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TurboKraft TurboKraft is offline
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Join Date: Mar 2005
Location: Phoenix, AZ
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3.2L short-stroke... ITBs... 993SS camshafts...
This engine is going to like RPMs!

Having done 3.0L through 3.8L twin turbos, I would not go smaller than the base "GT28R" aka GT2560R. With their tiny A/R turbine housings they'll spool very early.
However, for as many CFM as your engine should be able to consume in a wide RPM band, I would expect them to fall off hard before you run out of RPMs.

Probably the biggest mistake we see on EFI engines is undersizing the turbine wheel. Recent we sold off a whole shelf of "wrong sized turbos" we had sitting around -- ones customers brought in for their project that were too small, ones we tried based on "turbocharger calculators" or published flow maps, ones recommended by Garrett's own in-house engineers for a specific build we were doing. In each case, the turbine wheel was just too small. It came on quick like a positive displacement (screw) supercharger but fell off hard before the engine was done.

If you have a pair of GT2860RS turbochargers with 0.64A/R turbine housings, I'd bolt them on and keep building.
If they're too lazy, they have the same silhouette as the smaller turbochargers and will be simple to swap out.
If they're good but you want still more power, you can swap up to higher flowing units.
Chris Carroll
TurboKraft, Inc.
Tel. 480.969.0911
email: -
Old 05-17-2010, 02:48 PM
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