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RarlyL8 RarlyL8 is offline
Crotchety Old Bastard
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Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,563
If you have the correct grade of fuel the engine may not detonate. I doubt you wish to run racing gas.
Overboost is typically blamed on the elephant nose waste gate pipe design. The exhaust flow is disturbed by the sharp angle at the base of the turbo flange.
Lowering your boost pressure release threshold will help but the actual pressure seen by the engine continues to fluctuate with operating conditions. A boost controller may smooth the fluctuation but can do nothing to increase the pressure flow out of the waste gate pipe that will relieve the tendency for the engine to see boost greater than the spring setting. The spring setting on the stock waste gate is set to operate based on the pressure differential between the stock heat exchangers and the stock 3LDZ and stock muffler. You now have to find a spring setting that will best match the pressure differential between the aftermarket headers, turbo and muffler while dealing with the sub-optimal waste gate circuit.
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 08-09-2010, 07:59 AM
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