911SC cams

mark houghton · 07-15-2009, 01:00 PM

Contemplating throwing in some SC cams the next time I have my motor out (not planned, but at some time I'll want to pull it just to keep in practice and "while I'm in there...")

So, is there a marked performance gain with the SC cams, and does anyone have HP or Torque data to support? Is one SC cam the same as another, or are there certain considerations/years/valve timing/etc. that I should be aware of? Or are these just plug-and-play?

A930Rocket · 04:24 PM

You'll have to have the turbo scavenge oil pump drive installed on the left cam. No data on HP and TQ, but I've always read they are good for low end power.

x98boardwell · x98boardwell's Garage

Mark,

I had 964 cams (didn't know it at the time) when I rebuilt my motor and I sent them to Web Cams to get the SC grind. Once I found out I proceeded with the SC grind and installed in the new motor.

I have noticed a bump in off boost power but the downfall is the car does not wind out in RPM's like it use to. It seems to lose it's high end rpm curve that I had before.

In the end, I do not track my car and when I do drive it I like the off boost power more since that is what I use mostly around town.

Up to you. Hope this helps,

Bryan

billjam · billjam's Garage

While I don't have any before and after power numbers, and I did a few other things at the same time, I ended up with a much more driveable car with quite acceptable off-boost power (compared to what it was).

It is almost "plug and play" if you throw away the air pump (which I did). The hard line from turbo to pump had to be shortened about 30mm (= the width of the air pump drive housing that was removed) and the engine tin needed to be notched to clear the hard line from scavenge pump to oil tank.
The SC cams that I used already had two holes drilled in the end for two roll-pins to drive the pump.

SC cams in a 930 This link has lots of input from others who have been there, done that.

Scavenge pump on SC cams This thread shows in detail how to adapt the SC cams if air pump drive is deleted. Post #17 has most info.

jacksd3 · 07-15-2009, 02:14 PM

I just went with SC cams from camgrinder because I wanted more low end torque and I don't have the other mods that make the 964 cams work well. The SC cams drop off at about 5500rpm whereas the 964 cams run up to 6800rpm but you'll need other mods to make them worth it. The cost to add the drive for the scavenge pump to the left hand cam was about $165 if I remember correctly.

BTW, camgrinder's work was beautiful, timely, and priced very reasonably.

mark houghton · 07-15-2009, 03:33 PM

Quote:

Originally Posted by billjam

SC cams in a 930 This link has lots of input from others who have been there, done that.

Scavenge pump on SC cams This thread shows in detail how to adapt the SC cams if air pump drive is deleted. Post #17 has most info.

Thanks everyone, especially thanks for the links to further information. Since I'm running with a K27 7006 turbo that's more friendly to high rpm power, I wonder if maybe I would be better off with 964 cams. I'm really wanting that extra mid-range that everyone is chasing

xbmwguy · xbmwguy's Garage

mark i also have the 964 cams and a 7006 and it pulls very strong from mid to top ask fairman!

mark houghton · 07-15-2009, 07:13 PM

Quote:

Originally Posted by xbmwguy

mark i also have the 964 cams and a 7006 and it pulls very strong from mid to top ask fairman!

That's kinda what I thought. Doesn't make sense to use a cam that limits what the turbo can do. If I were running your garden variety 7200 turbo, then the SC cam is probably matched to it better. Nice to hear that the 964 still affords a boost to the midrange while not sacrificing the top end.

And I swore I was done with engine performance modifications....

hobieboy · 07-15-2009, 10:06 PM

My 2 cents... I have just switched from SC cam to Evo cams.

The SC cam is as what many said - gives you very strong low/mid end torque & power but it flattens around 5500 rpm. Evo cam gives you way more high end power but boost threshold is a little higher.

And with my K27HF, it holds 1 bar with either cam to red line but there really isn't much point with SC cam.

