SC or 964 cams in action

[zcoker]

Like most here, into the camshaft thing and trying to weed through all the threads about how these cams perform (964 & SC) in a 3.3. What I've found is that most grinders out there (Elgin, Webcam, etc) even with a lot of mods continue to recommend the SC camshafts over the 964's. But I see most here swing for the 964's but after watching this video http://www.youtube.com/watch?v=dALjM9N5_Rk of a more or less stock 3.3 930 with SC's, sure does make me wonder - the car destroys everything on the track and screams down the straits. I know a good driver helps but it sure does give an idea as to what the SC cam can do in a 3.3 with some basic mods. It does not look like it is running out of breath, either. Anyone have any vid's of a 964 cam'ed 3.3 in action? Without the music )

[agp22]

Can you elaborate a bit on the SC cam setup ( what year and engine do they come from?) and what difference does it actually bring to the car's response and continued power band?

Thanks

[911st]

My two cents. SC is a bit better pre boost as it supports a little better effective compression.

The C2 cam CAN support higher HP. However, it may or may not make for more HP.

Take a 3.2 normally aspirated Carrera with stock exhaust. If you put the C2 cam in it you will probably not make more HP and might lose some low end. Put a 3.2 cam into a 3.6 normally motor and you will lose HP in the mid to upper range.

If one is running stock ports higher lift might not let any more air in. Like wise, if the intake is such that the cylinders can fill with 1 bar boost with an SC cam, a C2 is not going to help much.

Cam timing is another factor. This can move the most efficient operation point and range up and down in the RPM range. Move it up and the same TQ achieved will make more HP. Move it down and the same TQ achieved will fill in the mid range.

For example 350 ft lbs at 4800rpm is 321hp, 350 ft lbs at 5300 is 355hp. However one might come on boost up to 500rpm earlier.

If one puts value on starting from a stop light and wants pre boost and boost onset as soon as possible, the SC might be the better of the two. If one puts a premium on HP through track HP range, a C2 might be a better choice of the two.

Must my thoughts.

[zcoker]

The car in the vid is using SC cams on the track. Trying to weed through that music, the car appears to rev out nicely on the straits. It's nice on the turns as well. The guy who owns the car claims: SC cams, turbo, exhaust, the rest stock 3.3 CIS. My point is that the SC cam'ed car screams on the track, apparently loosing nothing on the top end like so many say - it is pulling hard from what I can see. So I was looking for another vid of a similar car cam'ed with 964's to compare.

[911st]

To many variables. The turbo configuration, fueling strategy, ports, cam timing, all can effect where in the rpm range the power is made.

Muffler and exhaust configuration has to do with the sound.

[RarlyL8]

The cams need to match the turbo. For example, I prefer SC cams with the 7200 or K27S and 964 cams with the HF or HFS.
SC cams and a K27S or like turbo produce good low end and mid range torque which makes great useable power with very little lag. Would be a great combo on a tight track. The setup does fall off above 5500 or so on the dyno but you cannot tell on your butt until in high gear.

[David]

I put this Excel chart together from dyno runs before my rebuild and EFI conversion when it had SC cams and after the rebuild with 964 cams. There are too many changes for the actual hp and torque numbers to be comparable, but the shape of the curves give some insight into the power characteristics of the two cams.

The SC cam does seem to build more low-end torque but then quits pulling where the 964 cam engine keeps going.

[911nut]

Originally Posted by 911st

If one is running stock ports higher lift might not let any more air in.

Higher lift will always result in more power as the curtain area, the area between the valve seat and the valve, increases. Greater curtain area=more flow=more power.

[911st]

David,

I would have a difficult time makeing any comparison or conclusion between your befor and after except that you have a much better motor.

I suspect there are to many things that can effect effencys like intake maifold, port sizes, exhaust, CIS fueling limitation... Let alone cam timming of the SC cam.

What is interesting is how much better your power pre boost. I suspect that is because of the EFI. However, it makes the C2 cam look like it makes a lot more pre boost TQ /HP.

[David]

You really can't compare them, but it looks like if the cams were in the same engine, the SC cam'd engine would make more power from about 3400 to 4200 rpm. But since there are different turbos, intake and mapping, the curves may just not be comparable.

[wjfk32]

This weekend on a cool night, I hit the rev. limiter so fast - 3rd gear(short shift)..that thnk god I have my msd6al.to save me..My revs went so fast to 6000rmp. that I didn't have enough time enjoy the RUSH. My car pulls like a mother with 3.3T SC-CAMS & 7006 COMBO(etc) to red line..My car is a 82SC-Targa. Personally, one of the best things I noticed immed. was putting in the MSD & COIL-and different plugs--gap...040..
There is no let up in my set-up..Its an amazing feel, that no other car won't do with out paying big $$$$$$ in todays market. My mechanic knows how to build an engine.

