Lithium

And because people like this kind of thing, a loose translation of what kind of area these flow figures may convert to in dyno numbers if everything else is up to the task. Bare in mind, these numbers are not what I'd say are "on kill", but where the compressor is starting to really earn it's keep - they should have more to give, but the things start working harder to get there and you start moving more into "how optimised is this setup" territory. These numbers aren't a guarantee of what setups WILL hit using these turbos, it's what the turbos should be able to achieve working reasonably hard - but not too hard... and of course me making a bunch of assumptions lol. Turbo 20psi 25psi 30psi GTX3071R 339 352.6 359.3 GTX3071R Gen2 345.78 352.6 359.3 EFR7670 359.34 379.7 386.5 S257SX-E 366.12 386.5 406.8 G25 660 372.9 406.8 400 GTX3076R 400.02 413.6 420.4 Gen2 GTX3076R 400.02 413.6 420.4 GTW3476R 406.8 433.9 454.3 EFR8374 440.7 461 467.8 GTX3582R 474.6 488.2 501.7 Gen2 GTX3582R 474.6 508.5 522.1 EFR9180 501.72 535.6 569.5 GTX3584RS 508.5 542.4 569.5

Hi all, There have been all kinds of conversations on and off SAU about single turbo options for RBs (and other engines really) in the current state of the game and while I've not seen any evidence of compressor maps being inaccurate, different manufacturers use different ways to normalise and present the numbers, different cut off points, and different ways of estimating hp from compressor flow which can result in people expecting too much or too little from their turbos. I've decided to semi-roughly translate it all into an even measure and shove what I consider "the most relevant" turbos for most people who would be talking about turbo choices in here, and split the compressor flow potential they have at 20psi, 25psi and 30psi - using "65% compressor efficiency" as a cut off. Those are fairly familiar and reasonable reference points, and as you exceed 65% I view it that it's where the intercooler and hotside are starting to have to carry disproportionately more of the load to keep things happier. This is the "you're pushing it" zone, imho - even if it's not really maxing the turbo out. It seems to be a reasonable way of gauging them on a similar scale if you're going to being matching the turbos for real world performance. It may not be PERFECT but I think it gives enough of an idea of how they may compare, I'm pretty sure all these turbos have hot side options which are pretty close to supporting the exhaust flow needed these days - give or take, but some of the numbers here may explain a few interesting things seen.. Hope it's vaguely interesting reading Turbo 20psi 25psi 30psi GTX3071R 50 52 53 GTX3071R Gen2 51 52 53 EFR7670 53 56 57 S257SX-E 54 57 60 G25 660 55 60 59 GTX3076R 59 61 62 Gen2 GTX3076R 59 61 62 GTW3476R 60 64 67 EFR8374 65 68 69 GTX3582R 70 72 74 Gen2 GTX3582R 70 75 77 EFR9180 74 79 84 GTX3584RS 75 80 84

Yeah, hard to disagree with most of this. The last bit... I still need more data, and while I agree re: the choking engines - it seems quite a bit like the data is there, but Borg Warner have presented it in a way to make it seem "better than it is" They have mapped lines way past where compressor efficiency would be falling over, the "95lb/min" line which they so clearly mark for the EFR9180 is VERY misleading imho. You have to pay attention to the numbers, not just treat the right most lines as the target. I think there is a very real chance that the bigger G-series turbos coming out from Garrett could give Borg Warner a kick in the pants.

Yeah, next time I've got a dyno handy this will be worth a try to get a gauge of the NZWiring kit solution. To be clear, I've never debated that the crank trigger setup isn't the ideal solution *but* this data makes the difference look much worse than I expected... so far. Yeah going by the data so far it looks worse than I expected, albeit still would love to do this testing with something like NZWiring's kit.

These turbos are designed focussing on response for a power level, not max power level for a wheel size.... all the information is there to determine whether the flow will suit what you're trying to achieve, to make sure you are able to choose appropriately from that. There are plenty of cases where you can go up a size in EFR versus a competitor and still end up with better transient response and make up for, if not more than make up for the flow difference penalty you may have had using a size down.

