To RI RS4: Do you wish the RS4 came without FSI?...or prefer with it?
04-07-2007, 03:19 PM
#2
I prefer it. We would not have the power and throttle response we see without it.
It's an elegant system. Look at what BMW has had to do on the M3 V8 to get to this level of performance, without direct injection.
The same thing happened with diesel engines and direct injection years ago. And it took a while for solutions to come with fuel additives and special oils. But the solutions did come. And the same will happen with direct injection. Terry is on the solution trail big time. I'm just happy to be a part of it.
The same thing happened with diesel engines and direct injection years ago. And it took a while for solutions to come with fuel additives and special oils. But the solutions did come. And the same will happen with direct injection. Terry is on the solution trail big time. I'm just happy to be a part of it.
04-07-2007, 04:49 PM
#4
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I was going to ask about the power...
I've heard that, but I believe it is secondary to fuel efficiency benefits. Or am I wrong there?
Where's the push for direct injection coming from? Better power or better fuel efficiency? One is optional to car mfgrs, the other is mandated upon them(EPA fleet minimum fuel efficiency requirements)...talking US market of course.
Where's the push for direct injection coming from? Better power or better fuel efficiency? One is optional to car mfgrs, the other is mandated upon them(EPA fleet minimum fuel efficiency requirements)...talking US market of course.
04-07-2007, 05:58 PM
#5
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When it's not setting off the engine light, I love it. It's so fast up and down on revs that......
I have to blip twice to match revs for down shifting. Equally amazing how fast you have to shift on the way up at avoid the limiter.
04-07-2007, 06:15 PM
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Yeh, throttle response has to be a big beneft...
but that can also be accomplished by non direct injection engines. Consider for examle, the S4 0-60 time of 4.9 t 5.3... compared to the RS4 of 4.6 to 4.8.
If FSI was making such a positive difference in throttle reponse and power, then there should be much more of a gap there...because the engines are vey similar and so are the cars.
If FSI was making such a positive difference in throttle reponse and power, then there should be much more of a gap there...because the engines are vey similar and so are the cars.
04-07-2007, 06:29 PM
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Follow-up...
Correct me if I'm wrong but my feeing on FSI is that it provides better fuel efficiency, throttle response, and faster and more complete burning of fuel.
I do not feel that it provides more power, per se. In the RS4 at least, that is accomplished primarily by the very high compression ratio(which FSI also allows) and the very high redline. These are the two foremost things that get you over the top in that car, IMO.
I do not feel that it provides more power, per se. In the RS4 at least, that is accomplished primarily by the very high compression ratio(which FSI also allows) and the very high redline. These are the two foremost things that get you over the top in that car, IMO.
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04-07-2007, 08:36 PM
#9
Actually you do get a bit more power, because of the inherent combustion chamber cooling
It's direct injection that allows Audi to push the compression ratio up to 12.5:1, by virtue of a cooler charge and a more uniform charge distribution. And it's why even at WOT that the engine doesn't have to run overly rich.
04-07-2007, 08:39 PM
#10
Fuel efficiency for sure. More power is just a side effect.
Stratified mode is the holy grail, if they can ever get it to work in the US. But even in spite of that, the closed loop control that they have over the injection pressure and injector on time, when coupled with accurate wideband O2 sensors, allows much better control of emissions. I think ultimately that lower emissions is the prime reason to go to direct injection.
