16v head
04-19-2008, 11:09 AM
#1
16v head
Well, the time has come for me to seriously consider a 16v head.
I have already done a bit of research on this but all I really have are some pretty vague figures. What’s really appealing about the 16v to me is the more efficient chamber design. From what I understand, because of this, you don’t need to run as much timing advance (all else being equal) so there is less opportunity for knock – ie, you can run higher boost and/or use a higher CR to start with. The stronger 3.0l block would also help here.
As for flow and costs… I’m pretty clear on the 8v… around 180 cfm stock and around 250 cfm for Stage 3 and I know the costs. I also have an idea of what 16v heads go for but don’t know their stock flow rate or the cost of working on them or solid lifter conversion costs etc. I’ve heard that they can flow well over 300 cfm with work but I’m not sure what’s involved to get them to that point. I’ve also heard that a stock 16v will flow much like a heavily worked 8v but not sure whether that’s true.
The only other thing I’ve heard about the 16v is that there may be some reliability issues with the chain guides and tensioners and that the variocam system in the 968 setup can also be the source of problems and catastrophic failures which sounds a bit scary.
Any info available on the 16v setups to help me fill in some gaps would be greatly appreciated.
I have already done a bit of research on this but all I really have are some pretty vague figures. What’s really appealing about the 16v to me is the more efficient chamber design. From what I understand, because of this, you don’t need to run as much timing advance (all else being equal) so there is less opportunity for knock – ie, you can run higher boost and/or use a higher CR to start with. The stronger 3.0l block would also help here.
As for flow and costs… I’m pretty clear on the 8v… around 180 cfm stock and around 250 cfm for Stage 3 and I know the costs. I also have an idea of what 16v heads go for but don’t know their stock flow rate or the cost of working on them or solid lifter conversion costs etc. I’ve heard that they can flow well over 300 cfm with work but I’m not sure what’s involved to get them to that point. I’ve also heard that a stock 16v will flow much like a heavily worked 8v but not sure whether that’s true.
The only other thing I’ve heard about the 16v is that there may be some reliability issues with the chain guides and tensioners and that the variocam system in the 968 setup can also be the source of problems and catastrophic failures which sounds a bit scary.
Any info available on the 16v setups to help me fill in some gaps would be greatly appreciated.
04-19-2008, 01:24 PM
#3
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[QUOTE=Geneqco;5328789]I also have an idea of what 16v heads go for but don’t know their stock flow rate or the cost of working on them or solid lifter conversion costs etc.
I’ve heard that they can flow well over 300 cfm with work but I’m not sure what’s involved to get them to that point. I’ve also heard that a stock 16v will flow much like a heavily worked 8v but not sure whether that’s true.QUOTE]
1. The STOCK flow rate is over 300cfm on all 16v heads. That include 968, S2 and 944S. THe 944S head flows the least and the 968, the best. I have also ported and changed valve sizes on the 944S head to flow as much as a full ported 968 head. They are very impressive. I have a 16v 2.5ltr motor going together now.
2. The 16v flows way more than the best 8v head, that I have seen.
3. The solid lifter upgrade is double what a 8v Solid conversion cost. Although they are available, I would not use solid lifters for any street/De car. They are not needed. As long as you have good oil supply, the hydro's will be fine at high RPM's.
I’ve heard that they can flow well over 300 cfm with work but I’m not sure what’s involved to get them to that point. I’ve also heard that a stock 16v will flow much like a heavily worked 8v but not sure whether that’s true.QUOTE]
1. The STOCK flow rate is over 300cfm on all 16v heads. That include 968, S2 and 944S. THe 944S head flows the least and the 968, the best. I have also ported and changed valve sizes on the 944S head to flow as much as a full ported 968 head. They are very impressive. I have a 16v 2.5ltr motor going together now.
2. The 16v flows way more than the best 8v head, that I have seen.
3. The solid lifter upgrade is double what a 8v Solid conversion cost. Although they are available, I would not use solid lifters for any street/De car. They are not needed. As long as you have good oil supply, the hydro's will be fine at high RPM's.
04-20-2008, 04:52 AM
#4
Rennlist Member
Scott, I assume this car will be mostly track oriented while remaining road registered. Stripped and caged etc. Not daily driver.