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YOUR RESEARCHPiston change when installing x51 in 99 996 ?
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last one my supplier had
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Reported cause · Original poster
It was the last one my supplier had so he discounted it down to $5000.
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The pistons on the 3.4 X51 kit have the valve recesses "adjusted" or machined to provide clearance for the exhaust valves.
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Suggestion · Original poster
It is the same parts as the x51 pkg., but you must change the Euro pistons for the 3.4 with kit.
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Suggestion · Original poster
some say I must change the pistons to 00-01 models.
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Suggestion
The 3.6 has many other changes such as cam sensors, cam timing changes, valve lift changes, etc.
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I have purchased the x51 kit for my 99 996.
I have gotten different answers from different dealers. some say I must change the pistons to 00-01 models. The pistons will cost me $1250 more.
If I need them O.K. ,but I would like to be sure.
Does anyone what the difference, if any , is for sure?
I have tried 5 dealers with 5 different answers. I even called Porsche Motorsports in Cal. but can't seem to get a return phone call or speak to anyone in person.
I own a performance shop so I will do the install myself.
This will be a upgrade for our racecar.
As for the cost of the kit I think I got a great deal on it. It was the last one my supplier had so he discounted it down to $5000. Now I just have to tackle the piston issue.
There was a factory power upgrade package (X51?) for the 3.4L engines that was not an available option in the North American market. PCNA determined that at $14,000 for the option that not enough folks would go for it. I do not think the pistons had to be changed.
edit...
I thought the 3.6L engines were just bored out 3.4L engines. If that is so you would also have to bore out the cylinders for the new pistons to fit.
I stand corrected on the 3.4L. Nothing new there.
If it is a 3.6L X51 I really don't think it will work in the 3.4 by just boring out the cylinders and adding new pistons. The 3.6 has many other changes such as cam sensors, cam timing changes, valve lift changes, etc. That's a can of worms I would not open.
Jim
The pistons on the 3.4 X51 kit have the valve recesses "adjusted" or machined to provide clearance for the exhaust valves. This is due to the changes in the X51 cams (more lift and duration etc) compared to the std cams.
One more thing, the std 3,4 pistons are cast aluminum so they may or may not accept any extra machine work. You would have to find a reputable race engine shop to do the work, or replace the pistons with forged pieces. I wonder if the X51 pistons are forged?
Update -
Here's what I found out after calls to everyone you can think of at Porsche North America and Porche Motorsports.
The power package was offered in 99 through 01 3.4L motors.
However it was not available to the U.S. it was ROW only (rest of world)
It is the same parts as the x51 pkg., but you must change the Euro pistons for the 3.4 with kit.
pistons sold seperate and must come from Germany. $1350 comes with rings,and wristpins
A 3.6L does have the same bore but uses a different crank, bearings, and stroke.
I should have the kit by Fri. and the pistons by the end of next week.
I can post pictures of parts and part #'s , and let you know how it runs afterwords if anyone is interested
