Stalls needed for different A/R's on turbine housings

[it's just a six]

Hey guys,
just curious, in general what stalls are needed for different A/R's on T3 & T4 turbine housings.

I do know there are a lot of variables, (just in general if possible )

Stock engine 231-250 CI but with mild camshaft.
Would like to get to full boost or should I say good launching boost on a foot brake that does not take forever to spool-up.

Say a 60-1 wheeled turbo. A "P" trim turbine wheel or something close or bigger.

Example: T3 turbo, a turbine A/R of .63 will require, say, approx 2600 min RPM stall.
A turbine A/R of .84 will need?
A .96 will need
A 1.14 A/R will need
A T4 turbine A/R of .63 will need
A T4 A/R of .84 will need? & so-on
Hope that makes sense.

Thanks

 

[Dusty Bradford]

Hey guys,
just curious, in general what stalls are needed for different A/R's on T3 & T4 turbine housings.

I do know there are a lot of variables, (just in general if possible )

Stock engine 231-250 CI but with mild camshaft.
Would like to get to full boost or should I say good launching boost on a foot brake that does not take forever to spool-up.

Say a 60-1 wheeled turbo. A "P" trim turbine wheel or something close or bigger.

Example: T3 turbo, a turbine A/R of .63 will require, say, approx 2600 min RPM stall.
A turbine A/R of .84 will need?
A .96 will need
A 1.14 A/R will need
A T4 turbine A/R of .63 will need
A T4 A/R of .84 will need? & so-on
Hope that makes sense.

Thanks

I wish it was that easy

The same exact converter will stall more with a 250 than it will with a 231 due to the increased low end torque.

To get a car to easily launch off the footbrake, the stall needs to be higher than a transbrake car to get equal 60' times.

If a car can turn 5500-5600 rpm there is no reason to go tighter than 2800 rpm at 0# of boost. The only reason a car would need something tighter is in the case of a stock cam where the car shifts at 5100 rpm. A 2800 stall has a hard time coupling a decent hp engine by 5100 rpm unless you have something that can lock at WOT.

Let's just say a 60mm turbo on a 231ci with .63 T3 will need 2800 rpm to launch well. That same car would need 3200+ with a T4 1.14 but now you need to dump the mild cam for something with extended rpm range..now you need more spring pressure.....etc. It just keeps snowballing. The turbo, cam and converter must match or the combo will be a slug.

 

[it's just a six]

Thanks Dusty,

I know there is not one answer to each scenario.

I know turbine trim makes a big difference in stall needed also like a "Q","or "S" trim , back pressure will change qiut a bit also w.those 2 trim sizes.
Also how big or small the compressor wheel is changes spool up time.