Dale FZ1

It's on the centre cartridge, on a plate that is riveted to the casting. Something in a similar manner to the picture below:

Looking good. What is the design of your manifold? Got any pics of it bare (as in off the engine, or without turbo bolted up to it)? Still interested in the CHRA number off that turbo too, if you have it.

Get your friendly hose doctor in to do the job. It is not straightforward, and a "kit" may not just quite do what you need. Ring Pirtek or Enzed and a mobile unit can come to you. BTW, are you using a GT28 cored high flow, or a GT28 with adaptor to mount up? (off thread but just curious)

Go to an exhaust shop, and buy yourself 4 studs of the correct length. Put some penetrating oil WD40 or lanolin on the existing studs and leave it soak for a while before removing the originals and replacing with the new. Problem solved.

If you want ~ 300rwhp, then first port of call is the fuel supply. A suitably sized pump, (either Nismo or an 040 Bosch) and injectors are VERY necessary in my view/experience. I don't know of anyone personally who's gone the route of std turbo + cam upgrade, but given the generally fragile nature of the ceramic stock turbine would not suggest it to be the "best" way to go. Sure you will improve the mass-flow throughput of your engine, but you're pretty much limited to a boost increase up to ~ 10psi which is OK but not likely to get you there. On the issue of 2871 and 3071 there has been plenty of discussion and a few different combinations tried out. To be honest I don't think that any of them have been bad, just a little different. Basically all of the 2871 and 3071 combinations that use at T3 flanged turbine housing will use a modified OEM / OEM copy, except for one which will use the GT30 IW housing. That GT30 turbine combo is a different animal, and if you search you will find that we are waiting for the results of one of our members. The other hybrid type setups, which are a marriage of impellers and housings not originally designed or intended to work together, do actually work quite ok. My particular 48T 2871 high flow hybrid runs the stock RB25 housings both sides, and does a fairly effortless 300rwhp but I don't expect much more. Response is very little different from stock and it is a good upgrade. A logical step up from that is the 3071 hybrid which uses a 56T compressor and one of two trim sizes of a cropped 56.5mm GT30 turbine that will not accept the true GT30 turbine housing. There are a couple of sellers who marry up the R34/VG30 turbine housing (or copy) which is basically just a slightly larger A/R version of the RB25 housing. The bigger turbine rotor + bigger A/R allows better mass flow and hence higher engine power but checking back to back that spec vs mine the difference does not become pronounced until >5000rpm. Another unit to consider is the HKS GT-RS which is essentially a 52T 2871 with a properly matched T3 flanged housing to suit the GT28 turbine - something that Garrett does not supply to suit Skylines. The SR20 runners with T25 flange specs are better catered for in that respect. On a $$ for $$ basis, the GT-RS is well worth a look because you have a bolt on kit and nothing else to change. And they perform very well. Search for a thread by Al, and you might be surprised what one of those can do.

Edit: double post.

You've really identified the issue there. Yes, your cooler can work quite effectively, though Wolverine and Guilt Toy are correct. Unless there is something extra happening you won't get below ambient. Heat soak definitely works against the intercooler. Basically the cooler sheds heat, and then the manifold takes in heat from the engine bay and reheats (to some extent) the post-cooler air before it is drawn into the engine. Air speed, mass flow, and flow type ie. laminar vs turbulent will play some part in just how much the air is reheated. If you were running full noise, extended loading, and had reached saturation point for the cooler and achieved inlet temps 20 degrees above ambient then there is nothing wrong with that. Remember a cooler is a heat sink so it will initially accept a fair amount of heat before it begins to shed the heat. If you're stressing about highish temps in stop start, light load, low speed cruising, then don't. Heat buildup is what happens. Take the thing for a reasonable run and in 5 minutes you will see temps tumbling.

Look at eliminating the cat as a restriction point. $30-40 should see a 3 inch pipe with flanges welded up, and then you're not wasting workshop time and paying more $$ dropping pipes off etc. If you do a search under a thread by Al, you will find he experienced some high flow performance issues that ended up being exhaust system related. FWIW, the graphs themselves look quite respectable at the boost levels being achieved (namely dropping).

