Lithium

What fuel are you running? Where did you get the turbo? .50a/r compressor housings aren't really a thing I'd typically associate with a GT3076R, more a GT3071R thing and depending on fuel I'd imagine you are pushing close to it's limit already... on pump gas on a roller I'd have thought that is already pretty impressive, though a local (I'm not as savvy in terms of what the rear roller numbers mean in relation to "real" power made as some who will have more exposure to these dynos) if it were one of those. Is there a specific reason you're going twin scroll? It's a fair bit of effort, especially as the T3 TS setup is potentially a bit limiting in future proofing as not THAT many things use them. I'd personally treat a .83 one as an absolute minimum for that kind of setup, and actually be pondering the 1.03 if you are looking at pushing the limits of the turbo - assuming it's a GT3076R?! Sorry, I can't really answer on the housing thing... again, I have never encountered a GT3076R running a .50a/r so I'd be just plucking numbers from somewhere dark.

Oh - in terms of the boost spiking you referred to earlier, I'm not sure whether it's safe or not - not necessarily ideal, though. How unideal it is depends largely on the tune. What rpm does it happen, do you know? My old GT30R setup I had a crap boost control setup and ECU so I just left an ultra soft tune in it and put up with boost spikes as it felt better than a really soft boost curve, after it was all said and done. I never hurt my motor, or turbo - so I guess it depends on how steadily it is holding that kind of boost. I actually don't expect you'd be able to hold that boost up to peak power so again... depends on the tune or how much it bothers you. My view on the world in terms of this kind of stuff has definitely been spoilt by being exposed to cars running G4Link ECUs + boost control, makes it all a lot more usable.

I don't know of any reliable OEM ones yet, so I am guessing it's for the same kinds of reasons. The late model Porsches are frequently going back for warranty claims, afaik.

Agreed. The result isn't exactly bad, its not a lag monster and it is reasonable power.... but I also feel that there is room for improvement, which hopefully means there is an encouraging outlook for m@&k where he can hopefully pick up some response AND power if he starts feeling the urge for a bit more of both, going a more aggressive actuator and a smaller a/r turbine housing. The unfortunate thing is none of us at this stage can guarantee an outcome, we are all in the same boat - it's all hypothetical, unfortunately. I hope you enjoy the car, and I hope we're right that there is more to be had when or if you decide you need more.

I can't remember specifically, I just recall the EFRs looking familiar when I first saw them and then later remembering how interesting the ones in the book looked. When I get home tonight I'll try and remember to look it up and maybe post a pic

Funny thing is I have a pic in a book at home of a Pontiac Solstice turbo setup (I think?) which featured a twin scroll internally gated turbo with an integrated BOV in the compressor cover (I got the book before EFRs existed)... hard to say what else uses them, or similar ideas, but I found it really interesting.

You are definitely not the only one who mentioned that the thing is going to need higher rotational speeds to do it's thing, and there were a few of us who mentioned the .63 as being a good idea (or more specifically the .82 possibly being a bad thing) for this combination. I don't think it has ever been a debated thing that turbine choice/spec has the biggest overall influence on the spool/response - however on the same note that doesn't mean it is 100% responsible, it's not. The whole thing relies on a combination of things, not just the turbo, and not just the turbine wheel/housing. There are all kinds of GT30 based combos out there, and they do not all follow the same boost curves - we have people with GT3071Rs, GT3076Rs (52 and 56 trim), GT3082Rs and GTX and HTA equivalents all with .82a/r GT30 turbines providing quite different response and spool figures. You guys (Dale/Wolverine) seem to be implying that the GTX3067R is redundant as it has all the disadvantage and none of the advantage of a GTX3076R. Am I correct? And if so, any theory on why Garrett would have done something like that? And if not, what are your thoughts on how to improve this situation?

Agreed that the HTA68 would probably be more interesting on an RB25 with a GT30 hotside, but I'm not at this stage convinced that the GTX-67mm is (solely?) to blame for the response. Again not totally sure what is, I do wish it was the .63 housing - however. Not sure who you are disagreeing with here, but have to assume it's not me because it looks like our overall thoughts are more or less the same.

That really a bit surprising, I did suggest earlier that I could see the potential for the mix of small wheel which needs rpm and big a/r housing making a bit lazier than it could be but still - that sounds at best no better than my GT3076R which at face value doesn't seem right though perhaps spinning up a smaller compressor really makes that much difference? To put into perspective - here is my old 0.82a/r GT3076R on what should be a pretty equivalent setup to yours: ... internally gated, stock manifolds and motor etc. Your car clearly is going to be performing well - I don't doubt it'd be fun as it is, but I definitely want to try and work out what's going on as amongst other things I was one of the people supporting this choice and was expecting more impressive response (I was also banking on the 0.63- but still) and I've not really gone wrong in the past. I'd like to think you shouldn't need to do anything else other than the 0.63a/r housing to change it into a different car, but *normally* it doesn't make that much of a difference. Maybe in this case it could be more about shaft speed than inertia - the whole exhaust fed system makes a compounding effect, so perhaps it might fire up much quicker relatively speaking (to a 76mm compressor) with the lower inertia when the exhaust speed goes up, but maybe not? I am gonna do some pondering.

