discopotato03

I can see your point with the larger turbine housing and higher compression ratio though you may have been able to achieve the anti detonation result by using the 0.82 A/R housing and regulating boost (and turbine inlet pressure) lower in lower engine speed ranges . GT35R BB turbos . These are a bit of a Garrett hybrid and their largest BB turbo based on the GT25BB center section . Technically there have only ever been two variants , the one you have (GT3582R) and the HKS spec hybrid GT3240 . The HKS spec one has the same turbine though its been cropped or ground down to GT32 turbine dimensions . Also its compressor is 54 trim where the ones like yours are 56 trim . The GT3240 was only ever sold with a bored out HKS T28 flanged GT30 turbine housing in 0.87 A/R . The GT35xx plain bearing turbos are based on Garretts GT35 diesel spec turbine and large frame GT center section . A pity the head didn't get its exhaust ports reworked and slightly larger exhaust valves but that's what next times for . Sounds like fun , cheers A .

Hi all , the Pro S versions of the 2835 and 3037 usually work better than generic Garrett versions because they are model specific and tailored to suit the engines state of tune . Its all in the housings and dump . Good results , I've often wondered how the 0.68 A/R 3037 Pro S shaped up on an R33 RB25DET . HKS went to a fair bit of trouble with their GT Pro turbine housing and dump pipe for a reason - they work . Does anyone with access to Nengun/Greenline know what they charge for this kit ATM ? Are you intending to run the poncams to finish it off ? Cheers A .

I would hold out for a PFC , they are around if you are prepared to look . Interceptors are very limiting and most aftermarket systems make you use a MAP sensor which is a backwards step IMO . Your call , cheers A .

There's a hell of a lot of variation in the TA/TB34 series , mostly diesel apps . They are native to Nissan/Hino/Cummins/John Deere etc as OEM . I was looking at diagrams of some with T3 turbine flanges , some have the round 3 bolt type like Buick Grand Nationals . If that ones a HKS special you probably won't find it listed . Loosely speaking many in this series use the TB31 turbine which is what the back yardies call Sierra dash 1/2/3 . They can have T04E compressors and housings which is why they sometimes get called T3/T04E's . If we can see inside at the compressor and behind at the turbine housing that will tell more of its story . Cheers A .

I don't mean to spoil the party but if you place a Cat in the screamer pipe how do you keep it hot enough to do its job ? It makes me wonder if there is such a thing as a twin pass single cat converter as this would make it easy to run a big and slightly smaller set of exhaust pipes - and keep the bad gasses acceptable emissions wise . The reason why plumbed back WG's hurt performance is the pressure rise south of the turbo . Ideally you want as close to atmospheric pressure as you can get behind the turbine but its very difficult to achieve with much more than a megaphone behind its outlet . From an engineering point of view I think finding some way of plumbing the gate back into the front of a very low restriction cat and exhaust may be the answer . A few years back there was talk of automotive power system voltage climbing from 12 to 36V , I think part of the reason was to have high enough voltage to rapidly heat cat converters up to working temp for cold start emissions reasons . Without some gas going through them all the time I don't think they work properly if cool . Great thread , cheers A .

Dangerman4 that flange is more along the lines of what I was thinking only instead of having a figure 8 shape where the pipes touch I'd make the bypass tube the same shape as the housing side - D shaped if you know what I mean . You could achieve this by cutting the gates tube and adding fillets to form this D shaped section or just cut and grind a big tube and weld it to the outside of the dump tube so they have a common wall . Part of the advantage is that its closer to the same temperature on both sides so less thermal stress and expansion/contraction cracking issues . I'm not really sure how you go about feeding the bypassed gas back into the system and not affect the main gas stream . One silly idea may be to merge it with the front of the Cat's reverse funnel because it opens up gradually to expose the front of the core/matrix . Its a fair length to go and rapid temp rise as the gate opens could cause expansion and cracking problems without some sort of soft spot . Thoughts ? Cheers A .

It goes against the grain but possibly a GT2860RS or a GT2871R in a reprofiled RB25 turbine housing would be reasonably easy and cost effective . Someone on this forum a while back had a non IW real GT3071R on an RB20 and he felt it was ok though these days you'd used the GT30 0.63 A/R IW housing for convenience sake . Its a fair bit of turbo for a 2L six so may be a bit laggy for some . A .

