This article gets the concept slightly wrong.The compressed air becomes very cold air when it expands rapidly in the intake.
Colder air is more dense and therefore carries more oxygen. More oxygen allows more fuel, which allows more power.
Here's a better explanation in a single paragraph on the company's website:
> The end result of these expansion processes is that the charge air temperature entering an engine is dramatically lower than can be achieved with conventional MAP increasing technologies (supercharging and/or turbocharging with after-cooling). Hence very high charge densities can be attained at relatively low MAP levels.
The goal is to increase the amount of air going into the engine by making it very cold and dense, not by pressurizing it like a supercharger. Low MAP means low manifold absolute pressure. In other words, it's not boost like a turbo or supercharger.
EDIT: It looks like the website is also unclear. There is some mention of a secondary valve shutting off the intake valve to prevent air leaking out from the air filter.
Their website is strangely unclear. This isn't mentioned in the "Theory of Operation" section but does get mentioned later as an "isolation valve"
WWII era planes such as the Bf109 injected water and methanol into the supercharger to allow higher boost, side effect of that was charge cooling (and engine cooling).
My understanding is that the water is mixed with the fuel to help atomize the fuel as it's being sprayed out of the injector. If the fuel is atomized, it burns all at once which increases efficiency. I doubt a little bit of water is going to cool any meaningful amount of air.
It is boost pressure in the sense that the air going into the intake manifold is above ambient pressure. It isn't like nitrous where air still comes in the intake, with compressed air systems there is a valve that's closed to prevent the engine from ingesting ambient air, it runs entirely on the compressed air.
I know what the article says, but the author seems to misunderstand how the system works.
The systems has regulators that step the air pressure down from thousands of PSI in the tank to a much smaller, regulated number at the nozzle that gets sprayed into the intake.
From the source company that sells the system:
> The very low temperature medium pressure air stream is then throttle one more time in the Electronic Pressure Regulator before being discharged into the engine air intake tract. The throttling effect that occurs here is small compared to that which occurs at the Mechanical Pressure regulator but, similar in nature.
The tuner can adjust the pressure that is being discharged into the intake tract, but that's not equivalent to the pressure in the manifold.
The system works by having the air expand rapidly in the intake, causing a rapid cooling effect.
I guess in some ways that matter they are different. I’m not super familiar with turbo/superchargers, but aren’t they driven by belts in the engine or linkages? I would think that turbo lag shouldn’t happen with a compressed air system, for example.
But to your point, I agree. Once the boost is achieved, the effects of the boost occur, because they aren’t really related to the source of the boost or how it is implemented. However, systems that use the engine for power like turbos may lose efficiency compared to compressed gas at the same boost level, depending on how much the gas system weighs compared to your turbo. It’s an interesting idea, especially for drag racing.
I guess the cooling alone cannot reach the density (and oxygen amount) necessary for the designed power output.
Yes, they put in the energy to compress the air 'offline' and then have that free to propel the vehicle.
The cooling of the charge also improves the efficiency, the useful energy output is proportional to the temperature difference before and after the combustion.
A high capacity intercooler would be an interesting experiment also in utility vehicles.
I worked at a speed shop in my youth and at the time I was into Paintball so I had an idea.
We tried something similar to good effect, but we unfortunately had no good knowledge on how to refine it. It's hard to just shoot compressed air into the manifold and not have it blow back out of the intake. Either way we figured out a way to increase the volumetric efficiency as well as gains from running cool dense air. We were very close to pre-spinning the existing turbo/super setups and experimented with that as well. We gave up because Nitrous oxide at the time was much easier to work with and popular, and the tanks we had to experiment with was tiny compared to the large scuba tanks.
We also tried using compressed CO2 bottles to spray towards the intercooler to cool that down considerably, that worked decently as well, but no good data to support.
Take, for instance, Ford’s car from the 2003 FIA World Rally Championship. Through a knowledgeable automotive tuner and journalist named Stav from the UK (Facebook page), we learned that the 2003 Ford Focus RS WRC used an ingenious, mostly-hidden system to store excess pressurized air from the turbocharger in a titanium tank until it could be advantageously crammed into the engine on straight portions of the course, elevating power beyond what would otherwise have been possible.
What blew me away was that the high-end engines[1] turn just a few hundred RPM during a race, which to me seemed ridiculous when you see wall of flames from the headers when they release the car at the line.
Also how they use aluminum for the connecting rods instead of stronger and stiffer metals like titanium, as they can then act as shock absorbers protecting the crankshaft bearings.
Lots of interesting tech to eek out performance and lifetime.
I've been enjoying watching Steve Morris's YouTube channel[2], he shares a lot of such information. He's mainly making drag and drive engines, which has the additional constraint of having to survive thousands of miles of regular roads between races.
I've also enjoyed Brian Lohnes channel[3] for interesting historical accounts from the early days.
Yeah, obviously they don't use a CVT so the RPMs are anything but the same throughout the race.
I don't know the details of Top Fuel and such, but Steve with his SMX[1] wagon[2] keeps his car at 2000 RPM at the lights, so seems reasonable to assume Top Fuel is around there too.