So depends on how you use the car, SC cam is not bad. I used it on track for quite a few seasons without major complaint; until now

Ken911 · 07-16-2009, 04:12 AM

Any one know the difference in the sc cams and ssc cams the ssc cams were what was sent to me from imagine a couple years back when i was doing my build.

WERK I · WERK I's Garage

Quote:

Originally Posted by mark houghton

That's kinda what I thought. Doesn't make sense to use a cam that limits what the turbo can do. If I were running your garden variety 7200 turbo, then the SC cam is probably matched to it better. Nice to hear that the 964 still affords a boost to the midrange while not sacrificing the top end.

And I swore I was done with engine performance modifications....

Mark,
What R&P and exhaust system do you have in 930? If you have the standard tall 930 gearing, you will notice a slightly more laggy personality around town with the 964 cams. It's always been there, it's just 964's exacerbate the 930 low compression engine. Again I say slightly..........
I like the 964's lope at idle, the SC's mid-range grunt. The differences aren't all that great. After all, we are dealing with the 930's tiny intake ports.

mark houghton · 07-16-2009, 06:34 AM

Quote:

Originally Posted by WERK-I

Mark,
What R&P and exhaust system do you have in 930? If you have the standard tall 930 gearing, you will notice a slightly more laggy personality around town with the 964 cams. It's always been there, it's just 964's exacerbate the 930 low compression engine. Again I say slightly..........
I like the 964's lope at idle, the SC's mid-range grunt. The differences aren't all that great. After all, we are dealing with the 930's tiny intake ports.

Stock limited slip differential gearing, K&N cone air intake and Fabspeed dual outlet muffler. Stock exhaust manifold (someday I'll replace with a header).

I don't want to add to the turbo lag if possible, and don't want to lose the around-town performance. Since I rarely rap her up beyond 5800 rpm and do not track the car, perhaps I would be better off with the mid-range grunt from the SC cams after all. Decisions, decisions.....

wjfk32 · 07-16-2009, 06:46 AM

Greetings:

Back in 1994-I did top-rebuild on a 3.3Turbo-engine..Rings, valves, guides,oil lines..etc..etc..
I ordered my power pkg. from Windward Perf. This included B&B dual exh.,Hks-fuel enrcihmt sys.,7006-turbo,SC-Cams,-magnecor wires,1Bar Spring,.etc,etc,.Well, after all said in done. My car has incredible top-end past 6000rpm. Top-end is what I wanted. I know my mech. at the time when installing the cams he did open them up a little more. I know my mech installed SC-sport cams with a K-29 in his car with the total B&B exhaust system...In the end he wished he stuck with a K-27 upgrade..
Recently, I installed a MSD6AL-&COIL..NGK-racing plugs.& frnt oil cooler. You can feel the difference immed. The boost/feel or power on load is more linear, more direct..
50-130mph--is what I wanted..I have 5speed 915-in my 82SC-Targa-...I've been challenged by late 90's lambos and vettes..In the end, they wanted to know where the SPRAY was hidden....I responded K&N...

Walt.

xbmwguy · xbmwguy's Garage

walt just curious what heat range plugs are the ngk?

RarlyL8 · RarlyL8's Garage

Cam decision is part of the total package desired.
If your target is usable torque for street driving then then SC cams and K27-7200.
If your target is mid range to top end then 964 cams and K27HF.
The cams and turbo must work together complementary. You can then fine tune the cam timing and ignition timing to take the edge off or add to either end.

JFairman · 07-16-2009, 12:36 PM

Mark, I've got a some Andial SC330 cams with the scavenge pump and air pump drive for a 930 I'd like to sell.
They're in very nice shape and the power band is supposed to be something like in between the SC cams and the 964 cams.
With your 7006 turbo they may be the best of both worlds...

I was going to install them in my car to replace the worn out cams from a clogged spray bar that were in it when I bought the car. When I took those out I found out they were Webcam grind #40 which is their C2 or 964 cam with the scavenge/air pump drive for a turbo.
So I decided to send those back to Webcam to be repaired and reground.

