16v head and turbo myths
03-27-2015, 11:57 PM
#91
Rennlist Member
4V Turbo
Whew… This thread has provided some interesting reading! I think I’ve learned a few things - primarily that there really is anti-4V sentiment which probably contributes to guys choosing to stay 2V “just to be safe”. Shame, actually. Surely it doesn’t matter what might have be breaking on your other car.
There are more issues that probably prevent people from going the 16V route. First, there’s not a lot of general knowledge about its set-up and operation. People consider it complex, and don’t understand how to time the cams. It’s pretty basic, really; although it does require reading the factory manual (free on-line), and perhaps a few additional but inexpensive tools. Certainly not a big deal. Second, it’s considered a much more expensive endeavor. That’s clearly arguable, since none of this stuff is cheap, and most of the custom parts needed for a high-power 2V build are similar to those needed for the 16V.
I fully support Duke’s original post. When I was racing, I began with 2V modified engine. I went to a 4V not long after it was introduced and never looked back. The increase in performance was dramatic.
Yes, there’s prodigious power being generated with 2V engines today, and Shawn has made it easy to duplicate a very successful build and upgrade by documenting everything he’s done. My hat’s off to his home garage efforts and to the results he and Sid have achieved. It’s worth mentioning that the 2V turbo is making more power and lasting longer today primarily due to modern boost control, E85, tuning ability, data recording, and bigger engines. (A 3.1L is 25% bigger than a 2.5, and will provide up to 25% additional power from the displacement increase alone. Think about that.)
Failures still abound, and my experience is they typically result from poor tuning (way too often), poor machine work, lack of a basic skill set by builders and owners, and Glyco rod bearings. None of these issues are particularly difficult to overcome.
The advantages of 4V to the HP junkies go something like this: You can run your normal street boost setting and have the same power as your high boost 2V setting. Lower boost keeps parts in place, so the engine will last longer. A high boost setting will gain enormous power over a 2V. The head flow comparisons support this notion since potential power is a function of airflow. Further, once more folks correct the rod bearing issue, safe RPM will increase which will take the 944 4V power to the OMG level.
There are more issues that probably prevent people from going the 16V route. First, there’s not a lot of general knowledge about its set-up and operation. People consider it complex, and don’t understand how to time the cams. It’s pretty basic, really; although it does require reading the factory manual (free on-line), and perhaps a few additional but inexpensive tools. Certainly not a big deal. Second, it’s considered a much more expensive endeavor. That’s clearly arguable, since none of this stuff is cheap, and most of the custom parts needed for a high-power 2V build are similar to those needed for the 16V.
I fully support Duke’s original post. When I was racing, I began with 2V modified engine. I went to a 4V not long after it was introduced and never looked back. The increase in performance was dramatic.
Yes, there’s prodigious power being generated with 2V engines today, and Shawn has made it easy to duplicate a very successful build and upgrade by documenting everything he’s done. My hat’s off to his home garage efforts and to the results he and Sid have achieved. It’s worth mentioning that the 2V turbo is making more power and lasting longer today primarily due to modern boost control, E85, tuning ability, data recording, and bigger engines. (A 3.1L is 25% bigger than a 2.5, and will provide up to 25% additional power from the displacement increase alone. Think about that.)
Failures still abound, and my experience is they typically result from poor tuning (way too often), poor machine work, lack of a basic skill set by builders and owners, and Glyco rod bearings. None of these issues are particularly difficult to overcome.
The advantages of 4V to the HP junkies go something like this: You can run your normal street boost setting and have the same power as your high boost 2V setting. Lower boost keeps parts in place, so the engine will last longer. A high boost setting will gain enormous power over a 2V. The head flow comparisons support this notion since potential power is a function of airflow. Further, once more folks correct the rod bearing issue, safe RPM will increase which will take the 944 4V power to the OMG level.
