The new BMW 5 series commercial says "Making more power with twin turbos..using less fuel" or something like that.

I thought that when you increase the air going in you had to increase the fuel slighty even if it was still low boost.

Am I wrong?

I haven't been involved with turbos in a while, did I miss something?

Fuel use would only get changed drasticlly depending on driving styels?

Could someone lease explain what they might be meaning in their commercial? That I am missing.


Thanks,
-Brian!

 

there are more factors at work here than just adding a twin turbo to an engine and getting better mpg. but actually alot of guys here with boosted scion tc's say they have been getting better mpg.

the reason why is that just because an engine is turbocharged doesn't mean it is always in boost, consuming larger amounts of fuel. when the engine accelerates, the turbo spools up and the boost in power allows the engine to climb the rpm band quicker and reach its shift point faster and thenfore arrive at cruising speed sooner where it will go from boost into vacuum.

also there have been many advances in turbo technologies and fuel injection that has allowed them to make more power more efficiently. talking about twin-scroll ball bearing, or variable geometry set ups that almost completely remove turbo lag.

i'm not sure if the bmw is a true twin turbo, parallel turbo or sequential turbo, but on larger engines it is more efficient.

now i've heard the bmw commercial, but i don't know specifically what they are claiming. did they add a twin turbo set up to an existing engine and get better mpg, or did they replace an older engine design with a newer more efficient twin turbocharged engine. i don't know, but it isn't super unlikely.

 

for YEARS german companies have used turbo engines as alternatives to big gas guzzling v8's.

All they really meen by that commercial is that with a smaller motor and turbo, you are actually saving fuel. You dont need to compensate boost with fuel until you actually start making boost, and if your turbo doesent spool up until around 3k (the point where most shift when driving economically), than you actually save fuel and increase economy as opposed to larger engines.

...i hope that makes since i know i worded it a little funny.

 

I know a couple diesel engines have gone with a twin turbo setup to lower emissions and raise fuel economy. Im sure its similair technology with the gas engines.

They probably use a small turbo which forces are into the second larger turbo which makes the power.. So you really arent using any more fuel. With proper sized turbos and the correct tune in the factory ecu, it can be optimized for perfect a/r's and awesome mileage.

I know with my supra, with LARGE twins, cruising on the highway, I am up around 20mpg...

 

Before a Scion Backstage event I listened in on a Scion rep instructing dealers on the various TRD mods. They had all the parts there to play with: muffler, shifter, CAI, supercharger, struts and a complete front suspension for illustration.

The supercharger kit includes the belt driven vane housing, special intake, larger injectors and a revision to the ECU. The cost was quoted at $3,200 for parts plus 6 hours of labor.

We were told that the supercharger produces a more efficient combustion and will slightly increase MPG if the car is driven at exactly the same performance level as before. Like same acceleration and same speeds. However, most people do not spend $4,000 on a supercharger to drive the same way as before -- they use the extra power to accelerate faster or drive faster, and that uses more gas than before.