Lithium

Cheers for clarifying How did the S369 and the 6870 compare aside from the Borg not smoking? The G42 should be quite interesting, definitely a bit of a step up!

It had a 6870 on it previously, from memory?

OK that is what I wondered - the old "way off the map" trick is a prime cause for soaring EMAP. The "choke line" from Borg Warner is around 117,000rpm for the S369SX-E - as you start drifting further off from there compressor efficiency will go ballistic as the wheels need to spin way harder to try and move any more air, so the wastegate has to close to try and keep boost going in and you just get raising EMAP and it tries to drive the compressor to get air it really isn't meant to shift. Whether all that air was getting to the engine or not you were WAY off the compressor map, so trying to reduce EMAP by trying bigger exhaust housings etc would have been band aids to the issue. Don't suppose the airflow model you were using gave an estimate of the airflow it reckoned the engine was getting? Wonder if there is a chance there was an airleak or something, or does that power figure match up with 90+lb/min of airflow on that dyno?

Wow, yeah that is pretty bad. I've heard mixed things about the S369SX-E, and Matchbot has no data on the 80mm turbine so I have no idea what to expect... if this is how you would expect it to be or if there is something else going on to inflate it so much, definitely one of those things where turbine speed would work hand in hand to make it clear whether that is definitely "normal" or if there is something compromising the setup. What kind of power was it making, and have you changed now? I wish I had more data on this, again it's pretty clear it has dropped a crapload of EMAP but it's still not clear where it actually is - I don't doubt it's not magically low or anything... just at an acceptable level compared to previously.

Chur - also, link to a build thread for more details on the build:

