RC F vs M4
#301
Of course , the S55 is a masterpiece. The only problem as far as i know is the sound, and thats a result of the turbo layout. Bmw uses a pretty unique turbo layout in the M series. This reduces turbo-lag very well and makes the response much better, but sadly it kills the sound. Same problem occurs in the M5 and M6 V8. But then again, nobody is perfect. Picture below from the V8
#302
Of course , the S55 is a masterpiece. The only problem as far as i know is the sound, and thats a result of the turbo layout. Bmw uses a pretty unique turbo layout in the M series. This reduces turbo-lag very well and makes the response much better, but sadly it kills the sound. Same problem occurs in the M5 and M6 V8. But then again, nobody is perfect. Picture below from the V8
#303
Lexus Test Driver
More like, rob Tom and D1ck to pay Harry
p.s. A plummeting torque curve is another elephant in the room that will get swept under the rug by the Bimmer PR people. After 5500 rpm as the engine runs out of steam, it gives sensation and perception of rapidly falling rate of acceleration accompanied by that dreadful noise. Many reviewers said no point in shifting over 6000 rpm to get maximum acceleration as the engine is out to lunch. The 7500 rpm redline was only a marketing stunt. It absolutely did not need it. Optimally, it should have been around 6500 rpm max.
It is a good low end and midrange torque engine. Lots of it available everywhere in midrange from 1800 rpm to 5500 rpm with max. torque plateau. Hence the meat of the powerband. Then the ugly side reveals itself as per BMW's technical paper as it loses a full 100 Newton-Meters of torque in the space of just 1000 rpm as the engine is gasping for air. Then down another 80 Newton-Meters by the time it hits 7300 - 7400 rpm.
Definitely, a very lacklustre and unexciting engine to rev out since it is a twisting engine and not a revver. That is a 100% fact. It does what it is supposed to do and what it is designed to. This is what BMW wanted and this is what they got.
RC-F might not be torquey at the bottom end, but has a surging torque curve that keeps climbing beautifully giving the sensation of never ending increasing rate of acceleration. Even at 7100 rpm, according to my mathematical calculations, RC-F produces 90% of its peak torque based on its peak 467 HP power.
Case in point, you can't have your cake and eat it too.
p.s. A plummeting torque curve is another elephant in the room that will get swept under the rug by the Bimmer PR people. After 5500 rpm as the engine runs out of steam, it gives sensation and perception of rapidly falling rate of acceleration accompanied by that dreadful noise. Many reviewers said no point in shifting over 6000 rpm to get maximum acceleration as the engine is out to lunch. The 7500 rpm redline was only a marketing stunt. It absolutely did not need it. Optimally, it should have been around 6500 rpm max.
It is a good low end and midrange torque engine. Lots of it available everywhere in midrange from 1800 rpm to 5500 rpm with max. torque plateau. Hence the meat of the powerband. Then the ugly side reveals itself as per BMW's technical paper as it loses a full 100 Newton-Meters of torque in the space of just 1000 rpm as the engine is gasping for air. Then down another 80 Newton-Meters by the time it hits 7300 - 7400 rpm.
Definitely, a very lacklustre and unexciting engine to rev out since it is a twisting engine and not a revver. That is a 100% fact. It does what it is supposed to do and what it is designed to. This is what BMW wanted and this is what they got.
RC-F might not be torquey at the bottom end, but has a surging torque curve that keeps climbing beautifully giving the sensation of never ending increasing rate of acceleration. Even at 7100 rpm, according to my mathematical calculations, RC-F produces 90% of its peak torque based on its peak 467 HP power.
Case in point, you can't have your cake and eat it too.
Last edited by 05RollaXRS; 10-06-14 at 11:04 PM.
#304
Lexus Test Driver
LOL. "Even at 7100 rpm, according to my mathematical calculations, RC-F produces 90% of its peak torque based on its peak 467 HP power."
Oh look at me and my mathematical calculations. Yes, your complex calculation of HP = Torque x RPM / 5252. What is so bizarre is that you admit that the RC F produces it's maximum torque high in the rev range, which means its power band is very narrow.
Oh look at me and my mathematical calculations. Yes, your complex calculation of HP = Torque x RPM / 5252. What is so bizarre is that you admit that the RC F produces it's maximum torque high in the rev range, which means its power band is very narrow.
