discopotato03

Just of late I keep coming back to this turbocharger , I have been re-reading Mick os GTX3071R results and I keep wondering what the smallest Garrett GT30 turbo can do in a 0.63 AR IW T3 flanged rear housing . Garrett quotes 500ish I think . I'd like to here some opinions on GT30s in the lil 63 housing particularly the more modest compressor wheel options . If those that tried GT3071Rs with this housing can give their opinions I'd appreciate it . Garrett didn't have a port shrouded 0.60 AR T04B comp housing at the time AFAIK and thats what may have caused a few surge and wastegating dramas . Lithium I think you reckoned that this dryer should replace the GT2871Rs/GTRS on RB25s and my gut feeling is the same , I'm waiting still for some innitial results and if they look positive I might give one a whirl . I've been looking at that comp map and I think a good std engine can probably take 20-21 pounds of boost particularly if its infrequent . Decisions decisions , cheers A .

Mick I ment no offense , so don't be . I think I remember reading your account of how your car goes and thinking while the results sound very impressive probably a bit over the top for me . I don't really want to use a turbo with a T04E sized compressor housing if I can help it and have to space it out on the exhaust manifold . This is one of the reasons why I'm mildly interested in the GTX3067R - it uses a T04B comp housing of roughly similar dimensions to my GTRS . An EFR 7163 is also remarkably compact for whats claimed of them . To look in my engine bay you have to be very familiar with a GTS25T to notice much other than what Nissan put there . Its a big challenge to have a bit more oomph and have it look very standard . I wholeheartedly agree that a ride in your car would be interesting and if we can find the time I look forward to it . Now on this GT30/TR30 turbine business . The reality is that the TR30 one is not currently on offer where the GT30s are readily available . I have word that this is being looked at but no timeframe - in other words don't hold your breath . In the meantime the most responsive current tech GT30 turbo is the GTX3067R and the first real world results should be coming through any day now . The EFR 7163 is a bit further away and still going through final development . ATM I'm looking at other things with this car so turbo changes can wait . A .

I can't remember if I mentioned it but a feller inside Garretts aftermarket section reckons that the NS111 is not new but is still a very efficient design aero wise . Its not impossibe that it could be made of Inconel rather than Mar M and find its way into production aftermarket 30 series turbochargers . Thats what I would hope for but who knows what the future brings . Theres no sign of the 53.8mm NS111 turbine in the GT28 series being replaced and for what it has to do it works very well . A real rough hack formula based on the increase in diameter (area actually) from almost 54 to 60mm may give a vague comparison of what the 60mm version is good for . It looks to be about 24% greater area than the 53.84mm one . A .

4G63s are not exactly high tech engines though they were beefed up in the right places . The two best features of the 4 and later engines was the twin scroll turbo systems and the Mivec head on the 9s . I could so use a Mivec head . Lithium to have a 4 bar 60 pound a minute turbocharger means having a turbine capable of driving the thing reliably . A lot of heat and turbo speed and dud turbines don't cut it . If I had the time I'd be more interested in the application that spec TR30 was on , and the one with the 76mm 56T compressor as well . Mick o , I did not turn down the offer because I think poorly of your car/results . I just think that what you have is not what I want and I'm looking at other options . ATM I'm learning to use the ViPecs software and the next round of changes involve injectors and a different fuel pump . A .

Do you really want to know Lith or are you you just fishing for target practise . GTS like any dedicated competition component/assembly they were developed to suit the exact purpose asked for . When restricted classes came about a lot of changes were made because the existing crop of turbochargers were unsuitable - mainly too big to work in the restricted rev range . Like anything that runs on boost for extended periods they have to work efficiently and reliably on full load . Compared to an OE road turbo thats expected to operate over a wide engine speed range but mainly for short bursts - up a hill or up to lightly loaded cruise speeds - a race turbo is specced differently . The cars had anti lag systems to excite these things at no speed and lowish revs but once the hammers down its all up to the engine and etc to get the job done . Turbochargers like any pump don't really like running out of flow and when it comes to air all they have is atmospheric pressure minus any restriction . The people working with restricted turbo engines know what volume its possible to get through a given hole size so they work backwards from there to get the most out of the available flow rate . You would think that effective boost control would be mandatory and I think they used to wind it back getting towards the restrictors limits to avoid surge and damage . I doubt there was any enforced restriction on the exhaust side so they would have been free to set the turbine inlet pressures at or below boost pressures . The materials in these turbos and their manifolds and exhausts had to withstand tremendous heat levels because ALS is basically external combustion in the exhaust manifold turbine housing and exhaust pipe . Far more brutal than any OE car could take even if the noise and "emissions" levels were allowable . The only OE cars that I can think , there is probably others , that went to a lot of effort were the Evo Lancers namely the RS versions . They had better materials in their turbines and housings and twin scrolls as well . The ALS stuff is there in the road cars though its inactive . If you look at the Mitsy turbos on these cars they are hardly huge but they are designed to make lots of mid range torque not a massive extended top end . The TD05HR turbines are quite light in Ti AL form and there were compressors in some of them smaller than the usual 16g6 . The Aus spec TME is actually an RS2 and they have a smaller 15 ( I think) GK2 compressor wheel . I think one of the Evo 9 RS turbos may have used it as well . Anyhow none of these Evo turbos make big Kw numbers but they seem to give plenty of other road cars a big hurry up at times . My Evo 6 is showroom standard everywhere inc boost and the dryer I have for it is a second series Evo 9 RS one if I ever get round to using it . These have the same wheel and housing sizes as any Evo 9 dryer but the turbine and Magnesium compressor are lighter so the spool and transients are a bit faster/sooner . I'm more Skyline centric these days because my R33 is the daily and the daily always gets most of my attention . A .

