Compressed Air Supercharging

[shuvool]

I was thinking about the ability to make multiple passes in one day...you'd need several tanks do do it if you could get a system to deliver the compressed air reliably in the fashion that you desire. Compressing air into tanks heats the air up just like compressing air with a supercharger into an engine.

There would need to be some sort of bypass/manifold rig so that you'd seal off the throttle body from the air filter as well when you start discharging the tank, otherwise your tank would just be blowing the pressurized air out of the air filter, since the pressurized air is going to evenly distribute once released, and it's much easier to blow out through the filter than to push into the engine

 

[702GT]

Yes, that's what I had in mind. Honestly though, my real heat is coming from the SC discharge temps, so that's what I need to focus on. Once I get a handle on those temps, then I'll consider something like this.

There's always water/meth, unless you don't like the idea of spraying it through your rotors. Personally I like the idea of N2O/e-85 wet shot. I toyed with the idea a while back, but ended up picking up my D1 kit before I could put my N2O kit into practice. N2O makes the air charge dense and cold. Most people run regular gasoline mixed with the spray. Once the cooled/dense charge is ignited in the combustion chamber, it actually burns much hotter. If you replace the gasoline with ethanol, it should lower the combustion temperature significantly. I'm not sure if this application would work well on a PD setup though, as air is forced through the intercooler post-rotor. I'd be worried the vaporized N2O/Ethanol would make contact with both the rotors and intercooler fins and liquify the shot, altering its properties. But people spray on PD blowers all the time and don't seem to have any trouble. Personally I'd be worried about puddling in the intake manifold and having a N2O backfire under boost. It's an idea though.

I was thinking about the ability to make multiple passes in one day...you'd need several tanks do do it if you could get a system to deliver the compressed air reliably in the fashion that you desire. Compressing air into tanks heats the air up just like compressing air with a supercharger into an engine.

There would need to be some sort of bypass/manifold rig so that you'd seal off the throttle body from the air filter as well when you start discharging the tank, otherwise your tank would just be blowing the pressurized air out of the air filter, since the pressurized air is going to evenly distribute once released, and it's much easier to blow out through the filter than to push into the engine

This was covered already. You are correct that the air in the cylinder gets heated as it's being compressed. However, the heat dissipates over time, and when the air is released from the tank it comes out extremely cold (there's a fancy Joules-Thomson effect if you want to get totally scientific) basically from air moving from a high pressure to a low pressure very rapidly. Even if you just compressed the cylinder, the air will come out much more cold than when it went in.

If anyone does "rig" their engine for compressed air boosting, I just want to be the first to say, if you're going to put an air compressor on top of an air compressor, just buy a REAL over-engineered air compressor!

FEED IT MOAR!

 

[Department Of Boost]

I've seen that car in real life. I was like WTF!

 

[T-Neck]

I will be screening and packing my intake tube pre maf with dry Ice.

Nothing bad could happen at all. Trust me.

 

[Pentalab]

Here's a random thought: O2 is roughly 20% of atmospheric volume, and it greatly accelerates combustion.
Why not run pure oxygen? Seems like it would allow more fuel to be added due to combustion properties...

You are correct. 1 cf of O2 = 5cf of air. For a 666 crank hp eng, it requires 1000 cfm of air.... or 16.67 cf per sec. If o2 was used, it's then down to 3.33 cf per sec. 33 cf for a 10 sec run down the strip.

I thought of this compressed air /pure o2 idea 2 years ago...and everybody told me to piss off. Even supplementing the intake of a standard blower setup with a small amount of o2 would have merit. The problem as I see it would be the MAF sensor measures the weight of the air, not the O2 content. (I may be wrong here)

With O2, your AF ratio would be like down to 2.38 : 1
On paper, you should be able to stuff 5 x as much fuel into the cyl if o2 used. You wouldn't need a blower at all, just bigger injector's and a lot more fuel capacity. Tuning it would not be easy. Switching from plane air mode to o2 mode could be done with a one way damper on the cai intake..with the o2 injected downstream from the one way device. Then something... like an o2 sensor has to tell the ecu to add 5 x as much fuel..and asap.

Of course, with 5 x as much o2 and 5 x as much fuel...the eng will blow its brains out...with 5x more hp. The ideal would be to add a bit of o2 to the normal air..to supplement the existing 20% o2 content. Done right you should be able to increase the crank hp by say 20-100% more than NA..and no blower required.

Somebody needs to experiment on some disposable engs..to test the concept.

On a side note, a school buddy, back in 1969, "borrowed" some liquid ether from his dad... (who was a Dr in Seattle)....and poured a pint of it into the tank of his mini bike. Apparently the eng survived. It ran like stink, and was the 1st and last time he tried that stunt.

 

[s8v4o]

This isn't actually correct. I would have thought this myself, but testing has shown me otherwise. I have a thermocouple in my air filter (IAT1) as well as pre and post HE. All I do is review that data. At a certain point the IAT2 (post IC) will "flatline" no matter how far the IAT1's and water temps get. I've driven the car for up to an hour when it's 35deg out too. So it was as "cold soaked" as it can get.