[zcoker]

Originally Posted by wjfk32

This weekend on a cool night, I hit the rev. limiter so fast - 3rd gear(short shift)..that thnk god I have my msd6al.to save me..My revs went so fast to 6000rmp. that I didn't have enough time enjoy the RUSH. My car pulls like a mother with 3.3T SC-CAMS & 7006 COMBO(etc) to red line..My car is a 82SC-Targa. Personally, one of the best things I noticed immed. was putting in the MSD & COIL-and different plugs--gap...040..
There is no let up in my set-up..Its an amazing feel, that no other car won't do with out paying big $$$$$$ in todays market. My mechanic knows how to build an engine.

That's some encouraging news on the SC cam, how it handles, not letting up. Maybe it was the cool night. How does it handle on a hot day? Do you feel it fall off at all? Obviously not by your statement about hitting red line so fast, that goes against falling off. My setup is similar 3.3 7006 turbo, so I am very interested in your input on that turbo with the SC cam, how they work together. Major cam grinders are recommending the SC cam over the 964 even with major mods like porting, twin plug, etc. I do listen to them, so I am more inclined to go with what they recommend but still poke around for more info.

[RarlyL8]

This weekend on a cool night, I hit the rev. limiter so fast - 3rd gear(short shift)..

That has as much to do with the gearing as it does the cams. I also run a 915 and bounce off 7200rpm in 1st and 2nd due to tire spin and torque.

SC cams should work well with the 7006 as it boosts in the upper mid-range. I've not had that combo on the dyno (yet). The 964 cams work better with big turbos that power through redline with >1.0bar capability.

Tuning the cams allows a small range of adjustment to pull in or take away a little torque by shifting the (torque) range high or low. If the throttle is too touchy in a low gear you can move the range up a bit taking out some of the bottom end and vice-verca.

[wjfk32]

I got my SC-CAMS,B&B dual exhaust,magnecor wires,HKS-Fuel enrich.sys. 1-bar-spring back in the day -90's from Windward. My mech. and I did a top-rebuild on my engine- New lines,.tensioners-extrune honing,minor port polishing, new valve guides, new bearings, gaskets,seals,etc. Rebuilt my 915-also while the engine was out. The car was always fast..
I didn't drive the car for 10yrs--(out of the country). In July 2008- I started to putting the car back to together..Emptied the gas tank, new accumulator-fuel pumps,oil &gas filter-ngk racing plugs,front oil cooler&bradied lines,MSD-6AL & MSDCoil. New BIL- shocks hd front and sp.back. New tires-summataro. New front spoiler. Some paint work.
After all said and done--THE CAR SCREAMS...I do have a stock intercooler...I do not drive in hot weather period...But I did take it out last Sunday-HOT..NYC -hwy--the car still pulls to no problem to redline..I shake my head...No joke..

I know my wrench had his setup- SC-sport cams & 29S back in the day with full B&B set-up.-crank fire...And he liked my setup better...Now he did the motronic route-done..But now he enjoys and prefers his 996tt-epl- k24/18-hands down.

He recently took my car for a spin and just smiled..He estimated i have approx-450hp...His words to me..His opinion..So,I know what doubters will say about hp...He has driven many fast cars on a daily/track/mechanical basis, Its his job/career.
My car is a sleeper........................

Walt

[911st]

To me the C2 cam is just a big SC/Carrera cam.

However, the SC dose have a little higher effective compression pre boost for a small advantage. Bumping the motor compression should be done with either cam for a better motor.

On boost I suspect the cylinder fills much quicker than is such on a normally aspirated motor. Thus, longer duration and higher lift may not be required to accomplish complete cylinder filling.

I just do not expect much of a difference for most builds between using a C2 and an SC cam. How the cam is timed will have some effect. However, the Turbo chosen should have more significant impact on how far the motor keeps making HP and when and how boost comes in down low.

If building a 3.5 with 8/1 CR, I would probably then lean toward the C2 as a better fit.

A stock compression 3.3 I might lean toward the SC cams.

Anything in-between, I would not expect much difference between the two cams.

[Willy Leon]

Guys,
Its my 930 in the video. The car hauls ass but the driver, Kevin Roush had a lot to do with it. Runs Grand Am, Daytona, etc. Check his bio as he is a fast,fast Porsche guy and he makes it look easy. I was sitting in the passenger seat when we did the video. The car at the time was running SC Cams, stock CIS ( 79 euro model) muffler and RUF 5 speed trans. The car was running approx 2700 lbs plus passengers and fuel. Music is good because car was so quiet you could not hear it. Big mods beside the cams is a Kolkeln turbo based on a Garrett ball bearing housing and a Garret intercooler. Horsepower is only approx 330 to the wheels.

[lukeh]

When I was asking about cams several builders told me about the SC330 grind. If I remember it was a good compromise between the SC and 964. I didn't see this mentioned so thought I'd just throw it out there.

[mark houghton]

For those of you running with SC's, what have you got your cam timing set at?

[billjam]

Originally Posted by mark houghton

For those of you running with SC's, what have you got your cam timing set at?

I set mine at the standard timing for an SC and I am happy with the result. Can't remember what the setting was though - I think it was in Wayne's book, or was it Bruce Anderson's?
The SC cam seems to work OK with my K27 7200 11/11 turbo and ported heads.
It could always be better, but throttle response seems good to me and I have smooth power delivery from mid 2K to 6K+.