Post deleted . Lithium your life must be complete having a GTS25T with a GT3076R 0.82 AR . A .

Well we don't really know yet because its not oficially released . I think those working on them want it to be the best 500+ horsepower turbo on the market , by best they are hinting size weight response . In truth they are supposed to be a bored out I think 6758 so with a bit more compressor and turbine they should make more power . The 7163 is supposed to have a second generation turbine and there may be some turbine housing mods as well . I'm not sure which turbine housings will fit other than the T25 flanged 0.64 AR one , with luck the T3 flanged 0.83 AR IW can too . Anyway to get back on GTX track I think there is a need for a compressor wheel somewhere in between the 67 and 71mm ones . Really I should say pumping capacity wise because I think a GT30 turbine can easily power a less than 56 lb flow wheel and try to be responsive in a 0.63 AR turbine housing . Its been suggested that the GTX3071R could used a 0.63 housing but as I said I think thats counter productive . I'm waiting for one person to get back overseas on how their GTX3067R performs - I need some first hand results . A .

Yeh well thats kind of the issue because I never wanted GTR type power delivery . I was back at Insight today sorting out a few ViPec tune settings and got to talking about this GT30 business . Scott does enough tuning and travels overseas looking at all kinds of performance things and agrees about this turbine stuff . He thinks that there are good smallish and good biggish turbos around but until recently no-ones really done a good mid sized wheel turbocharger . He says that really the wheel sizes and trims need to be right and fitting small turbine housings to GT30/35 sized turbos is a bit self defeating . He's curious to see how this GTX3067R would go and reckons its an option , expensive experiment ... The more I research them the better EFR 7163s sound but solid results are hard to find because the only ones in existence are prototypes sill being fine tuned in some areas . I have to make enquiries OS about turbine housings for EFRs because I need an IW T3 flanged one if possible . Lithium I did ask him Scott wat would happen if I used that GT3076R 52T 0.82 AR turbo and he said it'd make good power but lose most of the nice drive it every day stuff . He knows what I like and what I don't and he knows I won't like it so why go there . I also asked briefly about TR30Rs and he said brilliant things in the right sizes . Almost forgot , these are more like a 10 grand turbocharger that comes with a contract so I don't expect to see many on road cars . Cheers A .

Lith I understand the point you are trying to make which is why I previously made examples of the BB P/60-1 and T04Z turbos , these days the GT30 and GT35 turbos can do virtually the same job and are lighter more compact and have more efficient wheel/housing combinations . I too played with those TB31/TA34 turbines which people incorrectly name "Sierra dash 1/2/3" . This is not the turbine that the Sierra Cosworth or RS500 variants used . That turbocharger is by todays standards a POS and thankfully the BB GT turbos went on to replace that kind of thing . Every thing you do to a GT30 UHP based turbocharger involves a work around for that turbine , in fact everything to do with every turbocharger ever made involves working around its turbine shaft/wheel . The reason people make hybrids based on these turbos is because the turbine housing and centre section are the most difficult and expensive parts to develop . If they weren't FP etc would be making their own unique turbos and not having to put up with someone elses compromises . Lith you are right that Honeywell to a degree doesn't care if there products aren't perfect - so long as they sell enough of them - particularly in the small volume aftermarket area . Thing is that they do actually care and the more we spread the word about their turbos shortcomings the less they can afford to ignore it . The WWW ensures that any brilliant new development gets plenty of exposure , lets just say that EFRs coming 7163 blows every other similarly sized dryer out of the water and nothing comes close in the 500 hp area . Within days everyone knows about it and every competing unit looks like shit . Suddenly noone wants a GTX this HTA that , they want the gun thing thats a known success . Big G is probably more concerned about its face than selling aftermarket turbos , if they lose face they may lose their attitude and actually get the lead out and do something . Anyway think what you will but at the end of the day the GT30 turbine is heavy crude ancient aero and laggy because of its trim size . If anything it may have worked better had it been 57-58mm OD because it would have been lighter and the trim size less of an issue for most of the engines these end up on . I'm watching very closely whats going on with the 7163 and its slightly smaller brother because if they are as good as those in the know reckon I may just buy one . A .

