Lithium

You're saying he wouldn't, and instead would inexplicably opt for sticking with rubbish transient response and generally ineffecient low mount twins despite knowing better?

Solid, a bit hard to tell much from the info though - no rpm scale or anything. What fuel is this, and the rest of the setup? Hub dyno? What does it spool/drive like?

Nice work, congrats on the result and cheers for sharing - have been pretty sure that it should be able to make more even with that housing. Looks like a nice fun delivery too, glad its making more the kind of power it should be now

Yeah 100%, glad it seems like its working out well so far - this kind of thing is 100% a thing I've been viewing the G-series range as having some advantage over. Also have a soft spot for the "single scroll RB sound", and a gripe I've had about the EFRs are how messy things end up having to be to run twin scroll and also the busy comp housings. Look forward to seeing how further meets go and if some more comparative data (like are you likely to get a dyno overlay?) would still be interesting. Cheers for updates and impressions, all very interesting and helps clear up some speculation

Awesome, was hoping it'd end up something like that, sounds probably like similar spool/response (and probably not miles off the flow) of an EFR9180... which is perfectly acceptable on a 2.8litre track car, especially with variable cam timing. Glad it's working out so far. Yeah, the single scroll setups definitely have a particular sound to them and the G-series aren't too bad with transient response compared to the GTx series Garretts and especially Precision turbos so while you're giving away response that you could have with an EFR it's not really likely to be a problem. As you said above, for a street car it'd be where it really makes a difference - like the EFR8474 doesn't sacrifice any flow over a G35 900, or noticable response over a EFR8374 buuuuuuut doesn't have the packaging and flexibility (or sound) advantages your new turbo have. Look forward to seeing an overlay to see how things go when you wind it up!

For you that's probably the case, the beauty with building cars is we can build what suits ourselves and we're not all forced to the same path. I've been around heaps of multipurpose builds that a single boost target configuration would not suit at all. If you have a car that is a weekend car that at events will run drag tyres and has potential to make a cr@pload of power but is still road friendly enough to be used for road trips etc then you really don't want to run the "run the quickest time you can on a drag radial" tune when you're going for a road trip on New Zealand running normal street tyres, I understand the "right foot" argument but straight up - sometimes when you're going to be driving for 9 hours on varying road surfaces, windy corners etc etc you don't want to have think about how much throttle you can give it every time you catch a campervan or truck with a small passing opportunity on a windy road. Maybe I'm a pussy, but I like having the option of just being able to roll on the throttle and blow past things without worrying about the car getting all frisky if I'm too heavy footed - buuuuuut also reserving the option to go "Screw it, I want to overtake a line of cars baking the bags"

ftfy

So I have the intake, the charge pipes, the XHP tune and MHD Stage 1 tune done on the car and jesus - it's actually QUITE a significant improvement. Will do the dump pipe and tinker a bit with the brain after that, but for such mild mods it is not at all a slow car and very very fun to drive. I am loving the hell out of having something that drives so nice and my not-car-people like the car as just a "nice car", gets around 7l/100k on the open road or 9l/100k around town (basically better than the Hondas I started out modifying but WAY faster) but I can do petrol head things and enjoy it more than anything else I've had. I think with the dump pipe and keeping the turbo at a point where it's not too strained should keep me happy for quite a while.

Again be interested in hearing your thoughts, be the first person I know who has gone from a G-series to an EFR or vice versa. I hardly follow Racepace as they seem to hold back info, sometimes showing a dyno plot but not sharing spec - or vice versa, and thats the main interesting stuff . For some reason they never posted the dyno plot for an RB28/VCam/G35-900 setup they did so I'm not assuming they'll share the G30 one either.