I'm not into straight line stuff, but those in the know might be able to throw some ballpark figures of the power required to run that sort of trap speed.

Does your mate use a boost controller? The reason for this question is to determine whether the wastegate is being held shut for longer than if only a pneumatic actuator was employed. He might be getting a sharp "knee" in the boost curve (ie quick rise), but if the mass flow increase is rapid then there might be difficulty venting and keeping things under control. Also what power level was targeted, and what boost level is being used to achieve it? The bolded sentence I agree with, however what is important to keep sight of is that the compressor and turbine operate in a mutually interdependent master/slave relationship. Each one feeds the other. You need a compressor big enough to do the job, and a turbine that is not so underdone from a mass-flow perspective that it chokes the thing. Pretty well put Adrian. The bolded sentence is the key for me. The change in VE that Nissan achieved with the RB25 Neo, purely from the double VVT (and perhaps changed cam profiles??) is how I see they got away with using the OP6 housing but not suffering any noticeable losses anywhere through the range. And obviously that's where things head when blokes install Poncams etc. The larger turbos start to give a better overall showing of their capabilities. I hope that Gary's 0.82 selection will give the right sort of response for street use, though I recall with his earlier criticism of the high flow, he was running into heat build up and knock on the track. The larger housing should (I think) give a slightly doughier bottom end and part throttle response, requiring a bigger throttle % to get it happening. But boost creep shouldn't come into the equation especially if it is spec'd with the larger wastegate version. I believe Cubes has better knowledge/experience in this area.

The R33 stockers are rated ~ 370cc + 0.64ms @ stock fuel pressure. That MAY help. FWIW, the lag time quoted for the Sards seems very large.

Weren't they a sequential twin - one small, one large?

Power is a function of rpm and torque. Even if your 280kW was at the crank, at a guess you'd be well over the 400Nm mark now.

Just to clarify. Targeted 270rwkW, street use. I think it's splitting hairs to say that there's much on-road difference between the 3071 + 0.63 IW and the 3076 + 0.63IW setup, primarily due to the combination of flow capacities and efficiency ranges that the compressors would operate in over the most often used engine rpm range. Let's face it, a street car might use up to 7000rpm somewhat regularly (relative term here), but can't do it for extended periods or else face loss of license or the lockup. So each may offer a technical advantage (3071 = transient response; 3076 = high rpm efficiency) over the other, but I don't believe the practical difference would be significant. Detectable yes; significant - no. Using a 0.5 compressor cover with 70mm snout on the 3071 may allow easier inlet plumbing and keep the compressor noise down (no ported shroud housing) compared to the 3076, and that may be a telling feature for some people. For me it's a case of look at the whole of picture and then decide.

No simple answer Gary. Every conventional setup has some drawback, whether due to design or budget, or application. Mafia and Lithium were (as I understand) wanting their cars to do different things. Mafia actually initially ran a 0.82 housing on his turbo but found the trade off between extra power and response not to his liking. Then he went down a size and has something he's happy with. Lithium conversely seems quite happy with his, though he is generating a lesser power level than Mafia. My views have a couple of facets: GT3071 will run to around 270rwkW, doable and repeatable - subject to correct cartridge spec and tuning. It's a bit more efficient down lower in the engine speed range, and comparatively runs out of puff up top - at that power level. Technically speaking, it should offer quicker compressor acceleration due to the lower moment of inertia. Don't know that it would actually result in quicker boost response (compared to a 3076) because it needs more compressor speed right throughout the range in order to push equivalent air mass. All of which makes it a good candidate (my view) for a fast road car. Put a 0.63 IW housing on it to make it respond, because the 0.82 would probably dull the very thing that makes the -5023 cartridge needs to make it work - speed and acceleration. GT3076 will run beyond 300rwkW and still be able to cut it effectively down around 260-270. For road use (my view), run the smaller A/R. Depending on preference, it would liven things up a bit in the response department and the difference in feel won't be huge. If your primary interest was track work then slip the larger A/R turbine on to free up the breathing if you're running more consistently higher rpm and load ranges. Part of this discussion belongs in that other GT3071 thread, as Mafia's was really focused on a couple of specific issues. But hopefully my view point (which is just my view BTW...) is reasonably clear. I don't believe there is a single best. There are some damn good options that can suit the particular application and driver's preference. And some people like the pissing contest with mine being bigger than yours

