How Fast Could Cars Theoretically Accelerate? 

A 2.7 quarter mile time would mean that the driver has to pull at least 11g

8:36 Actually, the top fuel dragsters get some downforce from their exhaust, which is significant off the line

You want to fuel a car with Hydrazine? Chemists that grew up after the 60s just had a stroke.

How's Project Inversion going? Is the ball still rolling on it?

Hydrazine! - good golly. You could kill the entire grandstand in one pass.

Monopropellant dragster... sounds like straight out of Kerbal Space Program.

The trick to using hydrazine as a fuel is the added weight of the space suit for the driver.

Nitro cars use aluminum rods and actually shorten during a run from the high cylinder pressures. They act somewhat as a shock absorber compared to steel or Ti rods.

The change to exotic materials does lower mass but it also dramatically changes the dynamics of the entire car, and when it comes to Top Fuel dragsters the mass of the frame and the very tuned way it flexes is specifically part of the process of getting the tires to grip the track. I think you would have to lengthen the chassis to get some of that back. And the tires struggle mightily to hold the 11000 hp now, doubt they can hold twice the power.

Dragsters are rear wheel drive, but also designed so under full acceleration, the front tires are barely even touching the ground. So 95% of the weight is on the driven wheels already during a run.

I saw Sammy Miller when he took the record at Santa pod, I was 11. I've spent the last 41 years as a Toolmaker and development engineer because of people like Sammy Miller & Angus McPhail on Jade Warrior. As I understand it, the conrods in nitro burning engines are forged aluminium alloy. The reason being that the percussive force of the nitro exploding can shatter steel or titanium. Another piece of nerdery is that the rod length shortens after each run as the rods compress under the force.

There's a component of tire grip that you seem to have missed. The rubber tread of the tire on a top fuel car is actually FLUNG into the pavement by centrifugal force. This is only possible if the tire is allowed to grow in diameter, which also results in the lifting of the driven axle.

Top fuel dragster doesn't have a transmission, they use a centrifugal clutch, and direct drive and a the reverse gear is in the rear end.

The biggest reason exotic, lightweight materials are not used in Top Fuel or Funny Car racing classes is the fact that those engines produce anywhere from 11000 to 18000 horsepower, and lord knows what the torque output is. That much power would rip apart carbon fiber like so much wet paper. The chassis would explode on the starting line well before 10% of the maximum power is produced. The mandated chrome-molybdenum steel tubing chassis is strong enough and flexible enough to take the power that is output, but still requires frequent inspection of the welds in the chassis.

Why not strap a large solid fuel rocket calculated to burn for 1.5 seconds on the chassis? It solves traction, power en weight at once.

"0-60 acceleration tests have been the go-to statistic for drivers all over the world" Correction: "0-60 acceleration tests have been the go-to statistic for drivers in about 5% of the world"

Pretty sure top fuel dragsters in current form are running regularly under 4 seconds for quarter mile runs, so unless I misheard, I don't think your quote on the fastest top fuel quarter mile drag run of 4.4 seconds is correct. So, the theoretical speed you originally calculated of 3.8 seconds is actually spot on and quite common. Brittany Force has recorded a 3.665 run of 338mph as the fastest ever.

Other than a few force/mass unit confusions, Driver61 certainly covered the bases if we restrict ourselves to a rubber tire-based force transfer concept. The only other thing to note is that the thrust force for a rubber tire is limited by the shear strength of the rubber itself. How about using a captive rack and pinion that runs the 1,320 feet? Steel has a lot higher shear strength than rubber. If we go completely "no rules" the limitation comes down to how much acceleration can a human stand. Does the human have to be able to control the vehicle? Does the human have to be in the vehicle? Col. John Stapp, strapped into a rocket sled in 1946 through 1951 survived up to 42.6 gs. Assuming that could be maintained over the ¼ mile the time would be 1.38 seconds crossing the line at just under 1,300 MPH. The human would not be capable of operating the vehicle during this, likely being unconscious, with broken bones, bleeding retinas etc. Col. Stapp was temporarily blinded by this; his friends have noted that he was changed by the experience. The fastest accelerating machine I am aware of short of an artillery shell is the Sprint short range AMB. Capable of 100 g acceleration. Lay it on its side (wheels or no), start it up and it will pass the ¼ mile point 0.9 seconds later passing 1,980 MPH, coming up on Mach 3. This assumes that aero drag would roughly cancel the decreasing mass as propellant was expended. I would not want to be in the stands, or within a mile. 20 if downrange, unless in a bunker.