The absolute worst case scenario is you can cash in on the advantages of having a compact turbo with vband stuff and swap without needing to change anything else if it is a problem. Shouldn't be though

To be fair I'd be surprised if the G30 would have been any spicier from low rpm than the 8374, and I guess it all takes time - but good tuning/boost control should ensure that you don't have too much being dumped at the tyres at once. I think with RWD cars use for corners people get a bit too carried away with trying to make turbos run all the boost they can from low rpm just because they can, nothing wrong with keeping the good response but holding it back from making more than is driveable in the lower revs. Like I just say that for discussions sake, I'm not expecting the G35 to be a nugget - but I do suspect it's going to be noticeably less snappy with all else being equal. Be cool if I'm wrong though, or at the very least its at the level where it works nicely for what you're doing Looking forward to results as data is way more fun than speculation haha

Will be interesting to see how it goes, look forward to results - shame the EFRs are so bulky/tricky to swap in that case but it is a thing, as you say you're likely taking a performance hit to make it more serviceable buuuuuut realistically with VCam and 2.8litre when you're keeping it on steam (and you have a sequential now?) I doubt it's going to be an issue. A 2JZ I play with has a G35 900 on and from what I've seen so it behaves quite a bit like EFR9180s that I've also been around on 3litre 6s spool/response wise, obviously not quite the same level of flow (But on the other hand, definitely more potential than the 8374) but you're not trying to make that power so the response is the main thing. EFR9180s are pretty proven on static cam RB28 track cars, so with VCam I'm sure it'll be fine. Would have been interesting to see a G30 900 with a bigger housing on it if you were aiming for low 400kw, but the G35 feels like a safer bet

That depends on how hori the ECU or tuning is. Depending on the car I usually use both timing retard and fuel cut to manage the launch control as I tend to get quite OCD with the control range of the launch setup, and also try and ensure it ACTUALLY does what you need from a launch control - such as spool the turbo. A lot of 90s/2000s launch control (and to be fair you still hear this used) did "100% cut" which basically meant all injection events were stopped until the engine speed fell under the target threshold, which is a bit self defeating as when those injection events stop so does the fuel which provides the energy you are meant to be using to spool the turbo. With a decent ECU the "fuel cut" doesn't cut every injection cycle, it just cuts a % of the injection events based off the rules set - so even during a full engine cycle where the is limiting happening there will often be at least 1 fuel injection event, so the retarded timing will be applied to that event. The reason for doing both is the retarded timing both means the engine makes less torque meaning you need to cut less injection events to not overshoot the target rpm, which means more fuel going through the exhaust, and also with the retarded timing less of the fuel's energy has been used driving the piston and is instead available for helping the spoolyboi. So yeah, that's the point of retarded timing if it's fuel cut - at least with a decent ECU

Motive DVD share a lot of good info, and try their best to interpret and explain data well but there are plenty of times out there where the same data can look different depending on what you know and what you are looking for. Truth of the matter is here.... This. There is no "RBs like big rears". RBs don't have a clue what is attached to their exhaust side, from the turbo's perspective its the dynamic of how fast the compressor needs to spin to pump the required air, intake manifold pressure required to achieve that and how efficient the compressor is at that point, and well the turbine/housing combo works at that point. Sometimes you need to go a bigger a/r to achieve what you're doing, whether it be that the whole setup works best there or sometimes just if you are pushing the turbo to the absolute limits and don't want to upgrade the rotating mass so going to a bigger a/r is a bandaid which is what imho has happened in a few situations that are used as evidence that "RBs like a big rear". I'm pretty confident that with everything else being equal that an EFR8474 with 1.05 hotside would be all around equal or better running at 520kw than the RB28 with the EFR8374 and 1.45a/r hotside in the example above. If the compressor is being more efficient to move a given airmass than a different compressor on the same turbine without making the turbine work any harder to the work then the wastegate will end up not having to close as much to keep driving an out-of-it's-depth compressor to do something to the edge of it's limits. It can take a pretty significant turbine wheel/housing upgrade to match the effects of boost control creating an exhaust leak that is required to hold back the compressor from pumping more air than is needed when comparing with something that probably effectively has the gate shut to achieve what it's doing. To throw a bit of data into it, here's a 1.05 EFR8474 on a big cam 3litre being revved to 8000rpm on ethanol. The car made over 600kw (/800hp) on this run, around 87lb/min of airflow which is WAY past what an EFR8374 can support - so while 39psi EMAP is getting up there a bit in this case (which is why it was stopped here).... the thing would be barely working up a sweat at 520kw on an RB28.