Like turbine housing AR variations trim sizing makes big differences to how a turbine family performs overall . Its not often you see big trim sizes on a turbine unless the intent was to increase the flow capacity for a given major diameter . AR and trim size work together and to see this note the GT30 UHPs turbine graphs - the flow rate increases quickly with AR size . The NS111 turbine design is also not new but people inside Honeywell claim aero wise they are very good , as I said recently the smaller VATN turbos are getting improved turbines and they look similar to NS111s in some ways . I wouldn't write the TR30 turbine off as being restrictive and in the 76T size with a suitably sized turbine housing they should be able to make real good power - with a good/better spread of torque than the GT30 can . Yep many have noticed over the years that other manufacturers use different turbine trim sizes on similarly sized turbines and I think its because they want a good spread of power . If you spend time looking in turbo families note how many but not all of Garretts Diesel spec GT turbines are 84 trim . Also note that diesels tend to work over a much narrower speed range than petrol engines and their usable rev ranges can be quite narrow too . To cater for a narrow power range and not be restrictive you'd think the logical solution would be to have a big trim turbine and try to limit the turbines major diameter - innertia . Generally "spooling" turbos on big diesel engines is not a major issue because they tend to run in a loaded state for longer periods than small/ish petrol engines and the transient priority is much lower . Next time out on the highway listen carefully to the turbos on truck prime mover engines and note they spend long periods of time on boost . In some ways these engines are more like competition car engines because they spend so much time loaded and boosted where a typical road car doesn't need boost just to cruise around . So to me big turbine trim means this thing is really only going to work well over a narrowish power/engine speed range compared to a lesser trim turbine . Now IMO 84 is a LARGE trim size not a normal one and most of what I see in the OE petrol world uses sizes more like say 62 to 78 . All your basic T25/T28 turbines were around 62T and its the 53.8mm NS111 that allows the more potent GT28 BB turbos perform as they do . You all know what happens when you change OE RB26 turbos for say GT2530s (GT2860R in todays speak) and let me tell you you were never going to make twin 2530 power with OE sized turbos - even if they had steel OE sized turbines . Dash 9/GTSS turbos have I think NS111 turbines but they are 62 rather than 76T . The only OE app that I can think of that uses a GT30 or GT35 BB turbo is the Ford XR6 and a GT35R is not exactly a big turbo for a four litre engine . I'd say Ford went this way because they wanted a reasonably cheap compact turbocharger and to have an integral wastegate + T3 flange . Soo they gets a big trim turbine in a compact ish GT30 big AR housing and it doesn't choke the thing at 1500 engine revs . Four litres doesn't need much boost pressure to make decent torque so the compromise is workable . Note that these don't need high boost from nowhere revs but they do need to be unrestrictive to make good off boost economy at low revs . I haven't had a turbo XR6 but we drive the NA ones often at work and these sit on 1700 revs at 110 (auto) . Now us in the aftermarket . We want strong torque over a wide range and very small is the segment of society that regularly winds their cars of the clocks on the street . Those that do are pure morons with no respect for their own lives or anyone elses . Accidents waiting for headlines . The rest of us want a usable spread of power because thats what works on the street , making too much power is easy peasy but making "good" power ie not Camry dog lag monsters takes a bit more effort . Trying to do it with GT30 based turbos introduces too many compromises IMO because to get them on song early means having twin scrolls or the sort of turbine housing that has higher gas speeds at lower engine revs - and then it falls off in the upper rev ranges . I have no doubt whatsoever that that a TR30 turbine substituted in some of the GT30R turbo range would wake them up significantly earlier than a GT30 UHP turbine does and still not be overly restrictive in the right AR sized turbine housing . It would be real interesting to compare TR30 and GT30 turbine maps in the same AR sized housings because that would tell you the real flow/exhaust pressure story . A .

This gets talked about often so obviously people are interested to know if the complete RB25 inlet manifolds can be substituted from R33 25DET to R34 Neo Turbo and vice versa . There are good reasons to attempt this ie R33 engine in R34 or the other way around . Obviously the injectors and throttlebodies/TPSs are different but if the whole assembly can be exchanged in some circumstances it could make life easier . Anyway its been said that the Neo RB25DET has slightly smaller inlet ports and runners at the manifold flange . Most people think the Neos make better power than the R33s do even in modified form maybe the ports and manifold sizes were changed for good reasons . The way to check if the manifolds are interchangeable is to compare inlet manifold gaskets I suppose because that confirms stud holes water jackets and ports line up - or not . I'm not sure of the wiring situation as in if the injector loom plugs are the same , I hear that the coil loom plugs are the same . I believe the throttlebody mount on the plenums are the same so you can go either way . The things I'm not sure about is air plumbing and the idle and cold start valves , wiring would be different here . Anyway first things first will they bolt up to their opposite numbers head ? A .

