New to turbo! how do I get 25 psi on boost?

[LudeBoy]

Larger turbine = more surface area = more air pushed per PSI.

Your not getting it, if more air were pushed there would be more psi.

 

[maykelcj]

Your not getting it, if more air were pushed there would be more psi.

I think he is talking about air flow, not psi. what most people here are tying to explain, is that if you fill a 20onz bottle at 10psi and a 55gal tank at 10 psi. The 55gal contains way more air than the soda bottle. In the engine is the same. Why do you think drag cars use huge turbos? At high RPMs the small turbo will not give enough volume of air to maintain the set PSI. The more air the engine consumes the more air the turbo has to "push" to keep up with the set psi. That said, I would be more concerned about turbo efficiency more that jut a random psi. If you have a turbo too small for the air flow of your engine at a set RPM, then the turbo becomes a restriction in the system regardless of air pressure.On the other hand if your engine is small and you are not going to rev it up to the moon a huge turbo will lag too much for a small restricted engine.

 

[93civicracer]

Your not getting it, if more air were pushed there would be more psi.

With a larger turbo there's more air compressed so there's a larger volume of air coming thru at 10 psi than from a small turbo and more air = more power, which makes sense because there's more air to push so it takes longer to push it which is why large turbos take longer to spool up. Am I comprehending right Blanco?

 

[maykelcj]

Which is also why I say that horsepower is the best judge of what turbo you wan to run and how you build your engine to handle it.

amen to that brother...
^_^

 

[LudeBoy]

No dude, you're not getting it.

edit:
Ok, I'll go ahead and try to explain this again.

It's all about CFM and a larger turbine moves more CFM at any given boost level than a smaller one.

What to run 20psi? That's great, are you going to be running that with a tiny turbo or a behemoth one? The power outputs will be drastically different as will the wear on the engine.

Thats incorrect. CFM is a result of pressure applied just like amperage is a result of voltage. I agree with the second statement and its due to turbine efficiency.

I think he is talking about air flow, not psi. what most people here are tying to explain, is that if you fill a 20onz bottle at 10psi and a 55gal tank at 10 psi. The 55gal contains way more air than the soda bottle. In the engine is the same. Why do you think drag cars use huge turbos? At high RPMs the small turbo will not give enough volume of air to maintain the set PSI. The more air the engine consumes the more air the turbo has to "push" to keep up with the set psi. That said, I would be more concerned about turbo efficiency more that jut a random psi. If you have a turbo too small for the air flow of your engine at a set RPM, then the turbo becomes a restriction in the system regardless of air pressure.On the other hand if your engine is small and you are not going to rev it up to the moon a huge turbo will lag too much for a small restricted engine.

We are on the same page. Thats basically what I was trying to get at in my last post.

With a larger turbo there's more air compressed so there's a larger volume of air coming thru at 10 psi than from a small turbo and more air = more power, which makes sense because there's more air to push so it takes longer to push it which is why large turbos take longer to spool up. Am I comprehending right Blanco?

Doesn't make sense and is also incorrect.

Which is also why I say that horsepower is the best judge of what turbo you wan to run and how you build your engine to handle it.

I most definitely agree with this statement. You could be running 10psi with a stock intake and replace that with an aftermarket one that is less restrictive and then run 8psi but put out more hp/tq.

 

[Matts96HB]

Hmm.
From my understanding, a turbocharger compressor wheel takes the air in through the inlet and slings the air towards the outside of the wheel, compressing the air particles.

With a larger compressor wheel, more air would be able to be taken in, and thus more air compressed into each CUBIC FOOT OF AIR, making the air molecules more tightly packed, more dense, thus creating more power. Correct?

 

[LudeBoy]

A large water wheel at a watermill moves more water than a smaller one while moving at the same speed, right? Right. Same principle. The turbine drives the compressor wheel, which pushes a given CFM into the engine. I never said that exhaust gas didn't have to drive the turbine. I said that a larger turbo pushes more CFM at a given PSI than a smaller one, which is true. It's a dynamic system, not a static one, just like everything else that has to do with how an engine actually works. If we were talking about tanks for oxy-acetylene welding, which are static, then yes 10psi will be 10psi regardless of what size the tank is.

Re-reading that post, I should've said compressor wheel instead of turbine. My full attention wasn't on the post, my bad.

At any rate, I'm done with this topic. A T25 at 10psi is putting out the exact same amount of air (CFM) as a GT45R at 10psi, if that's what you really want to believe.

Ahh I see what your saying. We are both saying the same thing with different words, yes the larger turbo will put out more CFM but it will be exhausted out the blow off valve. And yes it will be more efficient. The power increase from the larger turbo running at 10psi is not due to more air entering the engine though. The power increase is due to the better efficiency of the larger turbo.

Its not easy to debate crap over teh interwebs... For what its worth, I wasn't trying to be a dick or anything.

 

[93civicracer]

I'm glad we were having a debate the information is very helpful to my research for my first turbo project. rep to everyone in this thread from me.

 

[Matts96HB]

^ Nice

Blanco, am I correct? I'm still somewhat confused. I read up on this but I'm really not sure if the information I was reading was correct. I only really read about the purpose of the compressor wheel so I could get an idea of what the effect of a smaller/larger one would be.

 

[ls/vtechatch91]

i dont think that guy has anything else to say about pushin 25lbs anymore... lol