Just curious... if anyone's done an X51 Dyno before/after?

 

Would love to see that also.

 

Are you referring to X51 headers, X51 intake, X51 manifold or a complete X51 conversion?

Jason

 

I meant if there's any dyno before/after for any of the components... obviously the full package adds almost 30 HPs!

Mostly I am interested in the headers, then intake as those are the easiest ones to install. I have yet to see anyone do a proper before/after dyno, while there are a lot of headers or intakes installed!

 

I would also like to see something other than the manufactures claims.

 

Someone awhile back posted on a dynotest of his stock 997.1S with X51 and I believe it did close to 340rwhp, he then added 200cpi AWE cats and it made over 360rwhp. Sorry these numbers are off of the top of my head.

 

360 rear wheel horsepower for a 997.1S with headers and catalytics is totally unrealistic. Given a power train loss factor of around 15%, 360 rwhp/(1-.15)=420+ at the crankshaft. With headers only, 340 rwhp corresponds to about 400 horsepower at the crank. Not believable. We wish you were correct.

 

I think the 360 number is a factory x51 engine with 200cell cats.

 

I'm just the messenger reporting what was said, I remember everyone then thought the numbers were a tad optimistic. I've seen non X51 997.1S dyno 325rwhp with full exhaust, another 30+ for X51 package..maybe not that far off.

Dave

 

would love to know if there is any truth to these claims...

I just purchased a 997 s X51 and was wondering if adding sport cats (fabspeed or AWE) would add power? and noticeable?

 

It will, it added power to my non X51 997.1S, in fact the only mod I did that I felt was the cats.

Dave

 

lots written here on sport cats. consensus is that it's among the best mods you can do on a 997, given that the OEM cats are so restrictive (600 cell). i think the mod makes sense for you since you already have the improved airflow from the x51 -- the sport cats would open it up even further, removing a bottleneck. expect low teens hp for the sport cats, mostly in the upper rev range. is that noticeable? depends on how you drive and your sensitivity. imho, for $1600ish, i can't say it's worth it, unless improving sound is also a consideration (which it was for me)... the sport cats exhaust note will be noticeably louder (in a GREAT way)! i do my weekend drives in north jersey so if u ever want to check out mine, pm me.

 

I dynoed 321 to the wheels on a stock 997.1 I also dynoed on two separate dynoes with the same results

 

whats the deal with the ipd plenum ? Is it worth it.......... on the new DFI's 997.2 ?

 

oh man... that is a passionate source of debate here (as a search will reveal). after doing all the mods on my signature, most of them at the same time, (including the plenum), i can say the car is a bit quicker in the mid and upper rev ranges, but not dramatically so. the big difference is in sound, which i think is fantastic under my setup. so i stick by my humble view that non-FI mods are probably not worth it unless 1) shaving a couple seconds off your track time is worth the $$ or 2) you're seeking better sound too, which these mods will deliver in spades (though less so the plenum than the other parts).