Stall speed?
 

What kind of stall speeds you guys have? Original SVX tranny and 4.444 conversions?

The stall speed in my low pressure turbo SVX feels way too high @ 3200rpm. The turbo starts to spool at around 1700rpm, at 2000 rpm I can feather out 1 or 2 PSI before the TC unlocks..... I feel I am wasting the low speed grunt which is obviously available, starting from the stall at 3200 rpm torque curve slopes down.

The car actually runs better when I decrease the preload of the waste gate actuator so that the boost level is 4 PSI instead of 5 :). This way the hp curve stays flat from 5000 to the shift point at 6800 and I'm almost a full second quicker to 100km/h starting in second gear with the race tech g-meter (6.8sec). So, I think the turbine side of the turbo is too restrictive and strangles the mass flow at higher revs. The throttle response is also very much more progressive and the driveability in general is much improved.

One way forward would be to replace the turbo and gain more high end, but the 4.444 gearing is already rather short, especially in first gear, and traction becomes critical.

So,I think a tighter torque converter could be a big improvement - especially since I use the SVX now as my daily transport and the Outback stays home most days ;).

I browsed thru the factory manuals I have and this is what I found:

1992 SVX 2350-2750
1996 Legacy 2,2 & 2,5 2200-2600
1996 Outback 2300-2700
2006 Outback n/a 2400-2800
2008 Forester n/a 2200-2700
2008 Forester turbo 2700-3200
2006 Outback turbo 3100-3500

I trust my converter is from the same donor as the tranny - a 2,5 n/a Outback and the high stall speed is caused by the almost double torque. The 4 cylinder turbo converters are probably okay for their application - the power band is at much higher revs than mine.

Something like 2200 would probably be good for me.... any comments or suggestions who to turn to?

Thanks,

Tapani

Re: Stall speed?
 

Pat at level ten will build you a mean convertor.