Motortrend's Carlos Lagos reviews 2015 M3

[tooch]

Originally Posted by aeropixel

Ugh! I have to wait until April 30, 2015 in order to get my M4!

damn!! when did you order?

[Falafel Combo]

Originally Posted by VCP

it is 2-3%. Unless you are driving below 100km/hr with the windows up, car in Efficient dynamic mode and have your ear glued to the speaker, you will not hear this active sound. It is there so the calm driver with no stereo on can hear the motor revs slightly.

Very suspicious to me that BMW claims only 2-3%. It's quite glaring on most recordings I've heard. I guess I'll have to wait till I can drive it myself.

[chiplee]

Originally Posted by CanAutM3

... Further, E92 was run in 5th gear while F80 was run in 4th...

What impact on results are you suggesting this would have? You can dyno the same car in 3rd, 4th, and 5th and get the same numbers within a few %. Higher gears will be a bit lower, especially in automatic transmission cars, but only due to the higher drive train losses of higher gears. Ratio has nothing to do with results. If it did you could never account for rear end ratio variation.

[rngrjag]

Originally Posted by PhillyNate

It is looking more and more like the E9x M3 is the ONLY BMW in the history of BMW that was NOT underrated horsepower wise coming from the factory. What a shame too, I DO NOT want that to be the lasting legacy of what was truly a masterpiece. SMH
Bravo to the new one though!!!

What? You are saying that EVERY BMW motor in history EXCEPT the S65 was underrated? Where are you getting this from? Please explicate.

It won't be the "S65's legacy" because your statement is not factually accurate.

[CanAutM3]

Originally Posted by chiplee

What impact on results are you suggesting this would have? You can dyno the same car in 3rd, 4th, and 5th and get the same numbers within a few %. Higher gears will be a bit lower, especially in automatic transmission cars, but only due to the higher drive train losses of higher gears. Ratio has nothing to do with results.

Tire rolling losses do vary with speed and dependency to the cube of speed as demonstrated in this post. The higher the gear, the greater the losses.

Further, for a given acceleration rate, the faster the wheels/tires are spinning, the more power is consumed to accelerate the wheels (P=mva). Here it is more tricky. Since a lower gear increases the acceleration rate and a higher gear increases the rotational speed, by trial and error, you need to find the gear that is at the sweet spot to minimize inertial impacts.

Transmission efficiency does not vary much gear to gear, except for transmissions that have a direct drive 1:1 ratio. There is significantly less loss in such a ratio.

Originally Posted by chiplee

If it did you could never account for rear end ratio variation.

That is exactly the point. It is very difficult to compare different cars on chassis dynos.

[Ghetto2315]

This just makes me anxious for Chris Harris's review. I like Carlos, Jonny, Ed, Angus and even the beautiful Jessi Lang a lot over at Motor Trend but nothing they do can purvey what Chris Harris does.

[imserious]

He said mini-m5. Good or bad, the comparison makes sense.

[checkmate]

Originally Posted by PhillyNate

It is looking more and more like the E9x M3 is the ONLY BMW in the history of BMW that was NOT underrated horsepower wise coming from the factory. What a shame too, I DO NOT want that to be the lasting legacy of what was truly a masterpiece. SMH
Bravo to the new one though!!!

And the award for the most ignorant statement goes to....

[solstice]

Originally Posted by imserious

He said mini-m5. Good or bad, the comparison makes sense.

This is the only part of e review that concerns me. He's going on about how much it feels like a small M5. That is NOT good for me and I hope I disagree once I drive my car.

[TheBingoBalls]

Originally Posted by solstice

This is the only part of e review that concerns me. He's going on about how much it feels like a small M5. That is NOT good for me and I hope I disagree once I drive my car.

Don't think he meant it felt like a M5 in that sense. I think the comparison here is that it feels like a small M5 because of the (same?) DCT, both are turbocharged (hence the heaps of low end torque) and perhaps the differential and not that it feels bloated and heavy and handles as such.

[solstice]

Originally Posted by TheBingoBalls

Don't think he meant it felt like a M5 in that sense. I think the comparison here is that it feels like a small M5 because of the (same?) DCT, both are turbocharged (hence the heaps of low end torque) and perhaps the differential and not that it feels bloated and heavy and handles as such.

Yes, hopefully it's just about the power delivery because I expect that to be similar with hopefully slightly better throttle response and that it has nothing to do with the isolated feel of the M5. The size and weight aside the M5 is jut not a very visceral and connected drive in the sense of prior M3s and M5s. I think you are right though

[GregW / Oregon]

Originally Posted by Powaup

Seriously!

Yeah, I can sleep for 3 or 4 days!

[chiplee]

Originally Posted by CanAutM3

Tire rolling losses vary with the cube of speed as demonstrated in this post. Meaning if you double the speed of the wheels, you have 8 times more losses. The higher the gear, the greater the losses.

