944S head on a 951 engine Block
02-11-2003, 10:29 AM
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944S head on a 951 engine Block
Hello
I just purchased a 944S head and thought what is needed to build a 16V with
a 951 block.
Strange that the head has 104mm commbustion chamber. so either
somebody modified already or is it stock. The 944S has 100 mm combustion
chamber.
Of course I am talking about a Turbo 16V engine and not a NA engine.
what else is needed to build this engine?
Konstantin
I just purchased a 944S head and thought what is needed to build a 16V with
a 951 block.
Strange that the head has 104mm commbustion chamber. so either
somebody modified already or is it stock. The 944S has 100 mm combustion
chamber.
Of course I am talking about a Turbo 16V engine and not a NA engine.
what else is needed to build this engine?
Konstantin
02-11-2003, 06:04 PM
#2
Racer
I think the main things are different head studs (I think they are longer) custom intake manifold, and modify exhaust manifold. I am in the process of building a 3.1 16v turbo out of an s2 engine.
custom intake, pipes, and big intercooler are being done by Tim at Speedforce. I'll modify exhaust myself, and studs are from Raceware.
custom intake, pipes, and big intercooler are being done by Tim at Speedforce. I'll modify exhaust myself, and studs are from Raceware.
02-12-2003, 08:20 PM
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It is my understanding that the 944S head will bolt right on to the 944 Turbo block with no modifications at all. The stock bore of the 944S head should match the 100mm bore of the block. The water passages line up perfectly. And, the 944S head uses the stock length head studs used on the 944 Turbo.
Jeff
Jeff
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02-13-2003, 03:48 AM
#9
Former Vendor
Hi!
Is there a real performance gain available when using 16v head? Is it worth the trouble -how much more hp?- and what effect does it have on low-end torque?
So far those 4-valve engines I've noticed have been more or less high-revving with lesser low-end power/torque... This is not bad if you want a race-engine,but for everyday street use I'd need something completely different.
Pete <img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" />
Is there a real performance gain available when using 16v head? Is it worth the trouble -how much more hp?- and what effect does it have on low-end torque?
So far those 4-valve engines I've noticed have been more or less high-revving with lesser low-end power/torque... This is not bad if you want a race-engine,but for everyday street use I'd need something completely different.
Pete <img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" />
02-13-2003, 08:54 AM
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my head is a 944S head for sure. I checked the water passage and it is a 2.5L head not a 3 L head.
The starnge think is that the top of teh head has realy widened to 104 mm. I will make a pic and post it to teh board..
What I like on this head is that it has a much biger intake port that means a lot of air can go in teh engine.
It is now perfect for a 3 l conversion on a 951 block.
looking at the 4 valve design it seems much more capable of big HP as it will flow MUCH MORE air.
can I use teh cams from a S2?
what otehr diference is between the S2 and the 944S head?
Konstantin
Konstantin
The starnge think is that the top of teh head has realy widened to 104 mm. I will make a pic and post it to teh board..
What I like on this head is that it has a much biger intake port that means a lot of air can go in teh engine.
It is now perfect for a 3 l conversion on a 951 block.
looking at the 4 valve design it seems much more capable of big HP as it will flow MUCH MORE air.
can I use teh cams from a S2?
what otehr diference is between the S2 and the 944S head?
Konstantin
Konstantin
02-15-2003, 12:37 PM
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Here is a comparison between the 944S and 944S2 heads:
S and S2 both have the same size valves and port sizes for both the intake and the exhaust. If you step up to the 968 head, it has even larger intake valves than the S or S2.
S = 100mm bore
S2 = 104mm bore
S = short head studs used on 2.5 liter block
S2 = longer head studs used on 3.0 liter block
S = direct bolt on to 2.5 liter bottom end because water passages and head studs are all configured for this setup.
S2 = direct bolt on to 3.0 liter bottom end because water passages and head studs are all configured for this setup.