The 71mm 56T compressor actually looks to hit the wall at about 47 pounds of airflow over a PR of 2.25 – 3.1. That it can do so is more an indicator of being able to match the compressor to a wider range of engine capacities/efficiencies rather than the indicator that you’d be attempting to run the RB25 at the higher PR – shaft speeds of 140000rpm being run for what purpose? There is no more efficient mass flow to be had, and you’ll only be running to the PR (ie boost level) required to hit the power target. So it’s pretty safe to ignore those outer sections of the map because they don’t apply to the RB25 application. It’s unfortunate that there’s no official flow map to suit the 52T 76mm GT37 compressor, but the 56T GT37 shows all the necessary specs to get an idea of what is needed, and where the differences lie between it and the GT35 compressor. * Effective flow limit ~ 53 pounds/min airflow over the PR range of 2.3 – 3.5. * Difference of max flow capacity is 6 pounds/minute * Lower shaft speeds to achieve equivalent mass flows Those two factors point to the GT37 as being potentially more power productive, obviously dependent on turbine efficiency (amongst other things). So for me the issues to look at are Does the compressor unit supply enough mass flow at the required pressure ratio What efficiency ranges does the compressor pass through with the engine going through the speed ranges What is the speed trend and absolute values of the compressor shaft rpm What is the likely required turbine and wastegate performance required to track the compressor speeds As I’ve got some approximate calculations of what it should take an internally stock RB25 to hit 270rwkW, I will use them to assess the value of a GT35 compressor if chasing that sort of power range. Work on a mass flow range of 18 – 47 pounds/min @ PR 2.3, to cover an engine speed range of 3250 – 6500. Then find the compressor maps, plot them and review against the criteria above. GT35 works over a speed range of 108000 – 130000 with a broad efficiency range in the middle engine speed range. Over 6000rpm, the compressor efficiency is dropping fast + compressor speed is heading skywards for small increase in engine speed. 60% efficiency and rapidly dropping says the compressor has passed its best at this point. GT37 works over a speed range of 100000 – 113000 with efficiency not as good in the bottom end. The trade off is a high level of efficiency in the middle engine speed range but bugger all drop as the engine speeds get higher. 72% efficiency at peak power points to less heating of the charge and less compromise of ignition mapping or fuelling to cope with knock tendencies. Comparing the two, at that level the GT35 can’t do much more, and if you ask more it will need a heap more shaft speed, and deliver an overly hot charge. The GT37 can comfortably do more, with much better efficiency. For regular use, I see the GT35 working well up to 6000rpm with turbine speeds 8-10% higher. And down lower in the ranges it may well put the lower moment of inertia to good use, with quicker compressor acceleration rates giving improve throttle response. But in the higher speed ranges, the turbine is being asked to do extra work, accelerating to speeds 18% higher but driving a compressor that is (by then) comparatively out of its efficient flow range. The only upside (maybe) is that the rapidly rising compressor speed requirements probably won’t see boost creeping skywards as the turbine speeds rise – it really can’t push much more so the mass flow demands on the turbine + wastegate won’t be overwhelming. So on-thread, I agree that from a technical angle that the 3071 won’t/can’t perform to the level experienced by Mafia with his 3076 56T. The experiences of a few Adelaidians supports that idea, as Cubes outlined. I also think the idea of a 3076 52T cartridge is worth a look. But lack of product availability and good technical flow data on the compressor means it’s a bit pie in the sky. There must be a good reason why HKS don’t offer a Skyline spec kit with the 52T cartridge. For the money spent - and as a true bolt on – both Mafia and Lithium probably have hit a sweet spot and have the right spec to comfortably hit the 300kW mark. The larger turbine A/R that Lithium chose might well give better control of any likely boost creep and back pressure related detonation problems, but give a different sort of driveability. WI obviously clears the issue of detonation for Mafia. Still worth noting that they are achieving some pretty huge outputs from stock engines so let's hope longevity isn't too badly compromised.

