New Garrett Gtx2860R / 2863R / 2867R

[Dose Pipe Sutututu]

On 27/02/2022 at 8:34 AM, joshuaho96 said:

The F80 even stock sounds awful even compared to an RB26. I don’t know how but BMW figured out the ideal exhaust setup to make that engine sound as terrible as possible. 

As soon as a single turbo goes on, it's like a symphony played by the gods.

I think this is Brett's car (judging by the plates)

https://youtu.be/QvUwVTgi_Hk

 

[r32-25t]

On 27/2/2022 at 8:40 AM, Dose Pipe Sutututu said:

As soon as a single turbo goes on, it's like a symphony played by the gods.

I think this is Brett's car (judging by the plates)

https://youtu.be/QvUwVTgi_Hk

 

they do say the owners name is Brett about 50 times in the video, so I’d guess you’re right 

[r32-25t]

And I agree the worst sounding 6 cylinder I’ve ever heard was in an m4

[GTSBoy]

On 2/26/2022 at 12:08 PM, joshuaho96 said:

From: https://www.bmwusa.com/vehicles/m-models/m3-sedan/overview.html

Le sigh. I shall do all the f**king work then, shall I?

from https://www.bmwblog.com/2020/09/02/how-bmw-twin-power-works/

• BMW TwinPower Turbo is relying on a single turbocharger with two scrolls
• BMW TwinTurbo Power (yes, this one exists too) relies on two turbochargers

Granted, you have to read past more than half the web page's bullshit dumbo BMW customer spoon feeding bullcrap to get to the one useful bit of technical information. But when you, buy, it's a f**king doozy.

[Dose Pipe Sutututu]

On 27/02/2022 at 3:02 PM, r32-25t said:

they do say the owners name is Brett about 50 times in the video, so I’d guess you’re right 

Clearly I'm not good at listening lol... (Mainly skipped all the talking and just looked at the manifold design and listened to the car noises).

So many single turbo kits, just none in RHD.

Talk about going off topic, anyhow back on topic.

Twin turbos on a RB with a single plenum will always be shit. Only "real" way to make them less shit is to run twin turbos, twin ICs, twin plenums and keep them separate all the way.

@Piggaz actually found a video of the crazy Japs back in the 90s that actually did just that.

[BK]

Ok twins on a V will always make sense but

On 27/02/2022 at 4:30 PM, Dose Pipe Sutututu said:

Twin turbos on a RB with a single plenum will always be shit.

I don't really like to have an opinion on SAU these days regarding things potentially ruffling people's feathers, but let's get one thing straight - to simply say a GTR or RB with twin turbos = shit is ludicrous. I am in both camps - that is blanket statement, even though I might be singled out for being unpopular. I have a GTR or two currently and have had others before that over the last 20 years - so I am going to weight in on an RB26 in a GTR.

Majority of the time you'd be 100% correct if you're instantly aiming for over the 350kw at wheels region, which most people are, but under that there's nothing that a pair of Garrett -9, HKS GT-SS or Nismo R1 (pretty much all the same thing) won't fill the void for being excellent.

My personal opinion is that if you step into the -5 twin upwards region of power, then a single is always going to outperform everywhere for response and overall power potential delivery. Yes twins are a headf**k by comparison physically, but they CAN do the job at a certain required power delivery. If you want any sort of top end power delivery, well you are absolutely correct with ditching the twins. But the real world driving experience from 250kw - 350kw rear wheel GTR is not to be ignored as inferior to any single that competes in this bracket.

I am not biased as our blue GTR is single, the white GTR 32 is single but the 33 is twin. Would I swap the 33 from twin to single at under 350kw at the wheels target power ? - no fricken way in the world would that ever happen for that power bracket.

To suggest that a single makes more sense at this point is slightly ignorant with the actual changes required to do so. You want 400, 500kw whatever upwards well yes, twin low mounts is just retarded - just go single all the way.

Just my 2c.

To be actually back on topic of this thread with the turbos discussed, I will have to concur though that a single would be a better proposition than any these nuggets, I mean upgrades.