Further, for a given acceleration rate, the faster the wheels/tires are spinning, the more power is consumed to accelerate the wheels (P=mva). Here it is more tricky. Since a lower gear increases the acceleration rate and a higher gear increases the rotational speed, by trial and error, you need to find the gear that is at the sweet spot to minimize inertial impacts.

Transmission efficiency does not vary much gear to gear, except for transmissions that have a direct drive 1:1 ratio. There is significantly less loss in such a ratio.


That is exactly the point. It is very difficult to compare different cars on chassis dynos.

Meh, sounds like a lot of very accurate theorizing that doesn't really pan out in real world testing. I don't know why, but you may have to try it yourself with your own car some time if you don't believe me. Do a 3rd gear pull, followed by a 4th and a 5th gear pull. The graph will by broader in higher gears due to load, with similar peak numbers.

[CanAutM3]

Originally Posted by chiplee

Meh, sounds like a lot of very accurate theorizing that doesn't really pan out in real world testing. I don't know why, but you may have to try it yourself with your own car some time if you don't believe me. Do a 3rd gear pull, followed by a 4th and a 5th gear pull. The graph will by broader in higher gears due to load, with similar peak numbers.

I spent a big chunk of my 21 year engineering career around dynos testing aircraft engines. I can tell you with reasonable confidence, it is more than just theorizing. People just love those chassis dynos because they seem to provide so much bragging right. It truth, they are not very precise nor repeatable in providing absolute numbers.

[StealYourFace]

I like his videos, but he has such a strange speech pattern it's downright distracting.
Somebody clearly told him that a pause was much better than saying um or uh, and the big pause......before a verb... just gets old.

Yes I've had a few drinks and was raised by a speech pathologist

Great video, nice work, really want an M3, as quickly as possible.

[chiplee]

Originally Posted by CanAutM3

I spent a big chunk of my 21 year engineering career around dynos testing aircraft engines. I can tell you with reasonable confidence, it is more than just theorizing. People just love those chassis dynos because they seem to provide so much bragging right. It truth, they are not very precise nor repeatable in providing absolute numbers.

Oh, cool. I've been a pilot for around 21 years so I have a special appreciation for people who make aircraft engines safer.

As for this subject, I'm just going by the pulls I've made on dyno's with my other cars. I agree that there's variation between dyno's, but when you're on the same dyno, doing 3 consecutive pulls in 3 different gears, and very little changes, it calls into question the importance of the gear you do the pull in.

[Boss330]

Originally Posted by chiplee

Meh, sounds like a lot of very accurate theorizing that doesn't really pan out in real world testing. I don't know why, but you may have to try it yourself with your own car some time if you don't believe me. Do a 3rd gear pull, followed by a 4th and a 5th gear pull. The graph will by broader in higher gears due to load, with similar peak numbers.

I will just say that when it comes to posters CanAutM3 and swamp2, I respect their theoretical and practical knowledge and regard their posts here as well thought out and accurate. They have a VERY solid engineering background and also a practical experience that leaves most of us on here as mere amateurs...

[Maddict3]

Originally Posted by TheBingoBalls

Don't think he meant it felt like a M5 in that sense. I think the comparison here is that it feels like a small M5 because of the (same?) DCT, both are turbocharged (hence the heaps of low end torque) and perhaps the differential and not that it feels bloated and heavy and handles as such.

I agree, he was also referring to the differential since the m3 shares it with the M5. Regardless the M5 is a great car

[Swancoat]

Originally Posted by Boss330

I will just say that when it comes to posters CanAutM3 and swamp2, I respect their theoretical and practical knowledge and regard their posts here as well thought out and accurate. They have a VERY solid engineering background and also a practical experience that leaves most of us on here as mere amateurs...

Sure, sure. They may have theoretical and practical knowledge, but this is the INTERNET, there's no place for that kind of reasoning. This is where arguments are won and lost with GIFs and LOLCATs.

[-Wingman-]

People are failing to realize that the dyno they tested both cars on are very low reading dynos. And if you don't believe that the new m3 is that much more powerful than the previous m3, take a look at the 1/4 mile times. The best time I think I've ever seen from an e9x m3 with DCT is 12.6 @ 113mph. This current m3 runs 12.2 @ 117mph.

[Transfer]

Good stuff and good review

[Black Gold]

Originally Posted by -Wingman-

People are failing to realize that the dyno they tested both cars on are very low reading dynos. And if you don't believe that the new m3 is that much more powerful than the previous m3, take a look at the 1/4 mile times. The best time I think I've ever seen from an e9x m3 with DCT is 12.6 @ 113mph. This current m3 runs 12.2 @ 117mph.

Agree, but 117 is the worst trap speed for the new m3/4.

The highest trap so far is 120.9. So a 7.9 mph delta between the two cars. Big big difference