Hi all , if I was trying to develop a dump pipe for those Garrett GT30/35 IW turbine housings I'd take a leaf out of HKS's book . If you look at how they did their Pro S IW gates vent pipe its not to difficult though probably time consuming . They basically cut a section of pipe in half and seam weld it on the outside of the turbine outlets tube . It would not be very difficult to "form" it into the shape of the back of the IW turbine housing . I don't know who's making the flange plate for them in those pics but I would want it to be the same shape (outline) as the gates outlet area - not just another slightly smaller hole . From a manufacturing point of view merely hole sawing the two holes is simple enough - read cheap to do . Whats needed is a template taken from the housings outlet flange and possibly laser cut versions made . Cheers A .

I can , Garrett have designed the housing and turbine as a matching set and they even give you a turbine flow map for them . I wonder what sort of response AVO would give you if you asked for the map of the GT30 turbine and their housing , I think you can assume that it doesn't exist . If the price difference is not significant I don't see any positives in using a "bitzer" turbine housing - aside from the Hitachi dump pipe flange which is nothing to write home about . Also changing from a "Hitachi" type housing to a proper GT30 one means the turbo moves and that means alterations to all the plumbing , I think it makes more sense to base the conversion on a Garrett housing . That way you could make housing A/R alterations and know it will all fit back in . In fact if you really want to future proof it have a look at the spacers used to fit a GT3582R IW in the bay , most wouldn't fit these to an RB25 but hey if you inherited a fortune and had an RB30 under it you know it all goes in . I think you really only want to be doing this one off stuff once because the time and money involved in moving turbos around is not insignificant .

Adz a couple I'd like to know . Has the water temperature remained as it was in std inlet form ? What sort of boost response are you getting from the GT3582R and is it IW on a std exhaust manifold ? Cheers A .

Those results follow the usual trends , larger A/R turbine housing uncorks the hot side of the engine pressure balance equation and you often end up with the same power at lower boost pressure . This is a good example of increasing the gas flow by removing a restriction , it also means lower charge air temps and lower fuel rail pressure so mostly good . The only downside is that the turbine spins up later in the engines rev range because the larger turbine housing passage means low gas velocity through the turbine housings nozzle until the engines revs climb a little higher . Actually I always wondered what a GT3076R would be like with a 1.06 A/R GT30 turbine housing but its not a combination any ones tried as far as I know . Throttle vs boost response works really well with larger A/R twin scroll housings but until Garrett gets the lead out and makes twin scroll twin integral gate turbine housings like IHI and a few other manufacturers do don't hold your breath . Very interested to see how that real GT3071R 0.63 A/R build goes . Noise , yep nearly always goes up because there is less pulse damping between the exhaust valves and the turbine housings nozzle . Cheers A .

Sorry if this sounds like a silly question but are the GTR's std manifold outlets actually that much wider than the turbine housing inlet or is that mark merely a carbon stain from where the gasket doesn't cover the housing flange . I've had very little to do with RB26's but I do know they use a more compact and I think slightly differently angled turbine housing that your run of the mill T28/GT28 one . My best guess would be that Nissan was concerned with gas speed into the two turbine housings (vs one) and so the housings inlet was made smaller to keep the velocity up . If the std manifold is the same dimensions as the housings inlet I reckon I'd make sure there were no steps in the wrong direction and call it day - I don't speak through experience though . Cheers A .

Hi all , I was talking to someone about this topic yesterday and there may be a few gremlins that I didn't know about anyway . Its a little O/T for a thread I started but not unrelated to the RB26's six throttle inlet manifold . As I mentioned in the beginning - the burning question is to compare the conversion with just fitting the complete RB26 head and its inlet manifold assembly . Cost is generally greater with RB26 engine components but what are you actually paying for head wise ? Mentioned to me was better porting/exhaust valves/non hydraulic buckets/cams/valve springs/water cooling jackets . The downside compared to the 33 25DET head is the lack of VCT and slightly different exhaust manifold stud pattern . The more I think about it the more issues the 26 lid solves but it comes at a price . I suppose in the end the ultimate 33 25DET would run the complete RB26 top end with some sort of adaptation to a single turbo exhaust manifold - if you didn't want the added complication of twin turbos factory style . BTW I'm not knocking those who are going ahead with the 25/26 adapter plates its just that once you achieve it will the lack of the 26's cooling jackets valve train etc paint you into an avoidable corner and at considerable cost ? What's everyone think ? Cheers A .

