Lithium

These turbos (EFR9180s) are already proven to well >140mph in much heavier cars https://www.youtube.com/watch?v=fa-9q9VHocQ

Awesome, look forward to hearing. Good luck with pushing it off the map like that, it definitely doesn't guarantee failure and you at least know that rpm haven't spiralled off massively at the point it's dyno'd to (don't rev it higher though!!)... so while it's more dangerous it hasn't gone way out of control at that point. If it fails earlier than it should however, you also know you've taken the the risk and accepted it VERY keen to see how it drives and goes. They are a beast of a turbo!

That is a huge result - nice work! When do you pick it up? Keen to hear how you find it. I assume the 580kw run is a glory run - while you probably know it anyway would recommend dropping it down a little just to be safe, the extra 20kw on a stock motor probably aren't worth the strain. It's an awesome result even at 116krpm. The compressor obviously still can move more air but what the concern is that it has to work harder and harder to move any more air, which means at the point you are at the turbo rpm can start spinning a lot faster for much smaller increases in airflow which is where the overspeed thing comes from. Cheers for sharing the results - wicked to see and some good data there

Cheers for the update... Solid so far. What do you mean by stock head not so happy ?

No reason there should be any issue using a single gate - using a single gate to control boost on a single turbo is hardly a new or unproven concept.

That makes a lot of sense. Cheers for updating

Nice, I don't really think the 1.05 should be a show stopper at all - especially on a "mild" 2.6, I'd say the turbine speed would be the key thing to keep an eye on. Very interested to see what the difference is from the 1.05 EFR8374! Good luck

Nice work, this sounds like a mental setup. Keep us up to date - hope it works out well

Nice, good! I don't really know what packaging constraints Z32s do or don't have but I suspect this has little relevance to low mount twin configurations on GTRs due to the reasons which have been gone over many times. The single turbos (at least the cores) of the GT28 range are well known to be capable of decent flow in their own right, but needing the smallest possible compressor and exhaust housings, limited space for dump pipes and compressor inlets the turbo starts getting all of the worst case scenario options for performing mean that they really aren't going to perform as well as they are capable of when used as stock location turbos on RBs.

Nice - I look forward to results, I hope they are better than the other ones I've seen so far. What exhaust housing have you got?

Soft timing doesn't make the boost come on instantly or even necessarily much or any faster time vs psi, but yeah it does make for a more violent torque transition on spool which some people like. Have to admit I've done similar things with valve timing etc where people wanted a slower car that they liked the feel of more. Nothing wrong with that, either.

He was a low mount twins man before, was a bit shocked at how much power and torque it made so effortlessly - it still is running a stock gearbox so I doubt he will be winding it up until or if that is resolved. The car is "real world" FAST now so having headroom in the setup is no liability Results from that round of superlap - his fastest time was the one in the video which was clearly not clean, it started raining afterwards and he called it for the weekend but then it dried out later and others kept going... he probably had more time in it. His car is the R32 in the Pro-Street class below (Tony Satherly/Mitsi EVO in Pro Open is the 666 EVO which went sub 1:30s at WTAC 2017)

Correct E35 max

Pretty sure around 26-27 psi

Here is a mate's 2.8litre EFR9180 setup doing some laps at NZ's time attack series - bonus loose moment at the end of the timed lap https://www.youtube.com/watch?v=3klPPfce7W0&t=2m20s

A quite relevant detail which seems missing here unless I missed it - what were AFRS doing? Tracking as normal? Did you ever stop and check the exhaust manifold by eye to see if it was glowing like could be expected under those conditions?

