How do drag racers put down power and minimise wheel spin?
Discussion
(Very simplified answer) Most drag cars are automatic, they have a higher speed stall convertor which allows you to bring the engine near it peak torque on the start line. Combine this with slicks and traction compound on the track allows a hard launch. Top fuel/ nitro funny cars have no gearbox just a multi stage clutch which progressively engages as the car moves down the track.
You need wheelspeed to generate acceleration and allow you to put down the power, therefore you need to be spinning the tyre slightly faster than the rate of movement..
Dry hooking a tyre (i.e. 100% grip) will see a car reaching for the skies (like we experienced with RedVictor2
The optimum launch will lift the front wheels, providing maximum weight transfer onto the rears, but not in an uncontrollable way, hence the use of wheelie bars in high power, slick shod, cars..
Dry hooking a tyre (i.e. 100% grip) will see a car reaching for the skies (like we experienced with RedVictor2
The optimum launch will lift the front wheels, providing maximum weight transfer onto the rears, but not in an uncontrollable way, hence the use of wheelie bars in high power, slick shod, cars..
As a hillclimber/sprinter this interests me.
My personal technique involves holding fairly high revs and dropping the clutch, flooring the throttle which creates wheelspin, momentarily coming off the throttle a bit which seems to give more grip then back to full throttle.
This is not really a thought through process it all happens almost automatically and works fairly well for me as my 60m times are as good or better than most in class.
However if I could lose a tenth or two over that initial sprint it would be good.
My personal technique involves holding fairly high revs and dropping the clutch, flooring the throttle which creates wheelspin, momentarily coming off the throttle a bit which seems to give more grip then back to full throttle.
This is not really a thought through process it all happens almost automatically and works fairly well for me as my 60m times are as good or better than most in class.
However if I could lose a tenth or two over that initial sprint it would be good.
I've only been to drag racing once at the Pod.
But i do recall that of the many funny cars and top fuel one car left 11s for well over 1/8th of a mile ( couldn't see any further) he was the only one and even doing that didn't seem to harm his time much but at that level fractions of a second make all the difference. '
But i do recall that of the many funny cars and top fuel one car left 11s for well over 1/8th of a mile ( couldn't see any further) he was the only one and even doing that didn't seem to harm his time much but at that level fractions of a second make all the difference. '
maverickdrives said:
How do you launch best on a front wheel drive where the weight shifts towards the rear and you lose traction on the front where its needed?
Yes, FWD inherently has a disadvantage when it comes to acceleration for this reason.Here is a FWD car used for drag racing...
Edited by skyrover on Friday 15th November 08:02
Welshbeef said:
I've only been to drag racing once at the Pod.
But i do recall that of the many funny cars and top fuel one car left 11s for well over 1/8th of a mile ( couldn't see any further) he was the only one and even doing that didn't seem to harm his time much but at that level fractions of a second make all the difference. '
Slick cars always tend to blacktrack a little to make wheelspeed. see photo above what happens if you get 100% traction. Plus you can also run into tyre shake. (non of which is relevant to normal road tyres)But i do recall that of the many funny cars and top fuel one car left 11s for well over 1/8th of a mile ( couldn't see any further) he was the only one and even doing that didn't seem to harm his time much but at that level fractions of a second make all the difference. '
http://www.youtube.com/watch?v=mfJejgODr3E
maverickdrives said:
I meant more normal cars that you see on santa pod like rear wheels and front wheel drives or awd like Subaru and evos. How do you launch best on a front wheel drive where the weight shifts towards the rear and you lose traction on the front where its needed? if my car produces max torque at 4000 rpm would it be a good idea to launch at 4000 rpm?
Many normal cars don't fair so well and you often can't use all the power.Edited by maverickdrives on Friday 15th November 03:56
The simply answer is trail and error, you want to launch with as much power as you can without bogging or excessive wheel spin. But this will not only vary from vehicle to vehicle, but even conditions to conditions.
Coatesy351 said:
(Very simplified answer) Most drag cars are automatic, they have a higher speed stall convertor which allows you to bring the engine near it peak torque on the start line. Combine this with slicks and traction compound on the track allows a hard launch. Top fuel/ nitro funny cars have no gearbox just a multi stage clutch which progressively engages as the car moves down the track.
They aren't all autos. Lots and lots of manuals used for drag racing.
Will probably get shot down but...
If you are asking about how to launch your 1.2 corsa c the best way then the answer is probably simply to practice.
I'd probably learn how to complete an oil change myself as well, as if you are driving hard then it would proably be worth changing more frequently than the service manual advises.
Be prepared to buy a new clutch as well.
There are ways to have fun in a lower powered car, From experience I'd suggest that drag racing (whether santa pod or A38 traffic light GP) isnt the best, or cheapest, way.
If you are asking about how to launch your 1.2 corsa c the best way then the answer is probably simply to practice.
I'd probably learn how to complete an oil change myself as well, as if you are driving hard then it would proably be worth changing more frequently than the service manual advises.
Be prepared to buy a new clutch as well.
There are ways to have fun in a lower powered car, From experience I'd suggest that drag racing (whether santa pod or A38 traffic light GP) isnt the best, or cheapest, way.
300bhp/ton said:
They aren't all autos. Lots and lots of manuals used for drag racing.
I said most not all. Don't know about the UK but in Australia the percentage of proper drag cars that are manual is tiny. Far too many disadavantages.Edited by Coatesy351 on Friday 15th November 22:20
mikeveal said:
Most tyres have peak grip with about 10% wheelspin.
I was about to post the same thing 
This of course depends on the tyre and surface involved. With fat drag slicks and a rubber laden starting area, I expect the optimum slip is quite a bit lower - perhaps just a couple of percent? (IIRC a slick on a race track is about 4%, the 10 above is probably for a road tyre).Coatesy351 said:
300bhp/ton said:
They aren't all autos. Lots and lots of manuals used for drag racing.
I said most not all. Don't know about the UK but in Australia the percentage of proper drag cars that are manual is tiny. Far to many disadavantages.Most of the quick cars run Powerglide based units, which are auto from the factory but are manually shifted in most cases.
Gassing Station | General Gassing | Top of Page | What's New | My Stuff