Drag racing car setup
"A bit of a Drag"
This article is merely an introduction to those new to the world of Drag racing, looking to convert a street car for the drag strip. We have a whole forum dedicated to drag racing where drag racers can swap ideas and talk technical together with everything from engine tuning, fuel selection, and transmission mods to oil selection.
Racing on the road is dangerous, illegal and stupid. We at TorqueCars do not condone or promote illegal street racing. All drag racing advice here is to be used on the track in an organised event.
Do you really want to tune your car for quarter mile acceleration? First off you need to decide what your budget is and which you'd rather do, 1/4mile strip or circuit because you will not be able to have both.
A circuit car needs to be well balanced and handle well before you worry about going fast, and a circuit car needs more mid to top end power to be able to pull out of corners easily and have a higher top speed for those straights.
A drag car just needs to get from 0 to top speed as quick as possible. Top speed doesn't have to be an extra ordinary figure to get a good 1/4mile time, you just need to get there quickly. You may be up against a car that has a top speed 20mph higher than yours, but if it takes an extra 4-5 seconds to get there you will probably win.
When building a drag car it needs to be as light as possible and as powerful as possible, weather it handles and goes round corners is not important but you do need maximum traction at the driven wheels. If you wheel spin you loose time.
Turbos are alright on the strip as long as you remember to keep your rev's up, and that includes when you launch. This means screaming the motor off the line and gently feeding in your clutch to avoid wheel spinning and torque steer which will loose you valuable time.
With a N/A motor you have more control over your launch as you don't have to worry what your boost is doing but you have a harder task getting the top end power. Superchargers are best as you have constant boost across the rev range giving you more launch control and good top end power.
Building a car for the circuit and putting it down the strip with a little squirt of nitrous to help your time is probably your best bet. It is not possible to build a car specifically to do both and you cannot run a strip car round a circuit because it won't corner, but you can run a circuit car down the strip it just won't be as quick as a purpose built drag car.
1) Do you want the car to remain very comfortable, or are you prepared to throw all luxuries out the window and have it raw.
2) How much do you have/want to spend? As much as it costs, a lot, a little or build it on a shoe string.
The order TorqueCars would recommend tuning your drag car is this:
a) Get your engine first. Strip it down and make sure it is all OK. While you are there replace your piston rings, all engine bearings and oil seals. It may be worth fitting a high pressure oil pump too as the engine will get a lot of punishment. It will also be a good idea to fit any high performance parts while you're here too.
b) Get the car of your choice, put bigger brakes on it and put the engine in. While doing the engine swap, get rid of the power steering and fit a manual rack. they weigh less and reduce drag on the engine. When you fit the exhaust put an extra flange joint just behind the engine so when you're at the strip you can remove it. Once the engine is in drive the car round gently for 500 miles not exceeding 3000rpm and NO harsh acceleration during this period but do plenty of hills and really work the engine at different loads (keeping under 3000 rpm). Once you have done 500 miles do an oil and filter change and thats your engine sorted (in theory). Fit a good roll cage too.
c) I wouldn't bother lowering your car but I would put harder shocks on it to hold the wheels more firmly on the ground so they don't spin.
d) Get a spare pair of wide wheels to use your strip tyres on to go on the driven axle. You won't be able to use on the road as they are usually too wide for a UK car and are very expensive (and usually slick). For free rolling axle, I would use standard skinny steel rims, The thinner the better to reduce rolling resistance.
e) Go through the car and work out what you want/need and don't want/need. Back seat, carpet and underlay, door cards, roof lining, stereo and speakers, Spare wheel (when you're at the strip), passenger seat (also when you're at the strip) can all come out. The less weight you can carry the better your and the faster you will go. Anything else unimportant that you can think of can come out too. If you can replace the doors, wings, bonnet and boot lid with ether Fiberglas or carbon fibre panels as they are lighter and replace what glass you can with Plexiglass for the same reason. Don't bother fitting spoilers/body kits as they will not reduce drag enough to worry about only make the car weigh more.
f) A low ratio gearbox would be a good idea too, possibly use one from a smaller engined version of your car, ie a 1.3 box on a 1.8 or a 1.6 box on a 2.0l). You will lose some top end by doing this but you will get there a whole lot quicker, which like I say, is the important thing. Get your 0-60 time down to about 5-6 seconds with gear ratios that will give you a top speed of 100-110 mph and you should be able to get a 12 sec 1/4 mile.
I think that pretty much covers it. Once you have done this it is a case of fiddling with the car at the strip to try and improve your times. The biggest problem you will have with a fwd car is holding the power down and not spinning off the line.
How to avoid Torque-steer:
1) Use a RWD car.
2) Don't be so aggressive when putting the power down. Most high powered cars can't floor it off the line as you lose traction and time. Yes you need to get the throttle to the floor as fast as possible but in a controlled way, so you accelerate as fast as possible, keeping traction at all time and not inducing torque steer.
This article was contributed by Fingers - a forum member. We now have a forum dedicated to drag racing where draggers can swap ideas and talk technical together with everything from water injection to oil selection.
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