Camshaft selection
09-16-2018, 08:55 AM
#1
Camshaft selection
Hi,
I’m in the progress of putting my engine back together after a rebuild and have yet to purchase the last part, namely the camshafts.
I mainly use the car for track days where I drive the car back and forth to the track. I would be interested to hear your thoughts on what camshafts you would recommend?
the engines is currently being built with the following
-GT3 crank
-Autoverdi rods and pump
-Carrillo 11.5 CR 102mm pistons
-993 fully threaded cylinder head studs
-stiffer valve springs with titanium retainers
-lightly intake ported heads (42.5mm)
-valves 50mm intake 42.5mm exhaust 8mm stems
-GT3 intake with 82mm throttle body
-100cell cat and G-pipe
-MaxxEcu (ignition and injection)
since the car car is doing mainly track duty I was aiming for a red line of 7500.
Any thoughts on what cams you think would do the job? My current thought is to use the 993rs or ss grinds. My target is as always to be 1sec faster than my other 964 buddies!
I’m in the progress of putting my engine back together after a rebuild and have yet to purchase the last part, namely the camshafts.
I mainly use the car for track days where I drive the car back and forth to the track. I would be interested to hear your thoughts on what camshafts you would recommend?
the engines is currently being built with the following
-GT3 crank
-Autoverdi rods and pump
-Carrillo 11.5 CR 102mm pistons
-993 fully threaded cylinder head studs
-stiffer valve springs with titanium retainers
-lightly intake ported heads (42.5mm)
-valves 50mm intake 42.5mm exhaust 8mm stems
-GT3 intake with 82mm throttle body
-100cell cat and G-pipe
-MaxxEcu (ignition and injection)
since the car car is doing mainly track duty I was aiming for a red line of 7500.
Any thoughts on what cams you think would do the job? My current thought is to use the 993rs or ss grinds. My target is as always to be 1sec faster than my other 964 buddies!
09-16-2018, 02:21 PM
#3
RL Technical Advisor
Your single-throttle intake system is the biggest restrictor of camshaft choices since these are negatively affected by too much duration or narrow LC's.
Unless you install ITB's under that GT-3 intake manifold, I would be using either a custom profile or the RS cams on 114 deg LC's. Make sure you measure exactly how much piston-to-valve clearance you have to determine how much maximum valve lift you can use.
Unless you install ITB's under that GT-3 intake manifold, I would be using either a custom profile or the RS cams on 114 deg LC's. Make sure you measure exactly how much piston-to-valve clearance you have to determine how much maximum valve lift you can use.
05-19-2019, 06:12 PM
#4
Hi Steve,
Thanks for the reply! Why do you think the position of the throttle body with the same intake would make a big difference?
My thought is that once it’s fully open it would not matter where the open plate sits.
Thanks for the reply! Why do you think the position of the throttle body with the same intake would make a big difference?
My thought is that once it’s fully open it would not matter where the open plate sits.
05-19-2019, 07:58 PM
#6
Rennlist Member
I can't speak to the higher rev limit but I had Dema Elgin regrind my cams to the Super C2 profile and put in Euro 993 RS valves (51.5mm intake, 43.5mm exhaust), rechipped with a custom Steve Wong chip, 200 cell sport cat with the secondary replaced with a G-pipe. The car definitely woke up and runs awesome except for the occasional stall when coming to a stop, which is easy to avoid if you just blip the throttle while rolling in neutral to a stop and let the revs settle into idle. The car has a lovely rumble at idle and when you're on the cam above 4000 rpm, it sounds like the voice of God. Horsepower around 290-300 horsepower. Oh yeah, I had to recrown the pistons to avoid hitting the valves...ask me how I learned this one...