Compressor 71mm GT35, 56T Turbine 56.5mm, 90T The number you have there is a Garrett part #, rather than the CHRA which should be 700177-5004 on the above specs. GCG no doubt put their own tag on as a supplementary to help with tracking units in the field. The cartridge with the uncropped 60mm turbine rotor comes as only that - a cartridge (CHRA) to which the housings are added. The number off that unit is 700177-5023. I'll back it in you won't have a bad unit, so long as it's matched to the application and power range. It's only a pity you didn't get exactly what you asked for. Any housing A/R available, and/or pics please?

Yes, it does look a little lazy to get going. The GT35 compressor does take some rpm to shift the air, so with a large-ish turbine A/R it's not that surprising. By comparison, my hybrid 2871 with a much smaller turbine gets up and boogies early, looks like it shades the 3071 until about 4600rpm when it begins to trail behind and "only" makes 300hp between 5800 - 6300. Partly an issue of compressor flow, but high-end turbine efficiency has a big hand in that result too. So it's a case of trade offs and different driving experience no doubt. 13psi by 2800 rpm plays a big part there. I think Steve's setup in comparison with mine would be a better thing for track use due to the free breathing top end.

And there's the rub - to do so it's back to the money tree. Sure, more could be extracted - but it's going to cost. Airflow development with manifolding, cams, valves, springs, porting etc will improve engine efficiency and get more from the turbocharger. Freer breathing and higher engine revs may well produce the goods. But the guy's comments are tied to some budgetary constraint. Having read the compressor map, and checking what people are actually getting, and running plenty of maths, I'd say the comments aren't far off the mark particularly for a mechanically stock RB25 using stock manifolding. 270 should be about top whack. Maps for the GT30IW housings haven't popped up that I've seen, but if you've got them please forward through the links or a copy. Just providing some clarity to the original question/application for the vehicle, at this stage I'll stand by the comments from yesterday. Higher average engine speeds/loads for regular use on a race track would probably see Lithium's setup a good/better thing. For more regular road use the -5023 3071 + 0.63A/R is probably better at that power point. As usual it's a case of priorities / application / budget. Without the budget to play with engine internals and manifolding, the 3076 will take him further should he want it. As always, more than one way to get a similar (not same) end result. There are obviously a couple of punters in the throes of going 3071 so let's hear from Zilch* and Simon-R32 with real world results. Dynos are nice, but as per comments by Mafia in another thread, let on-road or on-track experiences fill the pages behind the cover.

The boost creep situation seems to result from hybrid setups; ie mismatched flow capacities between compressor and turbine, and turbine:rotor for the mass flow being specced by an operator chasing a certain power level. Boost creep comes about because the turbine + wastegate vent can't pass the mass flow that the compressor is able to supply. You'd need to ask inabox where the designs for their castings come from. At a guess (and purely uninformed here, no aspersions cast on them) they may have sourced a foundry that copies the Nissan OEM housings so they are selling brand new gear. I noted that those housings are a bolt on which includes the 6 bolt/stud dump flange, which is different from the GT30 family. If that's the case, then you end up with a hybrid (which is what mine is)which has limitations you need to understand/accept before spending the $$. That's why I've explained my thoughts and the research that's behind the opinion. Mix n match can be a performance and economic gamble, and I believe in doing the homework beforehand. My hybrid performs exactly to expectations and predictions because amongst other things I measured the OE spec impellers against those of the cartridge I selected (side issue). BUT I went through the same agony of working without precise knowledge/experience. Fortunately you have Simon R-32 and Zilch* doing the work ahead of you The -5023 CHRA combined with a 0.63 IW GT30 housing has the balls to efficiently get you to the nominated power target, but very little further. In a similar vein, you'd see that the Skyline spec HKS GT-RS comes with the 0.63 housing but not the 0.86. The extra flow capacity in that instance equates to no extra useable power, but takes away response. If you wanted to run past 270kW, then the 3076 would be a better deal. And my opinion is that if you want a free-flowing 260kw that didn't give big heat build up on track work, then the 3076 is still the better deal. But that's the performance trade off you've got to look at when deciding priorities. Both the -5023 3071 and GCG Hi flow are very good units in certain applications. If your #1 priority is hammering around tracks lap after lap then you could do better than either of those two. Then I'd probably follow Lithium's lead. But you'd want to be looking at other aspects of vehicle performance then eg. brakes, which will also take a hammering.

