Lithium

These guys: https://www.facebook.com/slapit.at/videos/947248725344266/ They since build a 2.7litre with an EFR9174 that seems to have made similar power to that but with much better spool... on the 2.7.....

Can't remember what has been said in here, but the boost peaks and then rolls off - not because the turbo had nothing else in it, but because the brief was more about low down/midrange and reliability as opposed to give it all she's got capn' - as far as I know. This is definitely not maxed out at any point of the rev range, and I'd say if it had a flat boost curve it'd look less like it rolls over. Pretty sure it's only around 20psi at peak rpm.

Ignoring how a dyno reads and looking at just sheer airflow and engine efficiency, the odds are the car is making >800hp @ crank when the EFR8374 hits close to the 120,000rpm peak that Scotty limited the turbo at

^ I think we're on the same page

Yeah, that was my gut feel too - but quite interesting, as FP really pushed the .85 T3 housing they put on those things as being capable of flowing a heap. The bigger hotsides on the GT35 turbines seem to really give the boost threshold a major hit as well, I remember thinking the first time I came across a car with a 1.06 T3 GT3582R that the lag it had (like ~5000rpm on an RB25 from memory) you'd may as well go to a larger frame turbo - but hopefully the Gen2 beast offers enough flow to justify whatever lag it introduces.

That is quite interesting! What about the spool difference? Do you know what rpm it's reaching 20psi by? What was it before?

Nice! What changes does it have from when it had the 3586? I wonder if it was hotside or coldside on the HTA which held it up.

Cool, Good luck! Cheers for updating with results, if it can make 525kw on 26psi or so the hotside isn't too shabby. Would be very interesting to know what they can do on kill and what the boost threshold is like, if they aren't too much laggier than the 3582 then they would be a really good thing

Makes sense, probably could have gone a bit smaller if you weren't after full effort though. When do you get to drive it? Did you get any impression from the dyno or real world what the spool is like?

Nice power!!! Definitely in the range we had talked about earlier. Why no rpm graph? Hard to tell what spool would be like but the graph makes it look like it could be later than I expected. Any reason it was stopped at 26psi?

Controlling fuel pump speed with PWM ftw, imho. Should be able to run MASSIVE pumps and have the fuel get no warming than with a stock fuel pump if you run the right amounts, you should be able to have headroom the whole way through so the regulator is still always busy but without nuking the fuel. Definitely. That is putting a lot of faith in that system.

Yeah, if you run flex then it's really hard to get up to >80% if you aren't using straight ethanol - which means that it's also not too hard to keep it floating around 50-60% if you occasionally top up with a bit of petrol.

Try and keep your tank floating around 40-50% range if you are doing a lot of road use, tends to have a good amount of the ethanol benefit but quite significantly better economy.

Let us know how you get on. While there is a good chance that it is to do with that, there is no guarantee BUT a MAP sensor that suits what you are doing is really a must have imho so not wasted money no matter what way you cut it. Obviously it'll need remapping to get rid of the guess work on the 250kpa load range - good luck!

Those are kind of the answers I expected though to be fair it's hard to know what is definitely going on - I obviously have my suspicions. I should have asked a 4th question, do you have a separate boost gauge to show you what boost you are actually running? My experience with tuning on the dyno is that it is really easy to get a consistent boost curve as the conditions will be consistent and the engine will always "pull" through the rpm at exactly the same rate. Because the car is always following pretty much the same boost curve, it will also seem like the tune is perfectly on point - so it'll seem like you have got away with mystery tuning and getting a solid tune, however that may not be the case in the real world. The first thing I'll suggest is entirely possible to be going on is that you aren't running the same boost curve on the road as you were on the dyno. Internal wastegates can be notoriously finicky and often need varying inputs from the ECU/boost control solenoid to be kept on track - this is why we have closed loop boost control and why tuning the base duty cycle tables can sometimes be a fine art, this is particularly the case when you are running a fair bit over gate pressure. Targetting 24psi when running 1bar actuators would fit well into that category, imho. The trick here is that the ECU can only see "21psi" so god knows what it thinks it's doing when it's trying to control boost, I have no idea what the tuner would have done with the tables but I can only assume that it's utilising a fixed duty cycle for anything over 21psi to try and maintain "24psi" and there will be no adjustment if it goes over or under 24psi. This means you could potentially be overshooting or undershooting your 24psi on the road and the ECU will do nothing at all about it, so you have the very real possibility of running mystery boost! That all by itself could cause a certain amount of what you are talking about, as you have said yourself - it feels like it's running less boost, but wait... there is more.... If the tune "looked fine" at 24psi on the dyno, that means that the timing and fuelling is mint for 24psi. What this means is that if you end up hitting only 22/23psi then the timing and fuel is retarded and rich for the boost levels you are actually hitting. But wait, there's still more! What if you overshoot 24psi? That could get much more exciting. What I can guarantee is that the transient areas between 21-24psi will be different in real life than on the dyno, so who knows what has been done to cope with that. I'm guessing it'll always feel slightly flat in that range before it hits your boost target IF it is actually successfully and consistently hitting the target boost. I honestly don't want to wager how likely that is. Just a thought, anyway.

