Courtesy of Flash from the Rennteam board:
Got my car back at lunchtime today. First the bad news... there's a Porsche instruction sheet provided with the kit, and it instructs you not to exceed 5000rpm for the first 300 miles. Therefore all I can tell you thus far is restrcited to sub 5000 revs, and I have yet to experience the extra 25 horsepower.
But read on...
I was expecting a barely discernable difference. Wondered if after a week in a courtesy Cayenne whether I'd be able to detect anything. WRONG. Immediately on pulling away from the forecourt the extra torque was obvious. Don't be embaressed if you've ever stalled a 997S, reckon I managed this at least twice a month, of not more often. Well it's the car's fault! The X51 adds LOTS more bottom end torque. The car pulls away cleanly without any clutch from tickover. The only thing harder to stall would come with an automatic gearbox. Sorted!
Out on the open road the kit was a total revelation. There are masses more midrange torque. Previously i found that the 997 only really delivered useful overtaking urge above 5000rpm. Mid-range in gear overtakes were sluggish for a car of this power, and lesser vehicles could prove difficult to catch without dropping down a cog. Not so any more! The car now pulls cleanly from 2000rpm. Yes TWO THOUSAND RPM! There is a VERY noticable step in power at 3000RPM and for the first time you feel yourself being pushed back into the seat like a turbo would. Then at 4000RPM there is an even more noticable step and now you're reall starting to fly. Then just as it touches 5000RPM you hear the beginnings of something more vocal... to be continued...
I already had the PSE fitted, and agree that it does get louder after 6000 miles. The new induction kit seems to add a noticably harder edged sound.
Based on my experience so far, if all the kit did was deliver extra torque, and no extra power then it would STILL be worth it. That feeling of being pushed back into the seat from 3000rpm is addictive. Where the midrange used to be weak, it's now reminisent of a turbo charged car. Anything without a turbocharger would struggle to live with the new midrange urge. I reckon it's midrange is as strong as my TVR Tuscan S was.
Everyone knows that the 996 was a great car, but people here will doubtless remember the shock the first time they experienced the 997, the thought of "WOW this is REALLY sorted". Well the X51 kit delivers something akin to that. It takes an already great car and makes it noticably faster. Going through my head was "WOW this has REALLY sorted out that engine".
The retro fit cost me £10,202.31. And I already had the PSE. Now it's possible to get a GT3 for that kind of spend... but my car is a C4S. So if you want the fastest and best 4WD NON-turbo car that Porsche currently makes, then this kit does fill a niche. IMO the Turbo has too much torque, enough to get it's chasis in a twist. After the X51 my C4S feels absolutely bang on. The perfect balance.
So to me the kit was worth every penny. i would not consider ordering a C4S without one. It would be really interesting to compare the midrange urge of a GT3 to the X51.
The 0-60, 0-100, and top speed figures do not tell the whole story. I would like to see some in gear 30-50, 40-60, 50-70, 60-80 etc times. And perhaps a G-meter to record the difference in accelerative forces through the midrange.
I should have completed the 300 mile running in period by Wednesday. Will report back then as to what happens above 5000rpm.
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