fly2low

I don't see that many diesel drivers around

SteVTEC

The N55 one was completely illegible, sorry.

Which is related to displacement!

duh? Maybe there isn't enough of a difference between tuned 2.0L and 3.0L engines both putting out around 400 whp to adequately illustrate the point. How bout a 10.0L engine and a 1.0L engine both tuned to produce 1000hp. Which do you think is going to have better response characteristics?

BMW 4.4L twin-turbo V8 vs tuned 2.0L. I'm guessing the 4.4L V8 isn't really going to need to downshift, or not nearly as often.

Doesn't always really capture everything there is to appreciate about engines. How often are you going flat out for a 1/4 mile in most driving situations? Never? What about 0-60? I've always been far more interested in passing time performance metrics.

Response characteristics of engines are an objective part of the design that result directly in a particular "feel", but don't make it into any consumer level specification. Do you think companies like BMW get the responsiveness that they do out of engines by blind luck? No, I guarantee you that they have internal specifications and performance targets to meet. The engineering level spec might be the "Q" factor. If you have 2.0L, 3.0L, and 4.0L all with more or less the same paper specs for power and torque, you're probably going to find that the 4.0L has the highest Q factor (responsiveness) and that the 2.0L has the lowest, resulting in a much different feel despite the same consumer paper specs. You can't dumb these things down enough to the point that your average Joe might actually understand as far as putting it on the window sticker. Just have to drive the cars.

If you look closely you'll see I also praised the BMW 2.0L turbo engine and called it a good replacement for the outgoing 3.0L NA engine. The more I think about this new BMW 320i, the more I think I like it. I sorta feel cheated thinking about an F30 328i and paying $37k to start when it's "not a six", but at $33k now I can stomach it better, and JB it for a few hundred bucks to get a tad more power out of it and still be perfectly happy. Love the sixes, but are they worth $10k more? Not so sure about that. Recently joked to some friends of mine that I was going to have to bust out my pro audio recorder to record my Inline-6 engine wailing so that I can listen to it in the future, because the odds are good that I might be downsizing to the 4-banger on the next go-round.

SteVTEC

The Audi A4 with a CVT that I drove was actually horrible about this. It's definitely how you get maximum fuel economy, but it was incredibly annoying to drive until I figured out how to get it out of that mode.

The point I was getting at was that if the SAE updated their J1349 spec to include a line that said maximum advertised torque at WOT at a given RPM must be achievable within say 3 seconds starting initially from closed throttle for at least 10 seconds, a lot of these gazillion pound feet of torque at IDLE rpm claims would go right out the window. The bottom line is that manufacturers are gaming the J1349 to come up with these numbers. Given the popularity of turbocharged engines these days, I wouldn't be surprised if the SAE updated this test standard eventually to reflect more realistic and accurate test methods for turbocharged engines.

ST430

The N55 dyno graph is easy to comprehend (just read the original thread link I provided). It shows peak HP at 308 and peak tq 315 at their respective RPMs. Just compare it again the other dyno sheet I showed you. It isn't too difficult to discern that the Evo's 4 cylinder made hp and torque at roughly the same rpm, which should equate to faster 0-60mph, quarter miles, and passing times.

As for your other points, I think you're starting to try to nitpick by showing larger variance. I've never said a 4 cylinder will be equal to a say a W18 engine. The discussion is about replacement for displacement. Can a smaller engine be tuned via FI to mimic a larger displacement engine? Unequivocally, as I have provided proof of that. And that's my point. For a set given parameter (say power/fuel/engine response), FI can be a great application to meet and beat all the goals of a larger NA engine (case in point again is the N55 vs. S65).

I guess I come from a different background having tuned NA vs. FI engine for quiet a while, as both a hobbyist and part time pro. I've messed around from everything from VQs, H22As, B18Cs, SR20DETs, 4G63s, JAZ80s, 2JZGTEs, etc. I've always found the most fun and bang for the buck (as well as customizatoins) in FI applications. The more you fiddle around with A/Rs, Compressor mappings, ignitoin/fuel/timing maps, and such, the more you'll appreciate how resoundingly it makes sense for vehicles to go FI to both make more power AND be economical about it, which is a win / win for everyone.

And FWIW - My next car (or rather my wife's) will probably be an N20 power car (whether in 323i or X1 guise). It's amazing how they packaged the vehicle for both power and fuel economy in a very well balanced package (even more so then the N55 powered supposedly). As FI technology further advances and people start accepting turbos again, I think we'll see it more and more mainstream (if it isn't already) and hopefully adopted by Toyco again!

mmarshall

Low-RPM lugging in higher gears can indeed increase gas mileage and lower the amount of piston-ring/cylinder/valve-wear, but the flip side to it is potentially more stress on the engine's crankshaft, possibly shortening its life.

ISFPOWER

iTrader: (20)

very amazing. i get about 5-6 mpg higher than what the EPA says. im not sure if it has to do with the car being new and with more mileage, it will get worse but bmw did right with the power out put on a 4 cylinder. im sure you know how weak the old 3 series were. im still waiting for people to modify the engines to see what it can really do.