On the top end the Top Fuel cars are limited to just over 8000 RPM[3], with the red line at 8500 RPM.
So an average of 3800 RPM seems reasonable.
As a cross check, given that Top Fuel cars are single-speed[4], I guess one could calculate the same using the diameter of the wheels, keeping in mind that the tire expands a lot compared to its size at rest.
Yes but they have lower Young's modulus[1] so compress more under the same force. Thus acting as a shock absorber to reduce peak loads on the rod bearings.
Again no expert but from what I can see, high-end aluminum rods can use 7075 aluminum[2], which has a Young's modulus of about 72 GPa, while titanium has a modulus of about 105 and up[3][4], depending on grade.
An aluminium part with 105/72 cross section of the titanium will have the same modulus and incidentally the same weight.
Aluminium is also significantly cheaper, and easier to machine.
Titanium (or high strength steel, which is the strongest both per area and per weight and also the most expensive and difficult to machine) would be used where the volume of the part would be a concern.
Perhaps I misremembered. Seems difficult to find some written sources on this.
In my quest I stumbled upon this[1] article where they discuss composite connecting rods for Fop Fuel dragsters:
Designed for Top Fuel engines, this connecting rod is half the weight of a conventional aluminum rod, yet is projected by company engineers to last an entire season instead of just 12 to 15 races.
Seems they're still at it, perhaps it'll be the next thing?
Some facts about top fuel dragsters: the supercharger uses around a thousand horsepower to run, but that's ok because the motor puts out over 10x that. It uses around 15 gallons of fuel for a single quarter mile run, but that also includes the burn-out.
If you're anywhere near the pits, and the crew fires up the motor, and then just blips the throttle, the sound waves generated are like physical blows to your chest.
The only sweeter sound is a V12 Merlin coughing into life.
I snagged a ride in a P51 once. OMG. That machine just leaped into the air. I was smiling for a week.
Story of coincidences, I guess: I'm adopted, but a total car nut. My adoptive family weren't really car people except my uncle. A couple years ago I found my birth family, and they are all car nuts. My half sister was a test driver for Audi, my mom and much of the family worked at the local drag strip.
When very little, I thought I wanted to be a farmer, and tried growing crops in the back yard. Total failure. I threw an entire bag of grass seed in my yard 6 weeks ago. Not a single seed sprouted (a flock of birds ate every one). Total failure.
But by age 7 I knew that I was a born engineer. Engines, electronics, software, structures, all of it.
> Compressed air is stored at 3,300 psi in carbon fiber tanks that weigh roughly 30 pounds each when full
When are the kids in California going to grab a tank, point the nozzle down, and ride that thing like a rocket from the beach, parachuting into the ocean?
Our Hyundai grocery-getter does a 1/4 in 13s, the "N" go-fast version does it in 11s. And those are Hyundais with full-sized, heavy-ass batteries, and abysmal stock tires. Porsche Taycan GT (with a full-sized, heavy-ass battery) turns 1/4 in 9.3s.
Now cut those heavy batteries in half because you're not driving from SF to LA, and I could see that Porsche turning 8s if you could get the power to the ground (IOW, launch control and much better tires than stock).
I don't believe there's anything even remotely competitive in the electric world to Top Fuel dragsters. You could also make the same argument about F1 vs E1
> Top Fuel is a type of drag racing whose dragsters are the quickest accelerating racing cars in the world and the fastest sanctioned category of drag racing, with the fastest competitors reaching speeds of 338.94 miles per hour (545.5 km/h) and finishing the 1,000 foot (304.8 m) runs in 3.641 seconds.
AFAIK the fastest "production" EV is the McMurtry "Spéirling" that does a quarter mile in under 8 seconds. Watching it set the record for goodwood is mind blowing, because it looks like the video is being played in fast forward, but it isn't.
Although you can in theory buy one, it uses down force fans so I don't know if it would even be street legal in most places. Personally, I find car like this to be way more interesting than drag racers.
The properties of air that you care about are basically immutable, so why not pre-compute a bunch of compressed air instead of compressing it on the fly, and then having to carry the equipment to do that.
There is an energy cost to supercharging. While you get an overall horsepower boost, it's less than what it would be if the compression cost nothing.
Question -- why not go with liquid oxygen? Does that push the danger-meter too high? On the plus side, you're not dealing with 3000 psi compressed gas.
I'm assuming the costs involved in making engines capable of withstanding cryogenic temperatures probably make that impractical (?)
I think it becomes easier to just use a different fuel that is partially self-oxidizing. E.g. Top Fuel uses nitromethane rather than gasoline. Gasoline's stoichiometric ratio is 14.7:1 air:fuel, nitromethane is 1.7:1. Nitromethane in Top Fuel is already so volatile that the superchargers have to be wrapped in kevlar because the fuel blows up in them sometimes.
Liquid hydrogen is very bulky, the tank might be large enough to impact the aerodynamics. Use kerosene instead, and maybe use RFNA instead of oxygen, just to bump the danger level up to Abjectly Stupid.
If you're going to cheat, way cheaper to put nitrous oxide in the tank and claim it's compressed air. 50% boost in oxygen content without having to engineer your engine to not burn when pure O2 hits it.