03-28-2015, 12:16 AM
#92
Convinced.....now if the dam dollar would just go up 
Whew… This thread has provided some interesting reading! I think I’ve learned a few things - primarily that there really is anti-4V sentiment which probably contributes to guys choosing to stay 2V “just to be safe”. Shame, actually. Surely it doesn’t matter what might have be breaking on your other car.
There are more issues that probably prevent people from going the 16V route. First, there’s not a lot of general knowledge about its set-up and operation. People consider it complex, and don’t understand how to time the cams. It’s pretty basic, really; although it does require reading the factory manual (free on-line), and perhaps a few additional but inexpensive tools. Certainly not a big deal. Second, it’s considered a much more expensive endeavor. That’s clearly arguable, since none of this stuff is cheap, and most of the custom parts needed for a high-power 2V build are similar to those needed for the 16V.
I fully support Duke’s original post. When I was racing, I began with 2V modified engine. I went to a 4V not long after it was introduced and never looked back. The increase in performance was dramatic.
Yes, there’s prodigious power being generated with 2V engines today, and Shawn has made it easy to duplicate a very successful build and upgrade by documenting everything he’s done. My hat’s off to his home garage efforts and to the results he and Sid have achieved. It’s worth mentioning that the 2V turbo is making more power and lasting longer today primarily due to modern boost control, E85, tuning ability, data recording, and bigger engines. (A 3.1L is 25% bigger than a 2.5, and will provide up to 25% additional power from the displacement increase alone. Think about that.)
Failures still abound, and my experience is they typically result from poor tuning (way too often), poor machine work, lack of a basic skill set by builders and owners, and Glyco rod bearings. None of these issues are particularly difficult to overcome.
The advantages of 4V to the HP junkies go something like this: You can run your normal street boost setting and have the same power as your high boost 2V setting. Lower boost keeps parts in place, so the engine will last longer. A high boost setting will gain enormous power over a 2V. The head flow comparisons support this notion since potential power is a function of airflow. Further, once more folks correct the rod bearing issue, safe RPM will increase which will take the 944 4V power to the OMG level.
There are more issues that probably prevent people from going the 16V route. First, there’s not a lot of general knowledge about its set-up and operation. People consider it complex, and don’t understand how to time the cams. It’s pretty basic, really; although it does require reading the factory manual (free on-line), and perhaps a few additional but inexpensive tools. Certainly not a big deal. Second, it’s considered a much more expensive endeavor. That’s clearly arguable, since none of this stuff is cheap, and most of the custom parts needed for a high-power 2V build are similar to those needed for the 16V.
I fully support Duke’s original post. When I was racing, I began with 2V modified engine. I went to a 4V not long after it was introduced and never looked back. The increase in performance was dramatic.
Yes, there’s prodigious power being generated with 2V engines today, and Shawn has made it easy to duplicate a very successful build and upgrade by documenting everything he’s done. My hat’s off to his home garage efforts and to the results he and Sid have achieved. It’s worth mentioning that the 2V turbo is making more power and lasting longer today primarily due to modern boost control, E85, tuning ability, data recording, and bigger engines. (A 3.1L is 25% bigger than a 2.5, and will provide up to 25% additional power from the displacement increase alone. Think about that.)
Failures still abound, and my experience is they typically result from poor tuning (way too often), poor machine work, lack of a basic skill set by builders and owners, and Glyco rod bearings. None of these issues are particularly difficult to overcome.
The advantages of 4V to the HP junkies go something like this: You can run your normal street boost setting and have the same power as your high boost 2V setting. Lower boost keeps parts in place, so the engine will last longer. A high boost setting will gain enormous power over a 2V. The head flow comparisons support this notion since potential power is a function of airflow. Further, once more folks correct the rod bearing issue, safe RPM will increase which will take the 944 4V power to the OMG level.
03-28-2015, 01:04 AM
#93
Addict
Rennlist Member
Rennlist Member
Its fighting with windmills, this thread.
Z-Man from pelican had an 89 S2 head crack and he suspect it could be due to pushing his car. I wonder what his take would be on the subject.
http://forums.pelicanparts.com/porsc...d-gaskets.html
What would be the result of using his head on a turbo car somewhere in between those couple of years he is talking about?