I believe current top fuel dragsters are traction limited about 2/3 of the run.

Problem with top fuel dragsters, is the are heavily restricted configurations, so they cant even modify their cars to make them faster, such as better superchargers, or non hemi engines, or non v8 configurations

I've watched a video about top fuel dragsters some time ago and apparently their designers could easily increase the power, but then they couldn't put it down, so I don't think your estimations make sense. Probably removing most of the power part of the video would not make much difference in real time, so it would be more like 3.4s assuming the rest stays constant... which is slower than that alleged unofficial record of 3.22s. Still, I don't think these calculations can be taken seriously.

Hypergolic fuels in a piston engine?! That HAS to be right on top of the worst possible ideas in propulsion technology... Also, top fuel dragsters are running their tires at the very limit of their grip. If you doubled the power and halved the weight, where would you get the grip from to transfer said power it into the ground? Thinking about how grip works, there has to be a maximum balancing between grip to transfer the power and rolling resistance. The optimum for force transfer would be to concrete the tires to the ground. The optimum for rolling resistance would be tires covered in soap or oil or better yet, not even touching the ground. Increasing one necessarily takes the other away from it's optimum.

Another BRILLIANT video Scott! It is incredibly interesting how you pull all the variables together.

damn taks for the sponsor i was about to skip but it is cool and useful

By the way there is different types of compounds used for drag racing tires as well as different prep for the strip itself so if you're on a big tire car you're going to be running less track prep so the tires can actually slip whereas with small Tire cars they're going to be running more track prep because you don't want the small Tire cars that initial slip

I used to think Drag racing was too expensive for the amount of track/seat time but watching Cleetus Mc Farland videos has made me really respect it and how fast they can go in drag cars on good prep, but they don't do much of it in Ireland 🇮🇪

I doubt the effect of AWD at maximum acceleration. It is like the opposite of braking with a bicycle. If I brake hard enough and have the grip needed, my weight shifts completely to the front wheel and I can lift the rear wheel. This is how I get the shortest stopping distance. With accelerating a dragster it is the opposite. Acceleration transfers the weight back and the front wheels don't have anymore grip.

Another key factor consists on reducing drag. Specially, if fans are added, it may be possible to decrease the rear wing size, improving aerodynamics.

As a motorcycle rider, i can tell you that rear wheel drive is only slower if your rear wheels don't have enough grip to lift the frontwheel of the ground

Not as fast as I can click the like button

Glad to see some of the science of drag racing as I just recently went to the Don Garlitts Drag Racing museum and drag race museum hall of fame

I'm glad you did this because when I theorize about stuff people seem to have blinders on past what they can see in front of them right now

Are we going to casually ignore the idea of cutting weight to an absolute bare minimum, then strapping on a load of fans which likely weigh as much as what you've just battled to remove? 🤔 Plus the insane levels of G the driver would be under likely require heavy pressure suits to be worn.

What happened to the tunnel experiment?

Saw legend 'Slammin' Sammy Miller do the Quarter mile 386mph run. Excelleration was clocked at 12G. 0-100mph in 0.36 seconds. First thing if watching 2/3rds along the track on launch you see the white shock wave . Then could hear the car over the Tannoy system before the actual sound hits you. Also saw him, again at Santa Pod do a 3.00 second run but for some reason it wasn't classed as official. I asked him about the force on his body. He replied because he was moving seated in a forward line position it wasn't an issue as unlike an aircraft that turns the blood doesn't try to rush to your head or feet so don't need a G-suit.

I'm old enough to remember when CalTech scientists declared "Given UNlimited horsepower & UNlimited traction, no dragster could ever go faster than 180 mph in the quarter mile." VERY shortly thereafter Tommy Ivo ("IF" I remember correctly / l'm old!) did it! 👍😮

I have another idea. remember that man hole cover, sealing an underground explosion, that got blasted into space? how about putting wheels on it and call it a car?!

Build a road with both lower and upper surfaces, so the rear tyres are held bottom and top. As they expand they push outwards on the upper and lower surfaces, providing maximum traction. The wing for downforce is replaced by pushing the 2 rear axles apart. Ultimate traction... @Driver61

I would love to watch someone build this machine. The amount of problems that need to be solve would be massive but ground breaking i imagine.

That McMurtry just raised the bar more than anything in the last decade or two, that fan system changes everything, handling is on a different level now

I saw Vanishing Point and Natural High race back in the early 80's at Englishtown New Jersey. It was unbelievable how fast those two cars went compared to everything else in any class at the time. They couldn't go full throttle at that track due to the size of the track, but it was impressive.