OK. I've taken a deep breath before saying anything Questions: 1) Is the Haltech controlling boost, or do you have a separate electronic boost control driving the solenoid which CAN see past 21psi? 2) Did you tuner at all oppose this idea of tuning past the MAP sensor's visibility? 3) Did you get the tune looked at after fixing the boost leaks?

I guess I haven't had HEAPS to do with SR20s, but they seem like they aren't that great on stock cams - at least from what I've seen so far a GT3076R would be a waste as you'd make well short of what they are capable of on 20psi but get heaps more lag. For what it's worth, even with the 16G on 20psi the turbo seems to have more flow available

Hang on - you are running a discopotato on 20psi already? I'm kind of inclined to think that there probably isn't a huge amount of point in upgrading the turbo and running 18-20psi without doing cams, the cams are potentially the limiting factor in your setup at the moment I'd have thought. 280kw @ wheels on 20psi with pump gas on stock cams sounds pretty optimistic, regardless of what turbo you use.

What power are you aiming for, with what fuel etc? Stock cams? One of the things I tune has been running a Kinugawa TD05-16G6 with the 3" intake (TD06 style compressor) for the last few years - completely stock internals (including cams), and flex fuel on up to 20psi. Honestly, it is an amazing match imho. I know it's not a Masterpower, but it works so well I don't know why you'd go for something different - especially if you are running with an external gate. The thing can hit 20psi+ at around 3000rpm in higher gears, and has trapped at around 120mph in the 1/4 mile - is pretty rapid.

A RB25 powered GTS4 circuit car running a .82a/r R595 - I didn't really mention that because the car does circuit racing, not time attack but actual laps and laps of racing on stock bottom end and 98 octane so I wasn't really squeezing out it's full flow potential on the dyno... everything was done to ensure he could rely on it for laps on end. It made ~295kw @ hubs on 98 octane at around 16psi, hitting target by around 4000rpm. Another was an R545 with a .82a/r housing on a Honda F20B engine (2litre twin cam VTEC, a bit like a destroked H22A) in a Honda Accord. That only had ~540cc injectors so was not making big power either, but was making good boost by 4000rpm - again another one I never got specific on because the turbo clearly had plenty of flow to spare, the power figure (just over 200kw @ hubs on ~10psi) wasn't going to do it justice.

The tune should be checked either way. VCT changes both the engine VE and the build of cylinder pressure, which means timing and fuelling requirements will change with versus without VCT engaged.

Yes.

I had at one point too - but the more I thought about it, the more I figured actually so long as the manifold was built like the one pictured above... the less it's really a thing at all, probably at worst it'd be much of a muchness with a full twin gate setup, and possibly have it's advantages. I certainly have been impressed with the Sinco single gate divided entry setups I've experienced

Just saw a post on Facebook of another 25T with one of these going on a 25/30 backed up against an auto - should be a couple running around at least in the near future. Any progress with yours?

No. If anything, the GTX3076Rs are LAGGIER than the GT3076Rs, the only reason you'd go to a GTX3076R from a GT3076R is if you were after more power.... otherwise it would be a 100% waste of money, IMHO.