[IS3andME]

Originally Posted by adc

I disagree with you on this, It's not hard to make the S55 reliable in race trim at 500BHP. Even if they had to use water injection, not a big deal - and personally I don't think they'd need to.

I have found the S55 to be incredibly thermically stable, and that in a stock heavy street car. And no oil consumption whatsoever, which is unheard of in any previous generation M car. Drop hundreds of pounds with a bespoke race car like they did with the M6, bump the HP by 50 or so and they would be in a much better spot.

Bad thing is that it's too late right now.

If it is not hard to make the S55 reliable in race trim, then why did BMW themselves pick and develop the M6 with the TTV8? Why not pick the M4? Again, are claiming that the S55 will last the endurance races, be reliable against the 911RSR, Corvette, Ford GT, Ferrari 488? Or in GTD class, the Audi R8, Lambo Huracan, AMG GT, Lexus RC-F? Many of these cars are making well over 500 comfortably, whereas the M3/M4 isn't. Plus, there is that crank hub issue.
And again, this is not a few laps, these are endurance races. 24 Hours of Daytona, 12 Hours of Sebring, there is the 24 Hours of Nurburgring, and the 24 Hours of Le Mans. If the S55 is as thermically stable as you say, why no M4? Why no S55? It is a lighter car than the M6. The smaller M3 coupe (now M4) has historically done battle with the 911, which is why BMW decided to go to a V8 with the E46 M3 GTR---their inline 6 wouldn't cut it.

[adc]

Originally Posted by bradleyland

Oh? You run a lot of 24h track days out in your neck of the woods?

What's your running cost at those 24h track days?

How many hours between rebuilds?

All I'm saying is that to my eyes, it's a more promising starting point than say the S62 or S65 were, that's all. No need to be sarcastic when you have absolutely zero evidence to the contrary.

What I was saying is that the big bugaboo of turbo engines on track has been heat management in the past, but the S55 seems to be incredibly well engineered in that respect. If you'd driven one on track you'd probably agree with me too.

I'm not going to sit here and pretend to know that the S55 absolutely isn't viable in the IMSA GTLM class, but the physics are stacked against it. The smallest displacement engine in the competition is the Ford GT at 3.5L. That's a 14% displacement advantage over the S55, and in endurance racing, displacement matters. Just look at all the teething issues the I4t powered DPi cars had. Meanwhile, the 6.2L V8 Cadillacs cruised to victory.

You are comparing a 4 cyl turbo with a V8 more than double in capacity, or is that triple the capacity. Hardly the same as comparing the 3.5 with a 3.0 both turbocharged. I'd agree with you if the HP restriction was 600 BHP or more, but at the 500 BHP level I'm not worried.

I imagine BMW can make a reliable 500 BHP 3L turbocharged endurance engine if Porsche can make a reliable 500 BHP 4L NA one.

I still think that the biggest disadvantage BMW has is aerodynamics, seeing as how they are starting with a sedan body shape/size and not with a bespoke super car like Ford did. It impacts everything from top speed to handling and fuel consumption which is incredibly important in endurance racing. If that is the case, then surely starting with a smaller/lighter car couldn't be a bad thing. And the engine choice would not be such a big factor, or maybe none at all.

Heck maybe they should have gone one smaller still and started with the M2 as the base car, with the S55 in it.

[bradleyland]

Originally Posted by adc

All I'm saying is that to my eyes, it's a more promising starting point than say the S62 or S65 were, that's all. No need to be sarcastic when you have absolutely zero evidence to the contrary.

What I was saying is that the big bugaboo of turbo engines on track has been heat management in the past, but the S55 seems to be incredibly well engineered in that respect. If you'd driven one on track you'd probably agree with me too.

And all I'm saying is that an individual's track experience with the car is irrelevant, because turning a few laps at a track day is about 1% of a full on endurance race. It comes across as an appeal to authority. Having driven an M4 on track has no bearing on your insight in to its appropriateness for the purpose.

[lan4]

Originally Posted by adc

All I'm saying is that to my eyes, it's a more promising starting point than say the S62 or S65 were, that's all. No need to be sarcastic when you have absolutely zero evidence to the contrary.

What I was saying is that the big bugaboo of turbo engines on track has been heat management in the past, but the S55 seems to be incredibly well engineered in that respect. If you'd driven one on track you'd probably agree with me too.



You are comparing a 4 cyl turbo with a V8 more than double in capacity, or is that triple the capacity. Hardly the same as comparing the 3.5 with a 3.0 both turbocharged. I'd agree with you if the HP restriction was 600 BHP or more, but at the 500 BHP level I'm not worried.