Yeah, glad you said that - I start rolling my eyes a bit when people make comments that "If it was a real 700+whp then it'd run xxxmph".... fact of the matter is dynos are just tuning tools and it's not that American dynos are happy, it's that MOST Australian dynos read lower than what pretty much everyone else in the world use unless they have imported a Dyno Dynamics dyno. 740whp sounds about right for high 130mph/around 140mph to me from the Dynapacks that I am used to, and sounds about right for what an EFR8374 is capable of. I'm guessing if this dyno reads like what I am used to then the turbo will be within safe rpm, JUST. Nice result, I look forward to hearing how it goes - E85 is awesome, tends to make the car feel better in general ... not just when tracing the target boost curve. Been good seeing this setup gradually be refined and start showing what the EFR8374 is capable of on a nice RB

Can you please clarify more here, I've asked how it drives - to put more specifically, you are basically calling the GTX3582R much of a muchness with the EFR7670. Everything I've seen anywhere else makes me strongly disagree with that sentiment, on the same engine and dyno the EFR7670 will fall over way before it and in the real world should be much more responsive. Again, all things being equal. Is the EFR7670 no more responsive than the GTX3582R to drive?

Ahhh you have a 2.8, that's a bit lazier than I'd have expected from a 7670 on a 2.8 then. Can you share your dyno plot? In all honesty, from everything you're saying it's really hard to not feel like asking you actually accidentally ended up with an EFR8374 haha. I know other people who have had quite conflicting results to yours, albeit with the .92 hotside

How is "400kw @ 17psi" lazy? You are showing 20psi before 3700rpm on a stock RB25 - right? That is not lazy if you are aiming for your power level, ignoring the fact this turbo would go >400kw. How does it drive?

Who is your tuner? Sounds like questions you should be talking to them about as that's who you work with an need to be on the same page with. I'd be content with a 5bar sensor, myself - I'd not want to be going over 500kpa one way or another. Just for sanity here, 32psi boost and 40psi are equal to 318kpa IMAP, 372kpa EMAP at 100kpa baro. I'm pretty sure @Piggaz said his EMAP peaked at 360kpa and he was getting ~122000rpm so loosely speaking the Matchbot numbers sound fairly on point. The EFR8374 with 1.05a/r seems a really really good match between compressor flow, turbine flow and response for a "nice" sub 3litre responsive RB setup - turbine inlet pressure is essentially starting to climb relative to inlet manifold pressure when you hit stonewall, so still "breathing" well while also not wasting turbine energy in the "transient" turbine rpm range.

Solid power and delivery for low mount twins near 500kw! Just for clarification, when you say "tested rear turbo feed and >10psi vacuum" - can you explain what you meant there? I've been REALLY keen to know about if or how much vacuum a high-pressed low mount twin setup is drawing at the intake as I have long suspect that the piping will force a restriction as required airspeed goes up and it will initially push the pressure ratio up quite high, meaning a lot of setups will go off the comp map before they necessarily actually reach their flow potential at atmospheric vs inlet manifold pressure... so choke earlier than they would. This would confirm that theory like a mofo. The next thing however, if that is what is happening - when you say 10+psi "vacuum", you mean atmospheric pressure (~14.7psi) - 10psi, or ~4psi absolute pressure? That is F-ALL. Like crazy low. The area of the map your compressor would be working in would be similar to if you were running near 90psi with no "vacuum" at the inlet

The power figure claims are pretty big, but Garrett tend to be pretty good with their turbine and compressor flow maps and they certainly indicate some impressive performance potential. On your typical Oz dyno I think of 500kw @ wheels as needing around 80lb/min of compressor flow when running E85, give or take - and so long as the turbine flows sufficiently to allow that. The G25 turbine wheel with all but the smallest option seems more than up to supporting that from what I've worked out and that is supported by the fact that Garrett are using the same turbine wheel on the much larger "G25 660" turbo. As a general rule of thumb it seems that your "decent" 26 headed RB needs near 30psi to make 500wkw assuming the Oz dyno/E85 combo, the G25 550s flow can flow ~48lb/min EACH at that level. That is a combined flow of around 96lb/min. If you managed a setup capable of utilising 90+lb/min of combined compressor flow then you are going to be comfortably north of 500wkw....

Actually I have a habit of understating things, but I might spell this out - I saw in your previous post you mentioned your "-5s". When I highlighted "ideal" setup, I would rate the stock location twin configuration as FAR from ideal - so if you are hoping to put G25-550s in the stock configuration then my response doesn't apply to that, at all.

I would say quite comfortably yes. Well and truly. I have bolded and underlined a VERY key word there.