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RarlyL8 RarlyL8 is offline
Crotchety Old Bastard
 
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Join Date: Jan 2000
Location: Huntsville, AL
Posts: 14,081
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I know you've had issues with the UMW K27HF series Jim. I've installed and bunch of K27HF(S) turbos over the years. They absolutely are capable of reaching 1bar before 3000rpm when the engine is set up efficiently. We had an HFS boosting at 2600rpm on one engine. Many things affect boost threshold and you must compare apples to apples, meaning test different turbos on the same engine and optimise that engine. Most folks haven't done that. I no longer use the HF(S) turbos but that has nothing to do with their performance. The K27-7200 remains a fantastic true bolt-on upgrade for the mid-level 930 build. Not big enough for this thread's application.
If you're looking to shed that last 300rpm of boost threshold then go split plenum GT35. The top end can only pick up so far before serious CIS mods are needed. The HF(S) does leave some power and threshold on the table when compared to a custom Garrett as the K27 does not have all the housing size options.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 04-18-2013, 08:40 PM
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