ls1 turbo build
11-09-2008, 06:01 PM
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ls1 turbo build Ok, here is the situation. We are rebuilding an LS1 with a rear mount turbo. Specs: 1.78 comp cams rocker arems and 5/16 push rods, Bullet custom ground cam: CLS 270/270 118 Dur@.050 I-218 E-218 Lift .595 on both I&E, block bored .010 over to 3.903, block decked .004 and heads trued .005 (65.8cc), boost range from 5-10 psi. We are sourcing forged pistons and rods (Mahle and Scat) for best combination of compresion to boost with stock crank. Mahle pistons come either 16cc dished (about 8.52 compression) or 9cc dished (about 9.13 compression) with 9.27 pins.
The challange, balancing the boost and compresion to run on the 91 octane gas available in the area for a streetable turbo set up. Ray Hall Turbo calculations show 8.52/1 compression with 5 psi of boost running 91.5 octane and 9.13/1 compression needing 93.34 octane. This seems low on the compression side to me.
We have a HP pro tuner ready for the tuning and I need advice on what others have done to make a combination like this work. How much timing needs to be pulled out to avoid detonation and how much HP do you lose doing this?
The challange, balancing the boost and compresion to run on the 91 octane gas available in the area for a streetable turbo set up. Ray Hall Turbo calculations show 8.52/1 compression with 5 psi of boost running 91.5 octane and 9.13/1 compression needing 93.34 octane. This seems low on the compression side to me.
We have a HP pro tuner ready for the tuning and I need advice on what others have done to make a combination like this work. How much timing needs to be pulled out to avoid detonation and how much HP do you lose doing this?