The car would be more powerful, and what else would the car do?
How many chances does a 16V head get from year 1989 to 2015, to be near red line for 20 minutes at a time or almost overheats?
Z-Man from pelican had an 89 S2 head crack and he suspect it could be due to pushing his car. I wonder what his take would be on the subject.
http://forums.pelicanparts.com/porsc...d-gaskets.html
... Throughout the summer, my mechanics tried everything - replaced seals, bypassed the coolant passages flowing through the throttle body....all the 'easy & cheap' stuff. Still, the problem persisted.
Finally in August, my oil pressure sender unit got fouled due to all the water in there, and the car lost oil pressure. At that point, the head came off. The head gasket was a mess, but didn't really show any signed of where water was getting into the cylinders. The head was magnafluxed, and a small crack was indeed found above the #2 cylinder. So small is the crack that you cannot see it.
What caused my head to crack? I suspect a combination of the following:
1. The loss of my H2O pump a couple of years ago, and the subsequent overheating, even though I didn't drive it once it got in the red.
2. The fact that I'm pushing my car while on the track - I'm at or near redline for 20 minutes at a time!
3. My engine has 150,000 miles on it. And while I've only had my car for 30,000 of those miles, that is still a lot of wear and tear on a motor.
Just my thoughts,
-Z.
Finally in August, my oil pressure sender unit got fouled due to all the water in there, and the car lost oil pressure. At that point, the head came off. The head gasket was a mess, but didn't really show any signed of where water was getting into the cylinders. The head was magnafluxed, and a small crack was indeed found above the #2 cylinder. So small is the crack that you cannot see it.
What caused my head to crack? I suspect a combination of the following:
1. The loss of my H2O pump a couple of years ago, and the subsequent overheating, even though I didn't drive it once it got in the red.
2. The fact that I'm pushing my car while on the track - I'm at or near redline for 20 minutes at a time!
3. My engine has 150,000 miles on it. And while I've only had my car for 30,000 of those miles, that is still a lot of wear and tear on a motor.
Just my thoughts,
-Z.
The car would be more powerful, and what else would the car do?
How many chances does a 16V head get from year 1989 to 2015, to be near red line for 20 minutes at a time or almost overheats?
03-28-2015, 01:31 AM
#94
Rennlist Member
Hard to say without knowing anything about Z mans build, tuning and how they ran that car??
The motor had a ton of miles on it and then could have overheated even though he says he didn't drive it under those conditions. Who knows.
What if one removes significant amounts of weight from the recirculating/reciprocating gear. Customise the pistons and rods to reduce the ellipse. You work on reducing the friction in each cylinder. You improve bearings. You secure the block/head as much as possible. And of course, we are presuming a proper tune with requisite sensors to detect any issues and reduce timing/boost etc. Reducing peak cylinder pressure and securing head/cam as much as possible with these old alloy motors. In the end, yes, it's possible that the 8v motor has a bit more meat in the head that might resist cracking a little more than the 16v head. But if you never try then you'll never know. Those that are chasing more than 550whp are having to go this way. Especially if they need to make power beyond 7000rpm.
The motor had a ton of miles on it and then could have overheated even though he says he didn't drive it under those conditions. Who knows.
What if one removes significant amounts of weight from the recirculating/reciprocating gear. Customise the pistons and rods to reduce the ellipse. You work on reducing the friction in each cylinder. You improve bearings. You secure the block/head as much as possible. And of course, we are presuming a proper tune with requisite sensors to detect any issues and reduce timing/boost etc. Reducing peak cylinder pressure and securing head/cam as much as possible with these old alloy motors. In the end, yes, it's possible that the 8v motor has a bit more meat in the head that might resist cracking a little more than the 16v head. But if you never try then you'll never know. Those that are chasing more than 550whp are having to go this way. Especially if they need to make power beyond 7000rpm.
