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930targa 930targa is offline
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Join Date: Nov 2007
Posts: 14
i am thinking the factory valves are SS ?

i know that the ferrea valves are , and if the OEM ones aren't then you can see some benefits from the difference of alloys alone as SS valves will withstand heat better ... also a 1mm oversized valve will benefit in low cam lift situations (more air coming in) , thus giving you a better low end torque.

the real benefits are in the valve seat and porting out the stock intake/exhaust ports .

if you get aftermarket valves and a good 5-angle valve grind you can see some benefits on the overall powerband, i believe the stock valve seat is a 3-angle . porting will gain alot more top-end but you might loose some low-end/mid-range torque if you really hog them out . the more agressive the valve grind the more flow you will see but it will also wear the valve seat out faster and vice-versa.

on other watercooled engines , i have seen a big gain out of grinding the valve guides flush with the head , granted that the engine is watercooled it had a margin of safety, on an aircooled engine this may not be very wise , uless its a race engine that will be torn down. consistently .

end rant..
Old 12-11-2007, 06:10 PM
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