At this point in time I'd have to agree it's best to add the money one would spend on the 997.1 X51 retrofit kit to the sales price on your car and buy a 997.2 Carrera S.

The best option is to try to buy a car with the X51 already on it, like mine, as it would be less than a new Carrera S anyways with less of a depreciation hit. This is my very well informed opinion for, whereas I love the X51 in my car and I paid about $13,500 for the whole kit including labor, at this point in Sept. 2009 it would make more sense to add the more than $15000 most users of this forum would pay for it on top of what they can sell their car for and get a 2009 Carrera S.

 

You are right..but what about those who already own.

 

I think his suggestion is to sell the car and apply the sale price plus $15k cost of X51 conversion to buy a 997.2 S.

 

That is exactly what I was suggesting. I already own the complete X51 Powerkit on my '06. I am sticking with my car because I cannot justify selling it for the very, very low amount being paid for used Porsches nowadays after what paid for it.

 

Hi there

Sorry to dig up an old thread but I have a 997.1C2S and have the following X51 parts:-
X51 exhaust manifolds
X51 centre radiator kit
X51 under tray


Now can I just add the X51 throttle body and X51 plenum?
Or will the throttle body only fit if I also get the air intake manifolds?

 

You need to change the complete intake from the heads to the airbox.

Another option I heard RSS will modify one of their plenums to fit the x-51 Throttle body.

You would still need the x-51 airbox and need to cut a hole in your engine cover for the other air inlet.

 

I don't want the X51 airbox though.

My plan is to stick with stock airbox and I was hoping to changing just the throttle body and plenum.

Is this not possible and if not how come?

 

I am not sure if the stock airbox can accomodate the X51 throttle body, maybe by changing the distributor pipe since the X51 throttle body has a bigger diameter. However, i do know that you will need to get it recoded because more air is going in and that would cause the MAF to give a red light. The computer needs to know know that more air is going in now.

 

Speaking to Porsche the remapping is not necessary but recommended to gain the full benefits, but there would be no red lights or poor running as the DME has so many sensors all over the car it can re-learn or you can just force it to re-learn.

What is the actual size of the stock throttle body and the X51 throttle body?

 

Not possible because they are different sizes. You cannot use the Stock air box with the X-51 TB. But with adapter rings you can use the x-51 air box with the stock TB. I don't remember the exact measurement but the x-51 is 6-10mm larger in diameter.

 

Another thought, if I got X51 intake manifolds, x51 plenum and x51 throttle body along with a custom hose to go between my stock air box and the x51 tb would it then be possible?

 

I would do this too if I wanted more power from a 997.1