RollingArt

When I went digging and found that article I was actually looking for info to back up your claim that cams are NOT included in the x51 kit. That has previously always been my understanding. I was surprised to see the article say "different cams". My understanding was the heads had porting work and maybe a different spring on the exhaust valve?

I believe now the article is in error. If cams WERE included I'd expect bigger gains than 26 hp.

911SLOW

I know from first hand that in Excellence they try to double checks their articles and data, and 99% of times they are spot on.

I also know for a fact that Porsche's technical literature, especially the early promo material, has a lot of mistakes, technical and from weak translation. Most of them are rectified in the updated WM and PIWIS.
If Excellence posted about camshafts, at that time they had an official document or an interview to back it up.

Tbred911

guys... lets forget about the HP gain and talk about the torque gained under the curve above stock curve... that's what is important here... the graph that cibergypsy posted shows us that the x51 kit would be a phenomenal track mod as well as providing a small bump in torque in the 2,000 rpm range... hp means nothing without a torque curve spanning rpm...

adding cams to the 3.8 x51 would give you GT3 "type" power and torque !!!

mobonic

For the cost of this "kit" you can have your 3.8 engine rebuilt and fully blueprinted to make even more power than the X51. You can even get it bored to 4.0L and get even more torque, but then be prepared to cough up close to $20k.

cibergypsy

I'm thinking that I will be keeping this car for a very long time... long enough to at some point need a rebuild due to it just wearing out (hopefully a very long time from now).

I wonder then, since I already have the kit on my car, taking it as a basis for a rebuild and even a displacement increase to 4L, what kind of gains may it obtain as compared to the same kind of rebuild on a standard motor? Or will such a rebuild and displacement increase render the gains from the kit null?

Can anyone shed some light into this? Thanks!

RollingArt

Adding 200cc is a 5% increase in displacement. You should see a 5% increase in hp from whatever you're currently getting from your x51. 381hp? Should see approx. 400+ hp..

So yes, the x51 bits are still adding their share of hp to a displacement boost.




Phil

betonred

reviving an old thread - but this is why i love rennlist -

i am in the process of having my engine rebuilt, i was extremely curious about the x51 package

i also was confused how the porsche parts catalog did not list the x51 cams only x51 cylinder heads.

well the answer is as others have stated, the 997 x51 powerkit did not compromise of upgraded cams.

personally speaking i decided its just not worth it for the $.. below is pricing just for the heads less the intake, airbox, revised ecu tuning and throttle body

OEM Catalog
CYLINDER HEAD $ $3,862.17 $0.00 $3,862.17
OEM Catalog
CYLINDER HEAD $$3,862.17 $0.00 $3,862.17

Sub Total: $7,724.34

i am going to drop some weight out of the car! at least that is close to being free