Alan C.

The head work does get pricey. I had the heads of my 93 RSA ported, flowed and polished while I was rebuilding the engine. I believe the head work was around $1500 in '97'.

cibergypsy

Fellows, reading from an article from Excellence Magazine about the Club Coupé (quoted on that link in your post) and reading from a web page doesn't necessarily make the information correct, even if that page is from a source which is a presumed authority on the matter. I have that issue of Excellence at home and that is the first thing I noticed back then; that they were wrong in their description of what comes with the kit. The different camshafts are for the 996 models, but I understand why the confusion arises, as there is conflicting information out there regarding the 997 version of the Powerkit.

Do either of you have this kit on your cars? Do either of you have carried out the conversion on your cars? Well, I have and speak from first hand experience and facts.

If one goes to Suncoast's website and clicks on the Powerkit link for the 2005-08 Carrera S, under performance on the engine section, one will see a paragraph talking about race tuned camshafts yet, immediately below, there is the following list:

Kit consists of
- Cylinder heads with flow-optimized intake and exhaust ports
- Intake Manifold & Throttle Body - Increases inlet size from 76 mm to 82 mm
- X51 Headers - larger cross-section and optimized flow behavior
- Carbon Fiber Airbox with two intake channels
- Modified maps for the DME control unit
- Sport Exhaust with Chrome Tips
- Third Radiator Kit (for manual transmission cars)
- Increased Engine Speed

The omission of those "race tuned" camshafts is very obvious. That is why I understand forum members' confusion since in the same page one sees conflicting information. Nevertheless, I had it done on my car in 2006 and can tell you there aren't any different camshafts on the 997 version.

To further illustrate these discrepancies, on the new car brochure "The 911 Carrera and Carrera S" issued in late 2005 to 2006, page 55, 1st paragraph it reads - and I quote - "The Carrera S Powerkit unleashes higher thresholds of performance by using a modified cylinder-head geometry to optimize gas flow on both the inlet and exhaust. Other key features include an aluminum intake manifold, revised exhaust manifolds with larger bores, and an upgrade to the Carrera S engine management system." There is NO mention of camshafts in this source.

I can understand the reasons why you might think otherwise but to assert and affirm that I am wrong and you must be correct, when all your knowledge of the 997 X51 version may not come from 1st hand experience - as in my case - is a bit bold, isn't it? So, which publication is correct? Excellence magazine, web page, Suncoast's website with differing info on the very same page, the new car brochure given to prospective Porsche buyers? Obviously, all cannot be simultaneously correct, so let's go to another source which is layed out on the next paragraph.

I had the kit retrofitted by my local Porsche dealer in 2006. I saw all the parts that came in the shipment - and have a copy of all the parts list - PLUS I also have the complete Porsche Technical Information pamphlet used by the dealer with title "Performance Increase Kit Installation Instructions (I No. X51)" at hand ever since I had this done. There are NO different camshafts on the 997 version. This publication has the numbers 911 (997) 7/05 ENU 1001 on the top right corner, in case this helps you sourcing this material. I have all the invoices from my dealer with everything purchased and I cross-referenced with the Installation Instructions back then to make sure I got everything that needed to be included and not leave anything, as important as different camshafts, out.

Some of the gains are also gained by increased engine rpm, by the way. Did you take that into consideration when saying that there is no way for that power and torque without having different camshafts?

cibergypsy

[quote=Tbred911;9308535]Web page is wrong, refer to my post immediately above for explanation.

cibergypsy

Information from Excellence Magazine is wrong. Why did they make such a mistake? Probably (not affirming this is the case) they used information that was readily available but incorrect nevertheless. The kit for the 997 does NOT have different camshafts. I have detailed info on what comes with it, as I had it retrofitted on my car. Refer to my post above regarding this for explanation.

alexb76

Now, could it be, that the X51 at car build stage HAD camshaft upgarde, while X51 upgrade kit, sold after, does not?!

Tbred911

the inreased RPM doesn't account for anything... it's the torque under the curve that isimpressive for a real x51 kit..


OMG ... they forgot to put cams in your car...!!

hope you got a discount...

RadiusTim

Joking and banter aside, Cibergipsy is telling the truth: the 997.1 X51 option uses the same camshafts as the standard 997.1 M97 engine. This applies regardless of whether the option was retro-fitted or was part of the original factory build.

This is neither a guess, nor wishful thinking - if you don't believe it, just read Porsche's own published technical documentation on the 997.1 X51 option, TSB 1001 7/05, which can be downloaded from renntech.org here.

Cheers

cibergypsy

If I remember correctly, increased engine rpm makes it possible for an atmospheric engine to produce more power. Can someone with mechanical engineering knowledge verify if I am right or wrong? After all, I am just an electrical engineer, not mechanical.

When one doesn't want to see the truth, no matter how clearly it is staring at oneself, then there's no convincing anyone can do. It becomes a "you say, I say" kind of thing. Pointless.

I know I am correct in my assertions based on real life experience and the evidence I have to the fact.

Tbred911

hey no worries I believe you! pdf would be interesting read thx

cibergypsy

I myself went through the same thought process when I bought it and asked these questions, for there was information out there that cited with or without cams. I understand your reasons to think this way.

The Technical Information mentioned in post #37 by RadiusTim is exactly the same that I have and was given to me by my dealer.

Bob Rouleau

Horsepower is directly related to RPM, all else being equal, higher revs means more power. Thanks to cybergypsy for the factual info on the power kit.

Regards,

USMC_DS1

I would like to see the pdf... since there is no cam replacement this may be a doable DIY project for me and makes it more interesting to do.

911SLOW

No camshafts for the 997 X51.

In fact, the camshafts used are the same ones used in the M97.21 engined Boxster and Cayman S.

Tbred911

Not necessarily... it's how you tune for it..... the 996 made it's fastest lap times with short shifting @ 6,500 rpm not 7,400... so even though the revs were there the tuning and the parts for getting the horsepower were not...

in any case I have 996 3.4 and am thinking about a camshaft upgrade and I'm surprised to hear the 3.8x51 doesn't have cams... looks like new cylinder heads to raise compression (thereby naturally raising horsepower) and bigger throttle bodies + associated parts and tune are all that is needed for what looks on a paper to be a great upgrade!! (for the 3.8 that is... )

cibergypsy

RadiusTim and 911SLOW: Finally, someone else besides me steps in and confirms what I've tried to assert! Thanks! Speaking for myself, I try to never state something or contradict someone unless I'm as certain as possible that my statements are accurate.