[BK]

On 23/02/2022 at 9:00 AM, Dose Pipe Sutututu said:

Twins on a RB will always be shit, all of a sudden the Muricans and Canadians are experts with RBs.

Still gold 😄 and do generally agree 👍

Just mostly shit, not always shit.

[AndyStuttgart]

On 2/27/2022 at 8:00 AM, Dose Pipe Sutututu said:

Twin turbos on a RB with a single plenum will always be shit. Only "real" way to make them less shit is to run twin turbos, twin ICs, twin plenums and keep them separate all the way.

@Piggaz actually found a video of the crazy Japs back in the 90s that actually did just that.

Actually I don´t think it´s such a good idea of potentially having two different charge temps and boost levels for the front and rear cylinders...so no, I won´t jump the bandwagon saying twins are shit.

For me both variants are cool and I´d leave it to personal preference for everone.

While I live by "it came in twin form by factory so I´d stick to that" for most of my cars, I still choose a single on some of my projects to try it out as well.

Hopefully this year I´ll be able to more or less compare an EFR9180 single vs. twin G25-550 on two similar built RB30s (forged bottom end, Poncams).

Edited February 28, 2022 by AndyStuttgart

[Dose Pipe Sutututu]

On 01/03/2022 at 12:36 AM, AndyStuttgart said:

Actually I don´t think it´s such a good idea of potentially having two different charge temps and boost levels for the front and rear cylinders

Why would the front/rear have different charge temps and boost pressure? 

[GTSBoy]

On 3/1/2022 at 7:32 AM, Dose Pipe Sutututu said:

Why would the front/rear have different charge temps and boost pressure? 

It's not unreasonable to expect that once fully divided, any little difference in the performance of the two turbos would compound on themselves. For example, the dump pipe layout is not the same on both, so the turbine vs. wastegate flow could differ, meaning that the same ex manifold pressure would provide a different amount of turbine drive. Then, the rear turbo has to pull its inlet air through a longer pipe, which adds restriction and also more heating, so it won't be pulling the same density air as the front.** The turbos then flow to separate intercoolers, which are unlikely to be exposed to the same ambient air flow conditions (likely one up high and one down low, with the bumper reinforcement, difference between intercooler grille opening and upper grille opening, etc etc) leading to them running at different temperatures and heat soak behaviour. Air then flows to 2 different plenae, with potential for more of the same geometry related issues attached to the turbo locations.

Shuffle all that shit together and it might average out, or the problems could add together in the same direction and make one half of the engine work quite differently to the other. If running to the same boost target (2 separate boost controllers!) then maybe one will have 10° hotter charge temp than the other because the compressor is working in a different part of the map, or the intercooler's not doing as well. And then that reports to the exhaust flow which closes the loop and possibly adds further reinforcement to the problems.

Two turbos....OK. Two intercoolers....OK. Two plenae? Probably not OK. V engines with twins and separate intercoolers have usually retained a single plenum for a reason, I suspect. Plomp all the air with different characteristics into the one place (the whole engine) to eradicate the possibility of the 2 halves of the engine migrating away from each other in terms of their performance.

 

** I mean, shit, the fact that turbo shuffle is already a problem indicates how differently the 2 turbos already work in the stock arrangement.

[Dose Pipe Sutututu]

On 01/03/2022 at 11:13 AM, GTSBoy said:

V engines with twins and separate intercoolers have usually retained a single plenum for a reason

On VR38, VR30 variants they run twin plenums, twin TBs - however there is a balance tube between them to reduce the delta between each side.

(aftermarket one just for a top down view & OEM) & VR30DETT

  

 

Not disagreeing with the difference between each group however I would suspect it would be a more efficient than two turbos fighting against each other to force air into what is essentially a Y connector. 

However the way @AndyStuttgart worded it, it sounds like the delta would be massive.

I would dare say if you could separate each turbo's charged air via separate piping, separate ICs and just merged before it touches the plenum you would already have gained efficiencies that way. Kind of how you bi-wire your speakers to reduce back emf. 

To summarise, twin scroll single turbo > twins on an inline 6.

(All the above is for entertainment purposes only, please don't get upset - especially if you're Murican or Canadian  ).