Amazed it didn't happen earlier. For a long time it's been seen that an economical way to store energy is to store compressed air in a cavern and feed it into a gas-fired turbine in lieu of turbocharging: see https://urbanao.com/post/compressed-air-energy-storage-caes-...
It didn't happen because like everything else that the peanut gallery deems "obvious" the actual pros and cons of implementing it didn't pencil out until recently.
This was tried in the 1950s and 1960s. IDK why it didn't make the cut then. Probably cumulative weight of tanks. It takes A LOT of air to run an engine.
I noticed the tank in the article's photo looks like carbon fiber wrapped aluminum. Those are noticeably lighter than the pure aluminum or steel tanks common in the 60's. (Source: Have carried each on my back as a volunteer firefighter)
I planned to implement this system in a project car years ago, but never got to it. Do have a parts list, and the overall cost is quite reasonable. My goal focuses on in-vehicle recharging rather than tank-swapping approach.
You'd get better energy density that way, but I think it's offset by worse efficiency & more damage to the engine. The inert gas fraction (N2, CO2, H2O) provides a useful working fluid to convert combustion heat to force pushing on the piston. Burning pure O2 would mean a lot more heat is needed for the same amount of force. Higher peak temperatures & more available oxygen will tend to create hotspots & knock/pre-detonation, & possibly erosion of the cylinder wall & piston from directly burning the metal.
Using nitrous or cool compressed air keeps most of the benefits while mitigating the problems of using pure O2.
Wikipedia says uncited that N2O produces heat when it decomposes into nitrogen and oxygen, but that's the opposite of other comments saying that cold oxygen is better because it's denser
This is pretty smart. Why carry the compressor and intercooler with you? Save the mass and complexity, as well as shifting the energy required to compress the air to a device off the car.
Drag racing is just about the purest most scientific competition of vehicle tuning you're going to get. The driver doesn't really make or break it as long as they're at least decent.
On the other end of the spectrum you have racing types that are more of a competition among drivers with the vehicle not really making or breaking anything as long as it's typical for the class.
I get racing on a twisty track. They are legitimate tests of human skill and vehicle endurance engineering. Drag racing has none of that. There's little skill beyond reaction time and drag vehicles have almost no relation to normal vehicles.
Think of drag racing like the CO2 cartridge race car competitions you see in lots of high-school science classes. It's an engineering challenge, not a skill-based race.
I disagree. Drag racing involves incredible honed vehicle endurance, just on a much shorter timescale. It’s an engineering problem with the goal of outputting as much power as possible within a short timespan (often only a few seconds) without detrimentally destroying the engine. As far as the drivers are concerned, the reaction time is obviously important, but they have to be extraordinarily consistent. At that, they have to drive the car at 5 g’s- not an easy task.
The engines still get destroyed. It's basically a complete rebuild between runs. Most of the spark plugs burn up, clutch disks get welded together, etc. The goal is basically to just not have the engine outright detonate so they can reuse the block.
You are absolutely correct. Perhaps I should’ve worded “detrimentally destroyed” as “catastrophic failure.” The rebuild process between runs is fascinating to watch. I’ve never seen an engine torn apart so quickly!
> I’ve never seen an engine torn apart so quickly!
The first time I took my 286 intake manifold off, it took 4 hours. The 4th time I took it off, it took 20 minutes. Once you know exactly what to do, it really cuts the time down.
I'm sure every member of the team knows exactly what to do and it's down to a dance.
For fun, look how fast they change the tires on a Formula 1 pit stop.
What is it the kids say? "Tell me you know nothing about drag racing without saying you know nothing about drag racing"? Drag racing has all of that, squeezed into 1/4 of a mile. That's why top fuelers get an engine rebuild after every trip down the track.
It's like saying, "I get ultramarathons, but 400m foot races involved little skill or training." Look, if you don't get it, fine. Probably best to just leave it at that.
You're thinking about this in only a professional way. There are a lot of amateur events where people race with their own cars that they have modified. It's really fun to see something like a vw rabbit beat a modern sports car etc. It's a fun event too but the tire burning shows do get old very quickly.
I participated in motorcycle track days on race tracks for 15 years. I've dragged knee at 90pmh. _That_ takes skill and balls. Drag racing seems dumb by comparison.
That's a long-winded way to say, "no, I've never tried it". If one has never tried a pursuit, I can understand how it might "seem dumb". What seems dumb to me, though, is doing track days for years on end, and never once trying to see how fast you could launch a bike down a drag strip, and then going on about how dumb drag racing is.
I've owned two Porsches, an Audi R8 V10, half dozen sport bikes. I've done laps at Laguna Seca. I've floored them all to see what they'll do. The V10 sounded amazing.
But I've never felt any interest in drag racing at all, it's a pointless waste of fuel. Press accelerator, press brake, done, little to no skill required. And in something like the R8, would require a $20,000 dealer visit after a weekend of runs.
Racing changed my life and you should definitely go to a meetup, drag race, or track event. The dream of the 80's is still alive in the car world. You'll meet the coolest people. Dummies get filtered and don't make it to the events/track. It's the best and easiest real life scene to get into if you're technical because car guys are absolute nerds.