The pause face that the video ends with 😂😂

If a Top Fuel Dragster makes 800 pounds of thrust at the exhaust tips then you can see how the 0-40mph down force is created. What they need is dynamic exhaust to change from down force to longitude and gain the speed on the back end.

that 3d animation of a dragster engine -- do the piston skirts really get that close to the crank counterweights?!

I don't think we'll ever see the likes of Sammy Miller and his amazing car, Vanishing Point, any time soon. That thing was absolutely amazing, and it's performance was difficult to convey to anyone who never saw it.

I believe it may be possible to go much faster in a dragster if the rules allowed for the following: - Carbon monocoque crash cell - Low drag carbon body - Fan forced ground effects for downforce instead of using big wings - No restrictions on engine design - Supercharger could be an axial compressor design or a centrifugal supercharger. Turbos would also be allowed. - 4WD hybrid using electric motors in the front wheels powered by supercapacitors to aid in acceleration and traction in the first few hundred feet - Supercharger or turbos use electric motors to help drive them (along with the engine)

Two things, one Top Fuel / Funnycar dragsters don't have transmissions they use a direct drive multi clutch pack which is setup to slip off the start in order to control power delivered to the rear wheels. 2nd less know is that the engines exhaust is pointed up and back for a season to push down adding traction and back for thrust forward the exhaust plays a bigger factor than most realize...

The top fuel dragsters are just a 4 second earthquake, Vanishing Point is an RPG

Something I remember from a Cleetus Mcfarland video where is friend Kevin was building one of his road legal drag cars was the work they did on the rear suspension. They changed trailing arm angles to make the vehicle squat under hard acceleration transferring more of the vehicle's weight to the rear wheels. That car (Mullet) has done a 6.8 quarter mile so far, and drives to the meetings.

Definitely went way over the top on your estimate, explained by many comments before mine. I do feel like if budget wasn't a limit, 3.5second quarter mile may be possible, but idk about much below that

Nhra actually has the nitro classes rather restricted to keep speeds down. They could gain a lot of power by unrestricting the blower and final drive alone.

You didn't take into consideration that top fuel and funny cars are limited to a 3.20 rear end gear ratio. That should have some effect on the acceleration.

I was wondering if you were going to go with an “explosion based” car like the Project Orion spacecraft :D

The connecting rods in those top fuel motors can also be made out of aluminum typically the blocks the heads, and the connecting rods are all made out of aluminum to reduce weight. But there’s significant longevity loss. Most of the big cars in NHRA use aluminum connecting rods when you get down bracket racing motors we use H beam steel rods. This is because at the top end you can be on and off the throttle killing numbers and it puts a lot of stress on the connecting rods and the crankshaft, and aluminum rods just can’t do that for a long amounts of time like these bracket motors need too.

if you wanted the fastest quarter mile this is my proposition where i recon sub 1 sec is possible have the floor and ceiling as rotating roads, like treadmills and keep the traditional right angled triangle shape of a drag car, have wheels on the front and back of the car, pointing up, with motors helping the car go quicker, this way, when the car takes off it will wheelie and have two wheels on the floor and 4 on the ceiling although whats wrong with having like 20 wheels helping out. also have it in a flying start because not worrying about acceleration means the car can start slowly, like two miles ahead of the 1/4 mile so it can reach its top speed for the start of the 1/4 mile and then with all this and the treadmills i think a car could do a sub 1 second 1/4 mile.

how is the finish time measured? is it the front of the car or the back of the car? or the centre of mass? could you make the car elongate itself during the run to get to the finish faster?

It would be great if you interviewed a US Top Fuel Crew Cheif , the sports governing body the NHRA has been consistently trying to slow the cars down to improve driver safety and reduce insurance costs,, such things as reducing the distance to 1000 ft, restricting rear gearing, limiting the % amount of Nitomethane, minimum weight,banning electronic traction aids, banning Hydrazine etc, etc. Yet the best crew chiefs are able to overcome restrictions and devise engineering solutions to over come these restrictions and in many cases far surpass the previous performance levels. It would be very interesting to find out what they could actually do without any restrictions in place or no consideration of driver safety and available braking distance. These guys may be seen as grass roots but they are equally as talented as any engineers in any other wheel driven motorsports. I’m ignoring unlimited LSR vehicles because they are not wheel driven and powered by jet and more commonly rocket thrust.

When you considered the changes in weight when adding the fans, did you figure for the weight of the fans and supporting hardware?

