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Old 08-07-2006, 08:33 AM   #23
Scooby Guru
Member#: 32792
Join Date: Feb 2003
Chapter/Region: NESIC
Location: lincoln, ri
2003 GGA MBP
12.9 / 105+


Originally Posted by cdvma

1 bar @ 3075
20psi @ 3373

3.0mafv @ 2770/6.8psi
3.5mafv @ 3195/16.8psi
4.0mafv @ 3546/22.1psi

Thats kind of freakishly similar. I think this is really important to see that the VF22 and the VF23 (or the rest of the VF series for that matter) spool almost exactly the same and the smaller VF stuff is good for that much boost down low (yay P20 housing). I'd like to get some upper RPM stuff to see what kind of MAF volts the 23 and 22 pull. It also shows that maybee P&P the exhaust manifold doesn't do a whole lot for high gear spool where there is enough volume.

My mods btw that really affect this:
Catless uppipe
Catless downpipe
3rd cat pipe (with a cat)
Borla Hush
Larger TMIC (TXS V1)
Stock BCS
No porting or polishing any intake or exhaust equipment, TGVs intact.
i agree that's remarkably similar.

i think it points back to boost threshold/spool being very closely related to hotside configuration, and not very related to cold side. the vf23 and 22 differ only in the compressor which is obviously bigger in the 22's case. i suspect that one thing that hurts my spool up (albeit very slightly) is the gutted oem up pipe. do you have a gutted pipe on the car chris? the reason i think it hurts spool is because it increases the volume of the pre turbo manifold, and this will reduce the amplitude of the peak pressure pulses. these high kinetic energy pulses spool up turbos better than the average flow does.

imo, most porting and polishing and gasket matching becomes increasingly effective as mass flow rates go up, but do not really help spool.
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