Twin charged 1uz in pickup

[rarson]

My very limited understanding of turbos has me thinking that a turbo will only produce boost in psi or whatever in the inlet manifold when the volume, or pounds per min, output of the turbo exceeds the ammount of air the engine is consuming. So I thought that boost in psi goes hand in hand with turbo flow and the air volume the engine is consuming. Is my line of thinking wrong? Kris

Exactly my point. A 1UZ with stock heads isn't going to flow ****, and thus no matter what turbo you stick on it, you're still not flowing **** at 5 psi. Boost is a measure of flow which is NOT entering the engine, so they ARE related. You can't just base everything off the turbo's mass flow because the engine has to be able to breathe just as well in order to use it. There are two axis on a compressor map, boost and mass flow rate. The mass flow rate axis is not for the turbo. The island is for the turbo. The mass flow rate would be the indication of how much air the ENGINE is breathing.

rarson two things.
1) learn what you're talking about.
I'll reiderate... psi has nothing to do with anything. The mass of airflow the compressor moves is the only relative bit of information that is useful.

If you took a bobcat turbo and ran it at 20psi, you would have a 100-120bhp 1uz-fe. It's 22psi comming out of the compressor, but guess what... It doesn't move much mass.

You don't get it, do you? If the turbo is undersized, you'll never get to 22 psi! How do I know this? Take a stock T25 on a 4g63, and disconnect the wastegate. The turbo can't hold 15 psi past 5500. Why? Because the engine is breathing more air than the turbo can push! It's called proper turbocharger selection, and it involves all aspects of the turbo, not just the compressor, but the turbine wheel and housing as well.

Likewise, there is no limit to how high-flow of a unit you can buy.
There are pleanty of industrial turbo's that would split any gasoline car engine in half at 5psi, I'm sure if you hooked a marine turbo up from a huge diesel ship, you could split one at 1psi...

Again, you don't get it. Maybe you should learn what you're talking about. If I take that same 4g63 engine and put a huge turbo on it, I'd probably never even get to 5 psi because the turbo would always be flowing more air than the engine. You can't split the block at 5 psi because you can't get to 5 psi!

Again... PSI doesn't mean crap. The MASS of flow means everything.

2) Learn to read something in context.

I will agree that boost is a generic term, because many variables affect it. Just because someone says "I'm running 20 psi" doesn't mean they are making x horsepower. I will agree that mass flow rate of air is a much better determination of power production. However, in proper turbocharger selection, boost DOES matter and that is why there is a pressure ratio axis on a compressor map. Just because you don't think psi means crap doesn't mean that someone shouldn't size their turbo appropriately for the amount of boost they want to run.

Oh, and it does mean crap, because altering the boost level affects other things like fuel delivery and cylinder pressure. So at 11 psi, no matter WHAT turbo it is (as long as you can actually make 11 psi), you're putting less peak cylinder pressure onto the engine than at 15 psi.

 

[Toysrme]

The only thing that matters is the mass of airflow shoved into the engine.

If have a 480bhp base engine that consumes 50lb/m, and you stick a 10lb/m turbo on it guess what? That near 500bhp engine is now going to make less than 100bhp, regardless of the pressure the air is at when it leaves the compressor housing.

If the turbo can support shoving more mass into the engine, the engine will consume it regardless.

A 1UZ with stock heads isn't going to flow ****

In practice, you can *always* shove more in, regardless of how "shitty" the system is... Trying to use, "it's shitty" as an argument to the fact is ridiculous!
This doesn't even have a bearing on what we are talking about... Way to skirt the issue there dawg.

Oh, and it does mean crap, because altering the boost level affects other things like fuel delivery and cylinder pressure. So at 11 psi, no matter WHAT turbo it is (as long as you can actually make 11 psi), you're putting less peak cylinder pressure onto the engine than at 15 psi.

You have a portion of the right idea - which is great. The problem is that is strays off into other areas.
Cylinder pressure is very proportional to power produced.
Horsepower(net) = Mean Effective Cylinder Pressure x CID x RPM/33,000 x 12 x 2
By what you are saying, you could take an undersized turbocharger at your given 15psi, and compare it to a turbo that will move twice the other's rate of flow at 11psi, and the smaller turbo would create more power because, "The cylinder pressure is higher".

No... That isn't even in our ballpark. The cylinder pressure will be higher, on whatever setup makes more power. What makes power is the mass of the mixture able to be consumed in the engine. The 1psi turbo moving twice the mass of air into the engine, get's to burn twice the amount of fuel. The cylinder pressure will be proportionally higher, and there will be more power.

In your mind, a small turbo moving HALF the mass at a higher psi could create more power. EEEEEEEP, incorrect!

There are two axis on a compressor map, boost and mass flow rate. The mass flow rate axis is not for the turbo. The island is for the turbo. The mass flow rate would be the indication of how much air the ENGINE is breathing.

Oh dear god...
The mass flow rate is the measure of how much air the compressor, or turbine (if a turbine map) can move. The maps show what range of mass a turbocharger will move at a given pressure, or what pressure is needed to supply a given amount of mass. (Same thing said two ways.)
The key is MASS. Not PRESSURE.
Look. You can bring up as many other things as you want. Saying the heads can't flow, fuel pressure, injectors flows & everything else under the sun is A-OK. All of that is important, but nothing more than an attempt at skirting the issue at hand. Trying to cover up the fact you're wrong by trying to relate it to things that are not a part of the equation doesn't change the fact that you are STILL WRONG. LoL!!!!!!!!!!!!

In the end all that matters is the MASS. Whatever can shove the most in is going to make the most power period. Regardless of pressure.

 

[rarson]

The cylinder pressure will be higher, on whatever setup makes more power.

Forget I even mentioned cylinder pressure. Obviously I was confused when I brought that up.

In the end all that matters is the MASS. Whatever can shove the most in is going to make the most power period. Regardless of pressure.

Okay, I'm confused. I think I misunderstood you before because I totally agree with that statement. I can't even think of what it was I might have been trying to get at. I totally agree, mass air flow is what makes power, regardless of pressure.

I'm going to let this one go because I'm totally lost.

 

[Muzza_NZ]

And they all lived happily ever after...

 

[Kiwilowlux]

amen to that muzza. Anyway we will see what happens. I have a basic understanding of thermodynamics etc, even if i didn't it wouldn't make my car any slower because when it comes down to it, you dont have to know why its fast but you have to know how fast it is.

 

[Pro]

(No methanol, use ethyl alcohol. Methanol eats aluminum like crazy over time!)

stuff the lot of them.

use liquid ammonia + water.

NH4+OH and H20.

nitrogen is inert, 6 parts hydrogen and 2 parts oxygen.

after all, technically water is the most flammable substance known to mankind. add MORE hydrogen and oxygen and...well, hindenburg anyone...?

better than just N20 with 2 parts inert nitrogen and one part flammable oxygen.

try to find liquid ammonia from an industrial source, not just the stuff off the shelf at your local supermarket. that stuff has lots of other additives that inhibit combustion.

just avoid getting it on your skin like ClH4 (methane/methanol) - nasty nasty stuff.

 

[rarson]

Ammonia is NH3. NH4-OH is ammonium hydroxide, which is formed when you add ammonia to water. Ammonia is a weak base and therefore you will have an equillibrium on both sides of the equation. The equation being: NH3+H2O <-> NH4-OH

We use ammonium hydroxide for pH control in the primary coolant system of the pressurized water reactors in our submarines. We have CASES of the stuff.