M1 engine speculation

[jeremyc74]

Originally Posted by dmboone25

First of all, I will admit ignorance before asking this question....

Why is is difficult to build an FI engine that is both 1) high revving, and 2) expresses minimal turbo lag?

I honestly don't know--but it seems like if they could make an FI engine that had a low RPM max torgque figure, and that revved (without the dropoff the N54 experiences at 5500 RPM) hard until 7K or more, that almost everyone could be happy.

Is it not possible?

The problem comes with sizing the turbocharger. As the RPM goes up, you have to flow more air per second to feed the engine. A small turbocharger has a physical limitation when it comes to flow, so that means the size has to be increased.

The problem with increasing the size is that it also moves the efficiency range of the turbo into a higher RPM band, which means the power curve isn't as flat and around town driveability suffers. Small wheels don't work well at high flow rates, and larger wheels don't work well at lower flow rates. Increasing the size also increases the spool time (the time it takes the wheels to react to a change in exhaust flow) as well, which hurts throttle transition times, making the power harder to balance in corners due to the "overshoot/undershoot" created by the boost coming on.

The sequential systems that have been talked about are an effort to get around these physical limitations by using a small turbo at lower RPM and a larger turbo at higher RPM, but it comes with increased expense, complexity, and possibly weight.

[dmboone25]

Originally Posted by jeremyc74

The problem comes with sizing the turbocharger. As the RPM goes up, you have to flow more air per second to feed the engine. A small turbocharger has a physical limitation when it comes to flow, so that means the size has to be increased.

The problem with increasing the size is that it also moves the efficiency range of the turbo into a higher RPM band, which means the power curve isn't as flat and around town driveability suffers. Small wheels don't work well at high flow rates, and larger wheels don't work well at lower flow rates. Increasing the size also increases the spool time (the time it takes the wheels to react to a change in exhaust flow) as well, which hurts throttle transition times, making the power harder to balance in corners due to the "overshoot/undershoot" created by the boost coming on.

The sequential systems that have been talked about are an effort to get around these physical limitations by using a small turbo at lower RPM and a larger turbo at higher RPM, but it comes with increased expense, complexity, and possibly weight.

Thank you for the explanation--that makes sense....

I have been reading many of these threads, and it seemed to me that the 1 small and 1 big would be the way to go, logically.

It seems that would require an assload of R&D, yes? Which is why we will get some "different" form of the N55, to try and pass the "special engine" test that is usually present in the ///M models...

I agree, too, and have said so in other posts, that the limiting of the M1 to not tread on the toes of the M3 is just nuts...just as the ///M models have different purposes than the standard BMW lines, why can't the individual ///M models have singular purposes themselves?

Small, fast, low on the comforts? M1. Bigger, still fast, more luxurious? M3....and so on and so on.....but we have basically been told that the M1 will not be as good as it can be, and I agree that such a stance by BMW is disappointing....

[JasonCSU]

Originally Posted by jeremyc74

The smallest, lightest car should be the fastest. It requires the most sacrifice in practicality, and should come with the most reward in performance. If a person is not willing to compromise on space to gain performance, they could step up to the M3, which could be a very close second.

I would agree as well, but wouldn't this mean there should be a Z4 M with a fixed roof and the S65 to power it?

[jeremyc74]

Originally Posted by JasonCSU

I would agree as well, but wouldn't this mean there should be a Z4 M with a fixed roof and the S65 to power it?

In the past it would have, but the current Z4 is heavier than the 135i if I'm not mistaken. It seems like I read it weighs in over 3600lbs.

[grant]

I think a good part of the weight comes from the folding hard top which would be lost with a fixed roof (preferably Carbon Fiber too).

[jeremyc74]

Originally Posted by grant

I think a good part of the weight comes from the folding hard top which would be lost with a fixed roof (preferably Carbon Fiber too).

I'm sure a lot of it is, but I'm not sure it's going to loose 200lbs going from a folding top to a fixed roof. I could be wrong though.

[grant]

I think it would lose 200 pounds going from a folding steel roof to a CF fixed one, but the 1er will lose weight by going to a CF roof too (so Z4M won't weight less than M1 anyways, in all likelihood).

[BMW86]

Originally Posted by jeremyc74

I'm sure a lot of it is, but I'm not sure it's going to loose 200lbs going from a folding top to a fixed roof. I could be wrong though.

The hard top will lose quite a bit more than 200lbs. Hard-top technology is very heavy.

[jeremyc74]

Originally Posted by BMW86

The hard top will lose quite a bit more than 200lbs. Hard-top technology is very heavy.

Ok, possibly, but the M1 is supposed to weigh in around 3300lbs, so they're going to be very similar.

Are there even plans for a Z4 Coupe right now?

[JasonCSU]

Originally Posted by jeremyc74

Ok, possibly, but the M1 is supposed to weigh in around 3300lbs, so they're going to be very similar.

Are there even plans for a Z4 Coupe right now?

Not as far as I know. We're just speculating based on BMW previously saying there would not be a Z3 M Roadster/Coupe, or a Z4 M Roadster/Coupe. It wouldn't surprise me at all if an M version of the new Z4 showed up. I must admit that I'm more intrigued by a potential Z2 roadster or coupe though.

[Advevo]

There is only one engine which belongs in a ///M motorsport car. That s high rev.

If it s a turbo than the ///M letter on the boot stands for ///M arketing.

Here is explaination from a man who knows and have driven almost everything he explains it s very well.

