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I am sure i can figure out a fix the throttle cable.
I have made many partial to full custom intake and exhaust manifolds. The problem is that for me I would have 20-30 hours of labor in making a custom manifold like that and then machining everything flat again. And that is plus the cost of materials....
I am sure i can figure out a fix the throttle cable.
I have made many partial to full custom intake and exhaust manifolds. The problem is that for me I would have 20-30 hours of labor in making a custom manifold like that and then machining everything flat again. And that is plus the cost of materials....
I have 20 to 30 hours just looking at it... I just called turbo Tim (SFR) and I'll be sending them my head to mock up an intake and stage two exhaust in a couple of months when I can afford it. This just got expensive! But SFR will have the ability (jig made) to make these manifolds in the future for others who may want to follow this idea.
I might try to make a simple intake manifold tomorrow, totally one-off.
It would be designed around my supercharger setup though, so it may not be 100% copiable for your turbo car.
I am picking up an S2 intake on Sunday and am going to make a sort of "sandwich plate" to go between the 928S3 head/intake gasket and the 944S/S2 intake manifold pattern. The ports/gaskets are different enough that you can't just bolt the 944 manifold onto the 928 head.
The 8v 944 manifold isn't even close regarding bolt pattern, and the runners come in at a bad angle - the 928 ports are straight into the valve where the 944 is more curved.
Also, the 4v (928 and 944) head moves the intake port horizontally about 3" relative to the 8v head so an 8v manifold bolted down would probably bump into the brake booster and stuff.
The 944 exhaust manifold itself is a perfect fit/match to the 928S3 head, but the movement/centering of the port is the "hard part".
I see no reason the 944 16v belt covers wouldn't work.
Question for you guys, would it be possible to use the left hand side 928 head, so that one may have separate hot and cold sides? In a similar fashion to Rod's mental WTAC build with the flipped 968 head:
There is not a Left or Right side head - the heads are completely identical, one is just installed "backwards" relative to the other.
Should be doable to reverse the flow direction if you phase the camshafts properly against eachother (so that the exhaust cam works as an intake cam and the intake cam operates as "Exhaust"...
But don't know how well the ports would work flowing backwards
Ahh, ok, I didn't know the 928 heads were the same either side.
So it would be the same deal as with Rod's 968 then, you could use either head, just rotate it around. No need to reverse the flow or anything, as the head is now facing the other direction. You just need to flip the cams back so that the cam gears are on the front. I believe the main issue was oil and water paths, according to the build thread.
Thanks guys, rotating the head was not overly complicated, just the oil and water paths, it meant we could make a better exhaust manifold and we now have the hot and cold sides of the engine separated.
Let's clerify this. All 928 4v heads are different then the 944S head being it's 100mm bore cousin. The 928 heads have a protrusion in all the castings so when the head is on the drivers side block bank the timing belt will reach the head assy. Because the drivers head sets back from the passanger head. So when we install the 928 head in the same manner as intended for the passanger side the protrusion actually needs to be modified in order not to rub on the engine wire harness were it passes thru the firewall. If the head was turned around then a custom ground intake camshaft would be needed using an exhaust camshaft. Would want to use two exhaust camshafts. You could still use internal chain drive if you chose to. The exhaust cam would have to be addressed at the protrusion on the head if the head were to be reversed. And the rear cam gear housing would usually mount on the protrusion side of the head (when it's on the drivers side bank on the 928's), so there is only one out of three mounts for the rear metal cam cover.
Won't fit without modifying.
See the problem. That cover needs to mount to the left side of the head were reversed. Not that it can't be done! Just more involved then I'm willing to go.
Last edited by Humboldtgrin; 01-08-2016 at 11:57 PM.
Yea, I don't see any real point to trying to flip the head around - I'd just time the camshafts backwards and run with it with less than optimal ports.
Spencer the exhaust moves back on the 16v heads and foward on the intake side from the 8v heads. But only about 1/2" to 3/4". So you'll need to just cut 1/2" to 3/4" out of the exaust before or after your cat setup that's if your using a supercharger. I'm not using a supercharger thou. Your aproch seems easier to me, regarding the exhaust and intake manifold fabs needed. But costly for the supercharger unless you can get a deal on a kit. I'm probably going to end up getting the SFR intake/exhaust set up. Although I'm interested in using the 16v headers I have and putting on some 951 header flanges. Maybe it would work for a year or just the summer. The exhaust would be an easy upgrade later because companies make 16v headers for turbo use so all they need to do is change the flanges at the head on their jig. The intake is a differant story. Oval vs round port flanges. Bigger vs smaller, different port entry angle.
My SC setup is not a kit - all custom fabbed brackets and stuff.
If it's just 1/2" or so, I may not adjust anything and just let the rubber exhaust hangers take up the slack.
Stand by for later, I think I will at least make an intake flange today...whether I add pipes and stuff, remains to be seen.
oiling and coolant flow all looks the same, with the exception of the blocked off tab on the front corner.
i have a 944S head and 928S3 head here side by side.
coolant outlet to rad and heater look identical too.
since the 944S cam gear and gear cover will work on this head, the 944S belt covers and belt kits and stuff should all work.
we (humboldt and i) are going to cut valve reliefs into the pistons for clearance.
i for one am going to try to make the reliefs deep enough for non-interference in the event of a broken belt, and to give me flexibility to play with the cam timing. i also only want to use a factory 944 head gasket for max reliability/field serviceability (can't imagine prepping a head surface for a MLS gasket on the side of the road, where i have done a few headgaskets for other 944 owners)
the 928s3 and 928s4 heads are the same except an oval intake port?
anybody have a cheap 928s3 head for sale? i am ready to do this on the motor on my engine stand. we are megasquirting out lemons racer so we can take full advantage of this swap.
I have a second 928 head and know a guy with a few as well.
If you are really interested I can connect you to him.
The 928S4 heads are very similar to the 944S head, with the main difference being the intake port shape. 944 ports are bigger than S4. Cam covers, tensioners, combustion chambers are the same.
What prompted all the interest in the S3 heads is the larger combustion chamber seen on page 1 of this thread - it is the same cc as the 944 8v head (56cc) vs the 944 16v head (42cc)...which means putting the S3 head on an 8v 944 block does not change the compression ratio.
01-08-2016, 04:44 PM
