Accelerated Performance 2013 BRZ - FRS Turbo Kit Designing

[Coheed]

Originally Posted by jedibow

Correct Serial, P=nRT is your best friend!

Remember turbos do not create pressure for free, the maximum effieciency on the turbo that Don chose is 86% which is very good aslong as you are running the turbo in this effiecency island, so AT Best you will see a drop of 14% in pressure due to the increase in air temperature from created by the compression of the turbo.

This is exactly why I state earlier that a BW EFR turbo would not be a viable option in our car UNTIL you build the bottom end.

PV=nRT.
Pressure increases with temp, so you lose air density. You won't see a drop in pressure with compression. What you can affect is air density by controlling the volume/temperature.

the amount of boost you run is dependent on the size of turbo as well.

My 6262 is happy running 15-16psi on 91 octane, but a tiny T25 would melt things. It isn't as efficient. I vote for a slightly larger turbo at the expense of lag, but better high rpm efficiency. I think the GT3071r is good. the GT3076r has too large of size differential in wheels imho. But the 6 bladed wheel sounds sick.

I think the GTX3071r would be a nice option but they are really expensive for what they are.

The disco potato is probably the best overall option for most people out there. It is small, but properly sized, and very efficient. I think 7psi on this turbo will produce a nice surge of torque right at 3000rpm. And also with tune should produce over 250whp. 10psi should put it around 280-300whp, but we'll know more when we see how the head flows.

There is a lot to consider on turbo efficiencies. A lot of variables at play here.

[jet86]

Originally Posted by Don@Accelerated

We'll be scavaging both front and rear. There is not a real great spot to feed oil into that will well suited gravity fed.

Can you not mount it up high kind of in place of the airbox? With the turbo mounted east-west obviously,

[Coheed]

It is also worth noting that picking a larger turbo, even if more inefficient, will still have lower temps than a smaller turbo. It will flow more air per psi, and since you will operate at a lower pressure ratio the intake temps and reliance on the intercooler goes down.

[yuli8466]

Originally Posted by serialk11r

Err psi != air mass. At room temperature you can do that, but compressing the air increases its temperature.

5psi may increase 50hp?

it is not enough for adding an additional turbo kit.

[wcbjr]

Wow people, I said best case. It's a vague answer to a vague question.

[serialk11r]

Originally Posted by wcbjr

Wow people, I said best case. It's a vague answer to a vague question.

Sorry to keep on nitpicking, but that's not best case. Best case is you get most of the way down to ambient temperature with a massive intercooler, have about neutral pumping loss, and a slight decrease in efficiency.

[jedibow]

Originally Posted by Coheed

It is also worth noting that picking a larger turbo, even if more inefficient, will still have lower temps than a smaller turbo. It will flow more air per psi, and since you will operate at a lower pressure ratio the intake temps and reliance on the intercooler goes down.

only if the lager turbo is efficient at that pressure ratio, if it isn't then you are only pumping hot air.

[Coheed]

Originally Posted by jedibow

only if the lager turbo is efficient at that pressure ratio, if it isn't then you are only pumping hot air.

A GT3076r will have lower intake temps at 8psi than a GT2860rs will have at 10psi. The difference of 2psi of pressure has a larger impact on temperature than the adiabatic efficiency does. You have to do some math, But here's what I get:

10psi GT3076r at 75% efficiency puts delta temps around 165*F
12psi on GT2860rs at 80% efficiency is around 175*F.

The difference in pressure ratio has a larger impact on the output temps than even a large 5% deviation in adiabatic efficiency. There is slightly more power consumption with a lower efficiency compressor though, but this is remedied by reducing backpressure and increasing VE.

On top of the lower PR, you get less pumping losses and better VE. Larger turbos have their advantages. I'd take a low boost large turbo setup over a restrictive low-rpm turbo any day, especially for an engine with a high redline.

Some may argue that large turbos cannot be as responsive, but fail to consider shaft speed and spoolup. A disco potato running 250hp is over 115k rpm. But a GT3076r at 300hp would be around 80k rpm.

Only when spooling that large turbo to higher PSI will you really start to notice the difference in lag, but transient response can still be really good.

[LSV8]

not safe with stock compression..

[Coheed]

Originally Posted by LSV8

not safe with stock compression..

That's what everyone said about the 11.5:1 compression 2zz motor in the Celica. Yet there were a lot of people who turbo'd them. They made great power too.

10 years ago, if Toyota said they were bringing a 12.5:1 compression engine to market, people would say "Impossible! It won't work on 91 octane!"

13:1 is out of the question... right? Then the Prius was released. Overseas, they get 14:1 with 93 octane. Blasphemy!

Then mazda pushed 16psi boost through an engine at 9.5:1 compression in the MZD. People realized over 20psi from stock turbo with tuning, all on 91 octane.

I don't think 8psi is out of the question here.

[Don@Accelerated]

Who wants to bet me I can't make 300hp on the factory compression w/ zero issues?
Any Takers?

[slow_frs]

lol bet u already have...

[Lee358]

Originally Posted by slow_frs

lol bet u already have...

X2

[Calum]

Originally Posted by Don@Accelerated

Who wants to bet me I can't make 300hp on the factory compression w/ zero issues?
Any Takers?

I'll take that bet. If I win I get what ever turbo kit you do release for free. If I loose I pay zero dollars for the kit. :happy0180: