Hello,

I have Bentley Flying Spur 2017 W12s (635PS) with the corrosion in one of the cylinder bloks.
Thinking about the strategy for the engine overhaul, I started digging into W12 engines and relized that it is basically the same engie family (w12) but different engine variants. They go for the second generation from 2013. My engine code is DBD. But there exist many others like DBDA DBDB DBDC DBDD....

My goal is to understand wether the engine blocks are compatible between the varians and what else is compatible. As I am thinking about swapping a block.

But then clearly there are some modifications for 6.0 GT Speed and W12s.
Are these modification only in ECU coding / turbines?

Does anyone know what are the difference?

Thanks,

 

My understanding is that the Speed engines get improved internals and then some tuning to increase power. I have never found anything that documents exactly what those internal improvements are tho.

 

Curuous what do you mean by the internals here?
Regarding the tuning yes, its certainly ECU re-programmed, perhaps different turbines...but in terms of the engine short-block -- they are probably identical? Or you think that "hardware" like crankshaft can be different, too?

 

I believe I read that on a Car and Driver review-typically when Car and Driver describes things that way it means that internal parts of the engine have been upgraded- could be pistons, rods, crank Timing chains, etc. I guess the only way to know for sure would be to start comparing part numbers of engine parts, but someone told Car and Driver that or they wouldn't have written it. Maybe I can find it back-I'll look

 

Found it- from Car and Driver review of 2010 GTC Speed:

Speed in More Than Just Name

As with the GT Speed coupe, most of the work to turn the GTC into a Speed model is mechanical. The 6.0-liter W-12 engine makes 600 hp and 553 lb-ft of torque, improvements of 9 and 15 percent over the base car’s 552 hp and 479 lb-ft. The engine now features a single-chain cam drive, lighter connecting rods and pistons, an oil pump that reduces pressure (and pumping losses), and a modified block. By opening a port between the crankcase divisions, gases can move more freely between the crank webs, thus avoiding crankcase compression.

The chassis changes include stiffer rear-axle bushings, retuned steering, 20-inch wheels with specific Michelin tires, a recalibrated stability system, and a suspension that features revised spring and shock settings. The GTC Speed also has been lowered by 0.4 inch at the front and 0.6 inch at the back. The standard brakes are large enough—15.9 inches in diameter up front, 13.2 inches out back—but the optional carbon-ceramic discs are simply enormous. The front discs are 16.5 inches in diameter, with 14.0-inch rotors at the rear. The front brake calipers have no fewer than eight pistons. And they cost $16,500, if you need to ask.

That's some pretty specific and not Minute changes!

 

That particular article and description, along with a number of others stating the differences, was the reason I scrapped the idea of considering a base model and insisted on getting a Speed. The differences may seem insignificant but they are a clear, well thought-out evolution of the base engine design and likely to improve longevity too. Less reciprocating mass and reduced parasitic pumping losses both fluid and gas is a Good Idea and in line with desirable engineering principles.

Not to mention the 6HP28 transmission having 100Nm higher torque rating, better thermal and mechanical efficiency and it shifts and locks the converter much quicker and smoother than 6HP26.

All in all the Speed model is a better package, an evolutionary leap. And consequently a better starting point for a remap when a need for even more speed arises.

 

I agree 100%, same reason this time around I really wanted a Speed and was going to be very picky about what one I bought. My first one was a base 2005 Gt and was a beautiful car, but was based mostly on cosmetics. I can attest to to the vast differences between the 2 cars, My 2009 Speed is faster, handles better and specifically the shifting of the trans is much, much better. I'm probably going to get a tune in the not so distant future and combo of the engine and trans upgrades gives me a lot more comfort with an upgrade. When I got tuning on the 2005 it tended to just highlight the cars shortcomings, rather than give it the last little bit it needed to be a great car. Hoping this time when I get both the engine and trans tuned, that it becomes the perfect package! being around 700HP and 700 TRQ with even better trans shifting characteristics should be amazing. Plus I already have a titanium exhaust that is a valved system which will help as well. I can definitely feel the difference between the open exhaust vs the one routed thru the muffler-supposed to be 30-40HP and it feels like it. I will probably consider spending a bit more on Bilstein Struts to get the best handling I can as well, or get my specific struts rebuilt by someone that can do something with shocks as the valving, along with sway bars are already an upgrade from the base GT. Just hoping to get more feedback on some of the better options versus the basic reman service that most people are doing. Coilovers would probably be a better handling pkg, but I like the ability to change height and shock valving with a touch of a button and I'm not going to be tracking the car, at least not seriously. My son has a BMW M2 that he thinks is a superior car, so I need to show him the Bentley is the King of the Hill!!

 

I've considered a remap as well. Celtic claims 734bhp/724lb-ft (vs. 680bhp/630lb-ft for base model) which may or may not be accurate, but the difference is substantial nonetheless. I'm not about to touch the exhaust as the FS is a daily driver.

Suspension upgrades are to be debated, OEM electronically adjustable shocks work well and Bilstein B4 is just a replacement, not an upgrade, I don't know if B6/8/12 is available with electronic integration. The car is fairly well balanced as-is and there's little to be gained by higher damping rates. My approach is more subtle, I already replaced one pair of front LCA bushings with polyurethane and the improvement in tracking and accuracy was noticeable so a full PU upgrade is likely to improve grip and feel further. Combining this with grippier tires like Michelin Pilot Sport S5 or Supersport, Continental SportContact 7 or the like should result in what these cars should reasonably be expected to be capable of. Full blown race coilover upgrade and R-compound tires are a massive tradeoff - I've been there with a number of other cars and wouldn't do it again, especially on a Bentley.

IIRC, Speed also has a different drivetrain and traction control programming. It feels a lot like my wife's Audi RS6 in that regard, devoid of the pronounced understeer characteristics of the base model and yes, it's relatively easy to powerslide too.

Even if the M2 has only been remapped it'll be well above 500bhp, it's massive 1200lbs+ lighter than the Bentley and quite a bit more handling-oriented to start with so the comparison is a bit fruitless. Not getting involved in a p*ssing contest like that and compromising the real strengths of your Bentley while doing it doesn't sound like a good idea. A lot depends on the driver as well, I've given quite a few reasonably (but not truly) well driven Porsches and Ferraris more than a run for their money with the Flying Spur "luxobarge" when I've felt childish and on street asphalt the suspension and tires are already pretty close to optimal. It's nothing short of amazing how far this "Dumbo the Flying Elephant" can be pushed as-is, and with bushing and tire upgrade it gets even better on all counts.

I currently have 21" 3W0601025CTU wheels that came with the car. I really like how they look and too bad the same design isn't available in 20", I'd downgrade the diameter for less theoretical but more real-world grip in a heartbeat.

 

My son is not remapping his M2, so that's a positive. I kinda agree on the struts, I suppose I could go with OEM replacements and I'm not going coil overs for the reasons you mentioned. Not sure I agree on the coil overs. I've run them on C6 Corvette suspensions, and Quite a few others , it just depends on spring rates, and how you adjust the shocks. I've always gone the the double adjustable and kind find a nice balance for street and performance. it takes just a few clicks to adjust them so easy to go back and forth. Of course saying that, I'm not sure what options are available for the Bentleys, but I'm not going that way, so have not looked. I'm running Vossen 21's with Michelin Pilot 4S, but might switch back to OE 20s to get a better ride. I have lowering links but I'm only doing about a 1/2-3/4" drop max. The sound deadening is so good in these Bentleys that on quiet mode with the Titanium exhaust you can't even tell you have an aftermarket exhaust inside, even the straight thru is not obnoxiously noisy inside, but it is loud on start up and full bellow outside. There is a noticeable increase in performance on loud mode. When I'm by myself I run on straight thru/loud mode, when the wife is along I go quiet mode. Did you notice any thing with the ride or NVH with the poly bushings? I've done it before and was not very happy with it from that standpoint. What do you think is the life of the OEM Damper before it's performance starts to suffer? I've got a very slow leak up front, so am going to have to do something, but don't want a downgrade for sure.

 

I am so glad you highlighted the difference in Speed Model. The conversation put my mind at ease and explained why the Speed is worth every penny more than the base model.

Before this I was contemplating upgrading to the base model Gen 3 Continental simply for the new modern dashboard / interface. Now I think I’ll just hold on to my Speed because it feels, sounds and drives like no other.

GTSPD

 

Post a pick of your Speed, I'd love to see it! Your right the Speed models are special and unique, I plan on hanging onto mine for a long time. The Tech is a bit old, but so am I and I don't buy a car for it's tech, I buy it for how it drives and how it looks!! And the Speed drives and looks great!

 

I've mainly used top shelf coilovers as consumer "tuning" and "sport" items aren't usually worth it. Öhlins, Aragosta, Quantum and so on. Having the spring rates determined on actual mass on each wheel and the coilovers meticulously set up in a shock dyno yields great results. Especially ones that have separate adjustment (even by re-valving) for high and low speed compression and rebound are the way to go. These, however are perfect for FUN cars. A GT-R with Hoosier Track Attack Pro tires is a prime example. A caged Corvette another.

They have no business whatsoever in a daily driver or a fair-weather-only summer car. Been there, done that, got the bill for a full refurb once a set priced at five figures oxidized and got its valving stuck.

Ride will be better but as street asphalt is anything but smooth unlike race track, the slightly increased compliance of sidewall is likely to result in more usable grip, smoother transition, more forgiving behavior at the limits and consequently a faster point-to-point car that's also easier to drive fast.

The only thing I noticed is steering feel and response sharpening up. I only replaced one set of bushings but it made a difference with no ill effects. It depends a LOT on what kind of polyurethane bushings you use. I've done numerous PU upgrades to all kinds of cars and settled on a combination of 70 and 80 shore depending on control arm and location. Going all 80 or even 90 will result in increased NVH but, again, that's not something you'd want in a street-driven car.

As far as shocks are concerned, I have little experience with electronically adjustable ones. With conventional shocks you can feel the difference at around 60k miles and serious degradation is obvious after 100k; some can hold up quite a bit longer, some are shot after 50k miles. I usually go for Bilstein or Koni with regular shocks, but YMMV. The Volvo project we completed earlier this year turned out great. A combination of 70 and 80 shore bushings, OEM springs to maintain suspension geometry that'll be compromised when lowered, and Bilstein B6 shocks front, B8 rear. It has the ride comfort of a brand new (nearly) stock one and can easily keep up with the Bentley in the twisties.

99% of people who think they "improve the handling" do it horribly wrong, losing both handling and ride as a result.

 

Thanks for your input, I mostly just want to maintain what it was when new, not get something that is not as good.

 

You're welcome. That's exactly what I've had in mind all along with my car, with some well thought-out improvements. For example, PU bushings are a great idea when executed properly. Strongflex don't mention Bentley in their make/model search but Audi S8 D3 kit will fit, with the possible exception of anti roll bar bushings that can be reamed out if need be:

https://www.strongflex.eu/en/phaeton-i-4motion/2790-274470-026247b-full-suspension-polyurethane-bush-kit-5902553539639.html#/48-front_arb_diameter-25mm/54-rear_arb_diameter-16mm

As far as shocks are concerned, Bilstein B4 replacement unit 45-260445 (FR) / 45-260476 (RR) / etc. is probably the highest quality OEM replacement on the market. Upgrading them is mostly pointless unless there's a model specific electronically adjustable upgrade available.

 

There are these:

https://www.miessler-automotive.com/...left-and-right-

they claim to rebuild both then air spring AND the Shock

https://air-tec.bg/en/services/shockabsorbers/-They say they have an ALL NEW strut with a new adjustable shock just as OEM!