15psi on t25 the same as 15psi on a b16

[redturboed95]

hey ive got an intake and 31/2" turbo back piping and some other supporting mods and i was wondering you get more hp at the same boost with a bigger turbo?

 

[me612]

Yes. You will get more power at 15psi with a 16g then with a t25. I'll try to explain this as easily as possible. I'm bad at explaining sh!t, but I'll give it a shot here to explain this as easy as possible. A T-25 has to work harder to make 15 psi then a 16g because the 16g is a larger turbo, and can move air easier. At 15psi, the 16g is still going to be efficient and blowing say 550 cfm at 15psi. Well the T25 has to work it's little butt off to get to 15 psi, so its spinning and just throwing all it can out to put out 15 psi. Well it's air is going to be hotter because its less efficient and so small, so it may only put out like 350cfm because its air is less dense then the cool air coming out of the 16g. Cold air is denser then hot air. So since the air is going to be hotter coming outta the t25, there is actually going to be less air at 15psi with it then with a 16g. Did that make sense at all? Sorry I'm not the best at explaining what I know sometimes, but someone on here will be able to explain it better then I.

 

[Parsalian05]

nah man i totally understood that, i had the same question

 

[GPTourer]

Good explanation except for:

Cold air is denser then hot air. So since the air is going to be hotter coming outta the t25, there is actually going to be less air at 15psi with it then with a 16g.

There will be the SAME amount of air, 15 psi is 15psi wether its from a little T-25 or a big T-88H. But since colder air is denser you can pack in more oxygen molecules which is what your car burns. Hotter less dense air has less potential energy (less O2) and thus produces less power.

 

[me612]

YA YA, I know 15psi = 15psi, but depending on the airs temperature, it will be denser air if it's cooler air and will contain more oxygen, which is what I meant by more air. Like I said, sometimes I can't explain things perfectly. My brain is not working at it's full capacity tonight I guess.

 

[DSMJim]

YA YA, I know 15psi = 15psi, but depending on the airs temperature, it will be denser air if it's cooler air and will contain more oxygen, which is what I meant by more air. Like I said, sometimes I can't explain things perfectly. My brain is not working at it's full capacity tonight I guess.

It will be more air because a 16G pumps more air at the same boost level than a T25 does.

Pounds of boost is not nearly as relevant as CFM on a turbo. Any turbo will do 15psi, the larger the turbo the more air it moves in mass volume. More air = more power. My buddys Supra at 15psi with his T78 makes 497whp on a 6 cylinder. A T25 on a supra at 15psi of boost (which woulnd't even be possible as the motor flows more cfm than the turbo could provide) but in theory would make less than a 1/4 of the hp but both would be at the same pressure level. A 16G simply flows more air due to it's larger compressor size which allows the motor to make more power.

I have a little plug in air pump for car tires that will pump upto 200psi but only flows .25 of a CFM but it would never be able to feed a motor because it flows so little air regardless of what pressure it's capable of.

 

[CanadianTSi]

Also don't forget that the Exhaust side of the turbo is alot bigger, allowing the motor to breath alot easier.