Drag racers are ditching superchargers for scuba-style tanks and compressed air

https://www.thedrive.com/news/drag-racers-are-ditching-superchargers-for-scuba-style-tanks-and-compressed-air

by PaulHoule • 1 year ago

57 93 1 year ago

PaulHoule• 1 year ago

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-...

potato37328424• 1 year ago

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.

rkagerer• 1 year ago

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)

hydrogen7800• 1 year ago

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.

mperham5• 1 year ago

[flagged]

potato37328424• 1 year ago

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.

mperham5• 1 year ago

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.

blahyawnblah• 1 year ago

People like to go fast and they like the challenge. And newer race cars have a good bit of technology in them.

MarcelOlsz3• 1 year ago

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.

jorvi• 1 year ago

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.

bigyabai• 1 year ago

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.

Dylan168072• 1 year ago

Most hobbies are pointless. I need you to explain how you got to "self-destructive" though.

mperham5• 1 year ago

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?

jimktrains2• 1 year ago

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.

stronglikedan• 1 year ago

You could say the same about just about everything except breathing, eating, and drinking nothing but water.

dave4270• 1 year ago

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".

JKCalhoun3• 1 year ago

I have been told that a lot consumer automobile advances began life on the race track.

tomhow• 1 year ago

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

hex4def6• 1 year ago

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 (?)

chongli• 1 year ago

And instead of gasoline carry liquid hydrogen. Dragsters are practically horizontal rockets anyway. Might as well stop pretending!

lupusreal• 1 year ago

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.

dabiged• 1 year ago

Liquid hydrogen can also cause hydrogen embrittlement. Not ideal in a high performance machine.

a_shoeboy• 1 year ago

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.

kazinator2• 1 year ago

Think: would a drag race last long enough that you need to cram that much more oxygen into a small tank?

toomuchtodo• 1 year ago

Nitrous oxide is the safer equivalent, relatively speaking. Pure O2 would make things burn that normally don't burn, and increase engine detonation.

Aurornis3• 1 year ago

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.

alnwlsn• 1 year ago

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.

everforward• 1 year ago

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

shipp02• 1 year ago

Liquid oxygen will oxidize anything it comes in contact with. You have to use specific metals for the connections and piping.

kazinator2• 1 year ago

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.

Aurornis3• 1 year ago

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

exabrial• 1 year ago

It says they're boosting to 10psi, in addition to the colder intake charge

Aurornis3• 1 year ago

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.

hnuser1234562• 1 year ago

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.

genewitch• 1 year ago

In to the cylinders! Water injection.

RandomBacon• 1 year ago

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.

lttlrck• 1 year ago

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.

maximilianburke2• 1 year ago

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.

munchbunny• 1 year ago

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.

danielsokil• 1 year ago

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...

ck2• 1 year ago

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

mikestew3• 1 year ago

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).

SideburnsOfDoom• 1 year ago

If you want to get into electric small-batch performance cars, BYD has you: https://en.wikipedia.org/wiki/Yangwang_U9

fanatic2pope• 1 year ago

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.

josefresco• 1 year ago

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.

jonfw• 1 year ago

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

linsomniac2• 1 year ago

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.

WalterBright3• 1 year ago

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.

linsomniac2• 1 year ago

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.

JKCalhoun3• 1 year ago

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".

johnatwork• 1 year ago

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.

arprocter• 1 year ago

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...

magicalhippo4• 1 year ago

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

hnuser1234562• 1 year ago

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."

magicalhippo4• 1 year ago

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-...

mjan226404• 1 year ago

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

magicalhippo4• 1 year ago

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-...

neilv• 1 year ago

Is there added fire and/or explosion hazard?

m463• 1 year ago

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.

DrNosferatu2• 1 year ago

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.

01HNNWZ0MV43FF• 1 year ago

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

DrNosferatu2• 1 year ago

Compressed - cold - pure oxygen, that is.

Held in a lightweight composite thermic bottle.

00N8• 1 year ago

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.

droopyEyelids• 1 year ago

These tanks are called “SCBA” self contained breathing apparatus… no “u” for underwater.

They’re what firefighters use.

hoseja• 1 year ago

Like at this point what's stopping you from strapping a couple SRBs on the frame.

Drag racers are ditching superchargers for scuba-style tanks and compressed air

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