Intercharging R33 and R34GTt RB25 inlet manifolds needs its own thread Starting that now , cheers A .

TR30Rs are a purpose built no compromise series of competition turbochargers with no regard to production road engines whatsoever . In the early days of competition turbochargers there were no inlet restrictors but the people writing the rules decided there should be a way to even the field , and allow NA engines to compete against them in some cases . I think the old saying that torque wins races horsepower sells cars is still valid . What the restrictor does is put a cap on the total volume of air you can have and that forces the engineers to make as much torque as possible before the flow limit is reached . History has shown that the pre WRC Group A Rally engines could generate 650 Nm of torque from a 2L turbo engine even with air restrictors . That they hit the wall at 5500 revs says a lot about what you can do with 2000ccs , though they did have anti lag systems as well . I don't think these engines or turbos would have had a problem with exhaust restriction , no turbo engine likes to be pushed hard with restricted exhausts and it really shows with torque output . When you think of "small trims" remember these TR30 turbines are 60mm like a GT30 UHP but they have less (9) blades and no doubt very carefully designed exducer tip heights . They have a range of turbine housing ARs and if ones not enough and the rules allow you strap on two turbos . Also note the range of compressor wheels and IMO the most impressive one is the 71mm 60T one . The 76.2mm 56T one looks good in a GT3076R sort of way too . I also doubt these would perform poorly at more mundane pressure ratios and some of these maps look vaguely similar to some GTX maps - higher PR capable than many of the GT ones . The trend these days is to run higher PRs in production petrol and diesel engines and the one that springs to mind is the Mitsy 4B11T that has I think 21 pounds of boost off the showroom floor . To make good torque with higher PRs you need to have even inlet and exhaust manifold pressure on boost and in the past that was hard to do if you wanted boost/torque from low revs OE style . These days we want our cake and eat it so the engine has to make good torque from low revs and then stick a boat load of boost into it . Things like good heads/variable cam timing and lift/direct injection/bore to stroke ratios etc all pay off . Personally all I'm interested in is that turbine because it makes the 1989 era GT30 look like a total piece of agricultural shit . All the woes of Gt30 turbos stem from that turbine and the sooner Garret improve upon it the better . If the GT30 had been the gun thing there would have been no need for the TR30 one . Later , A .

Just in case you never get to see them . http://classifieds.s14power.com/showproduct.php?product=759 And details . http://www.tdesystems.com/default.aspx?page=customer&file=customer/tudiel/customerpages/news.htm Note the 71mm 60T wheel comp map that looks cruisy and pumps out 60 lbs/min of air at 4 bar . Also I think I quoted in the past that TR30 60mm turbines were 63 and 76T , one of the pages in the second link shows them as 73 and 76Ts though they quote mm which was a typo - note the exducer sizes . A .

Seriously ? You really want to rat up something vaguely like a TB31/TA34 type T3 flanged turbine housing to fit one of those T3/T4 ball bearing hybrids . Lith the reason those things turned up in the first place was to offer a better more reliable BB center section to those already using that type of turbocharger . Ditto for the T04 P trim 60-1 cartridge . Balls for those with with real T04s . In fact the T04Z cartridge is exactly that with a T04R compressor instead of the 60-1 . Go straight to the parts bin Lith , or search online for pics of those old TA/TB31 turbines , and compare them to an NS111 or even a GT30 UHP . Not even close to the same aero and you don't have to be an engineer to notice the differences . Turbines are being looked into ATM but most of the effort seems to going into smaller OE VATN diesel turbos I believe like the GT2256v and GT2260v . I think European diesels like X5s and others use them . I think the aftermarket will get a few alternatives down the track but they'll need to be bigger than 50mm . A .

