Porsche 3.8L 997 S X51 Upgrade kit = $538/hp

I was browsing Suncoast Porsche's parts specials the other day [this blog post was originally published 8/2/2012 --cm] and saw this piece of eye-candy.

Eye candy, yes. It is Porsche's 3.8 Liter M97 "Metzger" engine. A jewel of a motor, improved over the M96 which had inital problems with intermediate shaft wear and seal designs. Fixed during evolution, as is Porsche's time-proven method, the standard 3.8L produces 355HP and 295ft.lb torque. Which is nearly 93.5 HP/Liter, a very high specific output for a normially aspirated engine. 

 But there's a more to this truffle than meets the eye. For this represents the X51 "kit", an upgrade option to the standard beast of an engine. Usually this is a checkbox option when you order a new Porsche--if you know about these sorts of "X" options, and if your wallet can stand being lightened another ten and a half grand for that tiny little "X". 

 Well, this isn't about the option code you get on your in-trunk sticker. It's what you see and don't see in the picture above that makes the X51 option actually much more like the rocket plane monniker than it sounds. In the picture above, you can see the carbon-fiber air cleaner. This covers larger air intakes, a seven percent increase in cross-section area on the throttle bodies and intake manifolds. Remember that number. There are also two new sport exhausts that flow free-er and with a concordant deeper tone. Connecting those two ends are some pieces in the inside of the engine. Starting with enlarged intake ports in the heads, to match the larger manifolds. The engine has to be able to get the more air which is now available into the head efficiently, so different camshafts are used with a profile matched to the intakes (seeing a theme here?) following that are larger exhaust ports, naturally, and matched larger headers feeding those new mufflers. 

End-to-end, what Porsche has done with the X51 is to add more air, in and out, and more air=more power. How much more power? The 355 HP goes to 381. That's, let's see, 26 more HP. I can hear you now, "Waitaminnit! Didn't he say above something about $10 grand?" I did, and more on that below. But let's stay focused on all that engineering goodness. You see, that rise is one of 7%. Hmmm. Exactly the size of the increase in the cross-section of the throttle bodies. Big deal? Well, yeah, it kinda is. Because that means that the actual efficiency of the engine--if we're to believe Porsche's published numbers--was increased to the theoretic limits allowed by the change. Which is very cool. To be sure, there's a DME (computer) change that goes along with, which must in order to balance the fuel to that greater airflow. Porsche could have (as many aftermarket "tuners" do) rebalanced that map to offer even a little more power, but guess what? With what they did, they don't have to change the EPA sticker on the car. Yep. It gets the same gas mileage for that extra 26hp. It's more efficient, you see. Free power.

 
Well, not totally free, of course. Because what the "more air" buys you, really, is the ability to rev the same pistons higher before that air just won't move any faster. The redline moves from the stock 3.8L engine at 7200 rpm to 7400 rpm. And at 7200 rpm is where the "HP Meter" moves from 355 to 381. Peaked at peak RPM, which is good, but makes you go "hmm". Because I know my own 3.8L Porsche Carrera S engine has spent only mere seconds of its long life at 7200 rpm. I bounced it off the rev limiter a couple of times when I first got it, and then have only been "there" a couple of times since, on purpose. Because you know that a candle that burns twice as fast, only burns half as long. 

 With engine internals, the ratio of running at higher revs to taking life out of your engine is nowhere near 1:1, it's like putting your finger down on the fast forward button of your engine's longevity when you get above 6500 rpm or so.  However, he additional torques from 3600 to 6300 rpm, which is much more frequented territory, is probably very, very tasty.

And of course it isn't anywhere near free in the actual, pull out your wallet sense either. You see, this is a "kit", as sold (in 2012) by the SunsetCoast Porsche People. The kit is usually $16,073 when you buy it standalone, not attached to a car build sheet order. Gulp. But here, today, you can get it for a mere...$6995.00 Hey! That's a bona-fide discount bargain, right? Wow! 

Okay, but that's not the whole story, you see. The base kit is $7k. But that doesn't include the sport mufflers, because you could have ordered those separately (for the sound, and maybe 1-2hp more power--not worth Porsche talking about). So if you need those, that's another $2000 But it comes with a cool profiling switch where you can open those cans up with a button on your dash when you roll into the show-n-shine. Or just $1500 more if you can do without that button, but really, how could you resist that?

 
So $9k in parts and you're still ahead for the upgrade, right? Well, no. Because that's just the parts, and as beautiful as they are, they come in boxes, not already on the engine (not included) as in the picture. No, you have to have a Porsche mechanic install the parts. Okay; technically, you could do this yourself. Maybe there's a You Tube video on how to do it yourself. But you probably don't want to do this as the cost of a newbie mistake could be very, very high. Suncoast & Porsche advise that this is a 50 hour job. With Porsche shop rates at $100 per, that's a cool $5k and you can see why, at $14,000 for this upgrade that had you bought it at the outset you would have paid less, your Certificate of Authenticity would reflect the option, and you could have financed your lust for power over your 36/48/60/72/84 months.

 
Moreover, at this price, you have to ask yourself, is it really worth it? What's the bang for the buck here? Well, it is precicely $538 for each bang, er, HP achieved. Yes. For $538 HP you get exactly one additional HP out of your engine, and you get that 25 more times, cash on the barrelhead. Or Visa, whatever. That's a lot of scratch. But you have to understand that this was adding to an engine which was already extremely well engineered in the first place--there wasn't a lot on the table. In fact, I would wager that it is pretty much 26hp before you have to crack open the bottom end and start throwing titanium pieces and cubic yards of dollars at the engine. Is that possible? Why, yes, it is, as the magnificent Porsche GT3-RS 3.8L shows us. Same motor, same volume, different internal bits, higher redline sum to more power. And cubic yards of money.

 
So we don't end on what appears to be a sour note let's think some more about what the upgrade gets you. By the way, the above isn't sour, really. As the man says, "You can have fast, durable and cheap. Pick two." Divide both sides by "cheap" in this instance and you can see the Porsche math in this equation. But I digress. What the upgrade gets you, with your 381hp, is entry into a very rarefied club. This is the 100hp/L club of engines. For street cars there are the aforementioned even more expensive versions of this Metzger engine, other, newer Porsche "M91" post-Metzger engines currently coming out of Stuttgart for the current crop of "R" cars which also have this feature. Casting about the web (2012), I find a very short list:

• Honda S2000 (F20C engine) = 2.0L, 240hp (very, very impressive)
• BMW M3 (E36) = 4.0L v8, 404hp
• Lotus Elise tuned Toyota 1.8L = 190hp
• Ferrari V8 (Italia) 4.5L = 452hp

There may be a few others, but you can see what kind of list this is. Oh, and of course there are manufacturers that take others' engines (like Lotus with Toyota) and pump them up before putting them in their own cars, but I suspect the EPA cycle isn't the same, to say nothing of longevity.