Interfreezer = Air to CO2 Intercooler

[Neutrino]

Originally Posted by rs182

I have since decided that the use of nitrous would be more effective. Nitrous oxide's boiling point is -127 F, compared to CO2 @ -109 F! I emailed a bunch of companies about the intercooling efficiency of nitrous, the general consensus was to double the horsepower output of the shot you are using (25 shot = 50 HP, 25 extra from intercooling).

are you talking about using nitrous into the manifold or sprayed over the intercooler?

[rs182]

I am considering a nitrous injection system. Just a 25 or 50 shot for now.

[SaabJohan]

Using nitrous is quite pointless, increase the boost from your compressor instead. It will give you extra power all the time and you doesn't need to bauy expensive nitrous to get the power.

You can not determine which of the two gases that offer the best cooling capacity from their boiling points, it's a lot more complicated than that.

The temperature drop cna be descibed by a polytropic process

T1/T2 = (P1/P2)^((n-1)/n)

If we say that the process is adiabatic and the fluid si an ideal gas the polytropic exponent will be equal to Cp/Cv for the gas which is around 1.3 for both CO2 and N2O.

If we then assume that the tank pressure is 100 bar and the temeprature 293 K (20 degC) the temperature i the inlet will be, where I assume I bar of pressure, 101 K (172 degC).

The cooling effect will then depend on the mass flow of the gas and the heat capacity (which is similar for both gases). This also means that the gases has the capacity to freeze themselves, as you pehaps have noticed if you have used a CO2 fire estinguisher.

Of the reasons mentioned it will therefore be better to chose the gas with the lowest price so we can use a larger mass flow. The tank pressure should also be as high as possible.

And no you won't get any double effect of the nitrous, the cooling effect also works for NA engines.

But I will still say that a normal air to air intercooler is the best option, you can also use water spray on the intercooler if you want to increase the cooling effect. Water injection I do not recommend on daily use engines except in a few cases where there are no other option.

[rs182]

Thank you for the information. If I do not use nitrous, what is the maximum amount of boost you recommend I use? My 540i has a 4.4L V8 w/ a 10:1 CR. Jimmy at www.Jimmy540i.com has run up to 9.5 psi.

[SaabJohan]

What type of boost you can use depend on many things. First you must know that the engine can handle the power, you don't want bent con-rods, blown head gaskets and so on.

The next thing is if you can get the power knock free, this depends on compression ratio, ignition advance, volumetric efficiency, inlet air temperature, lambda and so on.

The third thing you must think about is the compressor, you will here need a compressor map so you can see that you can get the flow and boost surge free and without a too low adiabatic efficiency. If the adiabatic efficiency gets lower the temperature of the air will increase, then so will the power to drive the compressor. At a certian flow and boost you can't get any more flow through the compressor, the increase in boost will only cause an increase in temperature and even the if the volume flow increases the mass flow won't.

[rs182]

Thank you for the information SJ, you seem to be very educated on this subject! The supercharger is a Vortech V-2 w/ straight discharge. Its compressor map can be found at http://www.vortechsuperchargers.com/...im_v2_map.html
If you wouldn't mind taking a look at that and telling me what it means or how to use it I would appreciate it!

[SaabJohan]

Well, if you look at the map there is mass flow on the x-axle and pressure ratio on the y-axle. Then you have the surge line which you can't pass. The different coloured areas are the different adiabatic efficiencies, sadly they don't seem to write out the numbers. The lines with the numbers like 45k is the compressor speed.

The pressure ratio is the difference in absolute pressures over the compressor, usually there are some pressure loss because of the filter and inlet and if we say the loss is 200 mbar we will typically have an inlet pressure of .8 bar. Say that you are using 9 psi of boost, that's 9+14.5=23.5 psi absolute, or 1.6 bar. So the pressure difference over the compressor is 1.6/.8=2.

Then let us assume that we need 3.4 m^3 per kWh, now I don't know how much power your car has but I assume that the BMW engine is producing around 300 hp, which should increase to around 480 hp with the boost I mentioned earlier. 480 hp is around 350 kW so the airflow needed is around 350*3.4=1190 m^3/h, now the map had the flow in lbs/min, so that means 1190 m^3/h equals 19.8 m^3/min, each m^3 have a density of around 1.2 kg which means 23.8 kg/min which equals 53 lbs/min.