No not really . What people need to understand is reasoning behind Garretts aging UHP turbines in big trim form , which is most of them . The whole point of getting away from ancient T series turbos like from T3 T4 , I'm talking real T3 not just any olld T3 flanged dryer BTW , was to make the units smaller lighter and cheaper to produce . Also to make them faster responding things that put less heat into the air under boost . Three important things to think about . Firstly smaller lighter higher speed wheels can often pump as much air as the old "T" bone wheels . Secondly compact rolling element bearings shit all over bushes and thrust plates friction and load carrying wise , they can take significantly higher shaft speeds and use less oil doing it . BTW think annular contact not just "ball bearing" or the "roller bearing" which is not a "ball" bearing at all . Thirdly for their flow range GT UHP turbines are smaller diametre and larger trim things than their T Series equivalents . A good example is a GT35 turbine which is approximately 68mm 84 trim . The T04 museum piece is 74.2mm and available in three trims or N O and P , From memory the P was the largest at I think 76T and the O around 69 trim and can't remember what the N was - guesses about 63T . The GT35 is going to be lighter and more compact than a P trim and is supposed to perform about the same flow wise - in a GT30 turbine housing . This is why when the T04Z (T04 R actually) turned up people started high flowing GT3582Rs with the T04R compressor wheel . You gets the Inco turbine with the Ni Resist housing plus ball bearings and machine out your own compressor housing . And you don't get bent over by HKS in the process . The GT30 UHP turbine was a really good thing in its day and to crank 540 odd horse power with a 60mm diametre turbine was pretty flash - in 1989-1990 . Wide exducer tips schmich looking paddle shaped blades and that big trim size to make a medium sized turbine flow 500+ worth of exhaust gas . You bloody beauty finally something less laggy than an O or P and this time - its got balls ! So time goes by and road performance engines are getting smaller or more performance is needed from the smaller capacity existing ones , basically people want the performance over a broader range starting earlier . The manufacturers race teams also wanted better and had the bucks and the drive to win at international levels . Garrett had reason to develop turbochargers that wiped their arse all over what HKS though was good "power and response" . The ask for a true competition turbocharger is a lot higher than any OE or aftermarket unit because so much time effort and money goes into competing at the top levels . Also reputations are at stake and winning means selling your product . Through the 90s tarmack racing was on the nose so competition turbocharger development was being aimed at rally cars ie Grp A . The ask was for a lot of boost soonest but with a restrictor limiting maximum flow . It forced Garrett to think very had about turbo size weight and innertia and they had to come up with wheels that worked in this environment . You can throw all the T and GT UHP turbines in the bin here because they don't work , too big too heavy not efficient . Then they think yeah this NS111 thing works well so why not make it a bit bigger , erm - maaayyyybe 60 mm but in smaller trims - like say 63 and 76 . Now if you remember the 53.84mm NS111 is available in 62 and 76 trims , don't think this was by accident ... Its now history that the TR30R series turbochargers worked well and put many cars in the winners circle . Great , but what about the aftermarket turbocharger scene . Well there was that time when Garrett wouldn't sell the HKS spec GT BB turbos and the just different enough pretenders were a bit yawnsville . Also you had problems if you wanted a T3 flanged IW BB turbo because the IW GT30 turbine housings didn't exist in those days and have not been around too many years in fact . So you get to the stage where you can have a few T3 flanged GT28 based BB turbos and Garrett rocks up the the GT30 IW ones so you can use GT30 whatevers on your 280ZXT/VLT/FJ20/RB20-25-30 . Alls good till you work out that she isn't as lively under 3000-3500 than you like it to be and suddenly the gap becomes obvious in turbine family performance . The easy fixes are tried like compressor wheel trims and port shroud housings - even a drop in turbine housing AR . All have compromises and none really fix the problem . Lith theres nothing stopping you from using those T series BB hybrids as Garrett calls them but the TA/TB turbines are nothing like a GT28 or GT30 - bigger diametre and narrower , nossle shape in a GT turbine housing is wrong for them as well . Could use a TB31 turbine housing I suppose . Yep that T04E 50 trim compressor with the nice map . I've got one of those here Brett brough me back from Sema too many years ago and woud have had it in some crazy hybrid until I started working out what was what with Garretts GT BB range . A lot of research went into that from countless sources and that GT30 turbo/cartridge list I posted here ages ago was the result of much of it . I wanted people to know what was out there and how not to get fobbed off by turbo agents etc , how to get into the HKS spec gear and not get raped for it . Now to the GTX era . Currently nothing has changed turbine wise and I reckon that while there are some minor efficiency and not so minor capacity gains to be had the two major improvements have been port shrouded comp covers and that they are QUIET , more an OE gain than a petrol heads one . The answer Lith is to give us the turbine or one like it thats known to work and maybe even think about a GT35 sized one . People work out eventually that torque is more important than horsepower and as long as the torque ox revs reasonably freely its all good . Me ? No I don't think GT28 GTRS performance is sparkling . It is to a degree a step on the path to learning what I want at around town speeds and realising that you can have that along with larger turbo potential performance . I know for a fact you are all over EFR turbos and some of them can do truly amasing things . A couple of the latest ones and some due out soon give staggering performance for their size and are going to be a very hard act to beat . Do I think Garrett people sniff around these forums for feedback ? Do I think they keep an eye on those pointing out the gaps in their ranges . Am I bitching about these things in the hopes that others start noticing the gaps and demanding fixes or shopping elsewhere . You tell me . I think better turbines are in the pipe ATM but unfortunately these things take time . Really unless there is some OE app needing a responsive 4-500 Hp capable turbine it won't get much priority . A .