Cool, yeah I hadn't done the math and just did a quick run through of my own and it does seem to add up with what you're saying - which is interesting as there is some pretty enthusiastic debate from some pretty respectable names about the likes of 12 @ crank not being enough etc... if your math (and the quick bunch I tried) add up then in theory there shouldn't really be too much error if you were to assume the crank velocity maintains a linear rate of change. I don't have any data on the realistic behaviour, though as you say... that would be VERY interesting. Still curious to see what you see if you maintain steady rpm at 5000rpm or so, just for interests sake - I've not got enough time to go fully through my math to make sure it's sane but it is starting to indicate that some things are overstated, which I guess explains how stock Evo triggering doesn't cause big issues haha. If that does work out as being the case, I am pretty surprised that the difference would be that big.

OK cool. To clarify, what I was questioning (to be clearly, not calling it out as BS - I more trying to analyse the data presented as it *is* good data but it'd be good to feel comfortable with the conclusion taken from it ) was this statement: I might be reading you incorrectly, you are only looking at a window on the cam disc - so checking it once every 720deg of crank rotation? And you are using that to gauge error between crank triggering and cam triggering? If so, then I'd be questioning your data if you DIDN'T see a big variation when the engine is not operating at steady state rpm... if you get what I'm saying? Hopefully this helps clarify what I am trying to get at, and at least we can get on the same page and work out how best to use the data - putting this kind of thing on the microscope is a worthwhile venture

OK, so what would happen if you compared a timing data between a car running the 36-2 and the 12-1 in exactly the same operating conditions?

Yes, I understand all this - this is my point. To try and get this on the same page, what do you think will be more accurate - 36-2 or 12-1 on the crank? What do you think would happen if you compared timing logs between both setups?

This is kind of the point I was getting at, the evidence you are presenting is partly comparing the ability to accurately estimate the crank position by comparing something that gets updated every 10 crank degrees versus something that gets updated every 30 crank degrees. Theoretically the error between the two should be negligible at steady rpm, but the error will increase the moment the rpm rate of change increases - it looks a bit like you selected a section when the engine was starting to go through a drag down after a dyno pull, which is much higher rate of change than the pull itself. And yeah, it should be more stable under steady state conditions which is why I asked if you can do that - it should mostly eliminate anything that may (or may not) be introduced by comparing 10deg updates with 30deg updates

Interesting data, thanks for sharing. It'd be nice to be able to separate any error which is introduced by triggering resolution - I don't have the time now to do the math to work out what (if any) meaningful error would be introduced via a combination of any signal filtering vs rpm rate of change. In your case there are 3x the amount of updates from the crank trigger as there are from the cam trigger in a given amount of time, which will create an increased amount of error even if there is absolutely no drift at the cam as the rpm rate of change increases. Are you in a position to be able do any more testing of this? I'd be interesting to do a brief steady state test at the higher rpm - ie, hold it at 5000rpm briefly to see the trigger variance.

Seems almost relevant

GTFO with your bias calls, I've been given shit from every direction because of my inclination to stay neutral Apparently as soon as I talk positively about one brand I am a fanboi for it, even if I could have just finished recommending another option over it 5 minutes earlier somewhere else. If you're talking about the excessive discussion about Borgs in this thread, check the title - of course you're going to get some stick for bringing Precisions up in here haha. Would be very very interested to see how the 8374 comes across after being used to a 6262, it's not a change I'd necessarily do given they're all going to be so similar - but if the change is going to happen I'm very interested to see how it comes out. The 8374 is (in theory) a step up in hot side flow, so depending on the housing chosen and how good the head is I wouldn't be too surprised if there is some loss in down low spin (purely gas energy versus the size of the turbine being spun), a bit more power per psi and no loss... if not an improvement in transient response once up on boil. People both for and against the EFRs versus other turbos seem to selectively suggest there is magic involved. There isn't, as with any turbo or really any product. A huge amount of getting the best performance is picking the right unit for your job - the last 5% of improvement getting the "best possible result" is often the hardest work and biggest expense. There always seems to be that someone at a track meet smashing guys the big dollar guys using the cheapest parts they can get which won't fall apart with what they're using it for. Doesn't mean that they wouldn't be happier or possibly doing better if they had the better bits on it - and sometimes the "most desirable parts" just won't suit a set up as well as something else, so the result will actually be better. We're lucky to be spoilt for choice