You are just a big bimmer forums rep who is so blinded in his mad obsession with the M4, which has resulted in being caught many time before exaggerating things. Yet again, you got busted. Plain and simple.
There are tons of cars that make 90% of their peak torque all across their rev range at least. LFA was the best example that as seen in dynos made at least 90% of its torque available from 3700 rpm all the way to 9500 rpm despite the peak coming in at a very high 6800 rpm. The 5252 rpm cross over point has nothing to do with how narrow or broad the powerband is. You make such laughable assertions makes me think how much time is wasted replying to such assertions.
RC-F makes its peak torque at 4800 rpm, but 90% of the peak might be available from as low as 3000 rpm, which can only be clear from looking at an actual dyno and not from your cynical blathering and frustration of people not seeing the S55 engine anything more than a lacklustre mid-range and low-end torque engine.
What I do know, the RC-F makes 90% of its peak at 7100 rpm.
That is a fact the M4 engine torque curve plummets hard after 5500 rpm. 100 newton-meters in the space of just 1000 rpm is huge! Your unconditional appreciation for the M4 will never let you admit that. That is the cold hard fact.
Here is something else that you'd benefit to understand. The S55's ability to make maximum torque at low RPM is a very good thing and of course it's going to fall off! That is why HP is a product of not only torque, but RPM's which the S55 happily revs to 7500 RPM.
All of those manufacturers are crazy and stupid for jumping hoops and trying to tune cam timing and headers of the engine to produce as much close to peak torque all across the rev range from low to very high rpms as possible. Right? BMW reins supreme with a silly and laughable plummeting torque curve after 5500 rpm. Do you realize how silly that sounds?
Let me guess, using your analogy, it is better to shift at 7500 rpm where I have only 360 Newton-Meters of torque rather than at 6000 rpm where I have ~ 480 Newton-Meters. Right? That is laughable.
That is a fact, BMW had no choice. The engine was tuned for minimum turbo lag and better low end response, which resulted in compromises considering it is a turbo engine at the high end rpm. There was nothing BMW could do. That is the cold and hard fact. Don't make it sound like it was something BMW designed it to do.
Fall off. Of course. Not the plummet like a sack of potatoes like the Bimmer does. Capiche? If the engine loses so much torque after 5500 rpm, the power band lies well below 5500 rpm. In the case of M4, it is somewhere between 1800 rpm - 5500 rpm. After that, it is completely lost steam and plummeting hard.
Face it, it is a lacklustre engine at anything above 5500 rpm. The torque curve falls like a rock. RC-F peaks at 4800 rpm and still has 90% of its peak available at 7100 rpm. Big difference!
Just put up a dyno. The RC F engine sounds glorious, but it can't touch the S55 in terms of power or strength.
You simply cannot deny this. This is the truth. Don't make it sound like it is a big selling point. You can try and put a positive spin on it as much you want, BMW had no choice. BMW had to live with the consequences of making the engine have better low end response and midrange.
RC-F might not be great at the bottom end engine, but has vastly superior throttle response and a surging torque curve to 4800 rpm and then much flatter torque from 4800 rpm onwards to the 7300 rpm redline. That is the 100% truth. I don't expect you to give any credit to the RC-F since you are so blinded in your obsession with the M4 that you are not willing to admit its flaws and weaknesses.
Now on to torque curve, here is an example of a dyno with a very late peak (7100 rpm) yet the car makes 90% of its peak torque in most of its powerband.
LFA vs Mclaren M4 vs Porsche 911 GT2 RS dyno @ MD Automotive
The Mclaren MP4 and LFA made 515 wheel HP and the Porsche 911 GT2 RS made 565 wheel HP
Being the only N/A and highest revving engine, LFA makes the lowest peak torque, but it has the broadest and the flattest torque curve of all the three despite having the highest peak of torque at 7100 rpm (according to the dyno). It was making 90% of its peak torque from 3500 rpm all the way to 9300 rpm where the dyno was stopped.
Last edited by 05RollaXRS; 10-07-14 at 07:31 AM.
#306
Lexus Test Driver
iTrader: (6)
Is Exception the same as AustinYellowMakesMeHArd at Bimmerpost? This guy started the thread below. LOL!!
http://f80.bimmerpost.com/forums/sho....php?t=1044074
http://f80.bimmerpost.com/forums/sho....php?t=1044074
#307
Forum Administrator
iTrader: (2)
Aaand we are done. Please don't start another one of these until the RCF is available for delivery
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