I can't fathom the reasoning in that graph . What I do know is that it takes X pounds per minute to support Y horsepower and boost pressure is how much extra it takes above atmospheric to drive it into the cylinders . I agree that GT28 turbines and housings are lacking on an RB25 but the issue is its hard to find an acceptable middle ground turbocharger . I was speaking to Scott today and he said he finds exactly the same thing . Good small turbos good bigish power turbos but SFA in the middle . I reckon what this illustrates the gap in the GT28 to GT30 turbine/housing area area and the band aid fixes aren't cutting it . Yes Lith we know GTX3071Rs work fine and the GT30 hot side is a good match for the 71X cold side . If a 0.82 T housing suits you along with the 55 lb/min cold side . Tough shit if you want a 50 lb/min cold side and the up to date compressor family . Currently the choices are 47 lb/min or 55lb/min and while its only a 8lb/min difference its right through the area that f**ks everyone up . This is why I think Garrett undershot and overshot at this point in the GTX line up and hence the "setting the bars right" question . And its only half the problem . There is still no answer to the turbine families void and the cropped GT30 turbine is one a half hearted compromise and two only usable (properly) in HKS turbine housings - namely the 0.68 AR GT Pro S one . I will be brave and say there is little you can do to increase the flow of a GT28 NS111 turbine with currently available bolt on Garrett turbine housings . There is SFA you can do to a 60mm 84T GT UHP turbine that doesn't choke exhaust flow up high engine rev wise . They can screw around all they like with the aluminium bits but in the end to fix the problem we need a better turbine solution . Lith you are probably thinking suck it up man there is no answer and thats correct - with Garretts currently available turbochargers . Have been shown another path that doesn't involve Honeywell anything so thats where my searching is going now . Andrew I'll be in touch soon to hear the fine details of yours vs the 71X car . A .

No its not a waste of time at all , its wanting the range of operation to suit a reasonably conservative ask . The sizes I think could be usefull are in betweens and larger than the smallest current GT30R GTX compressor . I very much doubt many here are going to use 3 1/2 bar of boost very often if ever . I also don't see a manufacturers race team lugging a GTX box from the local vendor and tossing on their race engine . More likely they would use something hand built like say a TR30R like the Audi and Rally teams used . To them 10Gs is so what . A .

I agree , its just what they mention in there Vol 5 Catalog http://www.turbobygarrett.com/turbobygarrett/productcatalog A .

GTX2860R 60.0 mm 58T 2.50 Bar - 40.0 lbs - 400 Hp . GTX2863R 63.4 mm 56T 2.50 Bar - 43.0 lbs - 430 Hp . GTX2867R 67.0 mm 55T 2.50 Bar - 47.0 lbs - 480 Hp . GTX3067R 67.0 mm 55T 2.50 Bar - 47.0 lbs - 500 Hp . GT2871R ..................48T 2.25 Bar - 39.0 lbs - 460 Hp . GT2871R ..................52T 2.25 Bar - 45.0 lbs - 475 Hp . GT3071R ..................56T 2.50 Bar - 49.0 lbs - 460 Hp . GTX3071R 71.4 mm 58T 2.50 Bar - 55.0 lbs - 560 hp . GT3076R ..................56T 2.50 Bar - 52.5 lbs - 525 Hp . GTX3076R 76.6 mm 58T 2.50 Bar - 62.0 lbs - 640 Hp . GT3582R ..................56T 2.50 Bar - 61.0 lbs - 675 Hp . GTX3582R 82.5mm 58T 2.50 Bar - 67.5 lbs - 750 Hp . Some of these numbers , from Garrett Vol 5 Catalog , don't always add up and in some cases they pushed the Hp up depending on hot side improvements . Note the GT3582Rs Hp looks high on the pounds flow number and in the catalog they show different maps depending on if the comp housing is port shrouded or not . I think 61 pounds for the std and 67 for the PS'd one . I threw in the GT2871Rs for comparison and you'd think 39 vs 45 pounds flow would net more than a 15 Hp difference . Maybe the 0.64 AR turbine housing is the Achilles heel of the GTRS and not the cold side . Cheers A .

Well thats one opinion but you can also look at the other end of the equation and explore where these things start to work as well as when they're going off the scale . The question I'm asking is did they get the maximums right to start with as where those numbers fit in with what the market wants - realistically speaking . Its obvious that they were aiming to have more out of each size in the GT range ie GT60mm through GT82mm which is where much of the market is anyway . We all know having excessive compressor capacity WILL add turbine lag because the things trying to churn more air than the user needs , someone here recently said that their GTX3076R is a bit disappointing as in that its lazy to get going . If it had been a 71 or maybe 73mm X wheel the story WOULD have been different to some degree . In the 60mm GT30R group compressors now range from 67mm to 82mm . 20G is basically the big trim version of the 16G 18G 20G group . From memory the 20G was native to some OE TD06 turbos and the reason they sometimes end up in TD05 "Hi Flows" is because its physically an easy change to make , basically swap wheels and remachine the compressor housing to suit . Laggy conversion on a TD05 turbine which is why the Evo crowd think they are dogs . A .