Now we take the pressure ratio of 2 and flow of 53 lbs/min and see where on the map that will take us. That will take us in the green area of the map, with a compressor speed of around 43,000 rpm.

The blue area of the map is where the efficiency is highest, then followed by purple and green. According to the figures I assumed you shouldn't use boosts that are so much higher, if the inlet to the compressor is improved you can increase it somewhat more.

If the values of the adiabatic efficiency was listed we could also calculate the temperature increase of the inlet air over the compressor, but I would assume I figure around 110 degC when the outside temperature is 20 degC. A good intercooler should be able to reduce the inlet temperature to around 30-40 degC at least which means a density increase of 26%, there will be a small drag loss but a power increase of about 24% should be expected.
When I calculated the power of the supercharged engine to 480 hp I of course assumed that the air was cooled which means that with uncooled air the power should be around 390 hp, possible power gain is therefore around 90 hp (much more than the nitrous).

With the correct values of couse everything can be calculated better. It's also possible to calculated the power consumed by the compressor, which in the case above should be close too 40 hp. This power should normally also be subtracted from the powergain by the compressor, but there is usually also a gain from the increased pressure ratio over the engine (inlet vs. exhaust pressure).

[TiburonDelAsesino]

I believe the co2 product "interfreezer" works muck like "ntercooler" from nitrous express, only they use no2. The unit from nitrous express is actually a No2 bottle, solinoid, a wot switch, and an interesting nossle system to get the No2 out. It basically works in conjunction with an air to water intercooler. An air to water intercooler circulates water through the finns on the super charger or turbo throttle body and then circulates it to a radiator. The "ntercooler" sprays gassious nitrous (-120 degrees) onto the intercooler's radiator. This causes the water entering the throttle body fins to be extremely reduced. Colder air makes more power =). So for these to work you already need a air to water intercooler. Its basically a super inter cooler but only at WOT (wide open throttle).

--Cheers

[KrimReefa]

Hello all,
One of you stated below.

"BTW instead of CO2 why not use regular air, even if its boiling point is higher its endotermic effect during expansion should be more than enough to supercool the intercooler. And air is much cheaper that CO2 to fill."

The ehaust system has all the carbon you would need, lol there is no need to pay money to "fill" your CO2 Intercooler.
The air intake would be very cool.

[beef_bourito]

please don't post in old threads. this thread is almost 4 years old.

and you can't use your exhaust to compress CO2 to a liquid in a tank. i won't go into details but you won't be able to do it (and if you do it won't be as cost effective as paying for it)

[KrimReefa]

Yes that is correct, you can't get enough pressure to make CO2 into liquid form unless you had a spare combustion chamber that you could dedicate to compressing CO2.

I was mearly telling people that there's allot of CO2 and it can be used in a way that that would benefit cars today.
ie: the cooling plus acceleration of CO2 using vacume, then it being reintroduced into the equation can be "very" benificial for engines my firend.

This topic is on Air to CO2 intercooler system so there for this post is on topic and I do not care how old this thread is for time is irrelevant in a age where tech is under the microscope.
Nikola Tesla died many years ago and his energy system is still at the heart of modern day life and allot of his tech is being brought back into the light.

Please do not post if you have no positive input for this discussion out of respect for others.

[beef_bourito]

guidelines

read them, specifically the parts about posting in outdated threads.

also i was informing you of something that is frowned upon in this forum (bringing up old threads), if i did so in a rude manner (i don't think i did) then i appologize, that wasn't my intent. if i hadn't, someone else would have, and possibly less politely.

I'll put this part bluntly because you seem to enjoy posting that way. your post didn't add anything significant to the conversation. there is no effective way to store CO2 from your exhaust while driving that we know of today so no, CO2 from the engine is useless to your car and should be ejected as quickly and efficiently as possible.

[KrimReefa]

ok dude.
I am sorry for old post and you seem like a good fella.
I shall not post on old threads.
Peace

[KiwiBacon]

Here's an idea.

Make a water/air intercooler and use the CO2 system for additional cooling of the cooling water.
That way you've got an effective intercooler all the time and a really really effective intercooler when you need it.

[2.2 Straight six]

Old thread. Case closed.

thank y'all.