I have a t3 with an a/r 60 compressor and a a/r 63 turbine. Would there be any difference in the t3/t4 with the same specs or are they about the same? Allinfo will be greatly appreciated.

 

anyone??

 

I believe you will get more top end power with the t3/t4 because of the bigger exhaust housing.

 

thanks, anyone else

 

When you go from a t3 compressor to a t4 you have take into account of whats changing. Even though you A/R ratio stays the same the area, radius and the trim of the wheel change.

Example A/R = Area divided by Radius
A t3 Area 2.5mm and a Radius of 5mm = .50 A/R
A t4 Area 3mm and a Radius of 6mm = .50 A/R

Example Wheel Trim = inducer diameter divided by major diameter Squared = trim
A t3 inducer diam of 1.674 and a major diam of 2.367 = .50 trim
A t4 inducer diam of 2.122 and a major diam of 3.000 = .50 trim

You should also take into account the rpm of the compressor wheel for the same psi and lbs/min a t3 usually has a higher rpm that a t4 compressor. so you need to account for the drag.

This is just a gross simplification do not take these numbers as gold.


[Modified by Quiz, 10:35 PM 10/6/2002]

 

Thanks Quiz. Just a few more noob questions i need to ask.

The a/r is the area of what divided by the radius of what?

What is the inducer diameter and the major diameter?

Is the inducer the intake side and the major the pressure side? sorry, i'm confused.

 

When refering to the compressor housing, the cone like scroll around the the compressor wheel, starts small and gets larger. If you messure the Area at any point in that scroll and divide that number by the center of the area to the center of the wheel, Radius, it will give you the A/R ratio.
When refering to the compressor wheel the circumference of complete wheel is the Major diameter and the Inducer diameter is the circumference of the inlet blades if you divide these numbers and than square the total it will give you the trim.

 

When using a T3 or a T3/T4 the turbine is still a standard T3 with a .32 .48 .63 or .82 A/R. the turbine wheel is standard and only the A/R changes. At a given RPM example 3000 a smaller (A/R) tighter scroll will spool up faster than a larger one. but at a higher RPM the smaller A/R will restrict flow and cause high back pressure or reversion back into the cylinder.

 

what are the full spool rpms for both?? just curious i have a straight t4 60 i believe and it his full between 4-4.5
Kevin

 

Thanks for all the info. Anyone else have anything to add.