This is probably going to be a theoretical thread because none of us work in the development halls at Honeywell . A search I did came up with this thread that Mike Kojima did a while back . http://www.motoiq.com/magazine_articles/id/1802/pageid/2596/an-inside-look-at-the-new-garrett-gtx-turbochargers.aspx Note this is the last of a five page article but it mentions that Garrett have ways of adjusting things to get the compressor airflow results they want - or setting the bar for each at a given point if you like . It also mentions the type of milling process they use to control cost and speed up production . If you search this stuff you come across other machined wheel suppliers and they make a few sizes inbetween the ones Garrett does . For example Garrett do 60 63 67 71 76 82mm etc versions of their GTX wheels , they get larger but are beyond what most of us consider usable . FPs HTA range inclide a 68 71 73 76 82 and more so you can see a few inbetween sizes appearing . I will go back and correct the GTX sizes later because many are actually slightly larger than the advertised major wheel diametre . You have to give the turbo manufacturers credit for continuing development though much of this is being driven by more moden engines and the regulators emissions and consumption demands . Note Mike mentions that typical boost pressures have been rising and some like the Evo 10 use something like 21 pounds of boost out of the box . The aftermarket portion of Garrett is small fry compared to OE production and they obviously have peformance targets for their aftermarket turbochargers . And they have a market to chase and you'd think the volume sales would be largely in North America . I think its fair to say that there are some gaps in the currently available GTX wheel range and my gut feeling is that they could use something in the 68-69mm area and also the 73mm area . Its been seen here that the GTX3071R can push real good performance but people are doubting the GTX3076R and it may be a case of overkill for the GT30 UHP turbine . No ones done much with the GTX3067R yet and I have to wonder if it could have had a slightly larger 68 or 69mm wheel . With a few more sizes like say 69 and 73mm I think Garrett could safely cover most peoples needs of power vs "response" . Thoughts ? Cheers A .

I personally think you have to be looking for big power at the expense of usable power to even consider a GTX3076R . I think Garrett screwed up with the compressor housing in an attempt to make people think more turbo for the same external size as a GT3076R . Maybe they expected everyone to race out and replace their turbo with the GTX version and have it fit in the same space . Most people are getting the idea that the GT30 turbine and housing isn't enough to drive the "GTX76" wheel and while using the GT35 turbine helps stuffing that in a GT30 turbine housing doesn't . As a minimum Garrett should have used a GTX3576R as a GT3582R replacement and used the T04S comp housing like GT3582Rs do . Anyway , I don't think people have found the limits of this GTX3071R yet . Don't think anyones had one on a warmed up RB25 and Garrett hasn't released the next range of twin scroll turbine housings for them just yet . There is mention of these being Vband mount with a locating pin and it should help with mounting and making manifolds for them . One version is going to be T3 flanged and the word is that there will be I think three AR sizes . I'd really like to see as I said a GTX30R turbo with a little less compressor than the 71mm mainly because I think most people would be tickled with genuine 300 RWKW performance . I would forsake the extra 35+ Kw potential to have it spin up a few hundred engine revs earlier , AND if it could fit the compressor inside a T04B comp housing it would be easier to fit an RB engine than the T04E housing is ie GTX71 and 76 turbos . I dunno not , real hard for someone like Garrett . We know the GTX67mm compressor has 10 rather than 11 blades like the others and one site reckons this was to make the GTX67 turbos respond a bit faster . How hard would it be for them to carve out a 68 or 69mm GTX wheel or even a 10 bladed GTX71 wheel . Just a slightly bigger pump than a GTX3067R has and a smoothed up 0.63 AR IW housing would be a nice match on a street RB25 with E70/E85 . And be reasonably easy to fit and make look close to std . Got to concentrate on rails injectors and tuning ATM so time to think about some of this other stuff . A .

Scotty the 78mm GTX wheel has more like GT40 82mm (56T) capacity and quite a few peple are now saying that there is SFA lag difference between a GTX3576R and a GTX3067R . The thing the 78mmGTX wheel probably lacks is the T04S 0.70 AR compressor housing like 3582Rs have and the after marked uses the S housing on their GT30 76 hybrids too . Andy I was hoping someone had a second hand one in good nick . This was a PM back from NRR . "The GT30 0.63A/R turbine hsg flows like the GT28 0.86A/R. However the GTX3067R has a better wheel match compared to the GT2871R so the turbine efficiency is higher. So you should make more pwr at the same boost level and have very close to the same boost response. But if you are still concerned about boost response then try and max out the GT2871R. Good luck." Also link from VW Vortex Forum . http://forums.vwvortex.com/showthread.php?5965002-Performance-differences-between-Garretts-GTX2867R-and-GTX3067R A .

