ritzblitz

The running lights look similar.

Dbltime

Those massive fender flares don't do much for her aerodynamics. Carrying more contact patch must offset the loss.
Where is the air jack wand connect fitting these days?

Carrera GT

A lot has changed over the years, but I believe it's still in the same spot, recessed behind the hood/bonnet in front of the windshield.

eg. from '08 car

Dbltime

The 996 cups had a hole in the hood with the connection sticking up. Guess I dated my racing experience.

GrantG

RSR's have used ITB's for years, but the roadcars haven't had ITB's since 1973. I would LOVE to see a return to ITB's for the street!!! Maybe this Limited Edition 4.0 GT3RS with >500hp will be the harbinger...

MJSpeed

Straightline speed is over-rated look at the F1 numbers. It's all about how fast you can can go through the twisty bits. There are a lot more corners than there are straights where aero would pay dividends.
One of the issues, is tuning the ITB's vs. one single MAF sensor.

Carrera GT

Water-cooled six-cylinder boxer engine, four-valve technology, dry-sump lubrication
Displacement: 3,996 ccm
Air restrictor: 2 x 28.6 mm
Intake manifold with individual throttle valves
Electronic engine management
Max. output: 331 kW (450 hp) at 7,800 rpm
Max. torque: 430 Nm at 7,250 rpm

I wonder what they put behind those "velocity stack" style intake trumpets? Presumably that's where they've compromised their intake design to accommodate the rules around the restrictor plates.

I imagine there's still some throttle response advantage in individual bodies, but surely all the tuning and balance advantages are long since removed by precision engineering and fuel metering. So I wonder if they have simply dual (left bank/right bank) butterflies behind those trumpets and tricks to preserve the charge density.

At 450hp, they're well within design, so I'm guessing they're actually more concerned about a) fuel efficiency (reduced pit stops) and b) drivability (handling control and tire wear.)

GrantG

That's one reason ITB's are superior (proper mixture of each cylinder). The BMW M5 and M6 have 10 ITB's...

Carrera GT

Street cars, these days, are built purely for cost-versus-emissions. No doubt all other concerns that might matter to the driver are secondary to running the business and tying off the red tape.

Carrera GT

Not all F1 drivers/engineers agree on turns versus straights. Hamilton f'rsintance drives the circuit according to the conditions, but tries to "minimize and shorten" the turns and get the car straight and full power as much as possible. This would be an atrocious "point and squirt" driving style that would see racers in street-car derived race cars at the back of the pack.

I imagine there's a continuous optimization cycle to adjust aerodynamics, drag, fuel consumption, braking, stability, susceptibility to upsets, drafting, tire wear, driver preferences for handling, balance, steering along with day to day and track to track variables like altitude or track surface or where to win or where to pass, where to defend, team orders (whoops) or all manner of the "craft."

As for a single MAF versus individual throttle bodies, I imagine there's all kinds of reliability concerns (more moving pieces is usually worth reducing to fewer moving pieces at almost any cost of compromise to achieve reliability using the principle of "to finish first, first you have to finish.") Given the MAF is an average of air flow and yet each cylinder has to receive the right fuel metering much faster than the complete replacement of air in the airbox or plenum, then the MAF is as timely to the fuel injector as the post race TV interview of the driver is to the race strategy on the day of the race ... : )

I don't pretend to know that much about engine design, but I imagine the MAF has evolved over the years as a combination of cost-effective technology offered by the OEMs for automotive applications. The car makers need a known quantity solution to long term fuel map trends to work with the long term (in engine rpm terms) performance of the exhaust system (cats) for confidence in meeting emissions regulations.

As for what the buyer might desire aside from engine characteristics (throttle response, power and torque curves) ... it seems that Porsche doesn't pay too much attention to exhaust music or engine bay appearance. Literally ever since the MFI days, the engine bay has deteriorated with every new model. Sure, they tart up the Power Kit, the air box or put a little faux metal strip here and there, but again, if Porsche offered a option called PEG 'porsche engine gorgeous' for $5K and it resulted in the alternator disappearing elsewhere (say the nose of the transaxle) and the intake plenum transforming into separate throttle bodies with gorgeous velocity stacks and all the cheesy plastic bits and cheap metal clamps disappearing (like a hot rod engine) then I'd have to admit to the vanity/madness of checking that box ... : )

GrantG

I'm fairly certain that those trumpets house the air restrictors and that there are actually 6 separate throttle butterflies just above the cylinder heads.

CRex

Can anyone pls enlighten me on the benefits of individual throttle butterflies? You see those in more "affordable" performance cars such as the M3, yet you don't see them in any of the street cars in the Porsche lineup...

GrantG

Biggest difference is throttle response (much sharper with ITB's) and you can make more horsepower too.

MJSpeed

If you look at the trap speeds for F1 cars, the teams at the back of the grid are usually the fastest in a straight line. Which is an attempt at trying to make up some time/speed lost through the corners. Those that can go faster through the corners will usually be fastest so as long as they don't get behind one of the "fast-in-a-straight-line" cars, especially at Abu Dhabi, just ask Alonso or Hamilton as neither could go around the Renaults.
Here are the Quali Trap Speeds for Abu Dhabi:

Qualifying Session Speed Trap
POS NO DRIVER__________ KPH
1 17 J. ALGUERSUARI _______317.6
2 16 S. BUEMI _____________317.4
3 12 V. PETROV ____________316.2
4 14 A. SUTIL ______________315.0
5 23 K. KOBAYASHI _________315.0
6 21 B. SENNA_____________ 314.8
7 3 M. SCHUMACHER ________314.7
8 15 V. LIUZZI _____________314.6
9 4 N. ROSBERG____________314.4
10 22 N. HEIDFELD _________313.9
11 7 F. MASSA_____________ 313.2
12 9 R. BARRICHELLO _______313.0
13 8 F. ALONSO ____________312.9
14 2 L. HAMILTON __________312.6
15 1 J. BUTTON ____________312.6
16 18 J. TRULLI ____________312.5
17 11 R. KUBICA____________312.4
18 10 N. HULKENBERG _______312.4
19 19 H. KOVALAINEN _______311.8
20 20 C. KLIEN _____________311.7
21 6 M. WEBBER____________ 311.5
22 5 S. VETTEL _____________309.7
23 24 T. GLOCK _____________308.5
24 25 L. DI GRASSI__________ 308.1
Yes and yes, however tuning ITB's can be cumbersome and one draw back as far as manufacturers are concerned, is fuel consumption.

But there's no doubt about ITB's being better on performance than a single MAF sensor.

Carrera GT

Perhaps my math might be a little stronger than my knowledge of F1. Those numbers are a random distribution. It would be "unscientific" to say the least, to put any meaning into peak trap speed and qualifying position -- beyond the empirical "fastest ain't first."

In any case, as the saying goes, the great drivers ask not for more power, but for more performance; though, all else being equal, none of them would refuse a few extra neddies.