Let say you were runing a T-28. How many rpm would the compressor need to run at in order to achieve 6 pounds of boost?

 

I'm not looking for an exact number here. So if you've got some speculation, feel free to share...

 

Thats a pretty tiny turbo so i would say that you would be running full boost at 3000 to 3300 rpm.

 

i run a t-28 and am at full boost (6.5 psi) by 2900 ish on an auto tranny

 

Dunno why, but I was expecting a lot more than that

 

na we get boost pretty quick

 

I think you guys got confused here.

I'm not taking about how many RPM is the engine running to hit full boost. I'm talking about the compressor side of the turbo.

 

bump

 

It depends on the compressor maps for the given turbo. I question why you want/need to know, as the information is useless to someone that isnt engineering the product.

 

Plus the turbo is not the one determining the boost, the compressor is just "on," the wastegate is what is actually controlling the boost.....

 

the turbo spools so fast from 2500 to 3000, you can reach 4, 5,6,7 pounds of boost, the wastegate expels excess pressure you don't need in the exhaust side.

in ex. if your wastegate is set to 6.5#'s, once you reach desired pressure the wastegate lets out exhaust through the dump tube to keep the turbine spinning at the rate it's set on.

 

Once again... I'm toying with some crazy ideas...

No matter how much the wastegate determines how much boost is applied, the compressor will run to a certain speed. If the wastegaste says 6psi, there as to be a matched rpm ratio with the compressor.

ie
If wastegate says 6psi = 10000rpm, then 10 psi will obviously not equal 10000rpm too. See my point?

and btw... let's change T-28 for T-25

 

Once again, Im pretty sure the wastegate controls how much boost the engine sees, not impellar speed on the turbo. (the impellar is what is spun by the exhaust gas and is connected to a mutial shaft from the compressor, hence impellar speed is proportional to compressor output) It is my belief that the compressor is designed to almost always work at its "highest" efficiency, and the wastegate takes that boost at delivers a certain amount to the motor. Hence why when a wastegate becomes stuck closed, a vehicle will overboost.

 

Since we are missing my point... let me put it this way.

Can anybody answer those 2 equation(no need for exact numbers)
x scfm = y psi on the 4g94
g compressor rpm = h scfm

Don't take any offense, but a wastegate has f*ckall to do with those 2 equations.

 

No, your missing my point, that information is based on compressor maps of the turbo, consult the manufactorer of the turbo to find the info you seek.....

Not trying to be an ***, actually looking forward to whatever your trying to cook up...