Compressed Air Supercharging

[weather man]

Latest issue of hot rod had a interesting article on compressed air supercharging. There might be be some drag racing style kits come out. Compressed air has some neat properties. I wonder how it would work with E-85...the temperature of the fuel/air mixture would be ridiculously cold.

 

[shuvool]

Would the weight be offset by the charge? You'd need a pretty big tank to store enough compressed air to supply a V8 engine for 1/4 mile. At stock, you're talking about 900ish CFM already, right? An air compressor generally delivers high single digit CFM at a high pressure. A 60 gallon 2 hp compressor that I was looking at provides 7 cfm at 100 psi. There's also the issue of the lubricating oil for the compressor

 

[weather man]

Would the weight be offset by the charge? You'd need a pretty big tank to store enough compressed air to supply a V8 engine for 1/4 mile. At stock, you're talking about 900ish CFM already, right? An air compressor generally delivers high single digit CFM at a high pressure. A 60 gallon 2 hp compressor that I was looking at provides 7 cfm at 100 psi. There's also the issue of the lubricating oil for the compressor

The kit was using a tank big enough for 1 pass.

 

[zeroescape]

I would think a welding cylinder at ~3000 psi could handle the volume running ~5psi boost. Creating a low pressure high volume valve with a constant temperature is the hard part.

 

[weather man]

I would think a welding cylinder at ~3000 psi could handle the volume running ~5psi boost. Creating a low pressure high volume valve with a constant temperature is the hard part.

Yep, the measured air leaving the bottle was -140F and 0F at the intake.

 

[Dubstep Shep]

Damn thats cold!!!

 

[Tbone]

If going for a temporary power boost, id rather have nitrous. Seems alot easier to me.

 

[shuvool]

how many cubic feet of air do the tanks hold? The part I'm having a hard time wrapping my head around is the volume of air that you would need to be able to supply at pressure in order for this to work. If an N/A 5.0 Mustang already inhales ~900 CFM at atmospheric pressure, you're going to have to supply quite a few CFM to get a benefit, no?

 

[DOFORLIFE]

I am just taking a guess here but if the air is leaving the nozzle into the intake or manifold that cold at -0 you wouldn't have to completely pressurize the motor. If you drop the air time from 98 degrees to say 50 or less then that would be a big boost right?

 

[weather man]

If going for a temporary power boost, id rather have nitrous. Seems alot easier to me.

The upfront cost will most likely be quite a bit more and really for drag strip guys. Filling a tank with air instead of nitrous will of course be cheaper.

how many cubic feet of air do the tanks hold? The part I'm having a hard time wrapping my head around is the volume of air that you would need to be able to supply at pressure in order for this to work. If an N/A 5.0 Mustang already inhales ~900 CFM at atmospheric pressure, you're going to have to supply quite a few CFM to get a benefit, no?

30 pound bottles filled to 3,300 PSI. Bottle can flow 1,000 CFM.

I am just taking a guess here but if the air is leaving the nozzle into the intake or manifold that cold at -0 you wouldn't have to completely pressurize the motor. If you drop the air time from 98 degrees to say 50 or less then that would be a big boost right?

The test was ran with a 355 CI 9.2 to 1 CR built chevy smallblock. Baseline HP was 422 HP. They then switched to 114 octane race gas, as they had no idea what detonation would be like. On 5 PSI of boost HP jumped to 655 corrected HP. On 8 PSI it jumped to 836 HP.

Just imagine a motor optimized to run this system on the strip.

 

[EGNARO]

The upfront cost will most likely be quite a bit more and really for drag strip guys. Filling a tank with air instead of nitrous will of course be cheaper.



30 pound bottles filled to 3,300 PSI. Bottle can flow 1,000 CFM.



The test was ran with a 355 CI 9.2 to 1 CR built chevy smallblock. Baseline HP was 422 HP. They then switched to 114 octane race gas, as they had no idea what detonation would be like. On 5 PSI of boost HP jumped to 655 corrected HP. On 8 PSI it jumped to 836 HP.