Are they? At least in Europe they are usually blue collar guys that pick a neighborhood at random to hold a car meet, terrorizing that neighborhood until deep into the night, including street races. And if they aren't accommodated they'll aggressively clash with the police.
They're easy to spot too, pumped up douches with tribal tattoos and gemstone earrings that behave like they're prone to pick a bar fight with you.
I am, which is why I specifically said drag, meetups, and track events. The only group I detest are the ones that takeover roads/highways and race in densely populated zones. I like hooners, 99% stick to parking lots and make a bit of noise. You'll be very hard pressed to find "racers" who embrace endangering regular people.
What do you expect when tracks are closing left and right? That energy has to go somewhere. But yes those guys are also nerds.
The meets I'm talking about are like this [0][1]. There's a lot of the tattoo gemstone guys in [1]'s timestamp. Is this what you mean? I'd love some examples.
As a race buddy of mine often says, one can teach a complete college semester on the math of drag racing. From the engineering of the vehicles to the tuning to the weather calculations. And then there is what we call "bracket racing". Staggered starts based on your own prediction of elapsed time that you cannot run faster than or you will "break out" and the other vehicle wins. A favorite t-shirt in the pits says, "Not everyone can do math at 150MPH".
Literally everything is pointless, even existence, from someone's point of view.
You don't have to understand how something amuses someone to understand that it amuses them. You also don't have to belittle people to ask them why they are amused.
If you think drag racing seems pointless and self destructive, it is in your best interests to not explore the other popular variants of competitive motorsports today.
When I look at a drag stripe, I see a gray, dirty rectangle of asphalt that generates huge amounts of noise and air pollution. Beyond the environmental destruction, it's a hobby that quickly destroys vehicle parts, engines, tires, brakes, etc. All of that destruction, for what? 5 seconds of extreme acceleration? To go one hundredth of a second faster this time?
How do you feel about model rockets? If it's the same then oof okay, but if you feel very different then I think you're being too harsh on drag racing.
This article gets the concept slightly wrong.The compressed air becomes very cold air when it expands rapidly in the intake.
Colder air is more dense and therefore carries more oxygen. More oxygen allows more fuel, which allows more power.
Here's a better explanation in a single paragraph on the company's website:
> The end result of these expansion processes is that the charge air temperature entering an engine is dramatically lower than can be achieved with conventional MAP increasing technologies (supercharging and/or turbocharging with after-cooling). Hence very high charge densities can be attained at relatively low MAP levels.
The goal is to increase the amount of air going into the engine by making it very cold and dense, not by pressurizing it like a supercharger. Low MAP means low manifold absolute pressure. In other words, it's not boost like a turbo or supercharger.
EDIT: It looks like the website is also unclear. There is some mention of a secondary valve shutting off the intake valve to prevent air leaking out from the air filter.
Their website is strangely unclear. This isn't mentioned in the "Theory of Operation" section but does get mentioned later as an "isolation valve"
See here: https://casupercharging.com/tech/#system-overview
Some cars have a system to spray water into the intake manifold to cool the air and increase power, this seems like the next step up from that.
WWII era planes such as the Bf109 injected water and methanol into the supercharger to allow higher boost, side effect of that was charge cooling (and engine cooling).
A very cool aircraft.
My understanding is that the water is mixed with the fuel to help atomize the fuel as it's being sprayed out of the injector. If the fuel is atomized, it burns all at once which increases efficiency. I doubt a little bit of water is going to cool any meaningful amount of air.
In to the cylinders! Water injection.
It is boost pressure in the sense that the air going into the intake manifold is above ambient pressure. It isn't like nitrous where air still comes in the intake, with compressed air systems there is a valve that's closed to prevent the engine from ingesting ambient air, it runs entirely on the compressed air.
It says they're boosting to 10psi, in addition to the colder intake charge
I know what the article says, but the author seems to misunderstand how the system works.
The systems has regulators that step the air pressure down from thousands of PSI in the tank to a much smaller, regulated number at the nozzle that gets sprayed into the intake.
From the source company that sells the system:
> The very low temperature medium pressure air stream is then throttle one more time in the Electronic Pressure Regulator before being discharged into the engine air intake tract. The throttling effect that occurs here is small compared to that which occurs at the Mechanical Pressure regulator but, similar in nature.
The tuner can adjust the pressure that is being discharged into the intake tract, but that's not equivalent to the pressure in the manifold.
The system works by having the air expand rapidly in the intake, causing a rapid cooling effect.
The company describes it better on their own site: https://casupercharging.com/tech/#system-overview
EDIT: There is some mention of an "isolation valve" but not within the "Theory of Operation" section of the company's own description: https://casupercharging.com/tech/#system-overview
So there might be some scenario where the system shuts off the intake valve, too, but it's weirdly unclear from their own system description.
The 10psi is still essential, saying 'it's not boost like a turbo or supercharger' is not entirely correct.
I guess in some ways that matter they are different. I’m not super familiar with turbo/superchargers, but aren’t they driven by belts in the engine or linkages? I would think that turbo lag shouldn’t happen with a compressed air system, for example.
