SC vs 964 cams

[trials935]

What's the best cam timing for SC cams for low end-mid- range drivability around town, ( I have the top end high rpm covered) I just removed my 964 cams set to 1.26, low end was not good. A few things I've done to my 88 3.3: K27 high flow, 1.2 bar adjustable boost, 935 led boost gauge, 964 cams, twin plugged, Electromotive, Carrera intake extrude honed, throttle body cut and rotated, 38 mm intake ports, ported exhaust ports, full bay intercooler, Mode headers, '91 3.3 fully finned p/c, ni-resist rings, boat tailed mains, gt3 oil pump, Arp head studs, Carillo rods, EBS racing valve springs and Ti caps, 5 angle valve grind, lightweight clutch and flywheel, wide band afr gauge, dual outlet zork, etc. And 42 degree A/C. Between 3800 and 6500 had wicked acceleration with the 964 cams.

[RarlyL8]

We use SC cams in all the street 930 performance builds, set them at 1.70 Awesome cams. If you want to stretch the torque curve to the right a little go to the SC330 profile.

[trials935]

Thanks Brian, I've already sourced the SC cams. My go as fast as I can days are over, looking for more low and mid range now. I built this engine over 10 years ago, only have about 6K on it since built. I would scare myself every time I drove it, lol.

[mikedsilva]

Originally Posted by trials935

What's the best cam timing for SC cams for low end-mid- range drivability around town, ( I have the top end high rpm covered) I just removed my 964 cams set to 1.26, low end was not good. A few things I've done to my 88 3.3: K27 high flow, 1.2 bar adjustable boost, 935 led boost gauge, 964 cams, twin plugged, Electromotive, Carrera intake extrude honed, throttle body cut and rotated, 38 mm intake ports, ported exhaust ports, full bay intercooler, Mode headers, '91 3.3 fully finned p/c, ni-resist rings, boat tailed mains, gt3 oil pump, Arp head studs, Carillo rods, EBS racing valve springs and Ti caps, 5 angle valve grind, lightweight clutch and flywheel, wide band afr gauge, dual outlet zork, etc. And 42 degree A/C. Between 3800 and 6500 had wicked acceleration with the 964 cams.

I wonder if you could have advanced your 964 cams to 1.5 or 1.6 lift? It might have brought the torque down low but still given you a pretty fat top end?

Curious: what sort of performance did this engine give you? It's an impressive build spec above.

[gsxrken]

Here’s what John said for my SC cam timing:
Note this is a milder, CIS build

[trials935]

That's a good question Mike, I should have tried advancing the 964 cams, instead I put the stock turbo cams back in last fall and feels like I lost 100 hp. I just dropped my engine this morning and was going to put sc cams in set to 1.7mm, but now I'm leaning towards putting the 964 cams back in and setting them about 1,6 or 1,7, if I don't have any clearance issues. I put the stock cams back in as an experiment to see if I could get a better idle, the 964 cams did not idle well with the a/c on, since I still have cis and big intake ports. The stock cams did idle better. I'm putting the stock heavy pressure plate back in this time also to help with the idle issue, maybe that combined with the advanced 964 cams will be sufficient.

[smurfbus]

I did some testing earlier: "I could not dial more than 1.96mm advance to get enough clearance and 2.1mm would contact piston/valve. My previous heads had over rev type valve contact but it must have been over 7500 rpms. " These on 3.3 with 964 cams. Later found out I wanted more top end and it might also had effect on my backpressure too (holset hx40super with zork and dual WG) so I went back to 1.26

[mikedsilva]

Originally Posted by trials935

That's a good question Mike, I should have tried advancing the 964 cams, instead I put the stock turbo cams back in last fall and feels like I lost 100 hp. I just dropped my engine this morning and was going to put sc cams in set to 1.7mm, but now I'm leaning towards putting the 964 cams back in and setting them about 1,6 or 1,7, if I don't have any clearance issues. I put the stock cams back in as an experiment to see if I could get a better idle, the 964 cams did not idle well with the a/c on, since I still have cis and big intake ports. The stock cams did idle better. I'm putting the stock heavy pressure plate back in this time also to help with the idle issue, maybe that combined with the advanced 964 cams will be sufficient.

Interesting about it not idling well with the 964 cams.
I have minimal turbo experience, but I always thought of the 964 as being just a little bit 'bigger' than the SC.... when I use 964 cams in n/a builds, I've never found them to be rough idling... but maybe they have more compression than a typical turbo build and that's why you noticed it a lot.

I'm planning to rebuild my turbo engine (3.5 litre, 8.5:1) and tossing up whether to use a SC or 964 grind.. I think at 8.5:1 (a true measured 8.5) the 964 should be ok down low and exciting up top

[confused]

The way Henry at Supertec explained it to me when I did SC cams in my 79 930 was it’s all about shifting, you get a big burst of power down low and feel that fun low acceleration. How fast are we allowed to go these days? The power is kinda better suited to lower speeds, passing other cars is so easy. Even with SC cams I still call my 930 crazy fast, true it doesn’t do near the high speeds as my GT4 does but the aerodynamics are wildly worse on a G model.

[sundevil64]

Originally Posted by RarlyL8

We use SC cams in all the street 930 performance builds, set them at 1.70 Awesome cams. If you want to stretch the torque curve to the right a little go to the SC330 profile.

I am running these and really like them. There is quite a bit of popping on decel which is kind fun, but your not sneaking up on anyone especially if you have dual out hooligan from Brian.