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Porsche Motorsport Division X51 PowerKit (320 PS/235KW)

Thanks to whoever recently re-opened this thread as I hadn't come across it before. Fascinating details on the X51 option and great pictures - thanks GT4.

Might be helpful for any prospective purchaser looking for an X51 car to know that the 40th Anniversary cars (1963 total of which 123 were UK registered) all came with this package as standard (albeit without the 3rd rad as mentioned earlier in the thread) and also with the LSD as standard. Might just help you to widen your search to find an X51 equipped car. The 40th Anniversary facebook page lists most of the current 40th for sale including in the UK. Mine's not for sale by the way!

Cheers.Ian
 
DrMEMS said:
Thanks for taking the time to document this. It seems like the X51 "power package" is as much about lubrication reliability as added power.

Previously you noted that for the 996.1 3.4-L engine, the pistons are different for X51 than for standard, while for the 996.2 3.6-L engine, the pistons are the same for X51 and standard. Are there any other differences you know of between X51 engines for the 3.4- and 3.6-L engines?

The 3.6 gained the X51 swirl know-how for the standard engine, so it's not that the X51 is less enhanced for the 3.6, more the standard engine is better equipped out the box.

Other than that, the recipe is the same for the 996.2.

It's when you get to the 997.1 that the corner cutting started: no new high lift cam shafts/valves, no additional lubrication lines.

The compensatory "upside" for the 997 was free PSE (option XLF) and carbon fibre airbox.

The GTS, which featured the X51 as standard kit did, however, lose the ridiculously expensive and zero performance merit carbon airbox (included PSE was retained).

Edited to add: some 997 details for comparison
 
Although the Carrera Cup and Power Up special editions of the 996 3.4 were mentioned on page one, I didn't include their production run:

3.4
Carrera Cup (Germany) :: 30 units
Power Up Edition (Japan) :: 25 units
3.6
40 Jarhe (World wide) :: 1,963 units

X51 total take up of the cost option (ie not including spec eds) during 996 reign was circa 1% (or 1,500 units).
 
GT4 said:
X51 total take up of the cost option (ie not including spec eds) during 996 reign was circa 1% (or 1,500 units).

And I am glad to have one of them ☺
 
Some more X51 info:

X51%20Training%20guide_zpsweagpaxh.jpg


Edit, hmm rubbish quality when linked to here, not sure why. Heres a link to the full document: https://www.google.com/url?sa=t&rct...=XAp8rJk-5IzAWOYhObSopg&bvm=bv.83339334,d.aWw
 
Thanks for that extra information Stever - have sent you a PM on the planned 40th AE meet up later this month.
Cheers.Ian
 
Just wanted to say a massive thanks for posting this thread!

Has anyone dyno'd a x51 equipped motor? the outputs seem to vary significantly? I was under the impression that the output was political due to the GT3 not pushing much above the 3.6 x51 - but wasn't sure if this was a case of playing down the figure, or if it was physically strangled back - would like to know how that transfers onto the 3.4 too.

Also wondered if with the additional cooling and oil delivery - if IMS upgrades were still worthwhile?

So many questions, sorry :lol:
 
Red993C4 said:
GT4 said:
The GT3 3.6 (M96/76) and X51 PowerKit 3.4 M96/01S engines were both developed together, in case what became the actual GT3 3.6 (GT1 derived block) failed racing regulations and/or reliability requirements for a successful homologation.
For what it's worth, your source did not get his information absolutely right. Whilst the development of the GT3 engine and the X51 Powerkit may have overlapped chronologically, they were not developed "together", since the X51 kit was developed by the same series-production motor team which developed the M96/01 base engine, not in the Motorsport division.

Here is some related information of interest. This is from Porsche Panorama, the magazine of the Porsche Club of America, July 2015 issue, pp. 66-71, in an article entitled "Main Stay" by Kieron Fennelly. This is in interview about Horst Marchart, "the technical backbone who oversaw Porsche's transition to water-cooled sports cars--twice."

Interviewer: You are also associated with Herbert Ampferer and the so-called Mezger engine of the GT3. How did that come about?

Marchart: The M96 [996 engine] would support a lateral force of 0.8 g, which meant at least half of the clients using the 996 on the track wouldn't have a problem. But if you used slick tires, the fastest drivers could have oil starvation. We couldn't allow that--it was totally the wrong image of Porsche. So Ampferer designed the GT3 engine for the Cup series. The trouble was the number of cars we would have to make for homologation was not going to be enough to offset development costs. So we had the idea of using this engine as the basis for the 996 Turbo, which would be made in far greater numbers and bring down parts costs, making the GT3 affordable.
 
What a great thread; thank you GT4 and everyone who contributed.
 
Can anyone advise how a X51 equipped car can be identified please. What are the external signs (apart from exhaust which has been replaced with a custom made assembly).

Thanks
 
Gurmot said:
Can anyone advise how a X51 equipped car can be identified please. What are the external signs (apart from exhaust which has been replaced with a custom made assembly).

Thanks

There are no external signs, you can only tell by either looking on the code sticker or in the engine bay the sand cast alloy inlet manifolds give it away.
 
Gurmot said:
Can anyone advise how a X51 equipped car can be identified please. What are the external signs (apart from exhaust which has been replaced with a custom made assembly).

Thanks

The third centre rad would be a good indicator (assuming not a Tip and not retrofitted, and don't forget the Anni and X51 C4S won't get the end rad either).

If you could peer under the rear end, the manifold would give it away too (again, assumes a genuine one hasn't been molested, or a non-X51 hasn't retrofitted just the X51 manifolds).

If you went further, at a push you'd notice the dual chamber oil pump and extra oil return line (extra "towel-rail" here):

post-12347-1229782604.jpg


post-12347-1229782618.jpg


post-12347-1229782627.jpg
 
I guess it won't have X51 on the option sticker under the frunk and inside the service book? Or should it have that as well?
 

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