964 cams in 204 bhp sc

bruboy · 10-22-2005, 11:41 PM

I have just done a search on "964 cams" and could not find the answer I needed, apologies if I missed it.

I am trying to find some dyno data on 964 cams fitted to standard CIS 204bhp 9.8:1cr euro spec engine.

My car runs great but I would like to extend the rev range and power at the top end a little.

thanks

Bruce
83sc

d S coupe · 10-23-2005, 04:30 AM

Good morning Bruce.
According to Dempdey's book,a 3l with 9.8:1 and a set of SSI,964 cam's will give you an improuvement of 30-50 hp over stock engin. It's suppose to be a nice improuvement.
Good luck Daniel

Joe Bob · Joe Bob's Garage

Extending the rpm range requires replacement of the rev limitting rotor. "I" went with a 7300 limit after I redid my 3.0 with 964 cams.

bruboy · 10-23-2005, 08:38 AM

Mikez

did you gain any usefull power at the higher RPM, my car will not pull much above 5800RPM in the higher gears on track driving days I was wondering if the 964 cams would give me good power up to around 6500rpm?

Joe Bob · Joe Bob's Garage

Mine did....it was a monster all the way up to 7K.

Of course THAT particular motor was in a light weight 914.

DARISC · 10-23-2005, 09:27 AM

Will the 3.0 Euro spec engine w/964 cams still pass CA smog test (probably wishful thinking)? My 82 coupe is my daily driver in SoCal, must keep it legal dammit!

If so, can these cams be installed w/o any other engine mod.s to apease the CIS, etc. (I admit I don't turn my own wrenches, just drive the hell out of it).

I'm a Porsche newbie and am learning a lot from all you people on the board - Thanks!

Joe Bob · Joe Bob's Garage

The CIS IS adjustable.....lean it out and don't run it too long that way.

Early_S_Man · 10-23-2005, 09:47 AM

Bruce,

Web-Cam 20/21 cams are a bit hotter than the 964 grind, and the ultimate performance gain for a CIS 3.0 engine. Many Pelicans have used them with unversal acclaim and praise, and though a bit more expensive than modified, used 964 cams, if the budget allows ... that would be the optimum choice for new cams.

Jeff Alton · 10-23-2005, 09:48 AM

It should pass emmissions with those cams. I put a set in a late 83 SC a couple of months ago, (california car) made a nice strong motor. Noticable improvement but certailnly not shockingly different.

Cheers

bruboy · 10-23-2005, 09:51 AM

Forgot to mention my car has SSI so will the 964 cams give me total of 30-50 bhp on top of the original 204bhp

Jeff Alton · 10-23-2005, 10:02 AM

That 30-50 is pretty ummm optomistic! You might pick up a total of 20-30, might. I think Dane"s 3.4 with CIS and bigger cams made around 250ish if I remember correctly. And that is with over 10% more displacement. I also think the author of the previously mentioned book pooh poohed Dane's numbers a little.

It will be a nice motor with the cams and exhuast, just don't worry too much about the actual HP number claims.

Cheers

Carrera3.5L · Carrera3.5L's Garage

964 or 20/21 cams will increase power somewhat on an otherwise stock or "mild" engine but will not significantly change the rpm where peak power is made.

If peak power on your SC is currently in the 6,100 - 6,300 range with the stock cams, peak power is not going to rise to 7,000 rpm with 964 or 20/21 cams. It will still be in the same rpm range.

What they will do is not fall off a cliff as rapidly as the stock cams would. They may only make a modest increase in "peak" horsepower, but they probably will make a significant increase in horsepower at the higher rpm ranges over the stock cams.

As an example to illustrate, we designed a nice set of CARB legal camshafts for the VW VR6 engines. They make 10-12 "peak" horsepower over the stock cams at 6,300 rpm but made 30 horsepower more than the stock cams at 6,800 rpm. The rpm where peak power was acheived did not increase, but the power held for a few hundred rpm longer than with the stock cams.

964 or 20/21 cams will both pass CA emissions in California, just make sure that all othe emissions related components is in good working order. This means that SSI's would have to be removed in order to pass the visual portion of the smog test.

I think the 250 bhp number for an otherwise stock 3.0L with 964 cams and SSI's is optimistic but who knows, one dyno test is worth a 1,000 expert opinions.

Either way, the cams and exhaust are a good place to start for engine mods on your SC and in conjunction will make a nice improvement that you will both notice and enjoy.

Ralph

bruboy · 10-23-2005, 10:43 AM

Extending the rev range a little is really what I am after as the "falling off" the cliff with the stock cams is a real pain on the track, I hate changing to fifth and back down to fourth with a 915 gearbox!!

I will do a litle price research on the 964 v 20/21 options,

is there any dyno data out there to illustrate the differences?

thanks

Bruce

Venetian · 10-23-2005, 11:26 AM

Not to hijack but could someone comment on what gains might be made on a 3.2L ie would it be similar? Also what would be the approximate cost of 964 cams?

Thanks

Jeff Alton · 10-23-2005, 11:30 AM

You can have yours reground for a around 300ish. Plus you should install new rockers or reground rockers to go with them. Try camgrinder (oelican member) The 964 cam in a 3.2 act like Ralph suggests. Makes the motor a little stronger but will not pull forever. When I did mine with SSI's and custom Steve W chip I though it was a great improvement. 2 weeks late I was planning my next engine build to get more power. It just behaves like a slightly more powerful stock engine.

Cheers

dd74 · 10-23-2005, 12:55 PM

Splitting hairs, I believe the 20/21 is a peakier camshaft than the 964. This could come from the lobe spacing of both - I'm not certain.

Nevertheless, the late Euro 3.0 is a very strong engine, and has everything in place except for the cams (of course) and backdated exhaust.

With two items in place, the car should produce at least 220 hp. Why? The compression (9.8) for one, plus the Euro 3.0 has the 4R runners and Euro fuel distributor, which are also keys to a stronger 3.0.

When I was considering modifications to my 3.0, which has the 9.3:1 compression of the late US 3.0s, the 20/21 cams were definitely a must as was early 4R CIS runners. The heads would also need to be ported to match the 4R CIS runners. I'm still not sure if the fuel distributor would need modification, but there is a possibility.

All said, with those modifications, I would expect the engine to produce about 220 to 230 horsepower. Sure, I might be dreaming about ultimate hp output, but in all, the engine would nonetheless produce more horsepower.

camgrinder · 10-23-2005, 07:24 PM

I know for sure the 964 cams will pass. They work very well with 9.8-1 compression.
Claiming a 50 hp increase is generous.

kstylianos · 10-23-2005, 07:55 PM

I built an engine silimar to what you are talking about. With this particular one, the CR with the JE's are probably a little bit higher than the Euro 9.8:1's Mahles. I used the SC330 grind which, in the grand scheme of things, are not much that differenct form any other CIS grind avail (small lift, minimal overlap). Your results should be similar.

Dyno Results - Thoughts?

dd74 · 10-23-2005, 07:56 PM

Quote:

Originally posted by camgrinder
I know for sure the 964 cams will pass. They work very well with 9.8-1 compression.
Claiming a 50 hp increase is generous.

But not impossible, correct? Implausible, but not impossible?

camgrinder · 10-23-2005, 08:19 PM

Nothing is impossible, I think.