I wish I hadn't been so busy since I got back to NZ, I would have liked to have commented on this while the iron was still hot but life just hasn't been quite compatible with doing online rants - though better late than never, right? First off, f**king sweet to catch up again Piggaz - and thanks again for the catch up and E85 burning session, was a day well spent and my liver still even functions! Next, this is my best effort at giving an impression of the EFR8374 with the 1.45a/r hotside.... considering I've not been in a vaguely comparable car in AGES, and I never experienced this car with the 1.05 hotside I have no choice but to rely on inference to build any kind of review about how this would stand up to any alternative. I had actually had talked quite a bit with Piggaz from the point the car was tuned and the point he picked it up, and been in common cars (including this one) so I had a general idea of how his perspective of delivery compares to the real world so almost disappointingly - it basically behaved how I expected it to. Disappointing in the fact that there wasn't a huge surprise, not that the performance was disappointing at all - I can just see how someone who hadn't been "primed" could go in the same car and be like "holy f**king shit, what just happened then?". Below 4000rpm as expected - it fell short of the initially descriptions I'd had from him and others of how it performed when it had the 1.05a/r hotside, which to be fair - a lot of people would not have believed if they didn't know the car and people in question... basically amounting to "it is ALWAYS on", almost like a totally undersized turbo which woke up at the whiff of the throttle. What I was greeted with was actually felt like it was turbocharged, but with a fairly conservative turbo setup. More like something which when he leaned on it could realistically have someone convinced that it was running something along the lines of -7s or -9s - the bigger hot side had clearly taken a bit of the low rpm windmilling/induction whistle effect you may expect at the very bottom end with a responsive single turbo setup. Between 3000-3500rpm it was starting to go from a slight boost climb into an aggressive ramp, and if still in it by 4000rpm - in pretty much any gear, the boost climb felt like it was going pretty vertical... basically by just over 4000rpm "full boost rpm" becomes academic, even if it is still building the car is accelerating hard enough that you're getting somewhere in a hurry - so hardly laggy by any stretch of the imagination, definitely one of those cars where looking at the boost curves on a dyno plot are very misleading. The trick here, is the ability for ANY Skyline GT-R to accelerate at that kind of rate in that part of the rev range is really impressive... let alone being under 3litres, and let alone with a car which has >500kw @ wheels. I've been in a few 10s GT-Rs, and this thing pulls the whole way through the rev range much harder than any which I've been in that run mid/high 10s at low 130mphs. For something that spools and responds the way it does, it's pretty mind bending stuff... even if rationally you know whats coming. Lets put it this way, imho if most people went in this car and the rpm were kept below 4000rpm and you thought you experiencing which was making mid 300kw @ wheels it would be something you'd not have to lie to say that how it drove in that rev range was pretty impressive, let alone if you consider that the car actually has ~50% more power than that and delivers in with a FAT delivery. I guess if anyone wants a real world way of quantifying this themselves, we did a "time exposed to danger" test - acceleration from 80-120kph, starting the timer when the throttle goes down at 80kph/~4200rpm in 3rd and stopping it when 120kph was reached. The elapsed time was in the 1.xx second range, which when you factor in the fact there was no "run up", no brake boosting or anything - just stomping the throttle at 4000rpm I think that is insane, considering the car is still not even in it's happiest part of the rev range at the END of the pull. Try stomping the throttle from ~4000rpm in 3rd in your own car and see how much speed you accumulate in 2s from the moment the foot goes down, gaining >40kph is not pissing around from those kind of rpm with a car that's making >180wkw/litre. So what do I think? The car is an insane setup, the engine package is simply awesome - and this speel doesn't even account for the fact it has a sequential gearbox (holy crap this makes the car that much more capable than the dyno plot suggests), amazing suspension and braking etc, I'm simply focussing on trying to communicate how the turbo works. The turbo itself is clearly pulling it's weight in a setup where the expectations are high. There are natural question marks for me, more for curiousity than the feeling there is any reasonable expectation for more. So thinking through the EFR options I feel there could be an argument for on this car: 1) 1.05 EFR8374 I would have loved to have experienced that. I understand the desire to move on from it as there were mid/low rpm surge issues with it, and those have been resolved by going to the 1.45a/r housing. What I don't know is if the 1.45 has fixed it purely by allowing the engine to breath better, or purely by introducing enough lag than the turbo doesn't cross the surge line anymore just to getting to higher rpm before hitting that boost level, or if it's a combination of the two. I am guessing it's a combination, but a combination which is particular to this particular engine setup - so not necessarily one that would apply to all setups. The idea of the car as it as at the moment with a softer boost curve down low to avoid the surge but with the extra life between 2500-4000rpm sounds interesting for academic reasons, it would just be hilarious - especially considering I at this stage can't see a reason it shouldn't be able to make up around 500wkw if the owner didn't mind EMAP starting to climb. One way or another, this is the smallest EFR I'd consider putting on a car like this - clearly it is running out of compressor at only ~23psi as it is, and it's spooling fast enough to get into the surge zone so for various reasons the .92 is just not an option I'd consider on a good RB... personally. 