Hi all, things are mostly dead in here but I figured its still worth recording this somewhere as people here or out in the world who google stuff may find some of this interesting as there seems to be a bit of interest in these turbos from a value for money stand point - but a fair bit of conflicting info... so I thought I'd add something which *I* view as kinda credible info, take it as you will As a bit of background, one of my best mates @Looney_Head has been chipping away at his build in his garage over the years - he has done most of it himself or with help from mates... doing things on a relative budget, but "properly". Probably unsurprisingly here he picked my brain for turbo choices, and around ten years ago the build was going to be a stock/reconditioned RB30 with an R32 RB25 head so the target was around 370kw @ hubs on BP98 so I suggested a Borg Warner S360SX with .91a/r hotside as it could be had for NZ$900 at the time, should offer decent response vs power vs reliability and being a large frame T4 divided turbo there should be an easy upgrade path with minimal changes if he decided to in future. Turns out that was a good plan as feature creep resulted in the build having a forged RB30 bottom end and an R33 RB25 head with some Tomei 256 cams and a mild port job. We knew that the turbo was going to now be well out of it's depth but being that the car is an R32 GTS-t it probably was likely to end up still being a bit of a weapon so when it was already ready we decided to tune it up and find any bugs etc and he could have fun with it for a while. On the dyno as I progressively increase BCS duty cycle it started becoming clear that it was hitting a brick wall pretty much bang on where I expected it to - basically being unkeen to support more than 18-20psi boost at 7000rpm, so we ended up stopping with boost peaking at 23psi and bleeding back to around 19psi and making a very fat 447kw @ hubs on E70ish. See the mighty S360SX dyno plot complete with choke as soon as it hits 600hp: That proved to be a very very fun street package, but the opportunity came up to get our hands on an upgrade for a good price so after much umming and ahhing we settled on an S362SX-E (aka S361SX-E, aka S300SX-E 8376, aka S300SX-E 61/68 depending on whose nomclementure you subscribe to). The process of chosing that was actually pretty challenging due to the conflicting info on the net which is part of the reason for me starting this thread - to share the process and reasoning and then the interim results, hopefully to clear things up a bit. Firstly, our hopes were to free up the flow up top with minimal cost to response. So, questions you may find hard to answer or generally look misleading when looking at these: 1) The S362SX-E with the 76mm turbine wheel (there is an option to use the 80mm wheel) can go directly into an exhaust housing which fits the the S360SX turbine wheel. They are an identical 76mm inducer/68mm exducer profile. 2) Despite being exactly the same size the SX-E turbine wheel is DIFFERENT to the SX wheel, the aero is very obviously different. The SX has "flat tips" while the new SX-E has cupped tips - I'll attach pics, but its pretty obvious how the exhaust gas will react with the wheel as it "hits" and flows through the blades will change. See below: (S360SX turbine left, S362SX-E turbine right): 3) The "76mm .91a/r" turbine flow map on Matchbot relates to the SX-E wheel. I had to work this out anecdotally, but it became clear that the S300SX flat-tip wheel is a bit of a nugget flow wise and in combination with the pretty average flow of the 60/83mm S360 compressor results in very high EMAP if you want to make >500whp. Due to that, and the internet being mainly convinced that the S300SX and S300SX-E turbines are the same people often go for larger a/r turbine housings than they need when going 76mm SX-E turbos. The 76mm .91a/r hotside combo on an S300SX-E flow the same as a 1.05a/r 74mm EFR turbine. It has been proven to support 900whp (US dynos)/ near 600kw (Oz dynos) on the right setup. People are often oversizing the hotsides on Borg Warner Airwerks turbos and living with more lag than they need, imho. So, after my research and deciding that there was a bit of misinformation out there - I decided that going for the 76mm turbine wheel in the SAME .91a/r housing we'd be running should make for minimal sacrifice to response but not actually choke the turbo despite the fact that we had seen massive signs of choke on the old turbo in the same housing (VE was dropping off increasingly badly in the 220kpa and 240+kpa rows in the engine efficiency table - and boost control duty cycle had a major dogleg after 5000rpm to target 240kpa MAP). In terms of compressor wheel, the "S362SX-E" actually has a 61.4mm inducer and 83mm exducer, so identical outer size to the S360SX (or 8375) that was being replaced but only 1.5mm bigger inducer. This wee thing is a bit of a gem on paper, the loose info on the net would suggest that the 63mm and 64.5mm inducer variations are big steps up but after close investigation I found that actually - the compressor maps for those turbos "cut off" at around 54-56% while the 61.4mm one only runs to 58-60%. If you compare these maps at "efficiency for efficiency" then the 63mm BARELY pips the 61.4mm wheel, and the 64.5 has a max of 6% more flow in the 2.2-2.7 pressure ratio range that your focus would be on a decent RB. When you consider that the 63 and 64.5mm wheels are both 87mm exducer, there is no way there is not going to be a significant impact to spool or transient response. The big flow advantages on those bigger inducers are at pressure ratios of 3+, which is not relevant - and the 66+mm inducer is just not relevant to our interests as we weren't looking for huge power. Here is the old and the new turbos: (SX-E left, SX right) I actually overlayed the ol' faithful EFR8374 compressor map (in red) onto the S362SX-E compressor map and it becomes obvious the SX-E is a good thing, having a better surge line but also providing equal or better compressor efficiency at almost every relevant flow/pressure point on the compressor map. So, decision made, turbo install and off we go for some dyno hilarity! At low boost it was like the turbo was identical, it was basically tracking the exact same boost curve and making the same power at ~10psi - no shocks there. What got interesting however is that as I started targetting higher and higher boost levels, the BCS duty cycle could stay relatively "flat" whereas with the S360SX I was needing to bump duty more and more from 5000rpm up - and I also ended up basically copying the VE numbers from 200kpa row and pasting it to every row above that and having lambdas hit target perfectly - while I needed to roll them back with the S360SX. Naturally, this was reflected in power numbers as well. Things were starting to get fun! When I targetted the 240kpa MAP level when there S360SX was done we were all excited and looking forward to seeing what happened things got more dumb than we hoped - the Link did a fuel pressure cut at 6500rpm, and looking at the logs there was indeed a fuel pressure drop starting to set in We ummed and ahhed about it and wondered if the surge tank was a bit too small so tried increasing the ramp rate to do a 6s sweep instead of a 9s sweep but alas no, protection kicked in at exactly 6500rpm We tried bumping base fuel pressure to see what would happen and it did allow is to complete a base run at 240kpa (20ish psi boost) and still no signs of dropping off in turbo flow but alas fuel pressure was still dropping. VERY annoying but we had to call it a day and we are looking the fuel delivery issue for now. Nonetheless, 466kw on 1.4bar with power climbing to redline while making 300kw before 4000rpm was very encouraging. We did do a "controlled" test run at 1.6bar to see what fuel pressure and turbo flow would do etc as dyno time is hard to get so we wanted to be sure that everything else would keep up with more and she is STILL eating it up, hits 1.5bar by 3700rpm on a 9s ramp and we saw a peak of 489kw with SOFT timing so I am very confident that we could have walked past 500kw if we hadn't run into fuel delivery woes! Firstly, shot from the link during a 9s sweep (as I forgot to get a pic of the boost curve from the dyno haha) And the dyno plot.... Red dotted line: Old S360SX-E at 1.4bar bleeding back (same BCS duty cycle as the SX-E runs here) a 9s sweep Solid red line: S362SX-E at 1.4bar on a 9s sweep with fuel cut Solid green line: S362SX-E on a 6s sweep with fuel cut Solid blue line: S362SX-E on a full 6s sweep There was no specific tuning done with the S362SXE at this boost level beyond targetting boost, timing has not been fully optimised at this boost with this turbo. Anyway, I've attached some pics to go with the long story that anyone who knows me will know this is what they were in for when I posted. Thought there might be some useful stuff for anyone who has been curious about these things, but either way this kind of thing is handy for our own records to look back on Feel free to ask questions or offer input or whatever, in regards the fuel pressure thing we are not looking for input on that thanks, please keep the conversation on topic... we have stuff to do there - I've just not shared everything to keep it relevant to turbos. Cheers all!

