Travis - sflraver

what is the diffrence between the 944 and the 951 head,cam,valves. Are they by chance interchangeable as a whole setup between the 2. I dont want to sound stupid just want some info. I know nothing about the 951 setup.

Loki

A 951's head has sodium filled exhaust valves and ceramic lined exhaust ports. They would not be interchageable, as far as I can tell.

Chris
'86 951

Huntley Racing

The turbo also has different valve springs, cam, and port sizes. You can mix them but usually we mix parts more than anything. N/A guys like turbo springs, turbo guys like N/A head castings because they can port the exhaust side (so long as they have everything ceramic coated).

Travis - sflraver

So I could take a complete N/A head, port the exhuast, ceramic coat it, change out the springs cam and exhuast valves and it would be good to go on a turbo? The manifolds (exhuast and intake) bolt up the same and it bolts to the block the same. Would I need to find a both the cam and cam houseing from a turbo or could I just change out the cam itself.

My problem is I am going to need a complete turbo head (head, cam , houseing) and I am trying to decide what would be more cost effectave. Trying to find a turbo one or picking up a cheep N/A setup and converting it.

Danno

Buying a used 951 head is more cost-effective at $150-200. Converting a 944NA head would cost quite a bit more since sodium-filled exhaust valves are around $100 each. Then add in a set of valve-springs for $150, ceramic-coat is another $125, labor, shipping, etc.....

Bones944

Hmmm, I thought the cam was the same for the 944 and 951. I replaced my stripped cam, housing and all, with a complete housing from a N/A, and I haven't noticed the slightest bit of performance loss. It might be there, but not from seat of the pants. Is the cam different? I've been told they were identical. I would like to see the lift and duration specs from one to the other and see what the differences are.

Travis - sflraver

Ditto that.

Anyone with specs on the N/A cam, Turbo cam, and your adverage performance cam please post. That would help out quite a bit.

Perry 951

Part numbers are diffrent, and I think there is more overlap in the NA cam... IIRC.

Danno had some charts on his site at one point.. again, IIRC.

Let me see what I can find.

Bones944

well there ya go.....when I replaced my cam housing with one from an n/a, a tech at a Porsche dealership told me the cams were identical. I guess the best thing to do would be to buy a mild cam and new lifters and put them in my old housing and switch.......again. At least the housing gasket is only a month or two old, it took an hour and a half of scraping to get the old one off without scarring the head.

Bones944

OK, from Danno's site:
944.105.155.05 83-85 1/2 944, 1986-88 turbo
944.105.155.09 1986-88 944/924s

Travis - sflraver

any chance of anyone getting lift and duration from those part numbers? It would be interesting to see the diffrence between the turbo and na. Turbo probably stays open a little longer on the exhaust and drops off sharper on the close. Dont know.. just guessing.

Bones944

<a href="http://members.rennlist.org/951_racerx/CamProfiles.pdf" target="_blank">http://members.rennlist.org/951_racerx/CamProfiles.pdf</a>

that's the url

Bones944

Fortunately the cam I bought was from an '84, so the part # should be identical.

Danno

Yup, the 951 has the same camshaft as the early 944NA cars. The spec book I have is an '88 version, so I only listed '86-88 951s as having those part#, but I'm sure ALL the 951s had the same cam. And there's only a minor difference between that cam and the later 944NA; about 3-5 degrees of duration and that's it.

One good upgrade would be the Elgin Cam's 'improved' stock grinds. Similar specs to stock, but they change the ramp-up rates to give you more average lift. You end up with a car that's got great ooomph in the mid-range with a wider torque curve and is quicker, even though peak HP/TQ numbers don't show it.