually rains but we're trying to bring in the tourists!)
For a 10 second, 1/4 mile run for this car you will need around 750bhp and 650ft/lbs (ET 10.98 at 137mph). For a lighter car the power figure is lower but for a heavier car the power requirement goes up. Trim the weight by around 240lbs and you'll be hitting a 10.48 second 140mph time.
Breaking the 10 second barrier in this car will need around 1100bhp and 1000lb/ft of power - so quite a big hike.
Weight reduction is usually the cheapest and best option. Increasing the power is a secondary consideration. Remember, grip, transmission, clutch and handling all play their part.
In terms of tuning we would suggest an engine swap, adding forced induction, head work and lowering the compression ratio, balancing & blueprinting, cryo treating the block as well as fitting fast road cams and uprating your fueling.
Our forum is a great place to chat with our resident petrol heads and drag racers to get some pointers on how to turn your car into a 10 second car.
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