Hp v.s. Engine/brand philosophy

[stvding]

For 3.0L-ish 6 cyls cars
The new rs5 features a 2.9L twin turbo V6 making 444hp/443ft-lb.
Alfa Romeo giulia qv has same displacement 2.9L V6 making 505hp!!!!! 443f-lb
Kinda out-dated our very owned F8x has 3.0L I6 with 425/406
However, they all go to 100kph in about 3.9 to 4.1 seconds. Even big thirsty v8 c63/s is in around same time.

What makes the difference???
Weight? transmission?

Love 505hp form alfa. The huge steering column mounted paddle shifter is a huge plus! Comparing to small paddle in german cars.

Will next m3 boost power to 500? Bmw always seem to be under dog in hp category, but never got outrun (0-100)by higher hp car in the segment. Magic?

[stvding]

Damn, what a sexy car! Too bad , its tech/infotainment sys is crappy....

[Ian1973]

Because first, none of them make the power they advertise, second, they all weigh different, third the chassis/suspension geometry is different to possibly allow power to be put down more efficiently, fourth, traction/stability control programming, fifth, transmission type/gear ratios, sixth, driver skill.

Get a manual, then you don't need to worry about flappy paddles.

FYI, dynos have proven the BMW is actually closer to 470hp at the crank, not 425. Time will tell where the Alfa and Audi land. But V6 = fail anyway.

[mc3456]

Originally Posted by Ian1973

Because first, none of them make the power they advertise, second, they all weigh different, third the chassis/suspension geometry is different to possibly allow power to be put down more efficiently, fourth, traction/stability control programming, fifth, transmission type/gear ratios, sixth, driver skill.

Get a manual, then you don't need to worry about flappy paddles.

FYI, dynos have proven the BMW is actually closer to 470hp at the crank, not 425. Time will tell where the Alfa and Audi land. But V6 = fail anyway.

Why would BMW intentionally understate their horsepower when most buyers are drawn to more horsepower? Is their strategy to sell fewer cars?

Honestly, the car doesn't feel a single horse faster than 425hp when the virtual drag parachute deploys at 5,000rpm. Just strains with no real force behind it.

[AIRPOWER]

Originally Posted by mc3456

Why would BMW intentionally understate their horsepower when most buyers are drawn to more horsepower? Is their strategy to sell fewer cars?

Honestly, the car doesn't feel a single horse faster than 425hp when the virtual drag parachute deploys at 5,000rpm. Just strains with no real force behind it.

Here is my Dyno numbers - Ian1973 was pretty much spot on

First set is measured Stock and then with my ACS tuner (uncorrected numbers)

M3 Stock at the crankshaft 475 HP
M3 Stock at the wheels - 405 HP
M3 Stock TQ: 451

M3 ACS tuner module at the crankshaft - 529 HP
M3 ACS tuner module at the wheels - 458 HP
M3 ACS tuner module TQ - 512

[Ian1973]

Seriously? It's common knowledge. Nearly all the turbo BMW's have been underrated, the 335 to the M5/6 to the M3/4.

https://www.dinancars.com/product/d4...ries&mid=1178/

Captured here...

EDIT: Beat me to it!! Crap

[996ttelise]

Gearing and total area under the torque curve.

Total area under the torque curve is more important than peak hp, hence all mfgs including Porsche going forced induction.

Even forced induction will have different torque curves for different engines and different setups. For instance, one can add an after market exhaust that increases peak hp, but results in slower 0-60 or 0-100 times. An aftermarket exhaust may sacrifice torque due decrease in back pressure for their peak hp gains they advertise, but the net effect is a slower car.

Peak hp and peak torque tells story, but not the full story. Total area under the torque curve with a nice flat torque curve is best for accellerstion at this level and at these rpms.

[stvding]

Originally Posted by 996ttelise

Gearing and total area under the torque curve.

Total area under the torque curve is more important than peak hp, hence all mfgs including Porsche going forced induction.

