I was reading aboutthe old Mickey Thompson compessed air powered engine
from 1970. Using air from scuba tanks@3000psi to supercharge a Boss 429 Thompson was able to exceed top fuel nitro engine power levels using methanol.
What interested me was the reduction in inlet air temp, dropping from +250F from a 671 to -70 or so from the compressed air dropping from 3000PSI to about 15PSI.
Thompson realized the super low AITs were the reason for the power levels reached.
I also saw on here that one of the really fast cars on here has an IAT of -10 by spraying NO2 upstream of the compressor therefore not needing an intercooler at all.
With ice and water you cannot get colder that 32 or so, but if you used antifreeze chilled by dryice to -70F or so the inlet temp should drop quite a bit.
Lower IATs should produce more power and ward off detonation.
I used to watch a turbo buick V6 car run in high and hot Albuquerque.
He had a tank of freon in the trunk and sprayed it on his ATA intercooler just before and during the runs. He swore by it.
Dryice is cheap and available everywhere, for a high output drag engine it could be a very cheap power adder perrun.
Any thoughts are appreciated.
Jarhead

 

Here's the quick and dirty equation for air density in lb / ft^3:

[ Pressure (in PSIA, not 'gauge' ) ] / [ 0.3704 * (Temperature (in F) +459.67) ]

Barring variances in engine efficiency, etc, you'll make roughly 10 HP per lb per minute of air you can jam into an engine (on gasoline, slightly less with methanol, much more with nitro / blend).

However you get the air density up works - high boost or low IAT. Low IAT has the added benefit of improving detonation tolerance when you're working with lower octane fuels.

 

Thanks although I'm a bit weak in math.
What I'm asking is if IAT was dropped 100 degrees, say from +40 to -60 to -70 and using the same boost level (say 15PSI) how much more power would the colder IAT engine make?
I'm thinking that no matter what fuel you are using, you'll make more power with a lower inlet temp.
Like Pro Stock cars when the air is cool and dense they fly.
Jarhead

 

You will make a little more but the main benefit from the low IAT would be the ability to run much more timing advance without the worry of detonation.

 

There is an Australian dyno car on here that has a 106mm turbo on it. It has a dry ice intercooler and makes insane numbers.

 

Anyone else?

 

There is an air temp of "too cold" for fuel to mix and explode efficiently...you need to find that temp......-100F may be way beyond that temp.

 

I think its close to -75 f. Not sure but it was a question on a test i had wayback in the day .

 

Well I doubt that you could ever get the inlet air so cold that it wouldn't burn right anymore.
The figure of minus 100F is the temp of dry ice. If you could chill down antifreeze to near that temp and then pump it thru the intercooler and tubing it would warm up some. As the heated air from the tubo gets cooled down the heat passed to the antifreeze would warm it quickly.
I was hoping that some guys on here would tell us what their temps are from the turbo and then after the intercooler.
Supercooled anti freeze pumped thru an intercooler would have to lower the temps quite a bit and should add horsepower at the same boost levels.
I really feel that "supercooling" the air into a turbo charged engine would offer increased performance and help ward off detonation possibly allowing higher boost levels and more timing on the same fuel. ie higher boost possible on pump gas.
I was hoping some info on the Australian car using a dry ice system might shed some light.
I noticed that Hot Rod Magazine used a water to air intercooler on the 1200HP stock shortblock 4.8 buildup.
They did not say how much the intercooler lowered inlet temps and I wish they had.
Jarhead

 

http://m.modmotortech.com/forums/sho...d.php?t=840176

 

Im the one that tuned the 5.3 with the nitrous in the turbo s10. Since then there has been many PM's, more testing, and more than a few actually running it. (especially here local) One has to understand that the cooling effect is all in relation to the gross amount of nitrous sprayed and the CFM of air flowing into the intake as well as the turbo's effeciancy levels at that cfm. Too small a compressor or a reversion issue (air backing up thru the engine, sometimes even due to exaust backpressure) will create higher than "standard" air inlet temps.