I have in my head they have a poor reliability record, though I could be wrong or that could be out of date info - look into it at least

I personally wouldn't go the 18Gs, especially for 450awkw - the 18Gs would be more comparable to GT-RSs. 16G should be the right tool for that job, imho... though I'm not sure that they'd be the "responsive as possible" option so much as good responsive power for not spending megabucks. Don't know of anyone running the Kando boltons so can't really say how they would work in the real world, not sure how good (or not) the housings perform

I've missed most of the updates, been very very busy - but looks really good. Did you get a chance to take it out for a drive over the weekend?

How much laggier does it feel than the stocker? Do you have a boost gauge? I had a bit of a sniff around about PZP and found this thread which makes it seem like they start a bit "late" and with fast ramp rates going by some of the boost curves coming from there: http://www.silviawa.com/forums/index.php?showtopic=71535 The turbo is always going to be laggier than the stocker, but how much is the question - hard one to quantify there really. It will be interesting to see what you think about it once you have driven it a bit... do some 3rd or 4th gear loading up from lower rpm and see how it comes alive. Do you have a boost gauge to track it a bit? Also, not sure that the compressor is going to have a massive amount more in it - as I mentioned earlier I would have liked it to have seen near 270kw but I wouldn't have counted on any more than Mick's prediction (250-260kw from memory?) but I really would like to see better spool than that from this kind of combo. I bet it is still no slouch, however.

OK, interesting. When you drove it did it feel conspiciously laggier than the stock turbo? A typical "full boost at 3750rpm" combo would feel very noticeable. Maybe we should just let you get the weekend and have a proper go?

The same will apply for any dyno - it doesn't matter what is stopping the engine from accelerating through the rpm, it's all about how much load the engine is for how long.... allowing the turbo to build up speed, eliminating the effect of inertia, and building up heat. Ben is mostly right about the readings often being higher with slower runs but as I said earlier, depends on how the car deals with heat.

Nah I don't - the turbos are IHI based, and the PE enterprise ones are pretty spiffy options so I'm not sure it will be so easy to just get them made up. The PE1420s which are used on 350Z/S14 etc kits are also IHI VN14s as fitted to some Nissan Autech SR20DET setups - a mate had one on his Silvia and it was impressively responsive, I can't remember exact numbers but 18psi was in the low 3000rpm range and on E85 I'd guess it was making around 270kw @ hubs or so (maybe 240rwkw or slightly over?). We never had it on a dyno with that setup unfortunately - turbo failed (it has been purchased secondhand in unknown condition off someone who was "upgrading" their Autech Wingroad).

That comparison looks a heap better when comparing apples for apples. So is your Nistune setup running VCT? If that's not with VCT and there is more boost available then the result starts seeming a lot more understandable. Driving (ie, response) should give a fair bit more of an impression of how well it works Thanks for keeping us updated through it all!

Hmm it's strange that it's coming on that late, looking at the curve it doesn't look to be a boost control thing to me. You are running Nistune? Is VCT being used? That boost curve doesn't look like it is necessarily using the full potential of the turbo but as you mentioned, good chance the actuator is making it impossible to go any further. It's decent power for the boost through, I reckon - and while in the range of what seemed doable there could be a bit more in it with a stiffer actuator. Let us know how it drives when you get more of a chance! Be interested in how quickly and easily it comes on, the curve makes it look no better than my old GT3076R which doesn't really make sense, I am assuming there is more than meets he eye going on there.

You seem to have read what I said but not fully taken it in. I am saying the picture is way bigger than just timing versus spool, they are two variables in a much bigger equation - comparing a turbo's performance between different setups makes the results less and less comparable, whether it be cams/fuel/displacement/you name it so imho you just have to take it as a general indicator against other like setups. E85 is awesome though, regardless of if the boost curve is (or isn't) favourable with E85 the power delivery tends to be nicer - boost threshold is not the most important thing imho... that is just one part of the puzzle that provides performance.

Did the S15 have a 5 speed box in it? If the gearing etc is the same that makes GTScoTT's GTX3071R capable of 20psi < 4000rpm - which is really quite impressive

Awesome - sounds promising, have you got a number yet... or are you wanting to check it all out before you report? Either way, glad it's done finally!

To be fair, I think it's a very effective setup but I'm not sure when I missed an engine with upgraded internals (including cams), aftermarket exhaust manifold/wastegate etc running 22+psi became mild!!! But yes, that thing is clearly going to be a weapon.

Nice Glad someone has had good results, even though it's not really what the thread is about - here's hoping m@&k's luck changes, seems like another "pick up date" has come and gone past like the wind

Congrats, again sir That has to be a fun drive Seeing as GTScoTT hasn't responded yet, I happen to know it's on 98 - get it drunk, boy.

Turbo knows nothing about the ignition timing, it just knows how much exhaust energy there is - while I haven't measured it admittedly, I'd wager a cheeseburger than in terms of exhaust energy a car running 20degrees of timing on petrol will have a different amount of exhaust energy available to drive a turbo to one running E85 and 20degrees of timing at the rpm/load point. Can't overly simplify the comparison, too many variables to say too much but at the end of the day on E85 you certainly don't suddenly get a huge amount better (or worse) spool - though to drive the car it can seem that way.