In NZ at least it's under $2200 for a T25 IWG GTX2860R Gen2 and over $3k for the equivalent G2560 which is a good start haha. That combined with the G25s being a bit laggier means that if I had a setup which would need a bunch more work to support much more than 250kw and I wanted it to be responsive I suspect the extra $800 would be a pretty hard pill to want to swallow.

There is no real data out on this kind of combo but I personally have been unsure whether even the EFR9280 would have enough exhaust flow for the 92mm compressor on an RB even with the 1.45 housing, let along the EFR9274 - granted the 9274 compressor is a bit smaller, but still. I wouldn't have run smaller than 1.45 on tbag combo on a strong RB30, really I would have just gone EFR9280 - if that was too big then the EFR8474 would be a better match but could prove to be entirely wrong. Will be very interested to know how it goes, probably make it easier to make a call on it if someone tries it but that clearly makes you a guinea pig but again - if you had to go 9274 on an RB30 then I personally would have pushed for the 1.45 hotside. Which turbo do you have? For some reason I thought it was an 8374, in which case Your experience probably wouldn't really translate well as the 9274 has almost 40% more airflow potential that the exhaust flow of the setup has to be able to support.

Not on hand, sorry - but I have seen results (1/4 mile and dyno) which have been enough to make me treat the 6062 as though it should be treated a larger turbo, both in spool and power capacity than you'd expect from the wheel sizes. 650-750whp on a US dyno is about the area I was thinking, which is pretty decent from a 60mm turbo - normally more what you expect from a good 62mm.

It's not all in...

Same with both of us - had no idea where to go or anything, but was fun to go out for a bit of a lurk about

Black 4 door, we gave you a wave when you were in a line of traffic waiting to head around the bays from Kilbirnie area - unless it wasn't you but either way the driver looked perplexed haha

99% sure you just drove past us parked outside Armstrong in town, we are in @Looney_Head RB30 GTSt

There have been some pretty big numbers from them to be fair, definitely more than a G30-770 will support but while I haven't seen results from a G30-770, it seems pretty reasonable to expect it to spool better too. The G30-770 is a more sensible match to this power range I think

This is true. Drifting off topic but more people are already showing up and designing cast manifolds, I have been pondering whether to invest some time with a design I've been playing with elsewhere which would probably earn scowls but have a lot of advantages with little disadvantage. No point having the tech we have now without using it.

lol. My concern is more that I've heard bugger all people using the divided v-band housings, but when I have heard of it - it seems people are having issues making manifolds sturdy enough to have a nice collector to suit the flange and not end up cracking or anything else less than ideal.