03-28-2015, 02:10 AM
#95
Rennlist Member
Voith, please give it up. It appears that you have no personal experience with any 944 4V head failures, and an obscure post from a third party on another forum hardly supports your position particularly since there's no detail. Drawing a conclusion on the durability of the 944 4V head from that vague post or from your BMW failure experience is hardly valid. For these reasons, and with all due respect, I don't think you're bringing any useful information to this thread. I really hope you'll think about that.
As an engine builder specialized in Porsche, I have a significant amount of FIRST HAND experience with the Porsche 4V head and with 944 performance engine development.
As an engine builder specialized in Porsche, I have a significant amount of FIRST HAND experience with the Porsche 4V head and with 944 performance engine development.
03-28-2015, 03:05 AM
#96
Three Wheelin'
Michael, Glyco rod bearings have been a problem with 911 engines also (2.2-2.7 and 3.0-3.3), did not know that 944 also suffers from Glyco rod bearings?
On 911's there are alternatives: Clevite bearings for 2.2-2.7 and GT3 bearings for 3.0 and up.
Are Glyco bearings not good at all on 944's or just track driving?
On 911's there are alternatives: Clevite bearings for 2.2-2.7 and GT3 bearings for 3.0 and up.
Are Glyco bearings not good at all on 944's or just track driving?
03-28-2015, 03:13 AM
#97
Rennlist Member
Three years of running 1 hour long races in Dubai heat running to a 7500-7700rpm redline on every gear change, and the head was the most reliable part of an engine that never had any overheating issues.
420+hp on barely 10 pounds of boost using a less efficient supercharger can be largely credited to the excellent 4V head flow. I personally wouldn't build another Porsche engine without it being a 4V.
03-28-2015, 06:41 AM
#98
Drifting
This ^^ is why I'd start with a 16V head now if I found one. For a road car that's enough power and the extra compression and ignition advance would be better on the road too.
03-28-2015, 07:25 AM
#99
Addict
Rennlist Member
Rennlist Member
Voith, please give it up. It appears that you have no personal experience with any 944 4V head failures, and an obscure post from a third party on another forum hardly supports your position particularly since there's no detail. Drawing a conclusion on the durability of the 944 4V head from that vague post or from your BMW failure experience is hardly valid. For these reasons, and with all due respect, I don't think you're bringing any useful information to this thread. I really hope you'll think about that.
As an engine builder specialized in Porsche, I have a significant amount of FIRST HAND experience with the Porsche 4V head and with 944 performance engine development.
As an engine builder specialized in Porsche, I have a significant amount of FIRST HAND experience with the Porsche 4V head and with 944 performance engine development.
He even strongly advised against running 2.7 head wthout the ceramic liners at anything over +1 bar.
I think he qualifies as first hand porsche builder.
03-28-2015, 07:54 AM
#100
Drifting
03-28-2015, 10:34 PM
#101
This thread makes me really want to turbo my 968 engine, I do wish there was a reasonable intake solution though. That looks to be the biggest challenge for the "putting it together" part of the build. The tune is another story lol.
4v for life here, even in na form, I can never go back to 2v on the 944 platform
4v for life here, even in na form, I can never go back to 2v on the 944 platform
03-29-2015, 02:56 AM
#102
Rennlist Member
There will be some options for intakes in the near future. Michael Mount is putting one together now. I wouldn't let the intake hold you back!
03-29-2015, 12:56 PM
#104
Rennlist Member
Glyco rod bearings
Michael, Glyco rod bearings have been a problem with 911 engines also (2.2-2.7 and 3.0-3.3), did not know that 944 also suffers from Glyco rod bearings?
On 911's there are alternatives: Clevite bearings for 2.2-2.7 and GT3 bearings for 3.0 and up.
Are Glyco bearings not good at all on 944's or just track driving?
On 911's there are alternatives: Clevite bearings for 2.2-2.7 and GT3 bearings for 3.0 and up.
Are Glyco bearings not good at all on 944's or just track driving?
https://rennlist.com/forums/944-turb...aring-fix.html