Lithium

Honestly you aren't giving much to work with at all, my last post was effectively a "questions that need to be answered" one and you've responded to it with questions. If you want anyyyy kind of answer that isn't taking the piss the more of these questions you can answer the better: - What limited it to 520kw @ hubs in the first place? Is there timing on the table? Was there anything else to be sorted which could result in more at that point? What is your tuner's view on it? - WHAT IS THE LOWEST POWER TARGET AT THE HUBS YOU'D BE HAPPY WITH? And what octane fuel do you want to achieve that on? There is no point worrying about response if you're going to be constantly disappointed with the power level. - If you're hazy on the above, are you looking for a fun fast car or a big power figure? You have to choose to a degree here. If you're sticking to pump gas and the current setup is reasonably far short of what you want then an EFR is *not* for you - so you're going to be taking a decent response hit no matter where you go. The more info you give the easier it will be to try and help, but I'm not agreeing or suggesting to any turbo until you fill in some blanks.

Looks to be carrying power reasonably well, the boost control solenoid duty cycle can often paint a picture of EMAP. If the duty cycle is picking up a lot through the rpm range then EMAP is likely to be running away - if you're holding fairly steady WGDC....so if you hit target boost at 4500rpm and it stays at a fixed duty cycle area from there until 7500rpm to hold the same boost then EMAP probably isn't out of control. If it gains 10+% then it probably is. Reason is here is you're having to compensate for the raising exhaust pressure against the wastegate valve

Ahhh the joys. I'm not going to make any assumptions on what you've tried or thought of, so just going to dump some thoughts haha. First area to consider, comparing the actual dyno results it's worth trying to see the wood for the trees Autos are a headfk when doing dyno testing at the best of times. For the last few years I've been tuning a mates Toyota he dragraces - it had been running a 1.5litre 4cylinder turbo engine through a 5-speed manual and got it down to the mid 10s before the W58s became an item to be replaced every meet. To resolve the issue he chose violence, and dropped a 2JZGE (with added Pulsar G35 900) onto the side of it and attached a Powerglide to it to get it running. It took him the whole offseason to do all that work and ultimately got it to a point it was able to start and run with the old diff he had with the W58, and the fuel pump setup for the 4cylinder. The 10.58 @ 131mph he achieved was 320rwkw with the dyno we use for this car, fuel pressure all looked sweet... however with the 2JZ the same fuel pump setup was dropping pressure badly at only 286rwkw. All indications were the it was swallowing heaps of more air than the old 1.5 even though it was running VERY little boost and the power was much lower, but the airflow / fuel flow numbers otherwise appeared to be adding up correctly. Seemed to be happy and healthy so we figured just get it to the strip and do some shake downs. Long story short, despite the new engine/gearbox combo likely adding 100kg odd to the weight of the car and making less power on the dyno we ended up coaxing it down to a 9.78 @ 138mph (crossing the finish line on the limiter because out of gearing). Heavier car with less measured power. Of course there are other variables at play, but at the end of the day the fuel flow and the MPH vs weight suggest the thing was making a significant amount more power than it was with the 4cylinder. Autos do weird shit. Comparing two different dynos isn't going to help the comparison As per our experience, sometimes the dragstrip can give you more of an idea than the dyno will when autos are involved. Maybe worth driving it or getting it down the strip before making any hasty calls - may turn out to be combo that works better than how the dyno number makes you feel. Second major thing to consider which kinda branches from the first is that when choosing a turbo you have to work out how much airflow you need, or maybe more to the point - are actually going to be making decent use of and is going to suit your setup: The whole topic is one you should be discussing with your tuner, but this would be the most poignant one - what held you back from making more power? 98+WMI is arguably a lot less potent a fuel than E85 etc, depending on the blend and how your tuner has chosen to use it. If for some reason "all the timing" that the engine needs to make optimal use the air/fuel mix in there hasn't been dialled in then you potentially have a turbo capable of making more power than it is if the fuel (or the tuner's confidence in it) isn't there. It's worth knowing if part of the reason the power isn't as high as expected is because the tuner hasn't been able to lean on it and there is power on the table with higher octane fuel, as if there is then a turbo upgrade may not get the significant gains you're hoping for as the turbo may not have been the key limitation at this point. I'm not saying this is the case, I don't have the data to know it but plenty of people have been in this kind of situation and done a turbo upgrade with underwhelming results because of this kind of reason. As @GTSBoyindicated, data is king. If you had turbo speed/emap/whatever data you'd be in a much better position to estimate yourself how responsible the turbo itself is for limiting power - ie, if the airflow is there or not. Bare in mind, the EMAP or turbo speed being high just means your turbo isn't going to be able to give you more air... if the tune is held back at all (refer point 1) then it could still mean better octane fuel would be money better spent than a turbo upgrade. Worth speaking to tuner if you want to get an idea of where things are at there if you have any doubt of that, you may gain more power per psi with a bigger turbo but if you want a significant amount more power then more boost is probably going to be necessary to get the extra airflow which is pointless if your tuner isn't happy with the fuel you're using at that point. Now to actually TL;DR answer to your questions: 1) See how it drives and how it goes on the track before getting too concerned about power figures - esp. when you get an auto involved. 650whp through an auto could be a much faster car than you're expecting it to be, maybe. Turbo may or may not be tapped out but because of how hard the tuner is pushing it and how the auto is delivering that to the wheels its hard to know how much to blame the turbo for the 650whp figure. This will put you in a better position to decide whether upgrade to the G40 is going to be worthwhile. 2) Housing will depend on how concerned about lag you're going to be. I'd be tempted to swing the .95 if you are concerned at all but if you're trying to make a big step up in power it's probably worth not being shy.