Even forced induction will have different torque curves for different engines and different setups. For instance, one can add an after market exhaust that increases peak hp, but results in slower 0-60 or 0-100 times. An aftermarket exhaust may sacrifice torque due decrease in back pressure for their peak hp gains they advertise, but the net effect is a slower car.

Peak hp and peak torque tells story, but not the full story. Total area under the torque curve with a nice flat torque curve is best for accellerstion at this level and at these rpms.

Haha, therefore tesla has the most area under torque curve..or rather a torque line..

[DS_BMW]

Originally Posted by mc3456

Why would BMW intentionally understate their horsepower when most buyers are drawn to more horsepower? Is their strategy to sell fewer cars?

Honestly, the car doesn't feel a single horse faster than 425hp when the virtual drag parachute deploys at 5,000rpm. Just strains with no real force behind it.

I don't see where it falls on its face past 5k. It makes most of its power 5,500 to 7k.:

[996ttelise]

Originally Posted by mc3456

Why would BMW intentionally understate their horsepower when most buyers are drawn to more horsepower? Is their strategy to sell fewer cars?

Honestly, the car doesn't feel a single horse faster than 425hp when the virtual drag parachute deploys at 5,000rpm. Just strains with no real force behind it.

Lol, you have dang near gone mental, definitely obsessive, trying to convince yourself and others that you made the correct decision to ditch your M3.

New to BMW, but owned Porsches for decades. Porsche has a long history of underestimating in terms of both output and 0 - 60 figures.

Only an immature bench racer who needs to put down the car mags and get a non-virtual girl would make their purchase decision based solely on mfg reported output and estimated performance data.

Contrary to your butt dyno you believe sufficiently sensitive to decipher accuracy of real dynos and single hp increments, real dynos show a very impressive super flat power curve. Based on the below, BMW did a heck of a job accomplishing a super flat early torque power curve and overall power curve. In my opinion, this curve maximizes performance and tuning differently to show increasing hp after 5,252 would decrease total area under the torque curve prior to 5,252 rpms.

[996ttelise]

Originally Posted by stvding

Haha, therefore tesla has the most area under torque curve..or rather a torque line..

You point? Have you seen a Tesla torque curve? Aren't they dang near flat and maxed out at initial rpms as opposed to a forced induction engine which takes time to spool up?

I have spent so much time, money and effort with Porsches chasing performance in NA engines. I also had a 996tt with 750 hp also, but the NA arena was my obsession from the 90s until mid 2000s. I built out several flat, air cooled 3.6 to 3.8s and 4.0s, redid internals and utilized stand alone fuel management systems custom made by companies such as Lenz and etc. Learned a lot back then about tuning with the stand alones based on application such as track, acceleration, 1/4 mile and etc. Build or tune to increase area under a nice flat torque curve and hp will follow . . .

[bruce.augenstein@comcast.]

Originally Posted by mc3456

Why would BMW intentionally understate their horsepower when most buyers are drawn to more horsepower? Is their strategy to sell fewer cars?

Honestly, the car doesn't feel a single horse faster than 425hp when the virtual drag parachute deploys at 5,000rpm. Just strains with no real force behind it.

As has already been articulated in these pages, the F80 may not in fact be underrated at all. It has to do with the alternative power measurement methods OK'd by the SAE for forced induction engines.

As you may be aware, M cars have traditionally been more about a balance of power and handling than about absolute power.

As to what your butt dyno is telling you, you're correct in that the F80 tends to feel flat in the upper rpm ranges, especially compared to the E9X cars. Here's why:

The formula for calculating power is:

torque X rpm
--------------- = HP
5252

In any given gear, a car will accelerate according to its torque curve (aerodynamics aside), so the car will accelerate hardest at the torque peak, and less hard above or below that point.

So with the exceptionally wide power peak on these cars, the formula dictates that the torque curve has to be falling as you travel through the range of peak power. Therefore, you feel acceleration tapering off as you near the red line.

However, at any given vehicle speed, horsepower dictates the rate of acceleration, with max power dictating max acceleration at any given velocity. Therefore, even as you feel acceleration tapering off, you still need to take it to red line, at least in the first two gears, because if you shift earlier, HP after the shift will be much less than at the shift point.

