[nublu2u]

Clearly a cost decision, BMW chose not to engineer a fix. BMW probably thought, no-one can tell the difference between a steel or CFRP driveshaft when driving, and the G80/82 is going to heavy anyway.

I believe Alfa Romeo, magically, still have CFRP driveshafts on the Giulia and Stelvio Quadrifoglios

[Sedan_Clan]

Originally Posted by nublu2u

Clearly a cost decision, BMW chose not to engineer a fix. BMW probably thought, no-one can tell the difference between a steel or CFRP driveshaft when driving, and the G80/82 is going to heavy anyway.

I believe Alfa Romeo, magically, still have CFRP driveshafts on the Giulia and Stelvio Quadrifoglios

It was a size constraint based on the chassis. Alfa is awaiting your dollars.

[Jproos]

Originally Posted by NISFAN

Great video........see what you could have had

Rule #1 in marketing - if something is worse or in any way negative on the new model STFU about it.

Exactly. I can't imagine what they think they're doing with this video. It's essentially a bunch of 'see what we wanted to do and how much we had to deviate'.

[VIERsr]

Giulia and Stelvio Quadrifoglio don't have any OPF, they meet the new regulations without it.
It's not hard to understand, the CFRP DS was too big to fit, making it with a thinner diameter would have meant making it thicker (more 'material') with no advantage in weight saving but a lot of extra cost. Basically useless.
But maybe someone lives better knowing there is a carbon fibre CF under their car at any cost even though it would have no advantage.

[thaalrasha]

Originally Posted by Poochie

I agree, it's total bullcrap reasoning on why it couldn't be done..

If they wanted to, they could of fitted a carbon fiber driveshaft, with an OPF filter and find some work-around but you know, that's just more added cost that they can't up-charge you for in some optional $4,000 "performance" package, so why bother when they can just increase the boost pressure to compensate for the potential lost of unsprung weight reduction.

Guys, they need to leave room for the up coming CS / CSL...
My guess is that all the CFRP parts that went missing from F80 to G80 ... we will see them again on the CSL version ... horse shoe, shaft, hood, trunk...

[Sedan_Clan]

Originally Posted by VIERsr

Giulia and Stelvio Quadrifoglio don't have any OPF, they meet the new regulations without it.
It's not hard to understand, the CFRP DS was too big to fit, making it with a thinner diameter would have meant making it thicker (more 'material') with no advantage in weight saving but a lot of extra cost. Basically useless.
But maybe someone lives better knowing there is a carbon fibre CF under their car at any cost even though it would have no advantage.

Agreed!

[filostrato]

Originally Posted by thaalrasha

Guys, they need to leave room for the up coming CS / CSL...
My guess is that all the CFRP parts that went missing from F80 to G80 ... we will see them again on the CSL version ... horse shoe, shaft, hood, trunk...

No doubt! They've already gotten many of the enthusiasts worked up over the generational weight gain and will come to the rescue with the CS/CSL

It will be interesting to see if the drive shaft is included though. That part seems like a lot of cost in materials and engineering for a minimal performance gain. But if people will pay...

[Poochie]

Originally Posted by filostrato

No doubt!
It will be interesting to see if the drive shaft is included though. That part seems like a lot of cost in materials and engineering for a minimal performance gain. But if people will pay...

They probably will magically be able to fit carbon driveshaft if they are going to utilize the CSL moniker; how else are they suppose to reduce weight and make it feel more free-revving.

Custom carbon driveshaft at the local level goes for about 2 to $3,000 and is paperweight in comparison to steel.

Deducing from that, I'm convinced that in the case with the G8X, there was some number crunching and the bean-counters triumphed over the engineers, so then steel was ultimately settled on. If they can save like say $500 per vehicle, it adds up.

I'm not upset, I just don't appreciate my intelligence being insulted but either way, I still want one but the truth would of been divine.

[VIERsr]

Originally Posted by Poochie

They probably will magically be able to fit carbon driveshaft if they are going to utilize the CSL moniker; how else are they suppose to reduce weight and make it feel more free-revving.

Custom carbon driveshafts at the local level goes for about 2 to $3,000 and is paperweight in comparison to steel.

Deducing from that, I'm convinced that in the case with the G8X, there was some number crunching and the bean-counters triumphed over the engineers, so then steel was ultimately settled on. If they can save like say $500 per vehicle, it adds up.

I'm not upset, I just don't appreciate my intelligence being insulted but either way, I still want one but the truth would of been divine.

This has been explained quite well. There is no room on the G8x to fit a DS larger than 50mm - compared to 90mm (before OPF) and 70mm (after OPF) on the F8x - and with this diameter the CFRP would offer no weight savings because it would have to be built very thick to provide the right strength and resistance.