Yes turbo is nice for open roads but for open roads i don t buy an expensive ///M motorsport car a 320d will do.

[adc]

Originally Posted by Advevo

Here is explaination from a man who knows and have driven almost everything he explains it s very well.

1. He doesn't address the 911 GT2 - surely the ultimate 911??

2. When he was winning rally races, he was doing it in a turbocharged car.

3. The only ///M marketing that should truly sting is that they shove us 4000, 5000lbs cars and have the audacity to say they are bred for the track, or some such nonsense.

The M1, turbo and all, has the opportunity to be the best M car in a looong time... whether or not it will fullfil that or not remains to be seen.

[sparoz]

Well, remember why the M3 was so successful is that you have a very capable car in a trim that you can drive in.

That's why M3 won so many awards previously, esp the E36 and E46.

The strip down version should be a GTS or a CSL and not the standard M.

[JasonCSU]

Originally Posted by Advevo

There is only one engine which belongs in a ///M motorsport car. That s high rev.

If it s a turbo than the ///M letter on the boot stands for ///M arketing.

Here is explaination from a man who knows and have driven almost everything he explains it s very well.

Yes turbo is nice for open roads but for open roads i don t buy an expensive ///M motorsport car a 320d will do.

We've been over this before though. While many of us enjoy and would like to see a high-rev NA engine, it's just not as feasible to meet the stricter fuel economy and emissions requirements like a turbo engine can.

[Advevo]

jason i get that.

But that s not the reason at bmw. if that s the reason they should not bring a 760i, x5 ///M x6///M in the first place. Even with turbo s they have huge Co2.

x5///M has 325 co2 an X5 4.8 has 324 co2.

So please stop.

It all has to do to with money. The easy way. Most americans buy it anyway.

Think about it. An ///M car. Motorsports heritage. Just grab an AG engine change some parts and you have motorsports engine. What a laugh.
6 cil and v8 and v10 are real motorsports engines from ///M themselfs. All those turbo s are souped up AG engines but with an ///M pricetag on it.

It s not even worth it to put an ///M logo on the boot if it has a turbo engine.

[amdmaxx]

It's EPA, not money..
And M is not just about engine....
and you have to get with the program. In 5 years ALL M cars will be turbocharged.. If you don't like - go on strike or something.
Personally, I'll love myself a Tuebo'ed M car.

[Red Bread]

Why does everyone assume that the carbon roof will save any weight? I realize that a sunroof delete will save weight, but just replacing a piece of steel with a non-stressed piece of 3k weave carbon is unlikely to save more than five pounds, if that. I think I recall that it was listed as 5 pounds for the M6 and I don't think I've seen any stats for the M3, but I'd guess it's
negligible too.

This is simply style over substance. If BMW could replace the steel roof substructure with stressed carbon, then we'd be getting somewhere with weight savings, but that would likely require new crash testing, where a beauty panel doesn't.

I'm also one of the few that hates the idea of a turbo M motor (and I own an imitation M motor already, the S52b32us) and hate that AMG's power game has led the M Division into silly power games instead of balance and useful power. I'm still hoping that there will be a four cylinder, light weight version of the next 1er, at least as a tii or similar model.

[PrimoM3]

Originally Posted by Red Bread

Why does everyone assume that the carbon roof will save any weight? I realize that a sunroof delete will save weight, but just replacing a piece of steel with a non-stressed piece of 3k weave carbon is unlikely to save more than five pounds, if that. I think I recall that it was listed as 5 pounds for the M6 and I don't think I've seen any stats for the M3, but I'd guess it's
negligible too.

This is simply style over substance. If BMW could replace the steel roof substructure with stressed carbon, then we'd be getting somewhere with weight savings, but that would likely require new crash testing, where a beauty panel doesn't.

The US didn't get a sunroof delete option, so it means reduced material weight (metal --> carbon) as well as no glass or motor from the sunroof. We're probably talking about 40 lbs. here and from the highest point on the car, which makes a bigger impact than "40 lb's" might imply. Similar to how unsprung weight reduction from the wheels and suspension can make a big difference.

RE: Turbo ///M motors - some of you guys just have to get over it. Right, wrong or indifferent - it's where we're at. It's outside of your level of influence, get on board or move to another make. With that said, really hope they figure out the throttle response on these cars.

[PrimoM3]

Originally Posted by jeremyc74

Ok, possibly, but the M1 is supposed to weigh in around 3300lbs, ...

I missed this, where'd you find the information or was it surmised?

I REALLY hope you're wrong.

[Red Bread]

Originally Posted by Primo135

RE: Turbo ///M motors - some of you guys just have to get over it. Right, wrong or indifferent - it's where we're at. It's outside of your level of influence, get on board or move to another make. With that said, really hope they figure out the throttle response on these cars.

Agreed, but it doesn't mean I'll ever buy one, and it also doesn't mean that anyone in Munich will care. They sell all sorts of things I have absolutely no interest in.

Dual clutch gearboxes are another area that the consumer has spoken, and I've chosen to think they're idiots. It won't concern manufacturers, and if anything, it will just be another thing that makes buying new cars hard on me. Oh well.

[PrimoM3]

Originally Posted by Red Bread

Dual clutch gearboxes are another area that the consumer has spoken, and I've chosen to think they're idiots. It won't concern manufacturers, and if anything, it will just be another thing that makes buying new cars hard on me. Oh well.

We are in strong agreement on that one for sure, amigo.

[larryn]

Originally Posted by Primo135

We are in strong agreement on that one for sure, amigo.

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