Just imagine a motor optimized to run this system on the strip.

holy shit

 

[s8v4o]

Would the weight be offset by the charge? You'd need a pretty big tank to store enough compressed air to supply a V8 engine for 1/4 mile. At stock, you're talking about 900ish CFM already, right? An air compressor generally delivers high single digit CFM at a high pressure. A 60 gallon 2 hp compressor that I was looking at provides 7 cfm at 100 psi. There's also the issue of the lubricating oil for the compressor

If an additional 100lb setup reduced your 1/4mi more than one tenth of a second it would offset the weight. Considering something like this can take seconds off your ET I'd say it's well worth the extra weight.

If going for a temporary power boost, id rather have nitrous. Seems alot easier to me.

Except you can't refill it yourself and nitrous is going for $6/lb here. One full bottle is 60 bucks.

30 pound bottles filled to 3,300 PSI. Bottle can flow 1,000 CFM.
.

CFM or CF? One is total volume and one is flow.

 

[weather man]

CFM or CF? One is total volume and one is flow.

CFM

 

[tjm73]

Article is not on the website yet. Sounds really interesting. Look forward to reading it.

Do they say how large the compressed air tank is?

 

[weather man]

Article is not on the website yet. Sounds really interesting. Look forward to reading it.

Do they say how large the compressed air tank is?

I don't think they have finalized that yet.

 

[kdanner]

CFM or CF? One is total volume and one is flow.

You're thinking like I am. I've got the big argon bottles here, they are 330cf. So there's 20 seconds at 1000CFM. That bottle is 5 feet long, where are you going to put it?

I'm thinking how are you going to fill the tanks at the track? If using something like a SCUBA compressor, you won't like those prices. Plus they take a significant amount of time to fill tanks, I'm seeing 20 min to take a 80cf tank from 500 to 3000 psi and that compressor costs over $3k. 80CF would be good for 4.8 seconds at 1000CFM. Really less because I can't imagine it being effective once pressure drops enough.

I have no doubt it can work, I just don't see the practicality until/unless the supporting hardware is much lower in price.

 

[702GT]

Except you can't refill it yourself and nitrous is going for $6/lb here. One full bottle is 60 bucks.

Can you even compare such a "bottled air" system to a nitrous system in method of delivery?

If you're serious about nitrous you most certainly can fill it yourself.

http://www.nitrousdirect.com/nitrous-refill-station.html

As for using a tank of compressed air for boost... how? Do you have a link for this article?

I'm just curious. Any conventional means of supercharging, positive pressure is achieved only when the system between the source of positive pressure and the intake valves are sealed. Under normal operation, a bypass valve or blow-off valve allows the induction system to relieve pressure, allowing the intake manifold to achieve vacuum. (Which some vehicle systems rely on that vacuum to perform other functions, such as PCV/EGR.)

This compressed air system can't be routed like a nitrous system would. In fact, if it was, it would most likely hurt performance or cause damage to the engine. If you try to introduce more, and denser air directly into the intake manifold, you would be bypassing the MAF with un-metered air. If you could even pump enough air into the manifold at WOT, the air would just back-flow out of your intake tube. MAF wash wouldn't even begin to describe it.

Unless you can find a way to completely seal the intake tube from the filter, and then somehow blow that cold compressed air over the MAF, such a system will never create positive pressure in the manifold, let alone be less than a mother fvcker to tune. Remember that positive pressure is, foremost, all the extra air that the engine *is not* consuming. Air will follow the path of least resistance. In the case of a typical N/A EFI engine, that would be right out the air filter.

 

[weather man]

No link up yet on hot rod. If it were easy, it would be in widespread use. There are always guys willing to try and make the engineering "fiddly bits" come together. Modern electronic controls and miniaturization are opening doors previously closed. It may turn out to be cost ineffective, be interesting to see if they can make a kit guys can buy.

 

[Department Of Boost]

Neat idea. I love stuff like this. You will NEVER get that through tech at the track though.

 

[weather man]

Neat idea. I love stuff like this. You will NEVER get that through tech at the track though.

Blue paint and a NOS stencil