Mike Murphy

Yes, I see your point and agree with you on the level that you are arguing. In fact, one great way to reduce your MPG is to drop weight. I think this might be one good reason why the new 'Vette has such great highway mileage, even though it can produce 500HP.

I think Porsche's argument might make sense if they are assuming that the 3200# GT2 will go from 0 to 100 mph quicker than the 3500# Turbo, thereby reducing the time the 530HP engine must produce work by consuming massive quantities of air and fuel. So with less time to move less weight, I can see a potential gain in MPG.

allegretto

I see you have not been properly indoctrinated...

Where are you papers?

You have relatives near Stuttgart, no?

allegretto

Actually in the Z 06 fifth and sixth are overdrives, this helps a lot! But mass doesn't hurt.

In truth it is kind of a comical claim that at full-throttle a car gets X% better milage. Like that's a concern at WOT?

So let's see...maybe one gets 4 MPG and the other 4.6MPG? Not the stuff of "Revolutions" exactly.

jimhuber

Well, like not having a 4WD system.

Jim Huber

Mike Murphy

Yes, I agree, it is fairly comical

Mike Murphy

I would say that this has to be "it."

Mike Murphy

Well, the idea of the intercooler is to cool the hot air caused by the compression of the turbo. So a more efficient intercooler should cool the air more, causing it to become more dense, which means that you have to add more fuel to the incoming intake charge, which produces more power.

So a more efficient turbo/intercooler would actually cause fuel efficiency to go down.

OldGuy

Murphy I agree with the intercooler but the Intercooler has alot of surface area and the area has to
be caculated to get the proper effect. I dont see how enlarging the intake area in a very small
area compared to an intercooler will do anything, and really its no genuine revolution.
It all depends on the the speed of the car and the mass of the air in the intake. There is a limited
amount of space in the intake area as opposed to increasing the surface area of the intercooler.
the air flowing over the intercooler fins is a lot more complicated that a simple compression of
a gas.
A nice marketing gimick.

NSXTC

Yep, Porsche is good at marketing gimick...Perfect example...the side vents on the GT3 rear bumper...brochure says it draws out hot air from the engine bay.

Well guess what. It does nada. Proof? ->https://rennlist.com/forums/997-gt2-gt3-forum/385831-gt3-rear-bumper-apron-porn.html

pole position

The Greenies have a very strong influence in Germany. Most of the new fuel savings, noise etc comes from their side. It is easier for Porsche to please those thinly disguised communists then to fight them.

Yargk

I think we are beating this to death when it's very simple. The car uses 15% less fuel under full load. The only measurement under full load that makes sense is liquid volume per time. You floor it for 10 sec with it stuck at 5000 rpm (use a dyno with brake) and measure how much fuel is used. It uses less fuel, but makes more power because the intake air is cooler. A basic result of thermodynamics says that the efficiency of a heat engine is limited by the difference in your high and low temperatures. The low corresponds to intake air temp and the high corresponds to the temp after combustion. I feel there might be additional, less basic (to me), reasons why cooler intake air is more efficient, but I'm not an automotive engineer.

Porsche is very intelligent when it comes to these things. Any remarks that this car is part of the problem are countered by the good gas mileage found on the European cycle and any further criticism that this car will be driven hard (not like European cycle) is countered by the fact that even when driven hard the car uses less fuel, which is actually quite an achievement, not just marketing bs. After reading the AMS supertest, this thing hauls and handles and to think it's cleaner and more efficient with a crazy 530 hp, WOW.

Pingo

According to Porsche, the expansion intake manifold uses the principle of oscillating air in the intake manifold during the cooler expansion phase, keeping the temperature of the fuel/air mixture lower than that of the 911 Turbo.

C.J. Ichiban

15% really isn't that much more efficient because like someone said earlier you're only getting 4-6mpg at full throttle anyway...but most of the improvements on mpg have to do with better either direct or indirect ECU stuff which, being computer hardware and software can evolve at an extremely high rate.

eclou

we had a long discussion on the expansion intake here

Interestingly enough, some Rennteam members have run a RUF 550 997TT vs a new GT2 0-300kph, and the RUF was faster by a hair (still using stock TT non-expansion intake and stock TT VTG turbos)

C.J. Ichiban

yeah but how many mpg? hahaha