Ok, So It's Stupid-Now Tell Me WHY It Won't Work!

[38flattie]

Rich, this is one of those 'out of the box' ideas', that get me into trouble!
 
In my quest to find out how much more HP a centrifugal supercharger is capable of making, over a roots style huffer, I got side tracked!

I started thinking about how I could get the benefits of a supercharger, without losing the HP it takes to run one.
 
Since all a supercharger does is compress air, why not just carry compressed air on the car, and use it for boost? Obviously, it's not that simple, because of controlling and monitoring the boost, compressing the air, etc. but that's another story!
 
If 14lbs boost could be achieved from compressed air, the HP gain would be staggering. I approached Woody with the idea, and he sent me the attached pic

The car was designed and raced by Art Malone, even though the caption under the car reads: The "Air car" at Don Garlits' Drag Racing Museum. Concerned that he was losing too much power driving the blower, Garlits came up with this ingenious car, which featured a large tank of compressed air which was progressively fed into the engine during a run, instead of a blower.
 
This started a google search, where I found this:
 
Initial testing of various forms of the system was done on three different dragsters and one of Mickey Thompson's Ford Funny Cars, but in all instances, no full quarter-mile runs were attempted. Recently, however, Keane got together with Mickey Thompson and, utilizing Thompson's exotic dyno facility in Long Beach, accomplished an exhaustive testing program. The results were phenomenal. Where a 6-71 blown Boss 429 Ford engine on 20% nitro had produced 1360 horsepower, the same type of engine equipped with the bottled air system in place of the Rootes blower, burning only straight alcohol, produced 2400 horsepower at 6000 rpm! On gasoline, the system made about 1550 horsepower. This success was not easily achieved, as in one week of testing, Thompson reportedly ran 150 gallons of alcohol through the dyno engine.
 
So, long story short, is this a possibility? Can enough air be stored on board, with either bottles, or utilizing the frame, etc., to to run a 366 CID engine, at 14lbs boost, for 3 miles at WOT?
 
If not, why?

 

[kiwi belly tank]

Oh, this should be entertaining! I love this out of the box stuff. 
  It's basically a math question, out of My field.
  Sid.

[ONEBADBUG]

You know, the other day I got the wood stove going in the shop by sticking my blow gun in there. Amazing how well that worked! Centuries old technology. All you have to do for the the math is take the CFM of the engine times the time on track. You would want to minimize the time you used "boost", just like nitrous, basically.
What about rules, though?

[johnneilson]

I have a comfortable seat and popcorn with beer, carry on!

[Captthundarr]

I'll get the ball rolling on this. 1) no math wize here. 2) had to take my shoes off to count that high.

Engine CFM calcutalion - CFM= CIDxRPMxVE/3456 where CID=366,RPM=6000?, Volumetric Effic.(VE) =80? give a volume of 50,833.33 cuft/min. plus how long (time)to make a run?

Thats a lot of air to pressurize and store. let the corrections begin.

[38flattie]

onebadbug, I know the rules say mechanically driven supercharger, but a guy can always ask! Even if it were not allowed, if it were possible to do, I'd be interested in running time only to see what net gains were.

I'll get the ball rolling on this. 1) no math wize here. 2) had to take my shoes off to count that high.

Engine CFM calcutalion - CFM= CIDxRPMxVE/3456 where CID=366,RPM=6000?, Volumetric Effic.(VE) =80? give a volume of 50,833.33 cuft/min. plus how long (time)to make a run?

Thats a lot of air to pressurize and store. let the corrections begin.

Haha! Well, now I know why I haven't seen anyone else ask this question-they thought it out a little more than I did before voicing it!

Still, I wonder how Art Malone got down the track, and why Keane and the Mickey Thompson organization thought the idea was worth exploring?

[Dean Los Angeles]

The rules do say you need a mechanically driven supercharger. I heard somebody stuck a heater blower from their truck on a NA vehicle to set a blown record that made that rule show up.

The weight of the air tanks might cancel the benefit. The amount of compressed air you would need is huge. You would also need a huge pressure regulator to provide the correct flow at 14 psi from the 100 psi? 300 psi? 1,000 psi? tanks. Pressurized tanks are going to make the safety guys raise an eyebrow.

On the other hand, if you were to run the blower and supplement with compressed air . . .

[Rex Schimmer]

Back in the "old days" I knew Bob Keane, it was after he did the "bottled air" project and as I remember he did not use compressed air as you would need to much to make a pass, the system used compressed oxygen which was feed into the engine at a rate that increased the  inlet air oxygen content and increased the amount of fuel they could burn, i.e. more horse power. One of the "unintended consequences" was that as the oxygen was decompressed (adiabatic decompression I think it is called) from the bottle it would drop the temp of the inlet charge down to below zero F! plus the latent heat of the alky and the engines would actually have frost on the heads while making 2000+ hp.

I hope that someone with a more direct knowledge of this project chimes in here as these are memories from probably 30 years ago and can be somewhat hazy. I just don't think that SCTA would let you carry compressed gas bottles that weigh 1-200 lbs strapped into your car. What a potential bomb. Ever seen one with the head knocked off?!!! Awesome and dangerous!

Rex

[38flattie]

But if it were pointed out the back, imagine the 'boost'!

Seriously though, I thought it might be accepted if they were mounted safely, Now though, I realize it was a pretty hair-brained idea!

Still, I wouldn't mind exploring the idea on a dyno....

[RansomT]

A non math way of doing it would be attach a huge balloon to the exhaust and run the engine for 3 miles WOT, you then can see how much "air" you would need before adding the supercharger. I am going to guess, a WHOLE lot.

The misconception here is boost is equal to flow.  What causes boost is the engine's inability to use the air that is presented or it's restriction.  You can take 366 CID engine, install a supercharger make 600 wHP with 9 psi of boost.  Then remove the head/intake track and properly port them.  When you put the same engine back together it you may only see 7.5 psi of boost but the engine could make 675 wHP. It's the flow that matters not the amount of boost you see.

[Jon]

Cram more oxygen by using a pressurised storage system sounds familiar.
Wouldn't it be easier to run NO2?

[Interested Observer]

Re: Reply #4   --  Correction No. 1 --  Air consumption value is actually 508.33 cfm.

To otherwise address the question:
Assuming 700 hp, 10 hp/lb/min air, and a run duration of 1 minute, the engine would consume about 70 lb of air.  At 28 psia (14 lb boost) air density would be about .15 lb/cu. ft., implying about 470 cu. ft required.  Assuming a 5 cu. ft. tank, initial pressure would have to be about 2600 psi.  In rough terms.

[38flattie]

Re: Reply #4   --  Correction No. 1 --  Air consumption value is actually 508.33 cfm.

To otherwise address the question:
Assuming 700 hp, 10 hp/lb/min air, and a run duration of 1 minute, the engine would consume about 70 lb of air.  At 28 psia (14 lb boost) air density would be about .15 lb/cu. ft., implying about 470 cu. ft required.  Assuming a 5 cu. ft. tank, initial pressure would have to be about 2600 psi.  In rough terms.

I like your math way better than mine! SCBA tanks run in the 3500-4000 PSI range, making this doable!

[Captthundarr]

There you go, thats what I meant to say. thanks IO.

[Dynoroom]

Like most things, yes it's been tried before.