Blow off valve. One of the very rare instances its actually useful on a diesel. The GT37 has so much rotating mass and the plumbing is so short that would surge really bad without it.

I have the hookup with turbonetics now.



T3/T4 GTK ceramic ball-bearing should spool just fine. and NO vanes to ghetto rig.

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-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

My turbo cost $90 and I'll still out-spool you.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Mine only cost $125 and it will still outspool it.

mine will flow more CFM.

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-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

For another $250 I can buy a GT3577V that will flow more CFM and still spool up quicker. For $500 I can get an HE551V that would flow more CFM than 3 of your T3/T4 turbos and spool just as quick.