993NA Engine vs. TT engine
04-20-2003, 05:46 PM
#1
Three Wheelin'
Thread Starter
993NA Engine vs. TT engine
Other than compression ratio and camshafts are there any other differences between the two? Same crank, oiling capacity, valve size etc? Thank you.
-dc
-dc
04-20-2003, 06:37 PM
#2
Rennlist Member
-Exhaust valves on the turbos are 38mm, 39mm on the na.
-The turbo uses forged cylinders, NA uses cast.
-Turbo has 11 blade fan
-And i think the turbo's pistons have some kind of special coating on them.
-No variocam on the turbo.
I think thats about it.
-The turbo uses forged cylinders, NA uses cast.
-Turbo has 11 blade fan
-And i think the turbo's pistons have some kind of special coating on them.
-No variocam on the turbo.
I think thats about it.
04-20-2003, 06:45 PM
#3
From Paul Frere's book the TT differs by:
The connecting rods a different from the early NA rods.
The piston extends 5mm into the heads at TDC to reduce the pressures on the head gasket.
Fins on cylinders are thinner to allow more air flow.
Only has a single ignition.
Exhaust valves are hollow and filled with natrium.
Hope that helps.
David
The connecting rods a different from the early NA rods.
The piston extends 5mm into the heads at TDC to reduce the pressures on the head gasket.
Fins on cylinders are thinner to allow more air flow.
Only has a single ignition.
Exhaust valves are hollow and filled with natrium.
Hope that helps.
David
04-21-2003, 03:28 AM
#5
RL Technical Advisor
Derick:
All of these 3.6 (and 3.8) P/C's use forged cylinders and pistons; the tops of the cylinders and pistons are different between the two.
Rods are different and the exhaust valves, as indicated above.
No Variocam in any air-cooled model. N/A 3.6's produced in '96 and later use the Varioram intake manifold.
Chris,
Porsche decided that they could control detonation in these engines with software and elected not use twin-ignition, due to difficulties in packaging and controlling costs. Frankly, they did a great job given the boost pressure range and compression ratio. The only difficulties that have arisen (in some cases) are with Californai 91 octane fuel & hot weather.
All of these 3.6 (and 3.8) P/C's use forged cylinders and pistons; the tops of the cylinders and pistons are different between the two.
Rods are different and the exhaust valves, as indicated above.
No Variocam in any air-cooled model. N/A 3.6's produced in '96 and later use the Varioram intake manifold.
Chris,
Porsche decided that they could control detonation in these engines with software and elected not use twin-ignition, due to difficulties in packaging and controlling costs. Frankly, they did a great job given the boost pressure range and compression ratio. The only difficulties that have arisen (in some cases) are with Californai 91 octane fuel & hot weather.
04-21-2003, 06:02 AM
#6
Addict
Rennlist Member
Rennlist Member
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Steve Weiner-Rennsport Systems:
<strong>Derick:
All of these 3.6 (and 3.8) P/C's use forged cylinders and pistons; the tops of the cylinders and pistons are different between the two.
.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Steve
Didn't the shape of the tops of the pistons change during the tt's model life span. A guru engine bulider I know says the earlier type piston always seemed to give another 20hp (in a modified engine) for some reason.
<strong>Derick:
All of these 3.6 (and 3.8) P/C's use forged cylinders and pistons; the tops of the cylinders and pistons are different between the two.
.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Steve
Didn't the shape of the tops of the pistons change during the tt's model life span. A guru engine bulider I know says the earlier type piston always seemed to give another 20hp (in a modified engine) for some reason.
04-21-2003, 08:39 AM
#7
Three Wheelin'
Thread Starter
Does Ruf do anything with the internals on the 993NA with the BTR conversion? I assume they've got to drop the CR quite a bit. Thank you very much.
-dc
-dc
Trending Topics
04-21-2003, 02:27 PM
#8
RL Technical Advisor
TB:
Good question. I am unaware of any changes in the TT's piston shape.
If Mahle/Porsche did that, the part numbers are unchanged and no notifications were made about any upgrades or modifcations on these.
I've looked over the Mahle P/C catalogue and therare only 3 P/C sets listed for the 993 TT:
1) OEM stock replacement 100mm
2) 3.8 slip in 102mm
3) 3.8 bore in 102mm
These are all made for the TT head design and have the same CR.
Derick:
I'm not familar with the details on the Ruf engines but I'd guess that they use a different piston to lower the CR. You might talk to them about that,....
Good question. I am unaware of any changes in the TT's piston shape.
If Mahle/Porsche did that, the part numbers are unchanged and no notifications were made about any upgrades or modifcations on these.
I've looked over the Mahle P/C catalogue and therare only 3 P/C sets listed for the 993 TT:
1) OEM stock replacement 100mm
2) 3.8 slip in 102mm
3) 3.8 bore in 102mm
These are all made for the TT head design and have the same CR.
Derick:
I'm not familar with the details on the Ruf engines but I'd guess that they use a different piston to lower the CR. You might talk to them about that,....