Quote:
Originally Posted by 911TT33
Hi all,
Got a fellow Porsche friend with a nice tight 911SC who wants to turbo his motor with a low boost setup.
Any of you guys done this before?
The 3.0 motor runs 8.5:1 C/R, so I guess it should be fine with approx 10psi boost using a bolt on setup?
Got a few questions:
1. Would 930 style headers bolt onto the SC motor?
2. What fuel enrichment options are there for such a setup? I've heard no extra fuel mods for low boost?
3. What about ignition timing for this setup? I've heard stock ignition timing for low boost?
4. What should one do to strengthen the motor? Aftermarket fasteners/studs?
Thanks!
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930 headers fit fine. I don't see how you could possibly run 10lbs of boost without serious fueling mods. The stock fuel pump easily handles the HP at EFI pressures (I have about 300-310 at the wheels with a nominal 2.5 bar fuel pressure and stock CIS pump) but I don't know about CIS especially at 10lbs which is almost 930 territory which runs 2 fuel pumps.
Timing is one key to minimizing destructive issues but impacts performance. I am actually seeing some sub-audible detonation with my car at only 0.6 bar with meth and an intercooler trying to run a little more aggressive advance (17-18 degrees with twin-plug).
I think the biggest weaknesses associated with this change are inadequate stock oil cooling, inadequate oil scavenging provisions, risk of piston failure from detonation, inadequate control of timing, transmission failure from excessive torque, clutch failure, inadequate brake capacity, and suspension. Then, of course, there is the problem of having more horse power than you need but it never being enough.