Hi all , I'm also curious to know if there's any interest in plate adapters to mount RB26 twin exhaust manifolds on an R33 RB25DET head . I can't make them but others may be able to . People quite rightly think that twin scroll turbos are expensive to do on an RB25 but if the RB26 manifolds could be made to fit then twin singles with their own integral waste gates could be a viable alternative . I know that the RB25's spec of cam/compression ratio is different as is the capacity but the right turbos could get you into the 280-300 Kw area without too much difficulty . In fact I think the 25's higher static compression ratio would work in your favor with the pump fuel available nowdays . Just a thought , cheers A .

Hi shanef , I had wondered if there was more to the adapter plates than just profile cut/machined holes . Just to press the point - will the injectors in a GTR manifold with these plates still spray down the inlet ports or will they now be aimed at the inlet ports floors ? I guess the only way to really know would be to bolt it all up on a bare head maybe with the inner section of the 26 manifold . Doughboy sold me an RB26 top end and inlet system a couple of years ago and luckily for me its R33 RB26 so the TPS and possibly the IAC could be electrically compatible , PFC ECU in my case . Cheers A .

BHDave I think the reason why the Nissan RB20/25 manifold flange is wider than GT30/35 turbine housings is because they are a split pulse design so probably more like a "Euro T4 twin scroll" housing flange pattern than single scroll T3 . Brett Lloyd once told me that there is lots minor variation like this and another one is the larger T4 and T4 "International" which some call T45 . Geoff Raicer (FullRace Geoff) had issues with some housings because they are large T4 twin scroll flange and stud holes but with T4 Euro twin inlets . The problem seems to come from the fact that Garrett is not one company and different parts of it in different parts of the worlds made different things to suit themselves . Once we start to mix n match different bits things like this are common . Cheers A .

Some would say that a 0.63 A/R is a little small for a GT3582R given the 68mm turbine and 82mm compressor . Sorry to sound negative but I think I'd have gone for a GT3076R and a 0.82 A/R IW turbine housing . IMO the trouble with small turbine housings on bigish turbos is they limit the gas flow through the hot side once it all gets going . Some people in the US have made the best of that situation by fitting port shrouded T04S compressor covers but you also have to be careful to get one that actually works . I think Precision Turbo (PTE) in the US does one that seems to work . Cheers A .

The viewers at home would probably like some snaps of the ID tag and that 0.63 A/R GT30 IW turbine housing so they know one when they see one . Cheers and thanks , A .

A couple of important things to know . Firstly what turbine housing is on it (please say Garrett GT35 IW) and in what A/R ratio . I wouldn't think too many waste gate systems would let you run your engine at full load to the redline and not make any boost at all . To do so would require enough valve area to pass all of the exhaust gas out of the engine - at any load and RPM and not spin up the turbine . Cheers A . BTW make sure the waste gate valve is opening up completly and not being restricted by the dump pipe .

Just starting a new thread on this topic . If this becomes an affordable mod to do what problems can people see when making it all work and run in say an R33 GTST . Firstly I suppose the 26 plenum has to physically clear anything that can't easily be moved because it gets spaced out maybe 20mm ? Then I suppose its wiring everything up and allowing for water and air plumbing . I guess you'd also have to make sure the three main passages between the head and manifold were adequate to avoid temperature differences along a long I6 head . One problem SK mentioned that may be an issue is where the injector tips are aimed with the manifold now 20 odd mm away from the head . I think it would be a fiddly job to weld up the injector bosses and re-machine them at a slightly shallower angle . Other than these issues it has the potential to allow far less restrictive throttling and warmer cams before things get too choppy . The obvious one is of course intercooler plumbing which would now be virtually as per GTR . The burning question would be is it more practical just to run an RB26 head and be done with it . Thoughts ? Cheers A .