At a point the IAT2's stop dropping. I'm sure like anything it is combination of things but I think the main factor is the heat coming through the intake manifold from the heads/coolant. That is a significant heat source.

That's interesting. So you're saying that your vehicle's IAT2's flatline at the same temp no matter the conditions? What temp does it flatline at?

 

[iwisefox]

Way too much difficulty for a 1 time run on the strip before a refill.. Who really would do this? Someone is going to destroy their car.

 

[weather man]

Way too much difficulty for a 1 time run on the strip before a refill.. Who really would do this? Someone is going to destroy their car.

It really is for a guy serious about drag racing. No parasitic engine losses, reduced complexity (fewer moving parts) and unbelievably cold intake temps allowing ridiculous power at low boost are very attractive traits.

 

[Pentalab]

I'm interested in this only as an IAT cooler. If I could mount a smaller bottle in the front bumper area, and blast air into the filter/inlet during maybe 3rd/4th gear at the track, that's all I need.

I think this concept has merit...and would work. Heck, you could even place the bottle on the pass floor, or back seat..and route the hose through the firewall..if regs allowed. Then stuff the end of the hose into the CAI box / cone filter. Then maybe 5-15 cf per sec. The CAI would ingest a mixture of cold air + outside air. With some minor tweaking, the concept could be proven one way or the other.

 

[Pentalab]

This isn't actually correct. I would have thought this myself, but testing has shown me otherwise. I have a thermocouple in my air filter (IAT1) as well as pre and post HE. All I do is review that data. At a certain point the IAT2 (post IC) will "flatline" no matter how far the IAT1's and water temps get. I've driven the car for up to an hour when it's 35deg out too. So it was as "cold soaked" as it can get.

At a point the IAT2's stop dropping. I'm sure like anything it is combination of things but I think the main factor is the heat coming through the intake manifold from the heads/coolant. That is a significant heat source.

Ok, how do you isolate the manifold from the heads ?? Some kind of heat resistant gasket or complete redesign needs to be done. The crossover (for the eng coolant) is another cause for concern. On the Roush aluminum intake manifolds, the crossover is on the leading edge, and integral with the manifold. Great, now we have 204+ deg F eng coolant flowing through the AL manifold... cooking it. Then bucketloads more heat from each head. Then still more heat, this time radiant heat from the V below the manifold. Then close the hood...and watch it all cook.

The bottom of the blower casing should also be heat isolated from the top of the manifold. Until all these issues are dealt with, everything else is a band aid solution.

Bolting an aluminum blower casing to an aluminum manifold,(with it's crossover), that's bolted to a pair of aluminum heads...that straddles an aluminum block. There's your heat soak problem / high IAT2 right there.

 

[Department Of Boost]

Ok, how do you isolate the manifold from the heads ?? Some kind of heat resistant gasket or complete redesign needs to be done.

We went the complete re-design route with our R-Spec. The aluminum manifold is completely isolated from the heads with 1/2" of composite. When we have time we have been toying with making spacers made out of the same stuff for other popular combo's.

The crossover (for the eng coolant) is another cause for concern. On the Roush aluminum intake manifolds, the crossover is on the leading edge, and integral with the manifold. Great, now we have 204+ deg F eng coolant flowing through the AL manifold... cooking it. Then bucketloads more heat from each head. Then still more heat, this time radiant heat from the V below the manifold. Then close the hood...and watch it all cook.

Using a 170deg T-stat helps this a lot. And you can coat the inside of the passages to reduce heat transfer.

The "pans" can be ceramic coated, heat shielded or both. This works great also.

The bottom of the blower casing should also be heat isolated from the top of the manifold. Until all these issues are dealt with, everything else is a band aid solution.

You don't want to do that. The manifold works as a heat sink for the blower case. It's needed.

Bolting an aluminum blower casing to an aluminum manifold,(with it's crossover), that's bolted to a pair of aluminum heads...that straddles an aluminum block. There's your heat soak problem / high IAT2 right there.

Sure doesn't help.

 

[o2sys]

You should make a composite gasket for the manifold for the gt450 owners as well. Something that replaces the oem green rubber ones into a one pcs design in hope to help with heat transfer. I remember doing that in my subaru intake manifold which also had alu to alu head and manifold. Odly a company called Hondata made them for my WRX.

 

[Department Of Boost]

You should make a composite gasket for the manifold for the gt450 owners as well. Something that replaces the oem green rubber ones into a one pcs design in hope to help with heat transfer. I remember doing that in my subaru intake manifold which also had alu to alu head and manifold. Odly a company called Hondata made them for my WRX.

If enough people will buy them I will have them made in short order. That would be EASY for us to design.

 

[o2sys]

Start a group buy on DOB Forums!

 

[Department Of Boost]

Start a group buy on DOB Forums!

I highly doubt I can get enough people to spend the $$$$. They wouldn't be cheap.

I'll throw the idea out at some point. But right now we have a ton of stuff to work on I know people will spend the money on.