This isn't to beat a dead horse or have a go or anything, just basically adding a +1 to the other comments about internal wastegates on "big turbo" RBs and add some further reason to it so it doesn't feel like you've just hit a trigger point that people are going to hate on because it's trendy to. For what it's worth, I've not yet seen a situation where someone has gone that way initially and not ended up regretting it, and potentially changing at significant expense. The stuff you see in regards to the design itself is perfectly right, aerodynamically the Borg Warner internal wastegate setup is very nice - no issues with boost creep and they also don't appear to negatively impact turbine efficiency. If you can keep the gate closed when it needs to be then you won't have issues with performance, and when target boost is achieved the wastegate path allows the drive pressure to be managed nicely. Borg Warner are not being misleading about this at all, in my opinion. The issue however is the actual control of the gate flapper itself. The significance of exhaust pressure on boost control is often massively underestimated, when you see wg spring pressures that really effectively is making a big assumption about what exhaust manifold pressure will be doing at that point and how whatever drive pressure management being used actually responds. Flapper style wastegates seem only too keen to crack open a little bit under any amount of pressure which can immediately start reducing the effectiveness of the turbine, and it only gets worse as exhaust pressure increases. A stiffer wastegate actuator can HELP, and often the solution seems to be using a stiff enough spring to be able to achieve the "high boost" target pretty much by itself - and then additional electronic boost control input to maintain the target boost. Basically the result OFTEN (but not always) seems to end up being pretty poor flexibility in terms of boost control, and often a lot of messing around to get what would often be seen as the bare minimum with an external wastegate setup. I would argue that if there was a good electronic wastegate actuator option (so it can keep the gate properly shut until it's meant to be open) that was compatible with the EFR IWG range then a lot of the criticism would be completely negated, buuuut a .92 IWG housing is still probably on the smaller side for a RB30 unless you're going with an 80-series turbine wheel. That's at least my limited experience and opinion on the situation, there could be other things I've not seen or considered.

So this is kinda relevant to this conversation, someone else have mentioned non-Garrett options so I feel like its not MILES from being appropriate to mention anyway as this suits the turbo matching concept and also possibly offers a housing option if you go genuine Garrett G35 900 core. A mate with a GT-R which was running twin -5s on an RB26 with Kelford 272s had one of the turbos fail recently and it was going to be annoyingly hard work to replace when he already was aspiring to put an RB28 in it and go single turbo at some point, probably the likes of an EFR8474 when the budget allows but he was not ready to take it off the road. Some big yarns were had about what would be the most rewarding way to get it running now but also not result in too much back tracking in the future. The target was be at least as good as the -5s, fairly typical low mount twin setup with just over 500whp on 98 and full boost in the late 4000rpm range. After much discussion around things like G30s, going straight to EFRs etc the budget right now wasn't suiting so partly to get it going sooner but also just to try something different he went with a Pulsar G35-900 copy with a .85a/r divided T4 housing. Hoping it will be going in a couple of months or so with the divided housing, I can report on how that goes but I do realise people view the Pulsars as not at all a comparison with Garretts and the T4 hotside isn't even an option from Garrett, but I mention it partly because Pulsar *do* do a .85a/r T4 divided hotside which in theory should suit a G35, genuine or copy. The Pulsar will at least be on there to get it running until an EFR/RB28 build can be sourced and delivered - though if the Pulsar performs too good it may stay in there longer haha.

Oh wow! Sorry, a bit sleep deprived today and I had started rewriting some of my original post and got sidetracked and managed to turn it from being hard to read into complete nonsense. The intention was to delete everything but the last sentence because I decided I was going too off topic, but seeing as I screwed up... the two points that paragraph was meant to convey and got garbled: 1) I know people pushing 10+ yo BMWs with mostly stock hardware hard enough to run 130+mph traps without issue 2) When our Skylines were that kind of age we thought nothing of replacing the equivalent kind of stuff to keep them happy, and make them go quicker. Ignition stuff, oil control, fuel bits, boost leaks. All par for course when playing with "special" cars - BMWs just have more sensors and flash more lights than the Skylines did when something isn't working, but helps you know something is up instead of eventually running a bearing, blowing a turbo or generally having a subpar performing setup and tends to not be a biggy if you deal with the things that need to be dealt with properly. Anyway, sorry - I had MEANT to make it a far more concise and less off topic post but fumbled it.