I finally reached the end of this thread and took three sessions to get here . As you know I've been looking beyond my GTRS and doing some reading on these GTX 28 and 30 based turbochargers . I first looked at the new "baby" or entry level GTX30R" which is the GT3067R . The 67mm GTX wheel is unique in thats its 10 bladed where most if not all other GTX compressor sizes have 11 blades . Now initially the 67X was a newer GT28 compressor option and in the same package outline as the GTX2860R and GTX2863R . Note they all use the same recently released Garrett 0.60 AR T04B port shrouded (surge slotted if you like) compressor housing . If you go to the turbobygarrett web site you can download their Volume 5 catalog and its interesting because there are comments about the GTX2863R and GTX2867R from I think drift people . I reckon these are aimed at 2ish litre four cylinders but they could be used on smaller capacity sixes if you had a suitable turbine housing . The "crossover" turbo is the GTX3067R because its literally a GTX2867R with a GT30 turbine and turbine housing . Someone at Garrett obviously thought that the GTX2867R could benefit from a larger turbine and housing combination and logically open a larger hot side flow path . There are probably other reasons like having a T3 flanged turbine housing and its possible that it suits an OE diesel app ie low reving engine needing a reasonable amout of air at high PRs with low exhaust restriction . I have not seen what happens when you bolt these to a 2-2.5L petrol engine and while the compressor sides capacity looks reasonable its hard to say how it would go with say a 0.63 AR GT30 housing to zip up the heavier (than T28 NS111) GT30 turbine . For us RB25 people it may work but its a bit of a dead end unless you only seek guesses 280-290Kw and its expensive being the Guinea Pig . That aside the next logical step is to look at the GTX3071R and thats what brought me to this thread , I have to say Micks result is very impressive and its a credit to him putting his money where his mouth is and having the balls to give it a go . Always good when results can be shown because it puts those that follow in the potential picture . Theres always a but and not to rain on his parade but the question has been asked can we haxe Millenium Falcon performance but starting a little earlier - can't please every bastard all of the time eh Mick ? Also thanks to Wolverine to giving real world comparisons with his GT3076R car vs the GTX3071R one . My goal is to have around 300 at the ground but with strong torque from boost starting reasonably early , I doubt I could use anything like 335 and to be truthfull I think even 300 is alot to put down through two 245 width tyres . Anyway I suspect that GTX71mm compressor is too much for me and I'd like to limit my 111K old R33 25 lump to 18 or maybe 20 pounds of boost at most . Into the theorising . The same old problem of GT30 turbines is still here and frankly the available GTX compressors can't fix it . In the right setup this turbine probably tops out at 550 engine Hp which is great if you want 500 but for less it has its compromises . The fixes in the past have been the cropped turbine (GT2835R) and the TR30Rs 60mm NS111 turbins which Garrett won't gives us . Twin scroll turbine housings achieve something but with one exception they need external wastegate/s . Garrett has a twin scroll twin integral gate GT30R turbine housing for the EVo 10s 4B11T engine but that has a unique Mitsubishi flange pattern . MIck these housings are made in 0.73 and 0.94 AR and its probably possible to have an exhaust manifold made to suit them . It locks you into two exhaust housings but at least I think they can be bored to suit the larger GT35 turbine if you need them ie RB30 implant . Turbos aside there is no reason for any RB25DET not to drive nicely if it has good electrics injectors and tuning . I don't think it matters if the turbo hanging off it is a GTRS or a GT4294R it should be nice driven sedately . The important thing with the dryer is when does it want to start pumping and its important to differentiate at this point how far open the throttle is when it does . My experience with the GTRS is that at 3000 revs (expressway) you don't have to moove the hoof very much for the manifold pressure to go positive and sail up any hill in 110k territory . Where rev wise I get full boost I haven't got a clue but then again where to I go at WOT ? My tuner said this turbo is too small and won't hold its 18 pounds and it drops to 15 up high . I really don't know where to go to get the perfect 300Kw just but comfortably turbocharger and the only ones I can think of are the GT2835 Pro S and the grey area GTX3067R . I spoke to some people OS at the VW Vortex site and the Nissanroadracing one and I'm still waiting for some feedback from a feller working for Honeywell over there . I would DEARLY love to get my hands on a 0.63 AR GT30IW turbine housing but I'm not paying the local mob $900 odd dollars for something that may not be usefull long term . If anyone has one of these housing for sale please let me know . I will link these sites I went to so you can see the compressor map overlays and note the one of the GTX67 wheel and the GT71mm one in 52T (GTRS) . they are actually reasonably similar in the pressure ratio (boost) ranges I'd use and this is why I'm a bit reluctant to go the GTX3067R , more hot side flow potential yes but if it didn't pump enough extra air then where has it got me ? Its possible that Garrett made the 67X wheel more to suit the GT28 turbine and my gut feeling is that the GT30 could use a little more compressor but not as much as as the 71X . The packaging issue also with the 71X and beyond is that they use the larger diameter port shrouded T04E comp housing which means spacers and obviously less stealth . For me it would be perfect if Garrett made a 68 or 69mm GTX compressor and used it in the B housing like the GTX2863/2867/3067 turbos use . Ideally it would have a little less lag potential than the 71X wheel and enough just enough capacity to comfortably get to around 300 at the bags . One last important one , note how at that Perrin GTX comparison article they show the torque/rev potential of these turbochargers and that the modest sized ones make more torque at lower revs . It isn't all about top end . Cheers A .