I imagine BMW can make a reliable 500 BHP 3L turbocharged endurance engine if Porsche can make a reliable 500 BHP 4L NA one.

I still think that the biggest disadvantage BMW has is aerodynamics, seeing as how they are starting with a sedan body shape/size and not with a bespoke super car like Ford did. It impacts everything from top speed to handling and fuel consumption which is incredibly important in endurance racing. If that is the case, then surely starting with a smaller/lighter car couldn't be a bad thing. And the engine choice would not be such a big factor, or maybe none at all.

Heck maybe they should have gone one smaller still and started with the M2 as the base car, with the S55 in it.

I like the M2 idea, and certainly agree that BMW can make a reliable I6 higher rev smaller displacement endurance race motor. Geez that's all they did years ago. Think you're correct about the aero disadvantage of 4 passenger sedan vs. 2 passenger mid engine super type car (i.e. Ford GT, Ferrari, etc). I would think the Ford GT, Ferrari, etc would be more appropriate in DP class (like the McLaren F1 used to run at LeMans), but that's not gonna happen.

[MiamiE93Vert]

The elephant in the room is the competitors in GTLM are putting out Huricans, GT's, NSX, 388's and R8's and BMW's answer is to convince us the M6 is their competition; it just isn't on that level. Put a TTv8 in an I8 body, call it an M8 or whatever to get it to the public and let's win some races.

[bradleyland]

Originally Posted by IS3andME

The Corvette win because the leading Porsche 911 effed up in the pits, ran over a hose. The Porsche 911RSR was showing some considerable speed and stability during qualifying. That was from observation. Even last year there was observation that the Corvette team was having a handful with the mid engined Ford GTs and Ferraris. And now the 911 is mid engined. Coincidence that GM is testing a mid engined car, that possibly is a C8 Corvette or a Cadillac halo car?
What is happening is GTLM is shaping up to be the GT1 of the 90s.

I get what you are saying.

I missed this earlier. I'm afraid that's a misstatement. Antonio Garcia in the #3 Corvette lead for 40 laps (only 6 of which were under caution) from lap 294 to lap 334 (finish). Garcia went purple several times during that period. Pilet made a heroic effort, but to characterize the Corvette win as having been a result of the pit lane infraction is just wrong.

Have a look at this lap position chart from Alkamel Systems. The #3 car starts its climb up the ranks at lap 272 after they came off that full course yellow. The #911 car traded ranks with the #3 one time, but Garcia came back and held his lead for 9 laps before the final full course yellow of the race. At that point, the #911 had to pit because they were on a different pit strategy than the rest of the GTLM field. That's when the air hose incident occurred.

The #911 wasn't leading when that occurred, and the #3 car had no trouble gapping the field. To characterize this sequence of events as the Corvette struggling is just mind boggling to me.

[bradleyland]

For anyone interested, there is a ton of data and information on Alkamel Systems' website:

http://imsa.alkamelsystems.com

They're the official timing provider for IMSA, so you can consider the data authoritative.

[bradleyland]

Originally Posted by MiamiE93Vert

The elephant in the room is the competitors in GTLM are putting out Huricans, GT's, NSX, 388's and R8's and BMW's answer is to convince us the M6 is their competition; it just isn't on that level. Put a TTv8 in an I8 body, call it an M8 or whatever to get it to the public and let's win some races.

This is homologation racing. If we were talking about an unlimited series, then sure, the M6 wouldn't stand a chance against cars like the Ford GT and the Ferrari 488. The manufacturers build to a performance envelope though.

The base car selection really doesn't have all that much to do with the racing results. Even though the M6 starts with massive frontal area and a large footprint, the performance envelope, combined with BoP packages, keeps the playing field even. Hell, look at the ST class in the Continental Tire series. There is a FWD Nissan Altima Coupe that came in 2nd place in a field of Porsche Caymans. A FWD Mini Cooper won the Rolex 24 at Daytona. You have to reset your mindset for homologation racing.

What I see when I watch the races is the M6 struggle to hold a line; it looks like a real handful. During the full-course yellow on lap 73, pit strategy put the #25 in 2nd place. The #3 Corvette passed Bill (in the #25), and as the M6 followed the Corvette through some esses, you could really see the difference in the line. The M6 practically looked like a drift car compared to the line the Corvette was able to hold. Even the commentators said something about the massive difference in line.

The BMW driver line up are turning laps within 1s of the leaders in a lot of cases, but they're working their asses off to do so. I don't think the M6 GTLM is a very competitive race car, but I don't think it's because they chose an M6. I just think this generation of BMW GTLM car is not competitive.