But to your point, I agree. Once the boost is achieved, the effects of the boost occur, because they aren’t really related to the source of the boost or how it is implemented. However, systems that use the engine for power like turbos may lose efficiency compared to compressed gas at the same boost level, depending on how much the gas system weighs compared to your turbo. It’s an interesting idea, especially for drag racing.
I guess the cooling alone cannot reach the density (and oxygen amount) necessary for the designed power output.
Yes, they put in the energy to compress the air 'offline' and then have that free to propel the vehicle. The cooling of the charge also improves the efficiency, the useful energy output is proportional to the temperature difference before and after the combustion.
A high capacity intercooler would be an interesting experiment also in utility vehicles.
The air can't go out the filter because a valve prevents air from going back through the filter.
Probably just a check valve for one way intake when from filter
I worked at a speed shop in my youth and at the time I was into Paintball so I had an idea.
We tried something similar to good effect, but we unfortunately had no good knowledge on how to refine it. It's hard to just shoot compressed air into the manifold and not have it blow back out of the intake. Either way we figured out a way to increase the volumetric efficiency as well as gains from running cool dense air. We were very close to pre-spinning the existing turbo/super setups and experimented with that as well. We gave up because Nitrous oxide at the time was much easier to work with and popular, and the tanks we had to experiment with was tiny compared to the large scuba tanks.
We also tried using compressed CO2 bottles to spray towards the intercooler to cool that down considerably, that worked decently as well, but no good data to support.
Volvo came up with a way of spooling the turbo by injecting compressed air into the exhaust manifold
https://www.carmagazine.co.uk/car-news/tech/volvos-turbo-lag...
Reminds me of this piece of motorsports history: https://fordauthority.com/2017/12/how-ford-cheated-the-rules...
Take, for instance, Ford’s car from the 2003 FIA World Rally Championship. Through a knowledgeable automotive tuner and journalist named Stav from the UK (Facebook page), we learned that the 2003 Ford Focus RS WRC used an ingenious, mostly-hidden system to store excess pressurized air from the turbocharger in a titanium tank until it could be advantageously crammed into the engine on straight portions of the course, elevating power beyond what would otherwise have been possible.
What blew me away was that the high-end engines[1] turn just a few hundred RPM during a race, which to me seemed ridiculous when you see wall of flames from the headers when they release the car at the line.
Also how they use aluminum for the connecting rods instead of stronger and stiffer metals like titanium, as they can then act as shock absorbers protecting the crankshaft bearings.
Lots of interesting tech to eek out performance and lifetime.
I've been enjoying watching Steve Morris's YouTube channel[2], he shares a lot of such information. He's mainly making drag and drive engines, which has the additional constraint of having to survive thousands of miles of regular roads between races.
I've also enjoyed Brian Lohnes channel[3] for interesting historical accounts from the early days.
[1]: https://en.wikipedia.org/wiki/Top_Fuel#Performance
[2]: https://www.youtube.com/@stevemorrisracing/videos
[3]: https://www.youtube.com/@brianlohnes3079/videos
From your first link, they turn at around 3800 RPM, but the race only lasts a few seconds so they only complete a few hundred revolutions:
"This calculation assumes an average racing engine speed of roughly 3,800 revolutions per minute over a period of 3.8 seconds."
Yeah, obviously they don't use a CVT so the RPMs are anything but the same throughout the race.
I don't know the details of Top Fuel and such, but Steve with his SMX[1] wagon[2] keeps his car at 2000 RPM at the lights, so seems reasonable to assume Top Fuel is around there too.
On the top end the Top Fuel cars are limited to just over 8000 RPM[3], with the red line at 8500 RPM.
So an average of 3800 RPM seems reasonable.
As a cross check, given that Top Fuel cars are single-speed[4], I guess one could calculate the same using the diameter of the wheels, keeping in mind that the tire expands a lot compared to its size at rest.
[1]: https://www.enginebuildermag.com/2024/12/4000-hp-twin-turbo-...
[2]: https://www.youtube.com/watch?v=LnrZdrp77Cs
[3]: https://www.enginebuildermag.com/2023/03/top-fuel-and-funny-...
> Also how they use aluminum for the connecting rods instead of stronger and stiffer metals like titanium
The 7000 aluminium alloys are similar to titanium in strenght/weight
Yes but they have lower Young's modulus[1] so compress more under the same force. Thus acting as a shock absorber to reduce peak loads on the rod bearings.
Again no expert but from what I can see, high-end aluminum rods can use 7075 aluminum[2], which has a Young's modulus of about 72 GPa, while titanium has a modulus of about 105 and up[3][4], depending on grade.
At least that's my understanding.
[1]: https://en.wikipedia.org/wiki/Young%27s_modulus
[2]: https://www.enginebuildermag.com/2017/03/racing-rods-builder...
[3]: https://titanium.com/alloys/titanium-and-titanium-alloys/gra...
[4]: https://titanium.com/alloys/titanium-and-titanium-alloys/ti-...
An aluminium part with 105/72 cross section of the titanium will have the same modulus and incidentally the same weight.