In the upper gears, you can shift a little earlier, as long as the rpm after the shift is still within the max power range.

Thinking about this, you can see that the F80 puts up very good acceleration numbers for its power-to-weight ratio, because it is at continual peak power from second gear up, unlike most cars.

Anecdotally, short-shifting in the upper gears has another mild benefit, because after each shift you have less rotating inertia, thus more acceleration than would otherwise be the case.

Bruce

PS - Again anecdotally, drivers of E9X cars tend to feel the car accelerates harder at the power peak (8300 rpm) than at the torque peak (3900 rpm), because the torque is dropping ever so slowly as rpm climbs (only about an 11 percent drop over, GOOD GOD!, a 4400 rpm span. Of course, the car's actual rate of acceleration has dropped by only that small amount over 4400 rpm, while the driver's ear dyno is getting pummeled as the car nears red line.

Result? Unlike the F80s, the E9X cars get more and more exciting as the revs rise.

However, as the aural delight approaching red line fascinates the E9X driver, he'll have to notice the F80 blowing exhaust in his grill, thereby tempering his excitement.

[996ttelise]

Originally Posted by bruce.augenstein@comcast.

PS - Again anecdotally, drivers of E9X cars tend to feel the car accelerates harder at the power peak (8300 rpm) than at the torque peak (3900 rpm), because the torque is dropping ever so slowly as rpm climbs (only about an 11 percent drop over, GOOD GOD!, a 4400 rpm span. Of course, the car's actual rate of acceleration has dropped by only that small amount over 4400 rpm, while the driver's ear dyno is getting pummeled as the car nears red line.

Result? Unlike the F80s, the E9X cars get more and more exciting as the revs rise.

However, as the aural delight approaching red line fascinates the E9X driver, he'll have to notice the F80 blowing exhaust in his grill, thereby tempering his excitement.

People said the exact same thing about the 991.2, when it first came out, over the 991.1 when describing the acceleration sensation when going from the NA .1 to the forced induction .2. People swear their butt dyno is telling them the .1 is quicker than the .2 and pulls harder in higher rpms, but not true on either count. The sensation is different and interpreted differently in quick spooling, smaller twin turbo cars, but the acceleration is still there. I have seen it plotted.

The flatter, more responsive total area under the power curve is optimal and the F8Xs hit that goal perfectly.

People going from a smaller twin turbo or forced induction set up generally say the NA is less exciting, at least in this price range. Something like an LFA, CGT and even a 458 are a intoxicating to me, but that is apples and oranges.

[Motorsportenterprise]

Originally Posted by stvding

For 3.0L-ish 6 cyls cars
The new rs5 features a 2.9L twin turbo V6 making 444hp/443ft-lb.
Alfa Romeo giulia qv has same displacement 2.9L V6 making 505hp!!!!! 443f-lb
Kinda out-dated our very owned F8x has 3.0L I6 with 425/406
However, they all go to 100kph in about 3.9 to 4.1 seconds. Even big thirsty v8 c63/s is in around same time.

What makes the difference???
Weight? transmission?

Love 505hp form alfa. The huge steering column mounted paddle shifter is a huge plus! Comparing to small paddle in german cars.

Will next m3 boost power to 500? Bmw always seem to be under dog in hp category, but never got outrun (0-100)by higher hp car in the segment. Magic?

I don't get the obsession with HP. Mostly what you see here is that BMWs dct makes up for its lack of hp and also is lighter than the auto in the other cars.
It's the same reason why a base 991.2 911 with only 350 hp and a better dual clutch than DCT is faster (in a straight and more so track) than an m4 despite a lot less hp, a lot less tq and a disadvantage in power to weight.

[Motorsportenterprise]

Originally Posted by 996ttelise

People said the exact same thing about the 991.2, when it first came out, over the 991.1 when describing the acceleration sensation when going from the NA .1 to the forced induction .2. People swear their butt dyno is telling them the .1 is quicker than the .2 and pulls harder in higher rpms, but not true on either count. The sensation is different and interpreted differently in quick spooling, smaller twin turbo cars, but the acceleration is still there. I have seen it plotted.