If I were picking a culprit (from a pure pace perspective), I would say that the engineering team is struggling with the massive leap between the Z4 GTLM and the M6 GTLM. These two cars couldn't be more different, and I have yet to see the M6 GTLM look competitive on track. I'm not talking about lap times, I'm talking about watching races and seeing the M6 GTLM go head-to-head with other cars.

And before anyone resorts to the argument that the M6 GTLM isn't a "real" GTLM car, the Z4 GTE/GTLM was developed from the Z4 GT3 as well. Also note that the GTD (GT3) field is only a couple of seconds off pace from the GTLM field.

[MiamiE93Vert]

Originally Posted by bradleyland

This is homologation racing. If we were talking about an unlimited series, then sure, the M6 wouldn't stand a chance against cars like the Ford GT and the Ferrari 488. The manufacturers build to a performance envelope though.

The base car selection really doesn't have all that much to do with the racing results. Even though the M6 starts with massive frontal area and a large footprint, the performance envelope, combined with BoP packages, keeps the playing field even. Hell, look at the ST class in the Continental Tire series. There is a FWD Nissan Altima Coupe that came in 2nd place in a field of Porsche Caymans. A FWD Mini Cooper won the Rolex 24 at Daytona. You have to reset your mindset for homologation racing.

What I see when I watch the races is the M6 struggle to hold a line; it looks like a real handful. During the full-course yellow on lap 73, pit strategy put the #25 in 2nd place. The #3 Corvette passed Bill (in the #25), and as the M6 followed the Corvette through some esses, you could really see the difference in the line. The M6 practically looked like a drift car compared to the line the Corvette was able to hold. Even the commentators said something about the massive difference in line.

The BMW driver line up are turning laps within 1s of the leaders in a lot of cases, but they're working their asses off to do so. I don't think the M6 GTLM is a very competitive race car, but I don't think it's because they chose an M6. I just think this generation of BMW GTLM car is not competitive.

If I were picking a culprit (from a pure pace perspective), I would say that the engineering team is struggling with the massive leap between the Z4 GTLM and the M6 GTLM. These two cars couldn't be more different, and I have yet to see the M6 GTLM look competitive on track. I'm not talking about lap times, I'm talking about watching races and seeing the M6 GTLM go head-to-head with other cars.

And before anyone resorts to the argument that the M6 GTLM isn't a "real" GTLM car, the Z4 GTE/GTLM was developed from the Z4 GT3 as well. Also note that the GTD (GT3) field is only a couple of seconds off pace from the GTLM field.

I hear you, but there is still a connection between the race car and the street car even if it is somewhat imaginary and this is worth big dollars in marketing and goodwill. I used to love watching my M3 on the track even if only the GS was mostly coming from the road version. Even the manufacturers stoke the connections. I forgot which company had the commercial during the race but there was a company that ran GTLM/GTD cars on the track next to the street cars: it was 911, GT, 488, R8 and M6. Clearly they are putting, or trying to put, the M6 in the same category; which of these would you choose to take to the track? The choice to make a connection between M6 race and street car was BMW's.

[bradleyland]

Originally Posted by MiamiE93Vert

I hear you, but there is still a connection between the race car and the street car even if it is somewhat imaginary and this is worth big dollars in marketing and goodwill. I used to love watching my M3 on the track even if only the GS was mostly coming from the road version. Even the manufacturers stoke the connections. I forgot which company had the commercial during the race but there was a company that ran GTLM/GTD cars on the track next to the street cars: it was 911, GT, 488, R8 and M6. Clearly they are putting, or trying to put, the M6 in the same category; which of these would you choose to take to the track? The choice to make a connection between M6 race and street car was BMW's.

Of course they do. That's marketing. It doesn't mean there is any technical truth to it though. The only thing meaningful in that context is how close the road car is to the race car. Word is that the Ford GT is pretty damn close to the road car; which isn't all that surprising when you consider that even the road car is going to be assembled by Multimatic in Ontario (the same people who build the GTLM cars).

Have a close look at the M6 GTLM the next time you get the chance. Any comparison to the road car is laughable. I'm afraid the road car is simply irrelevant.

I know I sound like a broken record, but the manufacturers given whatever leeway is required to develop these cars to a performance envelope. There are technical restrictions, but if you read through them, they're pretty loose. They restrict things like overall dimension and preservation of "key components".

For example, IMSA's GTLM regulation 9.5 for chassis says: "Entrants may execute minimum modifications for the installation of components." A sub-entry says, "All modifications must be approved by IMSA." There is no firm definition there. BMW can basically change whatever is required to get to the envelope, and IMSA can sign off on it unilaterally (without approval from other manufacturers).

