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Dynamohum Dynamohum is offline
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Join Date: Jan 2008
Location: Midland Ontario Canada
Posts: 173
Originally Posted by lucittm View Post
I don't think you would need to change your cams for this kind of upgrade.

Everyone sends their heads out for twin-plugging. Yes, the the shipping cost is not trivial, but this is specialized work. My brother was born in Ontario, so I know your area a little. I would recommend someone on the east coast such as Xtreme Cylinder Heads in FL. Their advertised price is $350.00.
Also, JB Racing is in FL.

I am not familiar with a Promotive stage 2 kit. My opinion is that the .05mm shim at the base of the cylinder will be just enough to upset the 140K miles of wear that your pistons and cylinders have accumulated. Maybe not. That shim will have very little effect on your CR.
The 1mm head gasket ring will reduce the CR. I'm not sure it will drop it to 8.8 and I'm not sure 8.8 is low enough. Even the newer 3.6 turbos only run 8.5 and they have forged pistons.
But you are correct, the impact to the cam chain deflection will be minor. However, the cam chain cases will no longer be in alignment with the cams/cam towers. This will require shimming the chain cases or shaving the cam towers.

ARP studs and a new exhaust system are worthwhile upgrades.

Thanks for your input Mark and for pointing out the cam tower alignment, I missed that one. I will have a look at that one and look for possible solutions vs shaving the cam towers, rather not go that route, to permanent...
Yes your right that shimming the cyl might upset things a bit, I can live with that one.
Promotive is showing 9.5/1 on both their stage 1 and 1upgrade, and 8.8/1 on their stage 2 with .87b with a single plug. They even show their stage 3 , 7.0/1 at 1.25 bar of boost running a single plug head. Not sure how they are getting away with a single plug, but would love to know more. I'm looking at possibly adding water injection for a measure of safety.
More research is needed. Meanwhile I will keep searching and inquiring on dual plug route. Would love to go with that and coil on plugs, but Ouch it hurts the wallet!
I went ahead and ordered APR rod bolts and studs, and a new Dansk header.
Thank You for your time, Paul. We do because we can.
87 911 3.2 (Turbo conversion, build in progress, Thermal Barrier Coatings, High Pressure Dry film coatings) Modified heads, boat-tailed case, ARP hardware, OBX Header, 930 clutch disk, G50 Trans
89 5.0 Mustang convertible (For Sale)
Old 01-21-2009, 07:06 AM
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