Aluminium is also significantly cheaper, and easier to machine.
Titanium (or high strength steel, which is the strongest both per area and per weight and also the most expensive and difficult to machine) would be used where the volume of the part would be a concern.
Perhaps I misremembered. Seems difficult to find some written sources on this.
In my quest I stumbled upon this[1] article where they discuss composite connecting rods for Fop Fuel dragsters:
Designed for Top Fuel engines, this connecting rod is half the weight of a conventional aluminum rod, yet is projected by company engineers to last an entire season instead of just 12 to 15 races.
Seems they're still at it, perhaps it'll be the next thing?
[1]: https://www.performanceracing.com/magazine/featured/08-01-20...
Some facts about top fuel dragsters: the supercharger uses around a thousand horsepower to run, but that's ok because the motor puts out over 10x that. It uses around 15 gallons of fuel for a single quarter mile run, but that also includes the burn-out.
If you're anywhere near the pits, and the crew fires up the motor, and then just blips the throttle, the sound waves generated are like physical blows to your chest.
The only sweeter sound is a V12 Merlin coughing into life.
I snagged a ride in a P51 once. OMG. That machine just leaped into the air. I was smiling for a week.
Story of coincidences, I guess: I'm adopted, but a total car nut. My adoptive family weren't really car people except my uncle. A couple years ago I found my birth family, and they are all car nuts. My half sister was a test driver for Audi, my mom and much of the family worked at the local drag strip.
When very little, I thought I wanted to be a farmer, and tried growing crops in the back yard. Total failure. I threw an entire bag of grass seed in my yard 6 weeks ago. Not a single seed sprouted (a flock of birds ate every one). Total failure.
But by age 7 I knew that I was a born engineer. Engines, electronics, software, structures, all of it.
That’s amazing how influential your genes were on you
> Compressed air is stored at 3,300 psi in carbon fiber tanks that weigh roughly 30 pounds each when full
When are the kids in California going to grab a tank, point the nozzle down, and ride that thing like a rocket from the beach, parachuting into the ocean?
We could call them "beach jumpers".
Isn't this basically cheapo nitrous?
is it skirting some kind of rule and being specifically NOT nitrous?
Or maybe it is just cost - scuba compressor to fill tank.
Aren't there stock electric cars now that do quarter mile under 10 seconds?
When battery weight gets cut in half next decade and capacity doubles, the only reason why they will race ICE engines is for the noise
Our Hyundai grocery-getter does a 1/4 in 13s, the "N" go-fast version does it in 11s. And those are Hyundais with full-sized, heavy-ass batteries, and abysmal stock tires. Porsche Taycan GT (with a full-sized, heavy-ass battery) turns 1/4 in 9.3s.
Now cut those heavy batteries in half because you're not driving from SF to LA, and I could see that Porsche turning 8s if you could get the power to the ground (IOW, launch control and much better tires than stock).
If you want to get into electric small-batch performance cars, BYD has you: https://en.wikipedia.org/wiki/Yangwang_U9
I don't believe there's anything even remotely competitive in the electric world to Top Fuel dragsters. You could also make the same argument about F1 vs E1
https://en.wikipedia.org/wiki/Top_Fuel
> Top Fuel is a type of drag racing whose dragsters are the quickest accelerating racing cars in the world and the fastest sanctioned category of drag racing, with the fastest competitors reaching speeds of 338.94 miles per hour (545.5 km/h) and finishing the 1,000 foot (304.8 m) runs in 3.641 seconds.
AFAIK the fastest "production" EV is the McMurtry "Spéirling" that does a quarter mile in under 8 seconds. Watching it set the record for goodwood is mind blowing, because it looks like the video is being played in fast forward, but it isn't.
https://www.youtube.com/watch?v=5JYp9eGC3Cc
Although you can in theory buy one, it uses down force fans so I don't know if it would even be street legal in most places. Personally, I find car like this to be way more interesting than drag racers.
I don't know if you understand just how much of a difference there is between a 4.5 second car and a 7.5 second car- it is orders of magnitude.
Even with half weight and double capacity- the worlds fastest EV will get walked by a fast gasoline street car
The properties of air that you care about are basically immutable, so why not pre-compute a bunch of compressed air instead of compressing it on the fly, and then having to carry the equipment to do that.
There is an energy cost to supercharging. While you get an overall horsepower boost, it's less than what it would be if the compression cost nothing.
Question -- why not go with liquid oxygen? Does that push the danger-meter too high? On the plus side, you're not dealing with 3000 psi compressed gas.
I'm assuming the costs involved in making engines capable of withstanding cryogenic temperatures probably make that impractical (?)
I think it becomes easier to just use a different fuel that is partially self-oxidizing. E.g. Top Fuel uses nitromethane rather than gasoline. Gasoline's stoichiometric ratio is 14.7:1 air:fuel, nitromethane is 1.7:1. Nitromethane in Top Fuel is already so volatile that the superchargers have to be wrapped in kevlar because the fuel blows up in them sometimes.
https://en.wikipedia.org/wiki/Top_Fuel
https://en.wikipedia.org/wiki/Nitromethane
Nitrous oxide is the safer equivalent, relatively speaking. Pure O2 would make things burn that normally don't burn, and increase engine detonation.