I bought the SC 330 cams from Lincoln Phillip. He's a member here and Rennlist.

I'd like to get $300 plus shipping for the SC 330 cams. I'll take pics of them if you're interested.

I've got a bunch of other stuff I've got to sell too...

911st · 07-17-2009, 11:28 AM

I think of a C2 cam as a high lift or big SC cam.

Unless you have the ports opened up, probably not going to be that much benefit with the C2 over an SC. I suspect that even with an SC the ports should be opened so the cam can achieve its potential.

Both the SC and C2 lowers the pre-boost effective compression ratio. The C2 dose so a bit more than the SC. However, if one builds a 3.5 with big ports and turbo, the C2 would probably be a better choice.

No mater which is chosen, the seat pressure of the springs need to be reset, lighter retainers, or sport springs need to be used to deal with the higher lift and steeper ramps.

If possible, one should consider increasing there compression ratio with an SC or C2 cam to recover some of the preboost effective compression loss that comes with the cam change. I believe the normal 930 cam is hard to beat for TQ up to 3k rpm.

I am wondering if those that felt a drop off up top ether had there cams timed for lower rpm torque and or picked up a lot more mid range HP and then started reaching the limit of there turbo earlier as they were flowing more air earlier.

An SC cam can make peak HP around 6000-6200rpm. Most K27-7200s on a modded 930 running 1 bar boost will start to lose efficiency and only hold about .9 to .8 bar boost much past that. Further, most AFR's will start to go above 13/1 at about that time depending on other fueling mods. Thus, for many an SC cam w ports that is timed for low end is going to be a great choice.

Just my thoughts.

JFairman · 07-17-2009, 11:51 AM

C2/964 cams have diferent lobe centers and longer duration as well as higher lift compared to SC cams.
SC and the later Carrera cams are the same other than the power steering drive on the end of the passenger side camshaft for the Carrera.

My Webcam C2/964 cams with scavenge pump and air pump drive for the 930 are installed with new stock OEM 930 valve springs and stock steel retainers and it revs to 7200rpm safely with no problems.
No expensive titanium retainers or special valvesprings are needed with 964 cams.
I usually shift at 6500 maximum and rarely ever rev it that high, but I have and I hit the igniton rev limiter under the driver seat doing it..
..that was at night and the huge orange flame out the back reflecting in the driver side mirror when the ignition came back on was a surprise..

I have raceware connecting rod bolts installed to hold it together at those rpms.

911st · 07-17-2009, 12:18 PM

Great move on the rod bolts.

I do not mean to dissagree however I belive something pretty much has to be done on the spring side with a SC or C2 cam change that brings with it increased lift and steeper ramps.

Reseting the seat pressure is sufficient and all that is truly required.

I believe that is what was done with the factory 3.0 SC motors. Do not know if it is worth noting but there a fair number of SC's that suffered from valve spring failure. Some think that there was just a bad batch of springs and that might be the case. However, we are more concerned with valve float.

I went with Smart Racing valve springs on my motor set to 3.2 Carrera seat pressure if I recall correctly when I changed to SC cams. I took out C2 cams because I had a couple of lobs go flat (oil choice?).

Some do not want the increased seat pressure from shimming and opt for the light weight retainers. I do not know if this with stock 930 seat pressure is sufficient or not.

I could be wrong, just what I believe so far.

mark houghton · 07-17-2009, 12:40 PM

[QUOTE=911st;4782580]Both the SC and C2 lowers the pre-boost effective compression ratio.[QUOTE]

Admittedly, I'm not real cam-savvy so this may be an ignorant question. Both of these cams, maybe more so with the SC, should provide more mid range power. But if they lower the pre-boost compression ratio, won't the low and/or mid-range power suffer as a result? In short, these cams would only benefit when under boost conditions?