Have a look through the technical regs for yourself. They're surprisingly sparse. It all comes down to getting the cars to the performance envelope. No consideration is given to how close they are to the road car, outside of some token requirements, like requiring that they use the same displacement engine as the road car.

http://www.imsa.com/sites/default/fi..._blackline.pdf

[adc]

Originally Posted by bradleyland

And all I'm saying is that an individual's track experience with the car is irrelevant, because turning a few laps at a track day is about 1% of a full on endurance race. It comes across as an appeal to authority. Having driven an M4 on track has no bearing on your insight in to its appropriateness for the purpose.

The experience of driving a particular car on track is not irrelevant. It is, for example, a lot more relevant than NOT driving it on track, yet claiming authority to comment on its potential for endurance racing.

The longest I've run it continuously was 55 min in 100 degree heat. Ran out of gas, the car was very solid up to that point.

How about you?

[adc]

Originally Posted by IS3andME

If it is not hard to make the S55 reliable in race trim, then why did BMW themselves pick and develop the M6 with the TTV8? Why not pick the M4? Again, are claiming that the S55 will last the endurance races, be reliable against the 911RSR, Corvette, Ford GT, Ferrari 488? Or in GTD class, the Audi R8, Lambo Huracan, AMG GT, Lexus RC-F? Many of these cars are making well over 500 comfortably, whereas the M3/M4 isn't. Plus, there is that crank hub issue.
And again, this is not a few laps, these are endurance races. 24 Hours of Daytona, 12 Hours of Sebring, there is the 24 Hours of Nurburgring, and the 24 Hours of Le Mans. If the S55 is as thermically stable as you say, why no M4? Why no S55? It is a lighter car than the M6. The smaller M3 coupe (now M4) has historically done battle with the 911, which is why BMW decided to go to a V8 with the E46 M3 GTR---their inline 6 wouldn't cut it.

M4 GT4 should come out soon and will no doubt be run in various endurance races.

Wait, actually it just ran in the 24 of Dubai in its maiden race and did reasonably well - certainly finished the race, and the lap times were better than all the GT4 cars (2:10 fastest lap, midway between the GT4 class - the best of which ran 2:11/12 - and the 911 Cups at 2:05+). Not sure why it was classed as SPX and not SP1, anyway...

So we'll see this year not only how reliable it is for endurance, but also how competitive in the GT4 class.

As to your other question my personal answers are marketing, and they obviously thought the bigger engine would erase some of the other sins. It makes sense on paper - since the HP Is limited, the shape of the torque curve is the only thing left that could give you an advantage along with fuel economy. Somehow maybe it just didn't translate? Maybe it's just too big of a whale and the aero is simply not competitive in a field of lean sharks.

Things have massively changed since 10, or 5 or even 3 years ago, there is more competition that actually knows what they're doing. BMW has also been absent from the higher forms of Motorsport - IMO it matters, it's all related. Their focus has shifted in recent years, and it's now percolating down here.

[bradleyland]

Originally Posted by adc

The experience of driving a particular car on track is not irrelevant. It is, for example, a lot more relevant than NOT driving it on track, yet claiming authority to comment on its potential for endurance racing.

The longest I've run it continuously was 55 min in 100 degree heat. Ran out of gas, the car was very solid up to that point.

How about you?

Which is less than half the duration of the shortest races on the IMSA schedule, and 3.6% of a 24h endurance race.

I know it really excites you to be able to talk about your track days, but it's irrelevant in this conversation. That is, unless you did a post-track-day teardown so you could understand which components underwent additional wear and tear.

Like I said, irrelevant.

I'm not claiming any authority, I'm citing the environment in which the S55 would compete, and pointing out a de facto displacement disadvantage it would have against the rest of the field. None of these rely on my status as an authority to be true. Thus, I am not suffering from any delusions, nor am I making fallacious arguments.

Vis a vis: a man who has never been outside can still assuredly assert that the sky is blue.

I'm also specifically not claiming that the S55 couldn't be used in an endurance context. Plenty of LMP2 cars run less displacement with more power output for the full 24h duration. My point is that it would be a disadvantage relative to the rest of the field in terms of cost and durability. How much so is open to debate.

[adc]

Originally Posted by bradleyland

Which is less than half the duration of the shortest races on the IMSA schedule, and 3.6% of a 24h endurance race.

I know it really excites you to be able to talk about your track days, but it's irrelevant in this conversation. That is, unless you did a post-track-day teardown so you could understand which components underwent additional wear and tear.

Like I said, irrelevant.

