Camshaft choice for 993 engine

[Classic 911]

Wondering how radical one can go with choice of camshaft for an all original 993 engine that uses either carbs or ITB’s.


Cheers


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[Bill Verburg]

Originally Posted by Classic 911

Wondering how radical one can go with choice of camshaft for an all original 993 engine that uses either carbs or ITB’s.


Cheers


Sent from my iPhone using Tapatalk

Among other things it depends on the pistons, stock upper limit valve clearance much more than race designs like the bottom,

[Classic 911]

Originally Posted by Bill Verburg

Among other things it depends on the pistons, stock upper limit valve clearance much more than race designs like the bottom,

Thank you for your reply Bill.

I was wondering what would be the absolute most radical camshaft for an 993 engine using only original internal components including original pistons.

Cheers


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[targa72e]

Changing the cam on 993 usually requires changing to earlier sold rockers as well. The 993 hydraulic rockers are one of the limiting factors. After the rockers are taken care of something like the 933SS from DC is about as big as you can go with stock pistons. If you are planning on going ITB/CARBS I would talk with you cam supplier of choice about what they can offer that would work with stock pistons. Rod bolts and RPM become the next limiting factor with stock parts.

john

[Bill Verburg]

You don't install a happy cam w/o going through all of the other components necessary to raising the rev limit, from he crank out

hp & torque come from displacement, compression, revs and boost

993RS cams w/ stock components
993ss if switching to mechanical lifters

The difference of either from stock is minimal

You rev limit is still < 7k

to make a real difference the race pistons and 993 Cup cam or even better RSR cams would be used but to really take advantage you need a better crank and rods to go w/ the pistons

best bang w/ a mostly stock engine is 102mm p/c w/ 109mm base, add RS cams to sweeten the pot

beyond that 997GT3 crank, custom rods, p/c, heads w/ better flow, Motec etc., pre inflation a $60k build

[Jeff Alton]

All this info is good, and true.

However, you never stated what your goals are for the engine. That dictates the parts and dollars that will go into it, to make it exactly what you are looking for.

Cheers

[Classic 911]

Thanks all for your answers.

The only thing I wanted to know was what is the physically most radical cam that could be fitted on a completely stock 993 engine.

Cheers


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[safe]

Ask someone who sells cams. They all call them something that's not the same as the competitors.

I have aftermarket cams from FVD. They made 330 in a 993 3.8, when switching back to stock cams (could not meet hydrocarbon levels for MOT) it made 300. Same dyno different year. In both cases the ECU was optimized.

If they are "radical" I don't know, you need solid lifters, better valve springs and higher revlimit.