Power improvement for NA's that actually works

[idgtd]

So, I had been thinking of ways to improve the performance of my 1.6NA, and after a bit of thought, I realized that one way might be to enrich the oxygen content of the air going into the engine using bottled oxygen. Not much, mind you, just up it from 21% to 25-28%,  so I can burn all of that extra fuel that my engine currently converts to smoke at maximum delivery (fuel screw turned up a bit). To make a long story short and cut out all of the boring research, it turns out that Argonne National Labs has been working on this for emissions and performance improvement for some time. So, I made a table for oxygen flow through a calibrated orifice at given pressure differentials, liberated my portable torch of its 20cf oxygen bottle, and set up some tubing for gas delivery to the intake snout. I also installed a Westach egt in the downpipe to monitor egts.

For testing, I found a flat section of road with two signs. I went the same direction for all of the tests to get a good comparison. Basically, I got up to 50mph in 5th gear, and floored it when I reached the first sign. I then recorded my final speed at the second sign. I played with the oxygen pressure a bit, but after a certain point, all of the fuel was used up and the speeds leveled off. Here are the results for the best runs:

Zero psi, zero cfm Oxygen(21%): Initial speed = 50mph, Final speed = 68mph
20 psi, 3.4 cfm Oxygen(25%): Initial speed = 50mph, Final speed = 72mph

This may not seem like much, but I finally got to apply my degree in physics, and using

Vf^2 = Vi^2 +2ad

Where a is acceleration and d is the distanced traveled, we find that the acceleration is 26% better over that engine speed range covered. Since

Force = Mass X Acceleration

And mass didn’t change between runs, this means that the average force over that speed range, and thus the average torque over that speed range also increased by 26%!

EGTs rose some, but not too much. Initally, on a long WOT pull at maximum vehicle speed, I’d see about 1250-1300F. With O2, I see about 1350F (where I chicken out) at max speed. But, during the above tests, the EGT’s never climbed above 1200F.  

Not to bad for $10 worth of parts and a couple hours. Now to answer some questions that I know are coming.

Ques: Why didn’t you just use nitrous oxide?
Ans: Here in Starkville, MS there isn’t any place to have a nitrous bottle filled that I know of. And in Jackson they charge $30-$40 per fill. O2 costs me $8, and the bottle lasts a long time. Hell, I just went through a 20CF bottle in all of my testing.

Ques: I read that my engine would melt with oxygen, like putting a cutting torch to it. Won’t it?
Ans: No. A lot of people say that, but none of them have tried it. I did the math, and it didn’t add up to melted engine. Apparently, leaders in the combustion research field agree with my findings, since ANL is working on this now. My engine agrees with me too.



Ok, this is too long. Comments? I’ve got ideas for next steps, but I’m interested some other peoples opinions.

If anyone wants them, I’ll post my O2 orifice/pressure flow chart, calculations, and pictures. Just didn’t want to clutter things up if there isn’t any interest.

[burn_your_money]

Ques: I read that my engine would melt with oxygen, like putting a cutting torch to it. Won’t it?

This is because the metal in the engine isn't hot enough and the oxygen isn't concentrated enough correct? I know when you are cutting with a torch if you hit the oxygen before the metal is hot enough nothing happens.

If anyone wants them, I’ll post my O2 orifice/pressure flow chart, calculations, and pictures. Just didn’t want to clutter things up if there isn’t any interest.

Please do, I'm very interested

So you used up $8 in oxygen in just 2 runs? How far apart were the 2 signs? How many tests did you run? Same day, same head wind etc?

[idgtd]

On the torch effect, yep pretty much. Adiabatic flame temperatures do increase with oxygen content, but not enough to cause a problem. As for the oxygen usage, actually, I've been testing all month. Multiple top speed runs, 0-60's, 2nd and 3rd gear roll ons, etc. The bottle lasts a long time. Let me see if I can find my spreadsheets.

[idgtd]

Ok, so some of the math. I looked at effective airflow into the engine at two speeds, 2000rpm and 4800rpm, the peak torque and horsepower points respectively. (according to the 1.6SAE paper). Although the actually flow may be a little more, these values represent what the engine is actually using to make power.

