Lithium

Sigh.

flamin mongrel. But you're right, I probably should have thought of that at the start

I keep getting asked to update this list with old and new turbos, so I've added some ones "based off request" and also added some current or future units I have some data on. The G30-770 I have not seen a compressor map for so just made an educated guess as to where it will sit:

Agreed, the 1.05 can work ok on EFR8374s depending on the setup but I wouldn't use it on an EFR8474 on a 2.8 with a good head. It sounds like a good combo from all I can tell. Looking forward to seeing how it comes out

That that size cams, engine and compressor you obviously want to party - so that turbine housing will be well justified I suspect What kind of power and power delivery were you looking for? Fwiw I've been in a GTR running an RB28 with a 1.45 EFR8374 and it was surprisingly punchy, the 280deg cams will probably soften it up a bit down low but I suspect it'll still have a hearty power delivery - so long as the black series 68mm compressor doesn't come at too much cost in spool. I suspect it should prove to be a pretty rewarding power delivery

I like it. Very cool, look forward to seeing how this comes together - sending it on E85? Please post results when it's done

Very nice! What kind of setup is it going to be working with? This is definitely the combination of the range which I suspect has the potential likely shine on an RB

I actually am more interested in seeing how the G25-660 goes, considering the .92a/r housing out flows most T3 options people use on RB25s as is. It could be a banger of a thing.

Nice work, I know this thread isn't for discussion but you left info on what turbo you used out which is one of the most critical bits of info?

Likely to be hard pressed to find much for a while - but I back the stuff I have posted to prove to be pretty on point once things show up, so should give a reasonable idea. Now that it seems more won't be shared immediately, I'll add that the G30 had .61 and .83 vband exhaust housings as options and the G35 has the same range of options as the GTX3584RS, but flows a bit more for each a/r.

NW. On this topic, just to clarify - I am making an assumption that they must be coming soon given there are compressor maps and other bits of info leaking out... I have no direct feed myself, I just keep ears and eyes open and people flick me things when they see it as I am clearly interested in this kind of thing - then I share what I find. There is no official announcement from Garrett at this stage so I wouldn't hold breath on how soon "soon" is until they actually say anything. It still could be a wee while away.

Oops, for some reason I thought I posted both the G35-900 (/ G3576) and G35-1050 compressor maps. Here is the slightly more down to earth G3576 compressor map:

Compressor map for the G35-1050...

I would put money on the G35-1050 (I'll call it G3584 because it makes more sense to me) being significantly laggier. These turbos should be compared on flow, not size. G3071 fits between a GTX3576R and GTX3582R in flow, or slightly more than an original GT3582R. G3076 is roughly equivalent to a GTX3582R Gen2 in flow, or more intriguing for some, it looks like the G3076 could be quite a similar match to an EFR9174, and the G3576 quite similar to an EFR9180 - but with MUCH smaller wheels. G3584 is drifting into the territory of a GTX4294R in flow. If you compared any of those G-series turbos with the previous Garrett equivalents flow wise then I suspect they will be much more responsive, however if you compared wheel size wise then they will behave like bigger turbos - both laggier, but also making WAY more power... just the balance of power and response will be better.

That would be really interesting!!! On paper it should be better all around, which would be nice

I think the G30-770 (or G3071) could prove to be the perfect point for Skylines/GT-Rs which people are going for solid power with but don't quite want to go to the point of big transmission upgrades etc etc - it fills a gap which I've felt has been left empty by the high end turbo manufacturers for some time, basically offering the kind of power that people used to (or sometimes still) use GT3582Rs or GT2860R-5s to reach but I would hope with WAY better response. When soon is, I have no idea - they aren't officially released yet, I usually try and share interesting news no matter how little (though I thought sizes and flow rates isn't THAT light) in asap as people would appreciate it being shared but apparently that's not enough so I'll just leave it from now, I guess folks at least have an idea of whats coming and that it can't be TOO far away.

Yep, I posted in the thread which is about Gseries - will update the table when exact dates is available. Some extremely promising looking options there

The new G30 and G35 series are going to be released soon - their turbines being pretty much the same in size to the GT30 and GT35 turbines respectively, but much higher flowing. Expect to see things along these lines: G30-660 - basically the G25-660 compressor on a G30 turbine G30-770 - 58mm inducer, 71mm exducer with ~69lb/min flow G30-900 - 62mm inducer, 76mm exducer with ~81lb/min flow G35-900 - Same as above but on a G35 turbine G35-1050 - 68mm inducer, 84mm exducer with ~95lb/min flow Should mix things up a bit!