Moral of the story, if you want use the 2.5 liter block (100mm bore), go with the 944S head. If you want use 3.0 liter block (104mm bore), go with an S2 head.
CAUTION!! If you just bolt the 944S head onto the 2.5 liter stock bottom end, your compression ratio will go from 8:1 up to approximately 9.5:1. This resulting high compression ratio should be used with caution on a turbo application. Of course, as an alternative, you could lower the compression ratio through enlarging the dish of the stock 951 piston or having custom shorter rods fabricated. But, tampering with the pistons and using shorter rods also have their risks.
Jeff
S and S2 both have the same size valves and port sizes for both the intake and the exhaust. If you step up to the 968 head, it has even larger intake valves than the S or S2.
S = 100mm bore
S2 = 104mm bore
S = short head studs used on 2.5 liter block
S2 = longer head studs used on 3.0 liter block
S = direct bolt on to 2.5 liter bottom end because water passages and head studs are all configured for this setup.
S2 = direct bolt on to 3.0 liter bottom end because water passages and head studs are all configured for this setup.
Moral of the story, if you want use the 2.5 liter block (100mm bore), go with the 944S head. If you want use 3.0 liter block (104mm bore), go with an S2 head.
CAUTION!! If you just bolt the 944S head onto the 2.5 liter stock bottom end, your compression ratio will go from 8:1 up to approximately 9.5:1. This resulting high compression ratio should be used with caution on a turbo application. Of course, as an alternative, you could lower the compression ratio through enlarging the dish of the stock 951 piston or having custom shorter rods fabricated. But, tampering with the pistons and using shorter rods also have their risks.
Jeff
02-15-2003, 12:45 PM
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I forgot to mention that probably the ideal way to do the 16 valve conversion and reduce your compression ratio would be to steel sleeve the block. This way, you could easily use the wide array of aftermarket (i.e. affordable!!) aluminum pistons which would allow you to design a custom piston with the proper dish shape not only to reduce the compression ratio but also to match with the shape of the pent roof (vs. 951 wedge) combustion chamber of the head.
With the stock pistons, you are quite limited in what you can do.
Jeff
With the stock pistons, you are quite limited in what you can do.
Jeff
02-15-2003, 06:03 PM
#14
Race Director
"This way, you could easily use the wide array of aftermarket (i.e. affordable!!) aluminum pistons which would allow you to design a custom piston with the proper dish shape not only to reduce the compression ratio but also to match with the shape of the pent roof (vs. 951 wedge) combustion chamber of the head."
$345 for a set of 8 pistons... can't beat that deal....
$345 for a set of 8 pistons... can't beat that deal....
02-16-2003, 06:29 PM
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</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by Jeff Lamb:
<strong>I forgot to mention that probably the ideal way to do the 16 valve conversion and reduce your compression ratio would be to steel sleeve the block. This way, you could easily use the wide array of aftermarket (i.e. affordable!!) aluminum pistons which would allow you to design a custom piston with the proper dish shape not only to reduce the compression ratio but also to match with the shape of the pent roof (vs. 951 wedge) combustion chamber of the head.
With the stock pistons, you are quite limited in what you can do.
Jeff</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">thanks Jeff
This is what I wanted to do.
@ Danno
what kind of Postons are they?
sent me some infos. can I buy only four or must I buy a set of eight?
Konstantin
<strong>I forgot to mention that probably the ideal way to do the 16 valve conversion and reduce your compression ratio would be to steel sleeve the block. This way, you could easily use the wide array of aftermarket (i.e. affordable!!) aluminum pistons which would allow you to design a custom piston with the proper dish shape not only to reduce the compression ratio but also to match with the shape of the pent roof (vs. 951 wedge) combustion chamber of the head.
With the stock pistons, you are quite limited in what you can do.
Jeff</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">thanks Jeff
This is what I wanted to do.
@ Danno
what kind of Postons are they?
sent me some infos. can I buy only four or must I buy a set of eight?
Konstantin