Late to the party, I feel like I've been involved in a few conversations about this setup here and elsewhere and I feel like it's a thing which is going around in circles so I'm going to keep it to bullet points addressing whoever they may be relevant to. Correct me if any of my assumptions are wrong here. There are various mentions of E85 tuning on here, I'm pretty sure this is running BP98? 30c intake temp is NOT high If you are running 24psi on a responsive setup and still have under 30psi EMAP when getting near the end of the compressor flow of the turbo that is really good. 1:1 EMAP vs IMAP and below that are great to strive for, but going over that is not a problem if it's within sensible levels. The ratio based off the logging in this case is not cause for concern at all, however... While the max compressor speed for an EFR9180 is 116,000krpm and you're "only" at 103,000rpm - 103,000rpm is still off the map in this case, note the red dot. When you go under 60% compressor efficiency everything starts getting a lot harder, the compressor air temp goes up heaps and your intercooler has to work harder to get IATs in check - the turbo has to work harder to get any more flow and EMAP starts creeping up. I'd call this setup fairly maximized without being stupid about it. So yeah, at least for pump gas this is probably the right place to call it - both tuners seem to be it pretty close territory with each other and the data lines up that you're near the end. 1000hp @ engine (if you're aiming for at the wheels then it ain't happening at all) is an ambitious target on an EFR9180 on a big engine, that turbo is actually probably better suited to smaller ones that need more boost to achieve those numbers. There are mentions of the cam timing, again - you are turbo limited at this point. Doing things to make the setup work better psi for psi is going to make it WORSE, not better in this case as the 9180 is happier at higher boost. If you dial the cams in a way that they are going to need less boost to make the same power, you're going to shift to a less happy part of the 9180's comp map and it's going to be even less happy than it is at the moment. Ironically if you go the other way, you're going to potentially start struggling with octane limitations. Things like cam spec, cam timing etc increase your engines ability to move a volume of air but it doesn't matter much if the turbo can't efficiently push dense charge at the volume you want at the boost you're trying to push. The ways of making more power at this point in my opinion are: Use a fuel that allows you to get more power out of the amount of airflow you are moving (ethanol, methanol, nitromethane hahaha) Add more air to the combustion process somehow... ie, nitrous oxide. Do changes which increase mechanical efficiency, like dry sump etc. That's only going to offer incremental gains though, none of these (well short of nitrous or nitromethane - but don't do that haha) are going to get you to a legit 1000hp. To be clear with the "out of turbo" thing, you are out of COMPRESSOR here - not turbine. Don't get sucked into the idea of going a larger turbine housing with this, it may let a tiny bit more power happen but you're just freeing up flow for a compressor that is pretty much out of breath and for a setup which is only barely past 1:1 EMAP/IMAP. The most obvious thing to help this combination would be a compressor which has more to offer, like going an EFR9280 (or bigger). You're still going to reach a point where you should run better fuel at some point, but a 9280 seems like the nicest compromise to get gains without losing lots of response or anything like that. Those are my thoughts, anyway. PS: @GTSBoy, matchbot is educated guesses at the best of times - pretty subjective so I'm hardly going to rip on it My only comment, and I'm not assuming at all that you don't know this but just for yours or anyone elses interest... adding compressor efficiency to the table base off where the associated "dot" on the compressor map makes a difference to all the calculations eventually ending up affecting turbine efficiency/emap, so is worth doing if you cbf. Often isnt a biggy buuuuut in cases like this where you're starting to go off the comp map it can show you how much "damage" it's going to do.