I'm not claiming any authority, I'm citing the environment in which the S55 would compete, and pointing out a de facto displacement disadvantage it would have against the rest of the field. None of these rely on my status as an authority to be true. Thus, I am not suffering from any delusions, nor am I making fallacious arguments.

Empirical evidence sometimes works you know.

I didn't do a post track day tear down, I drove home and later participated in other track days - all without needing to top the oil. By contrast, the E36, E46 and E90 I've tracked before have all needed ever so slightly increasing amounts of engine oil, surely the simplest way to asses the wear on the most obvious engine parts.

I could be wrong as well. But BMW has released the M4 GT4 with the S55 in it. If they weren't confident it could take it they would have done something different surely.

Vis a vis: a man who has never been outside can still assuredly assert that the sky is blue.

He can assert anything he wants, that's the definition of an assertion. Assertions cover both facts and beliefs.

My point is that it would be a disadvantage relative to the rest of the field in terms of cost and durability. How much so is open to debate.

You don't even know that for sure. Otherwise why would Chevy stop at 6.2L of NA displacement, or why would Ferrari stop at 3.9L and why would Ford use a smaller 3.5L engine if that puts them at a disadvantage? Maybe 8L V12 twin turbo is the best way to go.

Perhaps there's a sweet spot in terms of displacement for the given power restrictions, and perhaps it's different for turbo and NA engines. You have no idea if that is true or not (or if it's true what the sweet spot is).

You're just as much an amateur as most others on this forum, stop putting other people down when they offer a comment, even when you think it's silly. We're all here to talk about cars, so lighten up.

[bradleyland]

Originally Posted by adc

Empirical evidence sometimes works you know.

I didn't do a post track day tear down, I drove home and later participated in other track days - all without needing to top the oil. By contrast, the E36, E46 and E90 I've tracked before have all needed ever so slightly increasing amounts of engine oil, surely the simplest way to asses the wear on the most obvious engine parts.

I'm not sure why you're so attached to this. The differences between a track day here and there versus an endurance racing environment seem obvious to me, but OK.

Originally Posted by adc

I could be wrong as well. But BMW has released the M4 GT4 with the S55 in it. If they weren't confident it could take it they would have done something different surely.

GT4 run lower power levels than GTLM.

Originally Posted by adc

You don't even know that for sure. Otherwise why would Chevy stop at 6.2L of NA displacement, or why would Ferrari stop at 3.9L and why would Ford use a smaller 3.5L engine if that puts them at a disadvantage? Maybe 8L V12 twin turbo is the best way to go.

Perhaps there's a sweet spot in terms of displacement for the given power restrictions, and perhaps it's different for turbo and NA engines. You have no idea if that is true or not (or if it's true what the sweet spot is).

That's a fair argument. The physics are undeniable though; using the S55 would require more output per liter than the competition. That will work the engine harder, which has implications in engineering. I've been open all along to the fact that this is where the real matter of opinion lies, and I don't have any more authority than the next guy.

Originally Posted by adc

You're just as much an amateur as most others on this forum, stop putting other people down when they offer a comment, even when you think it's silly. We're all here to talk about cars, so lighten up.

This is getting really tedious. Again, I'm not trying to assert any authority. I'm pointing out some pretty obvious facts, and asserting some inferences from there. I also haven't put you down. Rhetorical question are a rhetorical device. I don't mean them to be incisive. They were intended to point out very clear differences between a track day and endurance racing.

[Ayrton91]

Just got this on my FB feed and thought the timing was perfect for this clearly marketing piece to meet the reality of last weekend's race. I found the design section specially hilarious...

https://drivetribe.com/p/CzNhXcG4Qjq...TXWziLD5TSxlYQ

[bradleyland]

Originally Posted by Ayrton91

Just got this on my FB feed and thought the timing was perfect for this clearly marketing piece to meet the reality of last weekend's race. I found the design section specially hilarious...

https://drivetribe.com/p/CzNhXcG4Qjq...TXWziLD5TSxlYQ

Man, this is hilarious. Is this satire?

[Ayrton91]

Originally Posted by bradleyland

Man, this is hilarious. Is this satire?

I know, right? And for it to be posted in the BMW Motorsport official FB page....

[MiamiE93Vert]

Originally Posted by Ayrton91

I know, right? And for it to be posted in the BMW Motorsport official FB page....

I drop the mike on my point above.

[3GFX]

I've always questioned why they wouldn't pull the M3 or M4 platform into this series.

Personally the M6 was a step in the wrong direction. BMW was adamant that the lengthened wheelbase and overall shape would increase stability and top speed.

What they've done is lose any advantage to gain neutral handling.

#bringbackthez4