Yes I think a lot of people here will be watching your progress because that's where many R33's , inc mine , are at meaning PFC/injectors/exhaust/pump etc . I don't know what a "JJR" split dump consists of but if it suits the std RB25 or VG30 turbine housing it won't suit the IW GT30 housings outlet side . You will have to have something made to suit the new turbine housing . With a few IW GT30 based turbos getting around nowdays its surprising no ones tooled up to make a dump pipe to fit between these turbos and the standardish exhausts first joint ie where the std cast dump bolts to the engine pipe . I don't like the idea of one piece engine pipes / dump pipes . All too often its difficult to get at the dump's turbine end bolts/nuts particularly around and under the short side radius of the pipe . If you can have a first joint approx when Nissan has it std should be easy to unbolt everything and lift the turbo out with its dump pipe still attached . Far easier to remove that on the bench from what I've seen . Keep us posted , cheers A .

My preference is to go with what the Garrett engineers designed to be a matching pair - GT30 turbine + GT30 turbine housing . To be confirmed but I believe that the cropped GT30 turbine was originally made for HKS and their "GT2835" turbos because there was no turbine sized between the GT30 UHP and the GT28 NS111 . Logically to take the larger one (GT30) and re profile it to the in between size is the simplest cheapest way out . As I said they work ok in a GT30 turbine housing because the nozzle and volute passage are made to suit a GT30 UHP series turbine . Naturally the housing itself needs to be profiled to suit the cropped turbines slightly smaller dimensions . Where HKS screwed up is when they had Garrett profile GT28 turbine housings to give them an IW GT2835 option on SR20's and CA18's . Those two engines have T28 flanged exhaust manifolds and they needed T28 flanged turbine housings to make it a "bolt on" turbo option . GT28 turbine housings are designed to suit GT28 turbines - notably that nice for its size 53.8mm NS111 type in 76 trim . This turbine is nothing remotely like a GT30 UHP turbine , 9 blades instead of 10 and completely different blade form . Even the trim is different at 76 vs 84T . Anyway Garrett seems to have followed suit with the cropped GT3071R which cartridge and wheel size is the same as a GT2835 but Garrett only market the 56T compressor version , HKS sell 48/52/56T versions as well in some applications . To be fair Garrett has only fairly recently come up with proper IW T3 flanged GT30 turbine housings so in the past we were out of luck . Also don't forget that some of these ball bearing turbos available through Garrett now were in the past HKS options only - end of story . Garret only sold their stock of some better cartridge options through HKS though I think anti competition and monopoly laws derailed that little sting . I can remember the days when there was no such thing as a GT2860RS/GT3071R/GT3076R . You could buy a GT2530/GT2835/GT3037 but you paid in blood - even if their custom housings did work well . Night all , cheers A .

Yes many people would like to fit those to the "stud" of the person who designed them . Cheers A .

Sometimes the manufacturers specify "ovalised nuts" in high temp situations . I have seen nuts with serrated threads that go on ok and lock up if you try to unscrew them , often why exhaust manifold studs break if you try to remove their nuts . Mafia you may need to support your manifold from underneath and lower down on the block . One fellow I know used to use the engine mounts top stud and nut as the foot of his brace . Cheers A .

Dano the "other" two versions use the cropped or ground down version (ground down from ~ 60mm to 56.6mm) of the GT30 turbine in 84 or 90 trim . The worst part is that they are sold with bored out T28 flanged GT28 turbine housings . The combination of the altered turbine and GT28 turbine housing is a abysmal failure IMO and results in poor turbine efficiency - shows up as lag and exhaust gas restriction . The cropped turbine can be made to work ok but only (IMO) in HKS's GT2835 Pro S turbine housings . So long story short , cartridge numbers 700177-3 and -4 tell you that they are the cropped GT3071R in 84 or 90 turbine trim . In any case and luckily I suppose they don't bolt up to your T3 flanged std RB20/25 exhaust manifold anyway . BTW the complete turbo part numbers are 700382-3 (84T version) or 700382-20 (90T version) . As I mentioned recently the cropped ones are turning up in a couple of locally sold turbine housings that are supposed to emulate the Hitachi VG30DET BB exhaust housing - possibly slightly larger A/R . My advise is insist on the real (700177-23 cartridge) one unless you particularly want to run a HKS GT2835 Pro S IW T3 flanged turbine housing . If the agent can't get one keep looking because they are around . Also to give it its best shot we should only be using genuine Garrett or HKS GT30 turbine housings so IMO the 0.63 A/R IW in a Garrett or the 0.68 A/R in a HKS GT3037 Pro S turbine housing if your lucky enough to find one . -33- , really looking forward to hearing the results of this turbo on your R33 GTST . Cheers A . ....... and did I mention -23 ?