2) 1.45 EFR8374 - The current turbo This spools very well for a setup which is able to make this much power on a 2.8, it doesn't surge even with an aggressive midrange boost curve (ie, hitting ~30psi and bleeding back to manage turbine speed), and it allows the compressor to basically max out without an excessive EMAP/IMAP ratio. It basically is able to use the full width of the compressor map with no big work arounds and isn't laggy, that has to count as a very good match. The car is just so exciting to go in, again - there are a lot of pieces to the puzzle which allow that to happen... but the way this turbo and the engine interact is just spectacular. For what Piggaz uses it for, I'd say (well I already have said) leave it here. A few years ago I'd say neither of us would expect that what his car does now would have been possible with the parts it has. 3) 1.45 EFR9174 I don't really have enough data from this car but I am starting to entertain the idea that this could be a very interesting alternative to the EFR8374. I wouldn't go any smaller on the exhaust side as it obviously already had surge issues with the 74mm compressor, the 91mm compressor's surge line is ~6lb/min to the right so would likely only be worse with the same hotside - however given the setup is already not surging with this hotside running lots of boost in the midrange, the 91mm compressor should add a little more lag so I'd hope that should dance around the surge line while also not adding too much lag - I do like the idea of the 74mm turbine having a much lower MOI than the 80mm turbine. I know the natural question to this will be "what about exhaust manifold backpressure with all that extra flow?" - I really don't have enough real world data, but I am starting to suspect one of the things which is giving EFRs the rep of falling over at higher rpm/getting high EMAP is Borg Warner's decision to print compressor maps using an rpm as the cut off - not compressor efficiency. Looking at the boost level Piggaz car is running at peak power with the current turbo it would need an extra 7000rpm of shaft speed to increase flow by ~1lb/min. The energy to increase the shaft speed that much comes from the exhaust, so less wastegating, so higher exhaust back pressure, and negligable change in boost pressure. Not a great mix. It may seem counter-intuitive, and I may be full of crap, but part of me wonders is this turbo with the exact same boost curve may actually result in lower EMAP than he has right now at full rpm - and also better power. I tend to think of 65% compressor efficiency as a point where you start going "ok, we're pushing it now" territory and realistically the EFR9180 compressor is already going to be under that efficiency if he tries to hold mid/high 20psi to redline so with his engine setup the 91mm compressor is not what I'd call a comfortable 95lb/min compressor. If it were mapped to stay within the >60% compressor efficiency parts of the map then I'm not sure if EMAP would actually take off like one may assume, turbine rpm would stay safe as houses and everything should be pretty comfortable. I suspect it could be a nice way of allowing the engine to operate a bit freer in the higher rpm without sacrificing too much down low, we're talking taking nearly 20,000rpm off the turbine speed and actually gaining power. Does it NEED the extra power up high? Not really, in the real world this car is FAST. Very very fast, everywhere. If there was any other option that I'd be VERY curious to see how it worked on this car, this is it - mainly because if my speculating is right it'd be working a little less hard and give a little more at minimal cost. In a world where there seems to be no perfect "sweet spot" match from the EFR range for this engine package, this could be the best alternate reality compromise from the 1.45 EFR8374. 4) 1.05 EFR9180 The idea of these make me feel happy in the pants, and I'd love to see how one behaved on the car.... but I know what Piggaz likes and again, with the overthinking above - I'm really not sure it's something he needs or would even necessarily suit his setup as well as other options, even though realistically if he put it on and anyone who hadn't experienced the previous configurations went in it with the current engine/trans setup and this turbo it'd not be surprising if it felt "perfect". 5) "The others" I think the .92a/r EFR8374 would be beyond pointless and would actually be a complete fail, and the 1.45 EFR9180 potentially just adding lag for sport. So yeah, I've overthought the shit out this and given a TL;DR post for people to take or leave - but given I started the whole bleating about EFRs in this forum and have often expressed frustration on the lack of input on how they work I felt obliged to share some thoughts now that I'm in a position to have been able to vicariously experience the process Piggaz has gone through and the result of it. Nice work mate, the thing is nuts - it's come a hell of a long way from the already potent machine it was when we first met.

