Drag Racing!

That makes perfect sense.

No, only1:1 gear. I just gave a hypothetical 3 speed gearbox scenario to show what a drivetrain would endure.


i guess i was right in saying from the beginning that power is not the issue in breaking records, but torque conversion.

i just can’t believe all these years of research and we can’t come up with a way to rev an engine up to 20k and rub a car all the way down a strip???

i guess there are limitations to this stuff, such as cavitation for fluids and heat for metals, but there just seems to have to be another way… ah well. anyone got theories???

Perhaps I do not understand what your getting at.

A top fuel engine goes to its max rpm’s almost immediately. they have so much power that the issue is not to make more right a way, but to make the best use of it. that is why i said that they would like to set-up the clutch for the least amount of slip (that is what you mean by rub, right?)

since a T/F or T/F / FC can and often does spin at the end of the track, the teams often tune down the engines or increase the slip in the clutch. they are testing the max traction all the way down the track

the multiple rpm’s i was talking about, in the next paragraph, was for the more common and far less powerful cars that have transmissions with 2 or more gears.

btw, the torque converter would fail before the trans fluid - which is under pressure. the fins in the case and stator would just bend.
HTH, because i don’t know what can be added to the replies you have.

Many of the Nopi Nationals and IDRA cars are doing something similar to this, although for the Civic V-Tec and similar engines, the idea is to keep the RPM’s in the band that V-Tec engages and runs in.

They aren’t really looking for a way to make any more power.

They don’t want to rev those engines to anywhere near 20k rpm, 5500-6000 rpm is ideal. Nitromethane burns pretty slow and is hard to light. Alot of the cars are moving to more than two spark plugs per cylinder to keep the spark advance under 40 degrees before DTC.

They make enough power to smoke their tires at any point during the run. The trick to being in the record books is figuring out how to use the power they have without spinning the tires.

if indeed they have all the power they need, and the only thing holding back is lack of friction, then PUT A 5000LB. ANVIL ON TOP OF THE REAR PART OF THE CHASIS!!!

sorry for being sarcastic, but why don’t they just make the car really really heavy? i guess a really heavy car would start making the torque conversion system have too much stress, is that the reason?

i’m just trying to gain an understanding of why we can’t go faster. thanks for your replies, they are helping tremendously.

Adding mass to the car would indeed increase the traction, but it also increases the car’s inertia.

The horsepower would then need to be jumped up to accelerate the extra mass, in the end no net gain and in fact it would raise a number of problems.

  1. The rules allow for a 500 c.i. engine. Trying triple the power to accelerate triple the mass (at least triple, those cars weigh in at 2500lbs or less I am sure) isn’t really feasable. Between 1 in 4 and 1 in 8 of the engines don’t stay together for the 4-5 seconds required to finish the pass the way it is.
  2. Tires need to be as soft as possible for maximum traction. Tripling the weight of the car will triple the load on the tires and they simply couldn’t take it. Altering the tires to handle the extra load would almost certainly cause a net loss in possible traction.
  3. The entire sport of drag racing (especially the top fuel class) is nothing more than applied physics directing the engineering to get the absolute maximum performance within the given rules. For the most part, price/cost is of no or little consideration. The cars are they way they are because physics (especially considering the durability and properties of the materials available to build the car) dictates the design.

There are a number of things that could be done that would in fact increase the performance of the cars, but they are not allowed by the rules of the sport.

  1. Mechanical or electronic aids to assist with traction control are not allowed.
  2. There is a minimum weight for the cars.
  3. There are minimum and maximum lengths for the cars.

when i said make car heavier, i thought we were talking about unlimited amount of horsepower available and the ability to alter anything about the car. that’s good info about the rules. thanks.

p.s. i’ll try not to be insulted by you misunderstanding the last post and “informing” me about more weight, more inertia. :slight_smile:

Clearly there is no such thing as truly unlimited horsepower.

However, there is such as thing as more horsepower than you can use in the situation. That is pretty close to accurate in Top Fuel today. The pretty much have the power to spin the tires anywhere along the run. Triple the weight of the car and that would no longer be true.

by unlimited horsepower i meant “more than enough”.

you definately cleared all this up by talking about the specifications that the cars must adhere to.

now my question is, why are there these rules? it seems like they are just playing this “grip the road game” and decided to not go any faster than 330mph for some reason. that’s not racing!!! that’s a little “guess and get lucky game”, not a “go as fast as you can” game IMO.

see what i am saying? maybe it’s for safety sake? maybe they gotta draw the line somewhere? why not make the cars heavier, bigger tires, more HP and draw the line at 375mph?

i’m just trying to gain an understanding of this whole scene. thanks.

… obviously they need rules, but why did they choose these specific specs?

You don’t need to make the dragster heavier.

The wing in the back puts several hundred pounds of downforce at speed. The size and placement of the wing is determined by the rulebook, but the angle off attack can be adjusted by the team based on racetrack conditions at the time of the run: barometric air pressure, wind direction, and the track’s coefficient of traction.

Less agressive angle of attack increases chances of wheelspin.
More aggressive, increased aerodynamic drag, slowing you down.

Well, there is some getting lucky in this sport. However, there are clearly teams and drivers that are better at it than others and win way more than their fair share.

  1. The cars are very steadily getting faster as they figure out more and more engineering tricks to get another couple thousands of a second out ot the cars. These little changes add up over the season to very large total changes.
  2. Even with the cars as good as they can build them, they are incredibly difficult to drive that fast consistently. Driver skill comes strongly into play as well.
  3. One or two of them teams always seem to have a car that is a couple hundreds of a second quicker on average than the rest of the teams. By the teams the other teams find the same improvements, they(the leading teams) have gotten a tiny bit better and kept the gap the same.

Still if they were going to make changes to the rules to make more speed it would start probably with:

  1. Removing the **minimum[\b] weight limit. The cars would certainly not be made heavier.
  2. Allow any engine type.

Actually it’s getting the guys to run fast in heels and skirts!!


No one has drawn any lines about speed. They keep running consistantly faster and faster times at higher and higher speeds. I remember when they first broke 290MPH, and now they’re above 330MPH.

BTW, speed isn’t the important thing, it’s time. You can have a higher speed (measured at the end of the run) and still lose a race due to slow reaction time and slower acceleration at the begining of the race. That’s why they report both numbers. Getting off the line quickly and keeping the tires from slipping throughout the run while applying full power is really the challange.

Then there’s the matter of safety. Right now there is a delicate ballance between thrilling racing and firey death. Any major changes to the cars would require some serious safety re-engineering. You can’t make wholesale changes to the cars without risking the drivers’ lives.