My background is from outlaw 10.5, dragradial ect and a typical Air inlet temp that we like to see is 60-70 degrees (thats obtainable with a large Air/water) A good example is Enzo Peccihini's NMRA dragradial mustang. I was involved with the chassis build from the ground up and everything on that combination was built for peak effeciancy. So much so that 3 years ago we started with a filled block, and ran icewater pumped thru the cylinderheads down the track from a secondary intercooler tank. The water temp in the heads and top of the block was 45 degrees on the start of the pass and 60 thru the quarter mile. We held the world record for an F1R procharger for a year with a 5.03 in the 1.8th mile with 342 cubic inches and trick flow heads.

ANYWAY you can cool the intake charge, with inlet temp or even block temp... it drives away detonation. When I tuned that car we ran 23 lbs of boost and 29 degrees of timing at 10300 rpm over spinning the F1r 30%.

Similar... lastnight we ran the s10 with the same stock 5.3 we have always ran. 250 shot on two stages... 27lbs of boost. Wild ride and spun damn near the length of the track. But we drove the truck home still alive and well.

The turbo heats up the air while it compresses it... THATS where the heat is created. If you spray 1 inch away from the compressor with nitrous thats -150 degrees... thusly cooling DIRECTLY the compressed charge. You will see big inlet temp drops.

 

Got any more info on the 5.3 truck with the boost and N2O? seems like a cracking engine.

There was someone on here with a procharge that was running a secondary W2A cooler with dry ice pumping through (wll methanol but its dry ice cooled). He had some pics and the secondary cooler was totally frozen up on the outside!

Dose anyone know hhow long two suba tanks would last by spraying into the itnake? you could recharge them in the pits pretty easily. In fact you could probably run a air compressor of the engine!

Chris.

 

Depends on the size of the cylinder. I always dive with an 80 cubic feet. It's about the size of a 15 lb nitrous bottle. As for refilling that in the pits... I'd feel safer standing next to someone heating a nitrous bottle with a blow torch, holding the flame in the same spot!

 

law of diminishing returns, and someone hit the nail on the head with correctly atomizing and combusting the gas you are using.


A perfect example would be the IAT optimization between c16 and c23 race gas. c16 combusts better with higher IAT's than c23.

 

Why would refilling them in the pits or even in the car be dangerous?

anyone know what presure truck breaking systems run at?

Chris.

 

Granted, most of them have been successfully recalled, but several years ago there were some defective SCUBA cylinders floating around that exploded while being filled. Since that, I've thought it best to refill them while they're submerged (in a tub of water for example), so the cylinder shrapnel doesn't travel very far. Yes, I know many dive shops don't do that, but that's just how I feel... and I don't foresee tracks providing a big tub of water just to put my mind at ease!

 

Ahhhh i see now! not being into diving i never really knew of the problem.

 

Would the compression stroke not add any required heat needed to the fuel air mixture? Not to menssion the heat form the cylinders / combution chambers.

Chris.

 

Here's some info on compressed air in drag cars.
Mickey Thompson used about 10 80 cubic foot scuba tanks for his Boss 429 powered fuel funny car. Never could get it to hook up as clutch management was in it's infancy then.
He made a ton of power but couldn't hook it up.
A few other guys also tried, Art Malone for one.
Then some guys tried an air powered thrust car, Cragar sponsored it but it was a flop.
Then there were the Hydrogen Peroxide rocket cars of the 70s and early 80s.
They used compressed air to pressurize the H2O2 and push it into the chamber.
I happened to own and drive one of those in 1977 and 78.
Called the Texas Starship it was a 260 inch rail, Marina blue and had a 5000 lb thrust engine by Ky Michaelson in Minneapolis.
After a plane crash ended my driving days I sold it to my friend Fred Goeske.
Fred went 4.50 and 353 at Orange County before selling it to a guy named Rob Phelps.
They quit making 90% H2O2 and Phelps put it in Garlits museum where it's sitting next to Tom the Mongoose;s funny car to this day.
It used three 80 ft scuba tanks and emptied them and 24 gallons of fuel in about 4 seconds.
I refilled the bottles myself with a scuba compressor. The reason you put the tanks in water is to keep the temp down as you fill it. It heats up as the pressure rises.
My best et in the 1/8 was 2.94 at 301mph.
Best 1/4 mile was 4.80 at 328mph at the Star Wars Drags in Oct 77 at Big Willie Robinson's strip in long beach.
A very easy, fun car to drive and quite a ride when I was 29.
Jarhead

 

WOW! some impresive stuff there Jarhead! Just to clarify your car only used the rocket motor?

Chris.