[Sedan_Clan]

Originally Posted by VIERsr

This has been explained quite well. There is no room on the G8x to fit a DS larger than 50mm - compared to 90mm (before OPF) and 70mm (after OPF) on the F8x - and with this diameter the CFRP would offer no weight savings because it would have to be built very thick to provide the right strength and resistance.

It's a conspiracy to the irrational and completely understandable to the rational.

[NISFAN]

Originally Posted by Poochie

They probably will magically be able to fit carbon driveshaft if they are going to utilize the CSL moniker; how else are they suppose to reduce weight and make it feel more free-revving.

Custom carbon driveshafts at the local level goes for about 2 to $3,000 and is paperweight in comparison to steel.

Deducing from that, I'm convinced that in the case with the G8X, there was some number crunching and the bean-counters triumphed over the engineers, so then steel was ultimately settled on. If they can save like say $500 per vehicle, it adds up.

I'm not upset, I just don't appreciate my intelligence being insulted but either way, I still want one but the truth would of been divine.

Whilst there were supposedly engineering reasons to drop CF DS from F82, I found it odd that it appears they made no changes to the tunnel heat shield. Which indicates the extra 'space' created by a narrower steel DS was not made use of.

I suspect in the case of F82, it was the heat from the OPF that they were concerned about damaging the carbon, not the size, but then why give the wrong reason? :

[xlover]

Originally Posted by Sedan_Clan

It's a conspiracy to the irrational and completely understandable to the rational.

I think it comes down to those who think the M3 is or should be some totally bespoke car.... it would have been idiotic for them to design a special opf filter dimension just for the series g8x so it could have a carbon fiber driveshaft....

On top of that I haven't seen one piece of data that showed the carbon fiber driver shaft actually affected lap times or acceleration in a measurable way.... my opinion is the carbon driveshaft was essentially a "because race car" marketing feature which is why it was so easy to ditch when they need the space back. Yes there is probably some some calculator that showed 0.0001% benefit but nothing any owner ever noticed in the real world

[Sedan_Clan]

Originally Posted by xlover

I think it comes down to those who think the M3 is or should be some totally bespoke car.... it would have been idiotic for them to design a special opf filter dimension just for the g8x so it could have a carbon fiber driveshaft....

On top of that I haven't seen one piece of data that showed the carbon fiber driver shaft actually affected lap times or acceleration in a measurable way.... my opinion is the carbon driveshaft was essentially a "because race car" marketing option which is why it was so easy to ditch when they need the space back. Yes there is probably some some calculator that showed 0.0001% benefit but nothing any owner ever noticed in the real world

I agree about the, "because bespoke/because race car" forum mentality.

[VIERsr]

It's amazing how people without any knowledge of the car and its specifics assume that Bmw's engineers are lying

[nublu2u]

Originally Posted by VIERsr

Giulia and Stelvio Quadrifoglio don't have any OPF, they meet the new regulations without it.
It's not hard to understand, the CFRP DS was too big to fit, making it with a thinner diameter would have meant making it thicker (more 'material') with no advantage in weight saving but a lot of extra cost. Basically useless.
But maybe someone lives better knowing there is a carbon fibre CF under their car at any cost even though it would have no advantage.

Thanks for that, didn’t know. So Alfa Romeo engineered a solution where they didn’t have to add OPF, thereby maintaining a great exhaust note? Maybe BMW should hire those guys

[VIERsr]

Originally Posted by nublu2u

Thanks for that, didn’t know. So Alfa Romeo engineered a solution where they didn’t have to add OPF, thereby maintaining a great exhaust note? Maybe BMW should hire those guys

They did and it was a great achievement. Even Ferrari uses OPFs on their new engines.

[Poochie]

Originally Posted by VIERsr

This has been explained quite well. There is no room on the G8x to fit a DS larger than 50mm - compared to 90mm (before OPF) and 70mm (after OPF) on the F8x - and with this diameter the CFRP would offer no weight savings because it would have to be built very thick to provide the right strength and resistance.

They can engineer a car from the ground up, the size of an old M5, that could probably fit the entire Noah's Ark but they can't design a work-around in a few inches in diameter. Sorry, I'm just not buying it.

It doesn't matter anyway, a carbon driveshaft was an exotic option and it was frankly a gift they added it to the previous model but steel is denser and cheaper but adds unsprung weight, the worst of all weights.

Like I said, I'm not mad at them, do your thing BMW AG, I'll still give them my money and I don't believe it's a conspiracy; like everything else, it came down to money. It's all good.

[wdskukm3]

90mm to 50mm is a big reduction from the carbon shaft. Just look at the thickness of the carbon shaft. The 50mm just looks small and thin.. Hopefully the shaft can handle the power increase from the motor when upgrading..

