EFI cams for 930

dean · 08-21-2004, 01:14 PM

Hi
I am going to recam my 3.0L 930 motor this winter. I will port the heads at the same time. Specs now are stock comp pistons, Carrera intake, K27 turbo, DTA EFI. If I ever blow it up and have to repiston, I will bump the comp. I asked a couple people what cams they recomend for my street use. One said with my EFI I can use 964 cams. The other said that 964 cams are too much and recomended SC cams. Anybody have and more input?

Thanks
Dean

911nut · 911nut's Garage

Bruce Anderson recommends SC cams for turbo applications.

5axis · 08-21-2004, 02:08 PM

One huge benefit of ditching the CIS is getting to run much more wild cams. Check into the GT2 or GT2 evo grinds. I think that is what Juan is using now.

BURN-BROS · 08-21-2004, 02:09 PM

You can use both(even with CIS).With lower comp you may want sc grinds to keep the torque a little lower on the rpms. P.M. camgrinder, He can set you straight.

camgrinder · 08-22-2004, 08:03 PM

I would use the 964 grind. The SC cam has been the normal upgrade cam for 930 turbos for a long time.
Using the K27-7200 with 964 cams will be just as driveable
and make more HP. The super cup grind is a slightly hotter than the 964 and would make more peak HP, but might be hard to tune
in a cis engine.

WydRyd · 08-22-2004, 08:25 PM

Why not go in the middle and install Carrera CAMs? I used these with the K27-7200 and it was an awesome combination!

I can sell u mine for $200 if ur interested?

camgrinder · 08-22-2004, 08:29 PM

The Carrera cams casting no. 930105147 9R / 930105148 9R have the same grind as the early SC. They are just timed in the engine different. If the left cam has the scavenge pump extension installed, $200 is a hell of a deal.

beepbeep · 08-23-2004, 01:30 AM

SC/Carrera cams are hotter than 930 ones but still qute mild (so mild that they can be used with CIS). If you are looking for ultimate power (and I bet you do , GT2 evo is way to go, EFI will sure support it and I seriusly doubt you'll see any problems with intake-reversion either.

Only real problem (or advantage, depending how you see it) is your ultra-low 6.5:1 C/R. You can use heaps of boost with it, especially if intercooled but it will be a dog off-boost.

dean · 08-23-2004, 04:34 AM

Thanks for the replys

I bought this motor used so I don't really know the comp ratio. I also don't know what cams are in it. but it was timed like it had 930 cams so I assume they are 930 cams. The strange thing is the off boost performance is awesume, even when I had CIS. Chris Bennet drove the car and said off boost it drives like a regular SC. And it does. I don't know if it is because of the gearing or what. I have never driven a 4 speed 930 so I don't know how to compare.

John, I have aftermarket EFI

I have heard from a few people who have the GT2 evos and they all love those cams. I think they all have higher comp. ratio than stock though. I still think the GT2 evos would be too radica for this old fart. So I am leaning toward the 964s.

Thanks again
Dean

beepbeep · 08-23-2004, 06:25 AM

If it's a 3.0 930 engine then it has 6.5:1 C/R. Later intercooled 3.3L 930 engines got C/R bumped to 7.0:1 beacuse intake charge wasn't so hot.

Talking about off-boost responce...yeah, they do pull decently well compared to N/A engine of same size but compared to "on boost" torque they feel little lethargic.

Factory tried to offset this by using choked 32mm intake ports (I guess that you didn't port-matched your 36mm Carrera intake to 32mm 930 heads?) , which raised gas velocity at low revs and thus provided better torque down low. It also strangled the flow at high revs, lowering the ultimate power.

I think you can expect some loss in low-RPM torque if porting heads and using hot cams but with that rev-happy short-stroke engine, better cams and low C/R pistons you can have heaps of power higher up.

I don't think your 0.5 points lower C/R will do much difference with GT Evo cams, but i guess 964 are pretty hot too (considering that they are made for twin-plugged high C/R engines).

With 1.1 bar of boost, EFI, ported heads, hot cams and good intercooler you are looking at 420HP to 460hp ...

dean · 08-23-2004, 02:06 PM

Goran,
I don't know if the PO replaced the pistons or not. I bet it was re-ringed though. You are correct, I didn't port match my heads. The Carrera intake is 41 mm and my ports are 34mm. So that is a huge step.
When I had CIS I had 328 RWHP and 318 ftlbs of torque to the wheels.

So I guess I am going with 964 cams

Thanks again
Dean

camgrinder · 08-23-2004, 02:49 PM

Do a normal compression test. That should verify which piston you have. Sounds to me like someone has been into the engine and has done some type of modification.

dean · 08-23-2004, 05:40 PM

I will do a comp check sometime. When I got the motor, I did a leakdown and the worst cyl was 2.5 % leakdown. The rest were 1 to 1.5%. So I thought it was re-ringed at least.
Dean