Lithium

What I mean by that is with the turbo doing EXACTLY what it is doing now, it shouldn't need to move any more air (ie, no more boost) or generate any more heat for that power gain. If anything, I'd have thought it'd be able to do that power and DROP EGT with the use of E85.

There is a pretty good chance that 270rwkw would be doable on E85 then, imho.

122mph sounds a tad unrealistic for 250kw tbh - complete turn around to the other turbos which were getting too low for the power! Will be interesting to hear what it does on a proper dragstrip

What kind of power are you guys making on pump gas with that turbo? Remember that E85 gives a big gain, even without any more boost or strain on the turbo...

Pretty much agree, will make quite a bit more power than the GTRS... probably not build from basement quite as enthusiastic as GTRS but once it is on (which won't take much) I bet it will be hell l responsive.

Yep they have been around since late ish last year, I have mentioned them before but was overlooked... Wonder if it was taken as a typo? Reckon that they could be a really good thing on RB20s/SR20s or in twin form.

How is the run in going? And was that on pump gas or E85?

Yeah - will have to see how this result for Bri73y's car goes, in my head the FP GT3076R is the perfect match for an RB25 and I'm pretty cool to see how that matches up with real world results

Wolverine - yeah sorry wasn't knocking you for doing it at all, but more looking for confirmation that my assumption was that they were close enough in performance to not provide an amazing improvement (ie, already had the GT3082R) but doing it right first time would be going to the GT3076R? Disco - Nope, I only know of one guy doing a build with one and he is mostly out of the country so in no particular rush to get it done

Agreed, I should have mentioned that - he gave the exact answer I was looking for. I wouldn't have changed from a GT3082R to a GT3076R if I already had the GT3082R, not surprised the spool improvements weren't worth the effort - though in saying that if I had a clean slate I would have gone the TS GT3076R over the GT3082R. Is that fair to say Wolverine? And which is your favourite after having tried the bunch? I also totally agree with dyno versus road comparison, more so than ever lately. I've experienced a bush bearing turbo rated to similar power as a GT3076R which dynos VERY similar to a GT3076R but on the road the difference is amazing, GT3076R makes a much quicker car in the real world. Same with tune, the percentage of the time you are hitting the bunch of load zones that you hit on a power run on the dyno isn't 100% by any stretch - if the rest of them aren't optimised sufficiently then a car can end up no way near as quick or smooth as the pretty dyno plot may imply. One just has use the dyno as a general indicator assuming all other things are equal, though if a turbo has smaller wheel measurements it is easily believable that it may "come alive" quicker even if the dyno plot doesn't suggest as such - one of the reasons I am quite excited to see how this GT30R HTA goes, I reckon it could feel VERY lively for whatever power it makes once it is done.

I don't know for sure tbh, I just threw in some thumbsuck stuff and it turned out real similar to yours - can't remember the exacts but I think we were on the same wavelength. Doesn't mean it's right, but it has to be worth something? haha PS. Just because matchbot thinks it is physically possible to get that boost with that turbine configuration doesn't mean it will. I am incredibly dubious of using that method to determine spool tbh - I had a quick play with it using that method and if it had any credibility then we should build SR22s and put EFR9180s onto them with 1.05a/r turbine housings and hope to hit 50psi by 3600rpm and dominate EVERYTHING

Pretty sure he is aiming to go up to around 30psi on E85

Yep very mindful of that too, hence being very non-committal to my comment. 388whp on 16-17psi with a soft tune is promising though! Cheers for keeping us updated

Hmm they're gradually crept up in price, still reasonably comparable with a GTX3076R - and I'd rather the HTA personally. Crikey - I'm not sure how much was said in terms of power potential of these things, and I don't want to set expectations - but it wouldn't surprise me at all if your target range turns out to be a good part of 100whp low.

Awesome, gives a decent idea of how it comes on already - pretty much how I hoped it'd look, keen to hear your driving impressions .... especially when it gets the full tune in and the timing is sorted.

Looks like we used very very similar settings - almost identical actually, except you are a lot more optimistic about spool. Looks like you had a fail with the VE plotting too, the EFR6758 is 71% efficiency for the 7200rpm spot.... see what I mean about them plotting through very similar? Interesting that the EFR7064 is a bit more generous at low rpm, probably the antisurge housing - ironically the EFR7064 will be lazier at those RPM so in real life the EFR6758 will probably "stand up" quicker at those rpm, more than enough to nullify the slight compressor efficiency advantage.