And instead of gasoline carry liquid hydrogen. Dragsters are practically horizontal rockets anyway. Might as well stop pretending!
Liquid hydrogen is very bulky, the tank might be large enough to impact the aerodynamics. Use kerosene instead, and maybe use RFNA instead of oxygen, just to bump the danger level up to Abjectly Stupid.
I'll just flip my copy of Ignition! open to a random page and build a car around that...
Liquid hydrogen can also cause hydrogen embrittlement. Not ideal in a high performance machine.
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If you're going to cheat, way cheaper to put nitrous oxide in the tank and claim it's compressed air. 50% boost in oxygen content without having to engineer your engine to not burn when pure O2 hits it.
3000psi gas is the easy way. You just need a couple valves instead of a bunch of insulated stuff that has to not freeze up at -200C.
You can't have liquid oxygen at room temperature. It's physically impossible. It would have to be stored at extremely cold temperatures at all times.
Look up "critical point" and a phase chart to understand why. It's an interesting physics topic that isn't obvious if you've never seen it before.
Liquid oxygen will oxidize anything it comes in contact with. You have to use specific metals for the connections and piping.
Think: would a drag race last long enough that you need to cram that much more oxygen into a small tank?
Amazed it didn't happen earlier. For a long time it's been seen that an economical way to store energy is to store compressed air in a cavern and feed it into a gas-fired turbine in lieu of turbocharging: see https://urbanao.com/post/compressed-air-energy-storage-caes-...
It didn't happen because like everything else that the peanut gallery deems "obvious" the actual pros and cons of implementing it didn't pencil out until recently.
This was tried in the 1950s and 1960s. IDK why it didn't make the cut then. Probably cumulative weight of tanks. It takes A LOT of air to run an engine.
I noticed the tank in the article's photo looks like carbon fiber wrapped aluminum. Those are noticeably lighter than the pure aluminum or steel tanks common in the 60's. (Source: Have carried each on my back as a volunteer firefighter)
I planned to implement this system in a project car years ago, but never got to it. Do have a parts list, and the overall cost is quite reasonable. My goal focuses on in-vehicle recharging rather than tank-swapping approach.
https://gist.github.com/s0kil/9bd6815ea2ab4e65a786c6382a5bfa...
Why not compressed pure oxygen?
Had this idea since the 90s, but no racing team listened to me just because I was a kid in school.
You'd get better energy density that way, but I think it's offset by worse efficiency & more damage to the engine. The inert gas fraction (N2, CO2, H2O) provides a useful working fluid to convert combustion heat to force pushing on the piston. Burning pure O2 would mean a lot more heat is needed for the same amount of force. Higher peak temperatures & more available oxygen will tend to create hotspots & knock/pre-detonation, & possibly erosion of the cylinder wall & piston from directly burning the metal.
Using nitrous or cool compressed air keeps most of the benefits while mitigating the problems of using pure O2.
Wikipedia says uncited that N2O produces heat when it decomposes into nitrogen and oxygen, but that's the opposite of other comments saying that cold oxygen is better because it's denser
Compressed - cold - pure oxygen, that is.
Held in a lightweight composite thermic bottle.
These tanks are called “SCBA” self contained breathing apparatus… no “u” for underwater.
They’re what firefighters use.
This is pretty smart. Why carry the compressor and intercooler with you? Save the mass and complexity, as well as shifting the energy required to compress the air to a device off the car.
Like at this point what's stopping you from strapping a couple SRBs on the frame.
Is there added fire and/or explosion hazard?
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It's fine to feel that way but it's not the kind of dismissive comment we want on HN; we're here to have curious conversations, thanks!
https://news.ycombinator.com/newsguidelines.html
Drag racing is just about the purest most scientific competition of vehicle tuning you're going to get. The driver doesn't really make or break it as long as they're at least decent.
On the other end of the spectrum you have racing types that are more of a competition among drivers with the vehicle not really making or breaking anything as long as it's typical for the class.
I get racing on a twisty track. They are legitimate tests of human skill and vehicle endurance engineering. Drag racing has none of that. There's little skill beyond reaction time and drag vehicles have almost no relation to normal vehicles.
Think of drag racing like the CO2 cartridge race car competitions you see in lots of high-school science classes. It's an engineering challenge, not a skill-based race.
I disagree. Drag racing involves incredible honed vehicle endurance, just on a much shorter timescale. It’s an engineering problem with the goal of outputting as much power as possible within a short timespan (often only a few seconds) without detrimentally destroying the engine. As far as the drivers are concerned, the reaction time is obviously important, but they have to be extraordinarily consistent. At that, they have to drive the car at 5 g’s- not an easy task.
The engines still get destroyed. It's basically a complete rebuild between runs. Most of the spark plugs burn up, clutch disks get welded together, etc. The goal is basically to just not have the engine outright detonate so they can reuse the block.
You are absolutely correct. Perhaps I should’ve worded “detrimentally destroyed” as “catastrophic failure.” The rebuild process between runs is fascinating to watch. I’ve never seen an engine torn apart so quickly!