Thanks for filling the blanks. I ran with the Garrett branded specs but worth throwing the full range of options that come from the HKS brand too. Frankly, going with anything other than the 0.63 A/R turbine + 60mm rotor is probably missing the best of the GT35 71mm compressor which does need extra shaft rpm to perform. If it is being spun comparatively lazily by the 0.82 turbine, then it's missing the speed to move the air mass efficiently with part throttle situations. You'd end up with an artificially high boost threshold, with no appreciable high rpm efficiency gain. Advice I received from a Garrett engineer is that the 0.63 GT30 is effective/efficient in service applications with 400 crank hp of mass flow, so working on plus/minus 10% I'd think it to be a decent match on the -5023 GT3071. Again though, 270 odd rwkW would be hard to improve upon without internal engine developments.

Would you do us a favour and post up the dyno sheets please. This will help with a few mathematical reviews of the results recorded. I note that the engine is internally stock, so that any airflow development work is limited to fairly typical bolt-ons. Also, either have a look at the ID tag on your centre section, to give us the necessary info to determine which spec GT3071 you have and gain the understanding of how it performed. There are three permutations: 700177-5003, or 700177-5004, or 700177-5023 All have the same 56T 71mm compressor, though housings may differ. Using some fairly reliable data, I’ve got calculations and a map plot that says it should require about 47 lb/min of mass flow at the boost level claimed to deliver ~ 430 crank hp which should deliver ~ 270 rwkW. That mass flow is at the edge of the map, and boost increase most likely won’t equate to efficient mass flow (and engine power) increase. Turbine performance, as I am still learning, is one of the major moderating variables of whether the compressor can work to maximum potential, or consume a fair bit of energy scavenging cylinders which are being backed up by increasing turbine inlet pressure. Before my understanding of turbine characteristics was much developed, I had reckoned about 245 - 250 rwkW to be as good as the 3071 with hybrid OEM housing + 56.5mm rotor would reliably do on an RB25. I can see that a GT30 housing + 60mm rotor would lift that significantly due to efficiency gains. Long explanation cut short: Zilch please supply the dyno sheet, turbo CHRA # from the ID tag and housing A/R so I can see how close to the money I am. If your dyno sheets aren’t overly “happy” as Mafia asked about, then you should smile. But don’t expect to find any magical top end gains by just running higher boost. Mid range would be another story…

I'd say probably, yes. He should be in a position to work with what he's got though. I posted a few ideas on #51. Changing to non-standard cams may well just move the characteristic (I won't call it a problem) around and upwards. The saw tooth torque curve I would think is the bigger issue to address. And there are things that can be done that cost more in the way of time than anything else. Again though - Lithium has got a generally good result. I'd just like to see something done to make it "happy".

I guess it comes down to what the budget will stand, and whether you can feel a difference on-road. VCT change point on a mechanically standard engine can have marked impact, but usually in a negative way if you alter it a long way from standard. But + or - a couple hundred rpm might be worth a try. I've seen using an adjustable cam gear also work well in terms of smoothing the torque curve - but no actual increase in my case. Just minimised the peaks/troughs so it was evident the engine was running in a happy mechanical zone. With that slightly saw-tooth appearance, I'd think that the ignition map might be worth a look. If it was mapped to the best output without knock, some columns will take less timing, meaning that as you advance through the rpm range the map is not moving smoothly through a curve. Can give the up/down appearance I'd commented on. None of this is a smart-arse commentary, just looking to see how the end result came about and whether it's possible to improve with comparatively little effort or $$. I like to know the how/why rather than just leave it to a tuner.

I have to say that I've seen that mid range dip more than a few times. Ignoring any stock ECU that's going into rich+retard, it's more with unopened engines but uprated turbo specs and with a new ECU. I see that Lithium has a Link setup. Which area of mapping should be used first to attack the problem? ie fuel or ignition? If it is fuel (and assuming that the AFR in that area is a "nice" repeatable value, should it be leaned off?