Either steel is 5 times denser than carbon fibre or carbon is 5x stronger, per kg, than steel in these appplications, I think you meant the latter. I enjoy your videos, and the way you make these things more approachable for the masses and look forward to more of your content in the future, thank you for your time and effort put into them.

1:14 ETH in under a second!

It’d be cool if f1 tracks used the same sticky track prep stuff over the entire track to see what really can be done if the driver knows grip is never going to be a problem

very skeptical about some of the weight savings ideas in this video. especially the motor ones. also did you add the fans in on the weight equation?

Could put a cable and pully like an aircraft carriers launch system down the center of both lanes and instead of pulling the cars all it would do, it would allow you to pull down on the car near the rear. This would allow you to get the best grip on the tires and allow the car to move down the track with the "Pull down cable" moving with the car down the center of the lanes underneith the road surface with just a slit in the Lane where the cable comes up to attach to the car, like an aircraft carrier has down the center of some of the runways

@12:59 Top Fuel piston connecting rods are made from 6061-T651 aluminum, not steel or titanium.

02:41 yooooooo homie's shorts give me LIFE!!!!!!

It would be a bit difficult to get more nitro/alcohol mixture into the engine, currently, dragsters have almost liquid lock at TDC there is so much fuel being pumped into the cylinder.

I just saw a video yesterday that a drag car hit 417mph with a 1/4 mile time of 5.76 seconds. Crazy!

Weren't it Sammy Miller, aka "Slammin' Sammy Miller" . I remember him taking Vanishing Point up Santa Pod in the '80's .

Insane ! I LOVE IT ! :)

Please update us on Project Inversion!

At some point, the limiting factor is going to be geometry. Because the center of mass *has* to be above the road surface, the max Gs that you can pull is limited to the angle between the rear wheels and the center of mass. Fans and aero can help somewhat, but with a powerful enough motor, adding weight can actual increase the possible acceleration. If the center of mass was 50 cm of the ground, 2.7s to go 400m would require the CoM to be almost 6 meters in front of the rear axle. For the motor, you're probably better off going with electric motors. 600kg going 400m (1/4 mile) over 2.7s would require average output of 10MW, which could be accomplished with about 15 of the Koenigsegg "Dark Matter" e-motor. (probably an easier task than getting an engine running on hydrazine). You'd need 30 MJ (8300 Wh) of energy storage, which could be done with 128 kg of Skeleton's "SuperBatteries". Another option for the motor is to go completely unconventional, and use flywheels. Their biggest disadvantage is that they make it hard to turn, but that can actually be a benefit for a drag car. Another benefit here is that dumping all that angular momentum can help push the front wheels into the ground.

Carowinds in NC used to have a roller-coaster that went 0-60 in 1.1 seconds. It was mind blowing how hard it accelerated. I wouldn't ever want to go quicker than that. Acceleration was linear and maxed out at 120mph in 2.2 seconds.

Using exotic material, it is more likely to boots the power up to 3 gazillion horsepower. Using an exotic frame would reduce the weight by 150%. So with that much power and a negative weight it should be doable, right? Well let me tell you, we tested it out after doing a lot of calculations and the result was astonishing. The car arrived at the finish line right before it started. Truly awesome, don't you think?

At some point, the driver’s reaction time becomes a factor too. A couple tenths either way makes a difference. The pavement itself also becomes a limiting factor. In order to get perfect acceleration, you need a perfect surface to do it on.

The driver staying alive is the limit.

_Vanishing Point_ (of which there were several) was rocket powered, thus traction wasn't an issue. Still, dragsters hit nearly 340 mph in just over 3.5 seconds, in only 1,000 feet (~305 meters).

At 10:59 I was so ready for him to say that steel is 5x heavier than feathers.

Eliminate wheel slip. Use cog-drive for the wheel to track interface.

i was lucky enough to see vanishig point race a santa pod, i'm pretty sure it's sammy miller

You mentioning hydrazine, a common fuel for spacecraft, makes me think - what if you upped to other rocket fuels? Hydrazine's pretty low end as far as those are concerned and mostly used in spacecraft for things like its simplicity and reliability, while launch vehicles use other fuels. For example, what if you followed the lead of most rockets and used a liquid bipropellant? For example, you can pair the hydrazine with something like nitrogen tetroxide (there are more efficient fuels, but fuel mass is a small amount so saving it probably doesn't matter much if it comes at the cost of power). If you're really crazy even go back to the '60s era rocketry and go for propellant mixtures including stuff like diborane and chlorine trifluoride

Can you do a video on the "Vanishing Point" please?