Because SAU went full potato with my first post, and won't let me delete it

Good point, or at the least an NZ Wiring cam angle sensor kit

Easily 450kw+ on E85 I'd say, if everything is set up and working well together

Still in NZ? Who will be tuning it? I'd expect with a decent fuel system on board you should be able to go WELL into the 400kw @ hubs range on their dyno, I'd say high 400s could be doable. One of the lads I know cracked 500kw at DTech with his HKS 2530Kais with some ethanol on board on a good RB28 build

I have on good authority there has been a bit of feature creep

Nugget. Spending money on the wrong things, needs a shift boot and a front lip ffs. I am too upset to talk about it in depth right now but will update with more when I am back in NZ ?

Keep an eye on the end of year trade shows

I am sure they know this, and I am sure a good percentage of the people discussing this realise that - I doubt it is either deception or ignorance so much as just like top level drag racing, time attack is pretty much getting the most you can out of a setup while still HOPEFULLY having it hold together long enough to get a result. Its clearly not going to be an endurance engine... though those reasons are why I assumed when they said "more drivability/wider power delivery" that they were hoping it'd be more responsive earlier - not at the drag racing end of the rpm range. It kind of backs up a lot of initial discussions of these turbos, considering wheel size wise they are comparable with GTX2867Rs or SMALLER than Trust T517Zs - they are not spool monsters by any stretch of the imagination, the G-series don't seem like a threat to EFRs in their realm however for this car the logic in why they went for them seems sound... so long as they can hardness the power delivery and keep the engine together long enough to achieve the results they are aiming for. The RB34/EFR9180 combo sounds like fun! What kind of rev range will that operate in? In Evo world from memory the "more reliable" setups tended to be shorter stroke/longer rod combos (so nearer stock displacement as opposed to 20% more than stock) resulting in slightly less displacement - the bit of extra rpm needed to make a given power level usable was considered to often be a better reliability trade off from the effects come from the lower rod/stroke ratios the strokers resulted in.

Yep, pretty much as expected really - initially I thought they were saying they expected better spool than the EFR9180 which seemed like a tall ask... but it sounds like as you say, it's a reasonable amount laggier but makes >100hp more (not sure about a few hundred). In the scheme of things - they are more turbo, they're laggier, and they make more power. One of the more impressive things about the comparison for me was that apparently the twin G25s give nothing away to the Precision 6870 they tried, but makes more power and the 6870 fell on its face after 8000rpm - while the G25s hold on past 9000rpm. So yeah, as expected the G25s aren't really cooking until will into the 5000rpm range but if you've built it to rev like hell and they are holding up high then it sounds to match what they were looking for to a T.

That's actually a GTW range turbo, a little off topic in here - but I've seen VERY little for the GTW range, most you can find is the GTW38s.

Ooops yeah, I meant to say the 2x 3port is an alternative to a 4port BUT you can also run a single 3 port. We are actually going to test 2x 3ports and a dual port actuator on the EFR7064/RB25 combo I tune because it's annoying having what seems like a clear amount of flow headroom but an internal gate setup which just won't stay shut.