@4800 VE = 52%, so 69CFM of air, or at 21% O2, 14.5CFM of oxygen

@2000 VE = 67%, so 37.5CFM, or 7.9CFM of oxygen


So, using a little math,

(((Flow(e) - Flow(o2)).21 + Flow(o2))/Flow(e)) = %O2

where Flow(e) is engine airflow


For oxygen flow, I machined a brass jet holder, and made some different sized jets. For the posted tests, I used the 3mm jet, which flows like this:

3mm Orifice
Pressure, psi         Flow, CFM
10        - -               2.5
20        - -               3.3
30        - -               4
40        - -               4.5
50        - -               4.9
60        - -               5.3
70        - -               5.7
80        - -               6
   

The power increase is kind of funny. It's not like a hard nitrous hit. The enigne just smooths out a bit and pulls harder. I guess the smoothness is due to the fact that increased oxygen concentrations improve ignition lag. Oh, I forgot to mention. The runs posted and compared above were done on the same day, car fully warmed up after a 1h drive, within 5 minutes of each other.

[rabbitman]

Wow, my brain is not set up for math :roll: so I would have to resort to trial and error. So do you have it set so the O2 comes on at wot? I wonder if a guy could use O2 w/ an LDA instead of a turbo? Have the O2 run the LDA and at the same time inject more O2 to compensate for the added fuel :idea:
Keep goin'....you might be onto somethin'. Since I can't afford a turbo :cry: maybe this'll work good enough.

[idgtd]

Right now I'm still testing with a simple regulator setup, so I just crank it down to the desired pressure to get the flow I want and go. For the final system, I'm planning on a WOT switch or something. It's really only effective if the engine is overfueled a bit. So, on a NA pump like mine that's been turned up, that's anytime the pedals to the floor. Gotta have fuel to burn with that extra oxygen. As for using the LDA, it's a neat idea, but I would want a gas isolator between the O2 and the injection pump LDA. Something about pure oxygen under pressure so close that much fuel seems worrisome. Anyway, hopefully I'll get some more feedback on this. If you have the regulator, it's really cheap to do, and the power increase is definately there.

[idgtd]

I agree. With a turbocharger, you add lots of oxygen, but you also add lots of extra mass in the form of nitrogen to absorb the extra heat produced. With the O2 injection, you get extra heat but little or no extra mass, so temps go up quicker. I think water injection would provide the extra thermal mass to keep temps down and allow more oxygen and fuel.

[vegfuel]

This sounds very exciting and yet risky at the same time. I must admit it caught my eye when I can't even go up simple 3% grade without down shifting and doing 40mph.

Questions: (I know it was just testing)

how did you measure the temperature increase accurately?
how did you meter O2 to each cylinder proportionately?
wouldn't this increase fuel consumption?

[idgtd]

"This sounds very exciting and yet risky at the same time. I must admit it caught my eye when I can't even go up simple 3% grade without down shifting and doing 40mph. "

Questions: (I know it was just testing)

how did you measure the temperature increase accurately?
I used a Westach 712-2DWK egt probe in the downpipe, right at the swivel connection.

how did you meter O2 to each cylinder proportionately?
I used the flow calculations posted earlier for a given size jet and pressure. I put the jet about 2" into the intake snorkel. As the air rushes in, the oxygen flow from the jet gets thoroughly mixed.

wouldn't this increase fuel consumption?"

No, especially not on an engine that's overfuelled. Think about it this way, I'm not adding more fuel than I had before, I'm just adding oxygen so the fuel I have can burn completely.


As far as the risk is concerned, it really isn't any more risky than turning up your fuel screw or any other power additions. You just have to monitor things when you make changes. I've been running this setup regularly for a few months now, and have had no issues.

[truckinwagen]

the only real risk I see here is that in an acciedent you have a potential rocket in the car with you.
I was always tought that to refill a O2 bottle one should always use a pickup so you are seperated from the fury of an O2 bottle should the top get knocked off.

[truckinwagen]

that and the possibility of the oil in the intake combusting in the oxygen rich atmosphere.

[idgtd]

"that and the possibility of the oil in the intake combusting in the oxygen rich atmosphere."


Again, not an issue because the air is only enriched from 21% to about 24-25%.  As for the rocket idea, it's probably safer than a NOS bottle, since I have a safety cap that goes over the reg and valve.

[truckinwagen]

I'm not saying that your setup will cause the oil in the intake to combust, but it is definitely something to think about before doing something like this.

if you have a cage around the regulator then that should be pretty safe.

I had thought about doing this before I got my turbo, but never actually got around to doing it.

[RabbitJockey]

iw ouldn't use 02 for sure, definitely go with n20.  i work for a biomed company and we mess with oxygen alot because we have rental ventilators and we also do sales and service of the, and sales and service of pft machines,  we always keep our hands clean and free of oil, and we always use silicon grease.  02 in your engine bay or anywhere in your car is a disaster waiting to happen. theres a reason people use n20 over o2