Anybody add a turbo to a 968 variocam?
08-12-2007, 10:51 PM
#1
Burning Brakes
Thread Starter
Anybody add a turbo to a 968 variocam?
Does anybody have a good plan for installing a turbo on a 968 variocam engine? It would be convienient if the 951 manifolds would fit, but I'm sure that is out of the question.
08-12-2007, 10:55 PM
#2
Addict
Rennlist Member
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Neither the intake or exhaust manifolds fit. Some use an 8v turbo head modified to match the 968 block, some use a 2.7l 8v head, some use a custom intake...
Search, there is a lot to read on this subject.
Search, there is a lot to read on this subject.
08-13-2007, 03:19 AM
#4
Instructor
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08-13-2007, 04:11 AM
#5
Wow that guy must have alot of money! Im curious how much cash he has in the turbo conversion on the 968. Id guess at least 3 G's. He had to destroke the 968 engine, down to 2.7. He could have just sold the 968 engine and used the 27 block? he lose the variocam but on a turbo who needs it anyway. I wonder if a 350hp LS1 swap would be the same price?
08-13-2007, 04:15 AM
#6
Three Wheelin'
You guys should know a bit more what's happening in Rennlist 
: https://rennlist.com/forums/944-turbo-and-turbo-s-forum/319257-the-saga-continues-this-time-more-valves-more-displacement.html
: https://rennlist.com/forums/944-turbo-and-turbo-s-forum/319257-the-saga-continues-this-time-more-valves-more-displacement.html
08-13-2007, 12:46 PM
#7
Burning Brakes
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much cheaper way to go...
http://www.ststurbo.com/
These turbo systems go near the end of the exhaust and then feed it back up to the intake. Some tracks do not allow them yet because the oil lines have to run to the rear of the car and there's some concern about them bursting/leaking. That will probably change soon though.
http://www.ststurbo.com/
These turbo systems go near the end of the exhaust and then feed it back up to the intake. Some tracks do not allow them yet because the oil lines have to run to the rear of the car and there's some concern about them bursting/leaking. That will probably change soon though.
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08-13-2007, 02:44 PM
#8
Burning Brakes
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Originally Posted by sillbeer
Wow that guy must have alot of money! Im curious how much cash he has in the turbo conversion on the 968. Id guess at least 3 G's. He had to destroke the 968 engine, down to 2.7. He could have just sold the 968 engine and used the 27 block? he lose the variocam but on a turbo who needs it anyway. I wonder if a 350hp LS1 swap would be the same price?
08-13-2007, 02:51 PM
#9
from the site:
"This was accomplished by de-stroking the engine using a Porsche 944 crankshaft in stead of the Porsche 968 crankshaft. This reduced the engine stroke from 88mm to78.9mm. Meening the piston work area is moved 4.55mm lower resulting in a compression ratio of about 7:1, which is suitable for a turboconversion. Redusing the stroke make for a engine which will rev more easily and be more accepting towards high rpm's, because the stroke vs bore ratio is reduced. The overall engine volume was reduced from 3.0L to 2.7L because of the de-stroking"
it says he used the 944 crank, which destroked the engine down to 2.7. yes, it still has the 3.0mm bore but without the stroke of the 3.0 engine it wouldn't matter.
"This was accomplished by de-stroking the engine using a Porsche 944 crankshaft in stead of the Porsche 968 crankshaft. This reduced the engine stroke from 88mm to78.9mm. Meening the piston work area is moved 4.55mm lower resulting in a compression ratio of about 7:1, which is suitable for a turboconversion. Redusing the stroke make for a engine which will rev more easily and be more accepting towards high rpm's, because the stroke vs bore ratio is reduced. The overall engine volume was reduced from 3.0L to 2.7L because of the de-stroking"
it says he used the 944 crank, which destroked the engine down to 2.7. yes, it still has the 3.0mm bore but without the stroke of the 3.0 engine it wouldn't matter.
08-13-2007, 03:11 PM
#10
Rainman
Rennlist Member
Rennlist Member
I bet the 16V head would be fine with a good valvejob...
I'd be more worried about the pistons. Have a dish cut out of them or have some custom low-compression pistons made and crank up the boooooost
I'd be more worried about the pistons. Have a dish cut out of them or have some custom low-compression pistons made and crank up the boooooost
08-13-2007, 03:36 PM
#11
RL Community Team
Rennlist Member
Rennlist Member
I wonder how much power potential is lost by giving up that .3 liters. I know a 2.7 turbo is more powerful than a 3.0 NA, but I'm wondering if it's wise to go 2.7 turbo instead of 3.0 turbo. The 2.5 crank IS much more available and cheaper than a 2.7 head, and 7:1 IS a lot lower than whatever you get with the 2.7 head on a 3.0 block, so more boost is possible. And like he said it can spin faster. Everything looks to be in favor of the destroke option...
Except you lose .3 liters. Why can't all the answers be written in a book somewhere.
Except you lose .3 liters. Why can't all the answers be written in a book somewhere.
08-13-2007, 03:40 PM
#12
Burning Brakes
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Originally Posted by sillbeer
from the site:
"This was accomplished by de-stroking the engine using a Porsche 944 crankshaft in stead of the Porsche 968 crankshaft. This reduced the engine stroke from 88mm to78.9mm. Meening the piston work area is moved 4.55mm lower resulting in a compression ratio of about 7:1, which is suitable for a turboconversion. Redusing the stroke make for a engine which will rev more easily and be more accepting towards high rpm's, because the stroke vs bore ratio is reduced. The overall engine volume was reduced from 3.0L to 2.7L because of the de-stroking"
it says he used the 944 crank, which destroked the engine down to 2.7. yes, it still has the 3.0mm bore but without the stroke of the 3.0 engine it wouldn't matter.
"This was accomplished by de-stroking the engine using a Porsche 944 crankshaft in stead of the Porsche 968 crankshaft. This reduced the engine stroke from 88mm to78.9mm. Meening the piston work area is moved 4.55mm lower resulting in a compression ratio of about 7:1, which is suitable for a turboconversion. Redusing the stroke make for a engine which will rev more easily and be more accepting towards high rpm's, because the stroke vs bore ratio is reduced. The overall engine volume was reduced from 3.0L to 2.7L because of the de-stroking"
it says he used the 944 crank, which destroked the engine down to 2.7. yes, it still has the 3.0mm bore but without the stroke of the 3.0 engine it wouldn't matter.
oops sorry, I didn't read what was one the site. I tought you were describing what happened when you put a 2.7 l head on a 3.0l block
08-13-2007, 04:06 PM
#13
Three Wheelin'
Again, you should read what Markus951 did in that thread I posted and that is by far the most reasonable way to have 3.0 16v turbo.
Putting 8v head to 3.0 is nonsense as Porsche did this only to follow the hp limit rules on 968 turbo. Why would one use crappy flowing 8 valve head on even bigger displacement engine that needs MORE air? This is reverse engineering.
Markus951 car has 30% more power on 30% less boost compared to 8valve head on the last engine, does that ring a bell?
Putting 8v head to 3.0 is nonsense as Porsche did this only to follow the hp limit rules on 968 turbo. Why would one use crappy flowing 8 valve head on even bigger displacement engine that needs MORE air? This is reverse engineering.
Markus951 car has 30% more power on 30% less boost compared to 8valve head on the last engine, does that ring a bell?
08-13-2007, 04:10 PM
#14
Nordschleife Master
There is a 3.1 ltr Turbo Variocam for sale in LA. You can buy if for 25k and take it apart and share how he did it. I have seen it but not heard it run nor looked under the hood. It is forbidden fruit for me with my lowly NA.