> I’ve never seen an engine torn apart so quickly!
The first time I took my 286 intake manifold off, it took 4 hours. The 4th time I took it off, it took 20 minutes. Once you know exactly what to do, it really cuts the time down.
I'm sure every member of the team knows exactly what to do and it's down to a dance.
For fun, look how fast they change the tires on a Formula 1 pit stop.
Drag racing has none of that.
What is it the kids say? "Tell me you know nothing about drag racing without saying you know nothing about drag racing"? Drag racing has all of that, squeezed into 1/4 of a mile. That's why top fuelers get an engine rebuild after every trip down the track.
It's like saying, "I get ultramarathons, but 400m foot races involved little skill or training." Look, if you don't get it, fine. Probably best to just leave it at that.
You're thinking about this in only a professional way. There are a lot of amateur events where people race with their own cars that they have modified. It's really fun to see something like a vw rabbit beat a modern sports car etc. It's a fun event too but the tire burning shows do get old very quickly.
Try it! Costs far less than you think and more than half the class sat wide eyed, refusing a second run.
Have you ever tried it?
I participated in motorcycle track days on race tracks for 15 years. I've dragged knee at 90pmh. _That_ takes skill and balls. Drag racing seems dumb by comparison.
That's a long-winded way to say, "no, I've never tried it". If one has never tried a pursuit, I can understand how it might "seem dumb". What seems dumb to me, though, is doing track days for years on end, and never once trying to see how fast you could launch a bike down a drag strip, and then going on about how dumb drag racing is.
I've owned two Porsches, an Audi R8 V10, half dozen sport bikes. I've done laps at Laguna Seca. I've floored them all to see what they'll do. The V10 sounded amazing.
But I've never felt any interest in drag racing at all, it's a pointless waste of fuel. Press accelerator, press brake, done, little to no skill required. And in something like the R8, would require a $20,000 dealer visit after a weekend of runs.
If you actually achieved a high level of proficiency you'd be able to respect what goes on at an equally high level in a different niche.
Racing changed my life and you should definitely go to a meetup, drag race, or track event. The dream of the 80's is still alive in the car world. You'll meet the coolest people. Dummies get filtered and don't make it to the events/track. It's the best and easiest real life scene to get into if you're technical because car guys are absolute nerds.
> because car guys are absolute nerds.
Are they? At least in Europe they are usually blue collar guys that pick a neighborhood at random to hold a car meet, terrorizing that neighborhood until deep into the night, including street races. And if they aren't accommodated they'll aggressively clash with the police.
They're easy to spot too, pumped up douches with tribal tattoos and gemstone earrings that behave like they're prone to pick a bar fight with you.
Or hoons as the Aussies call them. I think OP was talking about a different caliber of racer.
I am, which is why I specifically said drag, meetups, and track events. The only group I detest are the ones that takeover roads/highways and race in densely populated zones. I like hooners, 99% stick to parking lots and make a bit of noise. You'll be very hard pressed to find "racers" who embrace endangering regular people.
Europe doesn't have the same accessibility for motorsport so people doing stuff on the street is what you get. IDK, write your legislator.
What do you expect when tracks are closing left and right? That energy has to go somewhere. But yes those guys are also nerds.
The meets I'm talking about are like this [0][1]. There's a lot of the tattoo gemstone guys in [1]'s timestamp. Is this what you mean? I'd love some examples.
[0] https://www.youtube.com/watch?v=_bAq_qD9i2s
[1] https://youtu.be/q4lvEYLJaOY?t=340
>And if they aren't accommodated they'll aggressively clash with the police.
If you're a car guy you're basically begging to be hunted constantly. In my opinion this is all downstream of the death of folkracing.
As a race buddy of mine often says, one can teach a complete college semester on the math of drag racing. From the engineering of the vehicles to the tuning to the weather calculations. And then there is what we call "bracket racing". Staggered starts based on your own prediction of elapsed time that you cannot run faster than or you will "break out" and the other vehicle wins. A favorite t-shirt in the pits says, "Not everyone can do math at 150MPH".
Literally everything is pointless, even existence, from someone's point of view.
You don't have to understand how something amuses someone to understand that it amuses them. You also don't have to belittle people to ask them why they are amused.
If you think drag racing seems pointless and self destructive, it is in your best interests to not explore the other popular variants of competitive motorsports today.
I have been told that a lot consumer automobile advances began life on the race track.
People like to go fast and they like the challenge. And newer race cars have a good bit of technology in them.
You could say the same about just about everything except breathing, eating, and drinking nothing but water.
Most hobbies are pointless. I need you to explain how you got to "self-destructive" though.
When I look at a drag stripe, I see a gray, dirty rectangle of asphalt that generates huge amounts of noise and air pollution. Beyond the environmental destruction, it's a hobby that quickly destroys vehicle parts, engines, tires, brakes, etc. All of that destruction, for what? 5 seconds of extreme acceleration? To go one hundredth of a second faster this time?
How do you feel about model rockets? If it's the same then oof okay, but if you feel very different then I think you're being too harsh on drag racing.