Aside for the whole full boost before 3000rpm thing out numbers can't be too wildly different: 21.3psi = 2.45 pressure ratio 27.2psi = 2.85 pressure ratio (~16-17% higher for the .64 EFR6758 at worst) And the compressor efficiency is within a few points at worst - so obviously the EFR7064 is a bit more efficient, the twin scroll advantage can't be denied but when you look at all those details to me it shows that you are only JUST scratching the areas where it might show a bit of advantage. Looking forward to seeing the results, they should be decent - it will make very respectable power, and be a cool looking power curve as well as make an SR20 feel revvier than they naturally do. Definitely not how I'd have gone about it, but each to their own... seems like you've put some thought into it and know what you want - just don't hold your breath on full boost before 3000rpm, or even 3500rpm to be fair.

Going by some of the estimations you've made there I'm wondering what you've put into matchbot, and suspect it could be giving you quite "off" results based off what it has been given to work with. I am also a bit suss of the fact that you only changed the turbo - there are various other numbers which should be updated to suit the turbo to make the calculations work correctly, if you didn't do that it would explain some weird results as I think matchbot defaults to a 7064. I ended up giving matchbot a bit of a crack with your setup and the points of compressor efficiency were all within a couple of percent of each other between the two turbos - especially at so low boost level you won't see the result of that one way or the other. I also found that the exhaust manifold pressure (going by my calcs) for a .64 EFR6758 only exceeded that of the EFR7064 at around 5000rpm, and peaked at 17% higher at redline. The calculated required wastegated sizes for the EFR6758 and EFR7064 respectively were: 2000 3000 4000 5000 6000 7000 11 17 25 28 30 32 4 12 21 25 27 28 I agree the twin scroll is a nice advantage, but maintain that (in my opinion) the advantages of the TS EFR7064 do not outweigh the fact it is too big for your requirements. I'd love to see full boost at 3000rpm with one, or even with a EFR6758 - but it just ain't happening in the real world. This makes the most sense to me - how did you decide on a 'pull the plug' torque level? And how do you know what boost level will reach that if you don't know what power it is going to make?

Can I suggest getting it tuned to follow that boost curve, but also set it up to have a nice flat one too and try both out on the road to see how youfind them... Just in case?

So any general impression of how they all compare overall? ?

No stress with explaining, I have a pretty decent idea of how compressor maps look and what it all means. I don't have the time to do a bunch of specific calcs but as a bunch of thumbsucks, I figure you don't need more than 40lb/min (arbitrary number I picked easy to find on a compressor map) of airflow to make the power you are talking about using E50. If you look at the compressor map then at pressure ratio 2.2 the EFR6758 has a slightly higher compressor efficiency at that 40lb/min area than the EFR7064. The EFR6758 turbine is spec'd to go with a compressor which will choke at 49lb/min you won't be going near that on 16psi - if you had any issues regarding pressure differential to the level it will tangibly affect what you can do with your tune it is not going to be the turbine flow you'd have with an EFR6758 which would be responsible for it. I'm not saying the EFR7064 will be bad at all, it's nice having headroom - but as far as I am concerned that is the only advantage you've got in this case.

I get that - but you could make that power on that boost with a smaller EFR, if you are never going over 16psi then the extra flow potential of the larger turbo is pointless. I never said run the smaller turbo on more boost, you won't need to... you aren't going to be stressing an EFR6758 at that kind of boost level with that kind of setup imho. All you've done there is matched a turbo which will provide you with a bit more lag. I am sure it will be a nice setup regardless, but just interesting logic. I've tended to find the less laggy turbos (which make similar power) to have a more NA power delivery. In terms of leaner or more aggressive timing, those fuel/ignition curves will always be the same at those boost levels. You have the option of tuning for 24psi with the same turbo, but running 16psi and a good tuner will have the more aggressive ignition and leaner mix at those zones. Looking forward to seeing the results, all the same

I've been making noises for some time now that I felt the GTX3076R may be too little too late (from Garrett) due to the existence of the FP GT3076R - and that it seems like the perfect successor to the 56T GT3076R for better spool and better flow, for some reason for a large part the FP HTA stuff is largely overlooked but the Precision stuff has got quite trendy in terms of high flowing billet 'custom' jobs. I now find myself really hoping I'm right in regards to the match to an RB25, and very much looking forward to BRI73Y's results

Looking forward to seeing the result for this car too: http://www.skylinesaustralia.com/forums/topic/417832-precision-pt6766-vs-forcedperformance-gt3794r-hta-dyno-shootout/page__view__findpost__p__6735544 It's a RB25 with a GT3076R-HTA (essentially a HTA-spec 52trim GT3076R) and will be tuned on E85 - would make for interesting comparison with the PT and Garrett turbos.

Yeah I'd expect quite a bit more power than that on an ethanol blend, though 16psi is a strangely low boost level to choose to run on such a decent build. May as well run an EFR6258 or EFR6758 imho and get similar power and better response, and would be more likely to reach that boost by 3000rpm as I honestly can't see an EFR7064 spooling that soon.