First of all, a shout out to Mike Brown & crew at FFTEC in Hayward, CA. A dyno day had been arranged (unfortunately the arranger was summoned out of country on business at the last minute) and there were Porsches galore -- at least eight by my count. (They were coming in and out, hard to get a precise figure.) Not to mention several Nissan GT-Rs.

My wife's car is a 2011 Carrera S cab rated at 385 horsepower and 310 ft. lbs. of torque at the crank. Power to the wheels is a different story, of course; the gurus at FFTEC said to expect about an 18-20% loss. That would translate to about 316-324 HP and 248-254 ft. lbs., respectively, actually to the wheels.

Well ... disappointingly, my wife's car posted a measured figure of 294 HP (I couldn't make out torque #s; the shop will send a follow-on e-mail with the complete report). That's about 22-30 less than what would be expected, which I believe is a fairly significant number. My wife says she noticed a loss of power beginning about 4-6 weeks ago.

The car has just under 29K miles and is due for its 30K mile service in a week or two; I can't believe that a regular maintenance item such as aged oil or a dirty air filter could be the culprit. The car was purchased last December from a dealer as a CPO with 19K miles and I can't imagine they didn't service it properly prior to sale. We of course will inform the service rep of the issue -- any suggestions as to what they might look for? Fouled plugs (unlikely)? Ignition timing off? Exhaust restricted somehow?

Any suggestions or thoughts would be eagerly welcomed. Thanks!

 

If the power is, indeed, down my guess would be a dirty air filter. I could also be a high pressure fuel pump issue or injectors. My 2008 BMW 535 with DFI had chronic issues with the fuel pump and injectors. The service schedule does not call for a new air filter at 20K miles, I believe. You should check your owner's manual for that info. I doubt it is the plugs.

 

Just to clarify, this was a Mustang vs. Dynojet dyno. Further research showed that, evidently due to differences in the machinery, the Mustang will measure 8-12% lower than the Dynojet. (Highly technical explanation here:

http://imageftp.dynojet.com/CMD/Trut...Runs_Final.pdf

So it appears the car may be closer to spec than it initially appeared.

(Tip for Carrera S owners: Optimal shift point for HP and torque appears to be 6400 RPM. Max torque with not-quite-max HP, closer to 5400 RPM.)

 

What your Wife's car made is what I'd expect from that engine, if the dyno is a dynojet..

I've never had one of those vehicles break 300WHP stock on my dynojet, and I have tested dozens upon dozens of them during our procedures. Every car that comes to my shop goes on the dyno.

Your power is right where it should be. Remember, the factory rated these engines in DIN, not SAE power, thats automatically a 3% delta just between the formulas.

 

When i still cared to measure this stuff, after all mods my car pulled 289hp on a mustang dyno, top hp at 6835rpm, top torque 254 ftlb at 4400rpm. Before all tunaps and cleanups it had pulled 268hp. I still do not know if 289 was a fluke as other time car pulled 283hp twice, only first pull showed 289. It is a stock 3.6l m97 motor running on softronic ecu tune with 200 cell xpipe cats and ipd plenum and some other minor things altered.
I understand most 997.2 owners would want to beleive those cars are more powerful than old 997.1, but in a practical reality cars that pull away from me on a track are gt3 rs when they hit upper rev section and gts cars. Regular 997.2 and 997.1 S cars do not really go anywhere much. Real life difference exists but it is not nearly as big as nmbers in sales prospects may make one believe. So i am not surprised much to see those dyno readings, i would say they sort of match my own observations.

 

Thanks Jake. If you'd looked at my post 5 hours earlier than yours you'd see it was indeed a Mustang dyno. Appreciate your feedback.