[Patrik]

Originally Posted by VIERsr

Giulia and Stelvio Quadrifoglio don't have any OPF, they meet the new regulations without it.
It's not hard to understand, the CFRP DS was too big to fit, making it with a thinner diameter would have meant making it thicker (more 'material') with no advantage in weight saving but a lot of extra cost. Basically useless.
But maybe someone lives better knowing there is a carbon fibre CF under their car at any cost even though it would have no advantage.

+1

And there’s also the fact that a company never just gives something more expensive for free. A carbon shaft would’ve either increased the price of the car or taken away from something else.

As for the Alfa Romeo comparison, I’d much rather have the German-engineered car with the steel shaft than a car that breaks down already during their first drives. Fancy CFRP shaft or not.

[Boss330]

Originally Posted by VIERsr

They did and it was a great achievement. Even Ferrari uses OPFs on their new engines.

Originally Posted by nublu2u

Thanks for that, didn't know. So Alfa Romeo engineered a solution where they didn't have to add OPF, thereby maintaining a great exhaust note? Maybe BMW should hire those guys

Originally Posted by VIERsr

They did and it was a great achievement. Even Ferrari uses OPFs on their new engines.

It's not because AR have made a breakthrough in engineering... 😉

They just have added port injection to the engine in the Quadrafoglio. Port injection creates less particles during combustion since the fuel is injected in a more liquid state under low pressure in the port. DI engines atomize the fuel into a fine mist as it's injected under high pressure (same reason why diesel engines also need a particulate filter), which is why DI engines generate more particles during combustion.

Port injection is less fuel efficient and doesn't give as much control over combustion as DI.

The first version of the AR engine just had DI, they added port injection to cope with stricter particulate requirements. See attached spec sheets for 2017 and 2020.

I guess AR use the port injection to create less particles during the WLTP cycle.

One other advantage is that you don't get carbon build up in the intake port/valves.

The other petrol engines in the AR Giulia lineup is just DI. Which makes me think that AR was not able to make room for OPF on the Quadrofoglio or could justify to re-engineer the car to make room for the OPF.

The Cosworth V12 for the Red Bull and Aston Martin hypercars also use port injection and doesn't require OPF to meet particulate emision requirements.

[VIERsr]

Originally Posted by Boss330

It's not because AR have made a breakthrough in engineering... ��

They just have added port injection to the engine in the Quadrafoglio. Port injection creates less particles during combustion since the fuel is injected in a more liquid state under low pressure in the port. DI engines atomize the fuel into a fine mist as it's injected under high pressure (same reason why diesel engines also need a particulate filter), which is why DI engines generate more particles during combustion.

Port injection is less fuel efficient and doesn't give as much control over combustion as DI.

The Cosworth V12 for the Red Bull and Aston Martin hypercars also use port injection and doesn't require OPF to meet particulate emision requirements.

I guess AR use the port injection to create less particles during the WLTP cycle.

One other advantage is that you don't get carbon build up in the intake port/valves.

That's correct, but TFSI engines have been using port injection since 2013 (Golf GTI MK7, RS3 MK2 facelift) and they also need the particulate filter to meet regulations, I don't know why actually, maybe there's something else behind the Quadrifoglio engines that I'm not aware of.
The best part of port injection is the cleanliness of the intake, something FSI owners are familiar with

[Boss330]

Originally Posted by VIERsr

That's correct, but TFSI engines have been using port injection since 2013 (Golf GTI MK7, RS3 MK2 facelift) and they also need the particulate filter to meet regulations, I don't know why actually, maybe there's something else behind the Quadrifoglio engines that I'm not aware of.
The best part of port injection is the cleanliness of the intake, something FSI owners are well aware of

Originally Posted by nublu2u

Thanks for that, didn't know. So Alfa Romeo engineered a solution where they didn't have to add OPF, thereby maintaining a great exhaust note? Maybe BMW should hire those guys

Originally Posted by VIERsr

They did and it was a great achievement. Even Ferrari uses OPFs on their new engines.

The first version of the AR engine just had DI, they added port injection later on. See attached spec sheets for 2017 and 2020.

I guess AR use the port injection to create less particles during the WLTP cycle. Ie, they don't use the DI during the WLTP test cycle (unlike VW most likely). Running the engine on just port injection in the WLTP cycle creates a lot less particles, and they meet requirements without OPF.

The other petrol engines in the AR Giulia lineup is just DI. Which makes me think that AR was not able to make room for OPF on the Quadrofoglio or could justify to re-engineer the car to make room for the OPF.
If this was a «better» engineering solution they would have done the same on the lesser models as well.

I'm pretty sure particulate requirements is the only reason they added port injection and that they weren't able to/could afford to make room for the OPF on this low volume model with a larger engine with less room to play with. Port injection is a low cost compromise to the problem.