The flatter, more responsive total area under the power curve is optimal and the F8Xs hit that goal perfectly.

Agreed. The 991.2 is MUCH faster and IMO compared to the m3/4 it does pull harder up top but I can see where factors make you think differently. Porsche IMO has adapted to the turbo from NA much better all aspects considered than anyone else. I mean the turbo is still the epitome of a turbo car in my kind and experience.

[mc3456]

Originally Posted by DS_BMW

I don't see where it falls on its face past 5k. It makes most of its power 5,500 to 7k.:

If you can't see or feel it, then you've never owned a faster, more powerful car before. Said it before snd will say it again, it's like the car deploys a parachute brake at 5,000 RPMs. That's definitely NOT where it shines. The red line feels like it's set about 1,000RPMs too high.

Drive a Mercedes E63s or Alfa Quadrafoglio and you will instantly feel the difference. However, just don't judge a car based on your opinion without firsthand knowledge. Very accurate review:

http://www.caranddriver.com/reviews/...io-test-review

Compare that with the Long-term update of the M3:

Good, but not great. Best to remain humble with your criticism of the Alfa and upcoming RS5.

http://www.caranddriver.com/reviews/...wrap-up-review

[996ttelise]

Originally Posted by mc3456

If you can't see or feel it, then you've never owned a faster, more powerful car before. Said it before snd will say it again, it's like the car deploys a parachute brake at 5,000 RPMs. That's definitely NOT where it shines. The red line feels like it's set about 1,000RPMs too high.

Drive a Mercedes E63s or Alfa Quadrafoglio and you will instantly feel the difference. However, just don't judge a car based on your opinion without firsthand knowledge. Very accurate review:

http://www.caranddriver.com/reviews/...io-test-review

Compare that with the Long-term update of the M3:

Good, but not great. Best to remain humble with your criticism of the Alfa and upcoming RS5.

http://www.caranddriver.com/reviews/...wrap-up-review

If the anchor was being dropped at 5,000 RPMs on the F8X, this should be easy to see on videos such as the yellow 991.1 v. the F82 as the NA 991.1 would have pulled ahead easily after the F82 hit 5,000 rpms as would just about anything if the F8X was being shifted at or near the red line (anchor dropping rpms).

Some are just not accustom to very flat, ideal power curves that are very linear in feel in power.

I have drive the C63S around the track and its torque curve below was pretty consistent to how it felt when I drove it . . . very linear and similar to 2017 M3.

In fact, the C63 which you say kicks more and more in the upper rev range falls off harder than the F8X in the upper rev range. Perhaps the butt dynometer is lying to you or we are just making stuff up as we go along?

[DS_BMW]

Originally Posted by mc3456

If you can't see or feel it, then you've never owned a faster, more powerful car before. Said it before snd will say it again, it's like the car deploys a parachute brake at 5,000 RPMs. That's definitely NOT where it shines. The red line feels like it's set about 1,000RPMs too high.

Drive a Mercedes E63s or Alfa Quadrafoglio and you will instantly feel the difference. However, just don't judge a car based on your opinion without firsthand knowledge. Very accurate review:

http://www.caranddriver.com/reviews/...io-test-review

Compare that with the Long-term update of the M3:

Good, but not great. Best to remain humble with your criticism of the Alfa and upcoming RS5.

http://www.caranddriver.com/reviews/...wrap-up-review

Im not saying the Alfa is not a great car. I actually really like it.

If there was a huge drop off of power stock on the S55 after 5k dyno charts would show this, they dont.

[dkhm3]

add drivetrain loss on the throttle on a conventional automatic and the weight, that's the reason the m3/m4 consistently out performs its engine's rated hp compared to the competition.

each component of the car works better together than the separate numbers by themselves. In the f8x's case it is the less weight, great weight distribution, engine gearing matched with the quick shifts of the dct, that allow the car to be both as fast on the track and almost as fast on the drag strip as its competition even 3 years since the car's introduction.