As for creating more power...Last time I checked the rules regarding computers for controlling ignition timing and fuel injection restricted them to passive data gathering only. After each pass the data gathered is analyzed and tuning adjustments for ignition timing, fuel curves, clutch tuning, and chassis tuning were then made manually to add or subtract power, clutch bite, tire traction all based on what the crew chief felt the track surface and atmospheric conditions could tolerate. In some cases an 11K hp engine might be detuned to 9.5K for example if track conditions were resulting in "Blowing off the tires" on the launch or later when the clutch fully engages. But if they were allowed to use closed loop systems capable of monitering wheelspin, clutch slippage, chassis flex, fuel/air ratio, spark advance, exhaust temperature, etc... and making thousands of adjustments in nano seconds the way flight control computers do exactly that on planes like the F22 then I would be willing to bet it wouldnt take long before we'd see dragsters acheiving between 1 and 2 seconds quicker elapsed times. Which is the exact reason they do not allow these systems in Top Fuel drag racing. Currently these cars are already so quick that even an experienced driver can have a hard time reacting quickly enough in the event that something goes wrong. And things do go wrong.

1:44 isn’t that the old layout? Back when bus stop was a bus stop

Man forgot the huge rear wing which works opposite like in idle it do not increase the grip but when moving makes the car slower we need to replace it with some aerodynamic vents with the fans

You could vastly increase the power with an unorthodox engine. For example, the fuel pump on a Saturn V, first stage F1 engine, the rocket nasa used in the Moon missions, made 35,000 hp. It ran on kerosine and oxygen.

Would we even need the huge spoiler if we had Fans? I bet that would also save some weight

There's no substantial loss of grip from the front wheels on a top fuel dragster. They're essentially unloaded. There's virtually zero traction to be had that would be worth any additional complexity to drive them. Also, modern Top Fuel run 1000 ft. and not a 1/4 mile. That changed some time ago for safety reasons.

imagine instead of just rubber tires, you have gear teeth on the outer edge of the wheels that lines up with a rack on the ground for the like the initial 50 feet. you wont need to worry about the traction nor need fans for ground effect.

i met sammy miller :) the driver of "vanishing point" rocket drag car. he was a real legend. all his records his car was tuned down. the car was powerful enough to go sub 3.2 sec in the 1/4 but would ET at 450-500mph - far too fast for any track. 3.58 record run was coasting from the 1/8th mile. he never fueled the car for the whole run. also if you want to up the top fuel rail - change the supercharger. get a twin screw or centrifugal. far more efficient which is why they are banned. only the roots type is permitted to strangle the engine to a mere 11,000 hp. also to note goodyear cant make a tyre that works over 350mph. thats one of the reasons why there is a limit and why top fuel only runs to 1000 feet (no longer 1/4 mile). we did recently have a new record where during an NHRA event Mike Salinas broke 300.80 mph in the 1/8th mile. incredible.

One slight correction, 1/4 mile isn't "old school". Everything except top fuel dragster and funny car still run the full 1/4 mile. And the only reason those two classes run just 1000ft is because it was deemed too expensive & in some cases not possible to extend the safety runoffs. So they found that space by shortening the race distance by 320ft.

Imagining an accomplishment is easy. Implementing it is real work.

Take the dragster to the 1/8 you won’t need as much fuel means less weight

2:35 actually, Top Fuel Dragster does 0-60 mph in 0.4-0.6 seconds. The 0.8 is 0-100 mph

I would just like to add that Gran Turismo 3 or 4 had a F1 car that had fans the suck it down and that was the first I've heard of that and driving that thing was other worldly

Interesting video, thank you I enjoyed it! I thought the connecting rods[13;00] were aluminum or titanium for their, strength, light weight and ability to absorb shock loads.

How about a four wheel drive dragster with equal tires all around, with the engine (or engines) located near the front so weight on the tires would be roughly equal while accelerating, and fans for traction - and, of course, 22,000 HP!

During the 60s… scientists tested with what makes the most propulsion in the context of rockets. By the end of it they had melted their launch pad. Hydrazine was definitely involved.

By the time you're using hydrazine you may as well just switch to a rocket engine. Especially considering that hydrazine is way to unsafe to have spectators near the track

How about tires which have steel spikes which perfectly fit holes in the track. The acceleration and g forces would be off the scale

Top fuel connecting rods are not regularly made of billet steel or titanium. They are big fat chunks of aluminum