performance upgrades
07-16-2006, 02:55 PM
#1
2nd Gear
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performance upgrades
Im planing to upgrade my 964 na over the winter. First will be a rebuild of the engine, im going to put twin turbos on the na motor. I wanted to use the 3.8l lnengineering nickies cylinders with je pistons and carrillo rods also the gt3 oil pump. i have read that some people are using the gt3 crankshaft on performance buildups over the 964 na, is there a problem with the 964 crankshaft ? I was thinking of using the aem universal ems but thats open right now. what should be done to the na heads or should i just purchase some aftermarket heads such as the 9m. any help and insight would be greatly appreciated. im starting to collect parts now. Dj
07-17-2006, 05:11 AM
#2
You are going to need to lower the compression of the engine to allow for the boost. Why not speak to Protomotive as I assume you are in the US? No affiliation, just heard over the years that they do good work. The problem with doing a 'bespoke' or custom solution as you are is that it will be difficult to find someone who can adise the benefits of the upgrades you are choosing. For example, 9M might not know how their heads will fare together with your own particular situation - I guess you can ask? I have been in the same situation in the NA world, and I would speak to a good Turbo tuner before making all the decisions. For example, there may be no or very little benefit to going 3.8 for example....and this will save you a lot of cash!
07-17-2006, 08:50 AM
#3
Nordschleife Master
The GT3 oil pump fits into the case but will need to have the case webbing clearanced for the second scavage pickup.
The GT3 crankshaft fits into the case but you will need to have special rods built to work with the 964 engine components. The GT3 crankshaft has 180 degree oiling of the rod bearings where the 964 does not. The GT3 is fully counterweighted, the 964 is not. The GT3 is straight, the 964 are not so much, requiring the heavy nose balancer. There are two different GT3 crankshafts produced. The current one will need a custom pully for the front.
Carrillo rods are great. You will most likely need to clearance the oil pump (930, 964, or GT3) so the rod bolts don't hit the pump.
I don't like 3.8l for turbo engines, there isn't really enough cooling and the cylinders are too thin for sealing. Additionally, if you use the slip in ones, they are really too thin in the case spigot area. The bore in ones require the case to be bored out to 109mm and a sealing ring added. The gains are slight and if you really need the power, you can turn the boost up. 750hp out of a 3.6l engine is not uncommon. In my opinion, the 3.8l conversion doesn't provide much "value"
If your cylinders and pistons are within spec, I'd take your pistons and mill them down to 8.0:1 compression and use them. Alternatively I'd use the stock 964 3.6 turbo pistons, NOT 993. JE pistons aren't the greatest although a lot of people use them. They are not known for their longevity in the Porsche engine due to the wider tolerances due to the casting and the material. Mahle has their own issues, but they are known to be robust (and heavy).
What about turbos? Garrett GT28s are great turbos for your application.
The 9M heads are VERY nice, I have a set on my engine. I'd also have a custom camshaft ground to the specifications of your engine based on the airflow through your intake, heads, and exhaust. This is how to get a turbo engine to be extremely responsive and more area under the curve. If you want to use an off-the-shelf camshaft, the GT2 Evo cam would be the one I'd choose.
I'd consider the MoTeC M48 or M600 for engine management.
The GT3 crankshaft fits into the case but you will need to have special rods built to work with the 964 engine components. The GT3 crankshaft has 180 degree oiling of the rod bearings where the 964 does not. The GT3 is fully counterweighted, the 964 is not. The GT3 is straight, the 964 are not so much, requiring the heavy nose balancer. There are two different GT3 crankshafts produced. The current one will need a custom pully for the front.
Carrillo rods are great. You will most likely need to clearance the oil pump (930, 964, or GT3) so the rod bolts don't hit the pump.
I don't like 3.8l for turbo engines, there isn't really enough cooling and the cylinders are too thin for sealing. Additionally, if you use the slip in ones, they are really too thin in the case spigot area. The bore in ones require the case to be bored out to 109mm and a sealing ring added. The gains are slight and if you really need the power, you can turn the boost up. 750hp out of a 3.6l engine is not uncommon. In my opinion, the 3.8l conversion doesn't provide much "value"
If your cylinders and pistons are within spec, I'd take your pistons and mill them down to 8.0:1 compression and use them. Alternatively I'd use the stock 964 3.6 turbo pistons, NOT 993. JE pistons aren't the greatest although a lot of people use them. They are not known for their longevity in the Porsche engine due to the wider tolerances due to the casting and the material. Mahle has their own issues, but they are known to be robust (and heavy).
What about turbos? Garrett GT28s are great turbos for your application.
The 9M heads are VERY nice, I have a set on my engine. I'd also have a custom camshaft ground to the specifications of your engine based on the airflow through your intake, heads, and exhaust. This is how to get a turbo engine to be extremely responsive and more area under the curve. If you want to use an off-the-shelf camshaft, the GT2 Evo cam would be the one I'd choose.
I'd consider the MoTeC M48 or M600 for engine management.
