I will believe it when I see hard, cold, unbiased dynos comparing before and after under the same conditions on the same dyno. Until then, I will believe Porsche and Ruf, both of whom seem to be rather conservative.

 

Not to be a mag racer, but I figure this info would give us meaningful discussion...

Here's some data and links:
Comparing to the 997 Carrera S w/ x-51 vs (Carrera S)
-Boxer/6 (same)
-3824 ccm (same)
-381 hp/7200 rpm (355 hp/6600 rpm)
-415 Nm/5500 rpm (400 Nm/4600 rpm)
-1478 kg (1469 kg)
-Suspension: Sport (PASM)

-Top speed: 300 kph (293 kph)
-0-80 kph: 3,3 s (3,5 s)
-0-100 kph: 4,4 s (4,7 s)
-0-120 kph: 6,1 s (6,5 s)
-0-160 kph: 9,8 s (10,6 s)
-0-180 kph: 12,3 s (13,2 s)
-0-200 kph: 15,0 s (16,5 s)

-60-100 kph in 4th: 4,9 s (5,2 s)
-80-120 kph in 5th/6th: 6,0 s/8,1 s (6,3 s/8,9 s)

-100-0 kph (warm): 36 metres (35 metres)

-18 m slalom: 68,6 kph (67,9 kph)

http://www.germancarzone.com/997/156...e-figures.html

Ruf R Kompressor data:
0-100 km/h 4,1 s
0-160 km/h 8,7 s
0-200 km/h 13,0 s
0-250 km/h 23,0 s

Qrtr mile
0-402,34 m 12,2 s

http://www.autobild.de/test/neuwagen...rtikel_seite=2
From our very own on 6speed: https://www.6speedonline.com/forums/...ad.php?t=49537

Then, there is the magazine article from GT Porsche showing that the x-51 beat the GT3 in 0-60 mph due to its shorter gearing!!! No link to article, but discussion here:
https://www.6speedonline.com/forums/...ad.php?t=95527

 

If you have the money and want the X51 get it...I would if I wanted it. Another way to think of it is for just pure street use you might not need it, for the track it could be useful.

Any data on what these type of factory mods do for resale?

 

I know that I love mine for all the reasons noted by the others above, and the Club Coupe pricing mitigated the cost. Hey, plenty of guys spend $16,000 for options that don't have any performance gains, so at least X51 puts the money where it belongs. I will warn you to never drive an X51, because you may find it difficult to live without one.

 

TD: I'm a newbie to the site. Do you think that the X51 is underrated in terms of hp? Is that 25 hp at the wheels? Any opinon? I'm struggling with the decision and thinkin go going for muffler bypass pipes for simplicity and weight savings.

thanks,

997c4s

 

I don't get why the kit is so expensive. If I can buy the airbox for about $1000 and the headers for $500 and the extra radiator for $200. The only thing missing are the cylinder heads and the labor. So what do the cylinder heads cost? $6000. I am thinking of doing the aibox and headers. Anyone do this. How hard to cut the sheet metal in the right spot?

 

Neil there is a template out there that is included with the TSB for the retrofit X51 install for cutting out the sheet metal. The plastic piece above this you can see the outline where the other snorkel will go. I agree with you I don't get why the kit is so expensive. One thing you have to consider as well is the kit includes the PSE which by itself is quite expensive. The X51 "lite" kit has been done by a few people already I saw on Renntech and such with good results. The kept the stock heads but used all the intake pieces.

Neil I can forward you an email showing this kit being installed if you like.

Dave

 

That would be great Dave, Thanks. Do you need my email? Are you gonna do the airbox yourself?
I was on renntech and searched "x51" and read all the material. As far as the pse is concerned, I thought that does not add any hp. I would leave my exhaust stock as I like the sound as is. (although I know the headers will change it slightly)

neil.schneider@comcast.net

 

I honestly have no idea. I have not dyno'd the car myself, and I am highly skeptical of guessed numbers from butt dyno session. I do know that the difference between the acceleration and torque of the 997SX51 and my previous '02 996 is incredible.

Some of my buddies have speculated that the 996 GT3 was underestimated a little, but that the 997 GT3 is much closer to accurate, which means that the two cars are probably pretty close in terms of HP. I imagine that the X51 kit is a little below the 996 GT3 in terms of HP. Again, though, this is pure speculation on my part based upon hearing discussions of my friends.

I can say that it is a lot of fun!

 

Neil I sent the emails...in the emails the guy who owned the car didn't change the heads, but he did change the intake manifolds which you don't have to do. You are correct that Porsche claims no hp increase with the PSE and state in the X51 retrofit TSB that the kit w/o the PSE still makes 381hp.

Dave

 

I had tracked both my ex-997S (with PCCB) and current club coupe (X51 with standard brakes) and concluded that the X51 accelerates slightly better from about 4000rpm onward, but the difference is small. If I have to re-spec. another car then I'll probably put my money on PCCB instead of X51. However the uniqueness of the club coupe is hard to resist, and X51 in it is just a bonus to me. I agree that a regular 997 C2 is enough car for most of us.

 

Dave,

Can you sen me an email showing how to install also?

frankfoss98@hotmail.com

Thanks!!!

 

He only has some pics. He did not do it yet.

 

Ok, can someone who have done this change have a DIY?

 

Anyone have a price breakdown of all the components of the X51 should we choose to DIY it?