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Registered User
Join Date: Aug 2005
Location: san francisco
Posts: 1,545
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Lower compression for Supercharger?
I have a stock 3.6 that I was thinking of supercharging. I'd want to cross drill the crank and upgrade the rods/bolts but was wondering if you could leave the compression ratio the same. I'm guessing you wouldn't seeing that these engines are already high.
Anyone have any knowledge on this? Thanks- Craig Backer |
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Registered User
Join Date: Mar 2002
Posts: 3,563
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Depends how much boost you want to run. You can get away with 0.4-0.45bar on the stock C/R with intercooling and the appropriate changes to fuel & ignition timing. Any more boost and you have to decompress the motor.
You wouldn't have to upgrade the rods... they are the same as the Carrera/930 turbo rods. Just upgrade the fasteners. Common practise for the 964 motor is to machine down the crown of the pistons, since they have a lot of "meat" on them. You can get them down enough to run ~8.5:1 C/R and run 1.0+ bar ![]()
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition ![]() |
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Registered User
Join Date: Aug 2005
Location: san francisco
Posts: 1,545
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What kind of bhp are we looking at for a tight 964 3.6 with 8.5:1 cr at 1 bar using a whipple type supercharger?
Thanks- Craig Backer |
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Registered User
Join Date: Mar 2002
Posts: 3,563
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Sorry, that should be 8.25:1 C/R
![]() Not sure, but you're looking at about 560+HP with a turbocharged setup, but with a SC it'd be less due to the extra parasitic losses of the SC. 964 pistons can be shaved down to within .100" of the deck. It's a common mod, for aftermarket forced induction for the 964 ![]()
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition ![]() Last edited by WydRyd; 02-01-2007 at 04:10 PM.. |
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