So far I've not seen any reports from people I'd call "neutral" buuuuut I'm obviously open to finding out if they are something I should be more apprehensive about sticking up for. I have nothing to gain personally, not a dealer or anything - like yourself just like trying to give people "what I know" to try and help them be best equipped to make the right calls... the whole "are you ok with buying a copycat" is a different ethical decision best made by the buyer.

Lol funny, I was thinking when reading through this I thought about a couple of mates BMWs when reading the "funny how a 9 year old Euro car is considered old" when I've got mates pushing late 2000s (over 12 years old ) BMWs with stock almost everything harder than we'd typically not even think anything of having to replace a heap of stuff on our Skylines to be able to achieve when they were the same age. I've got a BMW around that age and it is still farrrrr from a horrid car, best thing I've owned in every way aside from fuel consumption haha. It's 1.5l/100k worse than my old Honda Jazz in equivalent driving conditions, but otherwise that too.

Are there any good examples of this in terms of media we can see? I've seen a couple of "just happen to be Garrett dealers/sponsored by Garrett dealer" people make these claims but so far have been involved in a pretty solid amount of Pulsar turbo based builds without seeing this issue. The only issues I have seen have been regarding needing to make sure things are done up properly, ie - not assuming vbands are done up, or turbo speed sensor plug screwed in properly etc. Have heard of 3rd party folks who are doing mix-and-match sells of Pulsars selling them with the wrong housing, ie GT35 turbine housing with GT30 turbine but that's not a build quality thing and could just as easily happen with the same people selling legit Garrett bits.

Yeah for sure, I figured seeing as you were on that track I might throw this in just in case you hadn't seen it - be nice if it all wraps up as being this kind of thing. Fingers crossed for you either way as it seems like a kient of an issue.

Just throwing this in here in case... fwiw, never run into issues with one of these kits though apparently some people have with G4x setups, but G4x aren't the most well behaved of ECUs at times regardless of what is trying to talk to them

Truth be told I've got all the parts but not everything is sorted yet, it's Christmas project stuff so I can't give a full review at this stage BUT I've got the MHD dongle and everything inc. XHP license purchased. I'm impressed with the trans even with the stock tune so pretty excited to see what it's like with the XHP tweaks, from what I've seen it'll be pretty key to making it "work" as well as it can well combined with the "Stage 2" (groan) level of mods and tune it'll have if I take it out for a sneaky 1/4 mile run. Is your E90 the N54 or N55 version?

Been a long while since I've owned something that seems at all related to Skylines, but my latest car kinda has aspects which feel make it related to my old R33 GTS25t - is an F20 BMW M135i: He runs the 3litre single turbo N55 engine, if you are a BMW propeller head it's the later model version of this engine with the larger electronic wastegated turbo (which brings it up to par with the old twin turbo N54 engines in terms of stock turbo flow potential) and suchforth. In stock form these guys are meant to develop 450nm of torque from 1300rpm, and a conservatively rated 240kw peak power. Mods for now are a Wagnar tuning dump pipe, Masata hard piping and CTS intake and retuned stock ECU (and not pops and bangs 🤮) which while don't make a huge amount of power, when combined with the complete lack of lag (turbo is pretty similar in spec to an EFR6758, which is a tad mental when combined with a high compression 3litre spinny cam 6cylinder and twin scroll :D) and the ZF8 8-speed gearbox real world wise it's a significantly quicker car than my old GT30R equipped R33. Aside from the nice handling, all the nice modern car comfort things its also pretty sweet being able to get sub 7l/100k fuel consumption on road trips where the roads are hilly and windy etc when combined with being pretty sporty. I'm somewhat surprised these things aren't more popular!

That's a fantastic result mate, nice work and cheers for sharing. The Gen2 3582 has often been well underestimated in terms of it's ability (and effective size), but that's probably gonna be on kill haha. What are you hoping to see with the G35 vs this?