Fwiw any time I've heard of or been involved with using GPS for this kind of thing it's turned out that GPS latency is too bad even it's fast. Remember the GPS speed is a "in hindsight" measurement, so it basically checks how long it took to cover ground and works out the average speed required to take that long... Which means you'll be going faster than what you've got from the GPS setup. The results I've seen are as you'd expect, basically it cuts the wrong amount and too late - could argue that the tuning could be tweaked for it but you are actually trying to make decisions based off things which have already happened which is going to be flawed. With 4wds I think accelerometers or predefined torque profiles for the situation are the less problematic way to go about things like this depending on how precise you want to be.

Any idea if some of the SX-R upgrades are going to flow over the to EFR range? The compressor map for the S200SX-R 7670 (/ S258SX-R?) looks like a cracker and could only imagine similar aero would make a worthy and needed update for the EFR7670:

Not an RB, but the nost recent result I've seen, and one of the more impressive is this 3litre VVTi 2JZGTE making 1130hp @ hubs with 30psi by 4000rpm on an EFR9280: https://fb.watch/kiHcr8Bydb/

Not at all. And this is a key point, aside from my wind up comments I made last night a few rums in after seeing morboost's smarta55 comment to someone who was simply stating their own preference as an opening to be a smarta55 myself - I have always been a huge fan of matching parts of a build to suit the purpose. I ultimately completely agree with you in terms of the stock R34 twins, or a mild twin setup for a mild fun street friendly setup. I'd never go out of my way to convince someone to go single turbo if they're aiming for under 350kw on a mild RB26 - the reasons I suggest a single turbo is better than a twin setup are not applicable at this point and if I myself were building a GT-R for that kind of purpose it's also how I'd probably do it. This again comes down to me mostly being pretty agnostic about brands or methods of doing things, and just trying to identify the most appropriate combo to achieve a purpose... which can include satisfying things the person who is going to drive it prefers even if they aren't specifically about peak performance. So yeah, realistically having an EFR8374 and saying that a single turbo or a EFR8374 isn't a great choice when you're using it for <350kw is bizarre when framed as a "people said and EFR/single turbo is best but its not" when it's a painfully poor match for what you're using it for is a kinda odd take. I'd never argue that you made the right choice going for that for this setup, or any single (though there are singles which would be wayyy better suited). The whole single turbo debate for me has LONG been about where people are running twins and trying to bend physics to make them work in highly restrictive setups and ending up needing to over turbo, massively engineer and strain the hell out of things to achieve numbers because of packaging limitations with the low mount twins - you end up with turbos not work in a balanced manner and both having to work WAY harder due to operating in temperatures and pressure ratios that a single turbo wouldn't have to when trying to move enough air to make >400kw @ wheels as you can package it well enough to draw in air and dump out exhaust without dealing with major choke points or trapping heaps of heat. That is not relevant in the case of what you're doing.... as such I am very pro twins in the right situations, and very pro single turbos in the right situations, and the same goes for picking brands of turbo, split/single pulse exhaust housings and the rest. One size fits all is not a thing that works with tuning cars, and having a personal preference is a very legit reason for choosing one thing over another - which again was the only point I made a dig, because two things that get my on my soap box are people choosing the wrong things for a job and then saying they're shit because they don't do that job properly, and people telling people their opinion is wrong

This is completely irrelevant to anything. Dose pipe was saying what he prefers for his own car, your opinion is irrelevant there. Also you mentioned a bunch of things where there is a compromise for a car used on the road, single turbo makes driveability and maintenance better than twins so is basically win win for a street car.

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.