Yeah. 3rd gear absolutely would show much better than that, would fully expect it to anyway. In regards to RB25 cams which support VCT: https://www.kelfordcams.com/nz/camshafts/nissan/rb25-nvcs/246-a-camshaft-set.html There are a few guys around here using various spec RB25/VCT Kelford cams and they've been pretty impressive, too.

Very impressive spool, I can see why you are happy with the 1.01 hotside! This looks better than it seems like people with open housing .82 GTX3076Rs are getting

Not entirely. There may be a SLIGHT bit of dyno control issue there but it will mainly be because there was a boost spike and drop from what I can tell looking at it - boost control isn't brilliant and I suspect the dyno would have been trying to ramp up resistance to oppose the rapid increase in torque as the torque was spooling, but then suddenly the boost dropped while the dyno was "anticipating" further torque increase so it may have dragged the rpm down for a split second before it adjusted it's resistance and that would cover the slight loop

That sounds real promising, if nothing else - if it is doing what makes you happy then that's perfect as it should have plenty of hotside flow. In regards to some of the a/r stuff above, I'm not quite at the "eat hat" stage but I am prepared to if it comes to it - the data Garrett provide on the turbine housing flow stuff is real ambiguous... you "liked" my comment in the Hypergear thread relating to someone I know losing a fair bit of power going from an open .63 to a divided .61 Garrett hot side so you can see where this is coming from. On further investigation Garrett don't specify in their turbine flow maps if their ".61" turbine flow maps are for open or divided, and perhaps they are only talking about the open housing and they aren't actually providing any flow info for the divided ones. I know one source definitely implied it was the divided ones but I am starting to question that, I've tried putting word out to the right channels to get clarification on that but so far no joy but it is something which would be VERY helpful to have. Andrew Hawkins made quite a lot of power with the divided .83 on his RB26 with the GTX3582R so it seemed reasonable to assume that they aren't shabby. Either way, if you are happy with the response of the 1.01a/r divided GT3576R Gen2 that is great - the Hypergear you were running before was pretty laggy from memory, but still.... the Gen2 76mm compressor is proven to be capable of a heap of power, so this setup is heading in the direction of delivery some very good goods Nice work, looking forward to data!

The theory on split pulse is pretty well discussed these days, reduces the collisions between high pressure pulses and keeps them separate until they are meant to drive the turbine. I suppose you could say that it should reduce turbulence and as such keep velocity up. In regards to people removing the divider in the stock manifold, I think of that more like a turning vane than a split pulse - without it there is nothing to make the exhaust flow think that it should just head straight to the other cylinders due the shape angles required to head to the turbine. I am not sure that has so much relevance in the twin scroll/split pulse discussion, aside from the fact that the only reason that is at all a workable design with a straight 6 is that you have alternating pulses on front and rear three so it makes it less likely to cause bizarre lean outs on certain cylinders. In terms of the twin gate advantage meaning that a smaller housing can flow like a bigger one, I could be missing something or misinterpreting - so how do you mean? At face value it seems like you are saying that having more gate means you will reduce exhaust manifold pressure, but just having a second gate won't increase the turbine's ability to drive the compressor for a given amount of exhaust gas, so there is no reason for it to open more... the only reason the wastegate would flow more is if the turbine needs less exhaust energy to do it's job. It's pretty easy to tell where more gate is an advantage, you get boost creep as you aren't relieving enough exhaust gas. If you relieve more exhaust gas then you lose the energy you need to drive the turbine and you don't hit target boost. Apologies if I've misunderstood what you said, keen to hear what you mean or where you are coming from with that one.

The twin scroll turbo manifolds are equal length, which is why a lot of the later Subarus don't sound like 5-cylinder RBs

Interesting thing happened around here recently, a guy with a 2litre Subaru running a twin scroll manifold and a open housing .63 GTX3076R decided he was happy with the power he was making but wanted more spool so swapped to a .61a/r divided hotside - using the same exhaust manifold, but changing the up-pipe to suit the twin scroll housing. The car improved spool by a couple hundred rpm and lost around 50kw @ wheels. After going through a bunch of diagnostics and deciding there were no other issues or changes other than the housing/flange setup he tried changing to a .83a/r twin scroll housing and it got back within 20kw of the .63 housing, but was also no better spool than with the open housing option. Again, after further head scratching and messing around he decided to swap back to the original up-pipe and .63a/r housing and boom! Back to the same power and response he had before trying the divided path. Definitely not what I would have expected, but it's a thing that happened - unfortunately I am not directly involved so I have no more detail than what I've shared here, I wouldn't count out the possibility there is some other variable at play but realistically the options are pretty minimal... especially when it came back to "full power and response". The car is definitely performing overall better with the .63 hotside.