I'm ok with this when collecting <4 cylinders, but otherwise twin scroll + v-band don't work for me, and throwing away pulse conversion also doesn't work for me, so your idea has flaws

Yeah, knowing Garrett they won't do the G30 in T4 split pulse - they haven't seemed too popular. Would be nice if there were more standard V-band options, tbh I haven't looked too far into it but I'm not sure how far the v-band option for the G30 range will stretch. Be nice if you could go all the way to a G35-1050 or something else with the same flange.

Do you have any preferences in terms of flange? As per Gtsboy, surprised you didn't mention the EFR range and did Precision - Precision are not really big players at this kind of power range and Borg Warner are arguably king, the G series looking like at best they are only just catching up to the EFR range. I haven't found a single result for G30s, yet- not for lack of keeping an eye out. I would love to see a G30 770 on a set up like this so just do it I suspect that it has a chance to be a banger of s thing for that power target, not just saying that because I want to see someone do it. If you are feeling adventurous the Xona Rotor XR7164S with the trick UHF turbine looks mega interesting but could be raising the hand for being a guinea pig. There are at least local dealers for Xona now and the results for the UHF range that I've seen so far have been pretty nuts so an intriguing option.

The finger over the lens at the end definitely a master stroke!

Hahahaaha I saw the other comments and expected that the other guys were just ripping on you for nothing, but holy crap that is actually impressively bad, good to see it driving but that video is so bad I'm impressed!

Not sure where any of this came from, but for what it's worth - I am pretty sure that the T25 G25 turbos will no be bolt on for the RB26, and there is no T25 option at all for the G30 660... currently only available in v-band. I suspect it would be folly to try making a G-series bolton upgrade to an RB26, really anything over 40lb/min turbos on stock manifolds on an RB26 is making life difficult no matter what wheels you use.. I suspect.

That's a tricky one, though. For the compressor to push air it needs force at the turbine to accelerate the turbine&compressor and move the air (which has a mass) - let alone to compress it. That force comes from drive pressure, which is essentially the raw EMAP value you are reading. If you do headwork to require the amount of boost pressure required to move x-amount of air it will reduce the amount of work the turbine needs to do to a degree, meaning a bit less drive pressure required - but the trick there is you have reduced numbers from both sides of the ratio.... so your EMAP reduces, but so does your IMAP and you COULD even find yourself making less power as a result of the reduced boost you have to run to keep the ratio at or below 1:1. It's a bit hard to say which will reduce more, but if I were a betting man I'd be backing the cost vs reward benefit as not being anywhere near as rewarding as just using the turbine speed as the primary warning for overwork, and maybe relaxing your EMAP/IMAP ratio cut off back to even about 130% (which is still quite conservative imho) you will get much better gains than the headwork for no cost or compromise. Just my opinion, but it's become a conversation so I'm throwing it in there. If you were happy with the current power level then thats all good, but if you are looking at spending a bunch more money to try and get more performance when the data suggests the performance is available comfortably with the current package - I'm not sure why you'd not use the obvious approach. As @GTSBoy said - 1:1 is crazy conservative for most cases, and is more of what you'd see in they higher levels of drag racing where you have something you are looking to make MAX power so reducing forces and restriction is the priority, response is absolutely not.

Exhaust manifold pressure. When talking about turbocharged spark injected cars 1:1 boost versus exhaust pressure at full power was pretty much the realms of drag car setups not a really long time ago, I have had conversations with people who actually have doubted it is possible to have equal exhaust pressure to intake pressure so managing to have a reasonable amount of response while not having boost pressure go past intake pressure is quite a big deal - albeit still meaning it is leaving a heap on the table. An EFR8374 making this much power with a 1.05 would have a scary amount higher exhaust pressure than boost pressure - if it was possible to even do it

100% agreed, 1:1 suggests it's FAR from restrictive. It's very very impressive, but it also looks like it's probably reasonable to believe because.... If you read @R32 TT's comment and he reads yours - the picture starts getting drawn. If you've ever looked at how emap tends to behave, it seems very much like he has let boost climb until EMAP is starting to catch IMAP and then dropping boost to stop EMAP from running away as the rpm increases. Reading between the lines the whole thing has been done very risk adverse/being very gentle on it - if you can call peaking at 37psi and making 500kw "gentle" on an RB26 haha. But you know what I mean. It seems from all that has been said that the EFR8474 is doing this really quite easily, which is pretty impressive considering this would be a very fast fun road car.