discopotato03

HKS say thay use a 0.50 ratio port shrouded cover though the one on their 2835 Pro S is a special so no AR marking shown . If anyone has one of these turbos kicking around could they look inside the compressor housing outlet and tell us if is has 50 or 60 marked just inside . Cheers A .

Compressor housing kits for Garrett GT3071R using Centre Housing Rotaring Assembly (CHRA or cartridge) number 700177-5023 . Includes Housing , adapter ring , O rings , clamps and bolts . 1) 756021-1 2" Outlet 2.75" Inlet . 0.50AR 2) 756021-2 2" Outlet 4.00" Inlet . 0.50AR 3) 756021-3 2" Outlet 4.00" Inlet . 0.60AR Port Shrouded . The good news is that the 4" inlet port shrouded version is 0.60AR ratio so you have a bit more leeway with exhaust housing AR sizes and less likely to suffer compressor surge . HKS uses port shrouded compressor housings on their RB specific GT2835 series which uses the same family of compressor and in fact the GT2835 Pro S almost certainly uses the same comp wheel . Again I'll have to have a look at theirs to see if the housing AR ratio is 0.50 or 0.60 . And thinking about it that comp cover would be the one to reprofile if anyone wanted to build up a GT3076R using the smaller 52 trim 76.2mm GT compressor . Cheers A .

Dale FZ1 that Turbomaster cattledog has a misprint , 76.2mm by 57mm is very close to 56 trim . Had the number been 76.2mm by 55mm it would be 52 trim . If you have another look at the GT3776 it should show the compressor dimensions and trim number . If not do a search on their GT3571 because I think there was also a GT37 compressor option of 52 trim . I know the GT3576 is 52 trim but not easy to find data on . You should probably look at the GT3076R's map and compare that with the 54AR GT3776 , the housing AR is part of the reason for this . Fingers crossed the .65AR housing would make the 76.2mm 52 trim GT37's map look a bit more like the GT4082's map , wider or fatter across the lower pressure ratio region . I have a pic of that .65AR cover and notice it uses a different clamping method than the TO4B/E/S type housings . Mafia that turbo you are looking into is a GT3071R not a GT3076R , the only available (off the shelf) compressor trim option is 56 . There are three optional compressor housing kits (housing/adapter ring/seal/circlip) and I'm sure one is port shrouded so must be 4" (100mm) snout . Have to dig through my lists to find its part no and AR ratio number . Busky2K , posted last night but lost to WiFi . Yes the 48/52/56 trim TO4S wheels are around 76mm , actually my Garrett 52 and 56T maps say 76.1mm . The HKS GT2540 was a little unusual in that it used a 76.something mm TO4E compressor in 46 trim . Not positive but I expect the 76.2mm BCI-18C (GT37) wheels were not available at that time and HKS could not stoop low enough to use the 48 trim TO4S compressor like Garrett did in their GT2540R . Neither are very good the HKS version just a bit less useless , their GT2871R 52T (GT-RS) not perfect but much better than the other two . What Arnie said , cheers A .

Dale I think you'll find that the 700177-5007 is the 56 compressor trim GT3076R/GT3037 cartridge , I believe the -5006 variant is the GT3037 52 trim cartridge . That comp housing may not be a bolt up either as the GT37 bush/plate bearing may have different back spacing on its compressor wheel . May need a one off machined adapter/backplate to get it all right . Also I would think the .54 AR comp cover ratio is less than ideal , HKS used a .60AR port shrouded cover on their GT3037 52T . As I mentioned looking at a .65 version soon , just have to con the masters into tilting the cab on the said truck so I can get at the *&^% ! Lithium that doesn't lok like a GT30 turbine housing , more like a Ford style Garrett T3 housing . Sorry to be negative but the ext gate would have been better on the manifold as the 90 deg turn into the housings outlet hole upsets the flow in the tapering section of the turbine housing . Cheers A .

Firstly Lithium the TO4S compressors are not real flash things in fact I'd avoid at all cost even if it means importing a real GT3076R from Aus or the US . Those wheels are 76mm where the real GT37 series are ~ 76.2mm , I know this is spliting hairs but its an unfortunate legacy of Garretts vague numbering system . You can import the right ones , just because the turbo people don't bring them in doesn't mean you cant . Exhaust manifold pressure or turbine inlet pressure is an evil and should be delt with accordingly : Quote Corky Bell . The idea is to recover as much velocity energy from the hot expanding exhaust gas as possible while posing the LEAST possible restriction to its flow . The aim is to have lowest exhaust manifold pressure because when both inlet and exhaust valves are open in the cam/valve overlap phase if exhaust manifold pressure is higher than inlet manifold pressure it backflows into the chambers diluting the clean incomming charge air and pre heats it as well . Bad , very bad . The idea of the valve overlap period is for the cool incoming air to blow through the chamber area and purge the residual spent gasses past the exhaust valves into the exhaust manifold . The correct term is scavanging . The waste gates function is merely to bypass exhaust gas away from the turbine when the compressor is spinning fast enough to achieve the desired boost . As the engines speed (rpm) increases its air demands rise so the compressor must turn faster to maintain the regulated pressure head across the inlet manifold . The downside of this is that the waste gate is regulating compressor outlet pressure not turbine inlet pressure which can get out of hand if not watched . This is why having a good balance of turbine to compressor (and their housings) is so important . If you look at big Diesel turbos you'l note that many don't have a waste gate and are said to be "free floating" . The turbine and housing are sized so big that the turbo never overboosts because there is insufficient gas velocity to go beyond a set boost pressure . This is all about minimum turbine inlet pressure . Granted those engines work over a narrow range with low peak revs . Some later designs are using smaller turbine sides and waste gates in an effort to have lower rpm boost response like OEM petrol engines do but it is a compromise . Overall power is usually more important than peak power because usually so little time is spent up there . Most efficient use of exhaust energy to efficiently generate just enough airflow is what tends to work best . Mafia the 700177-5023/-0023 is a GT3071R meaning 71mm or GT35 series compressor . They usually have a .50 AR ratio TO4E comp cover , yours is .70AR TO4S so won't fit . .86 is a GT28 turbine housing so you would need a .63 or .82 GT30 series turbine housing for the real GT3071R . Basically nothing off you turbo except oil/water plumbing will fit it . Even the oil drain pipe would need to be slightly modified depending on how far the turbo moves in relation to where it is now . R33 Racer from my maps the comp/housing combination gives ~ 53Lbs flow at 2.5+ pressure ratio (1.5 bar or 22 pounds positive pressure) on the bleeding edge . If you can run it to its limit (130 000 + revs and 60%efficiency) may be good for ~ 580 Hp worth of hot air and maybe near the wheels mechanical speed limit . I'm not certain but I think the turbo people have mentioned as being the 600Hp GT30R may be the GT3040R . I'm also researching ATM a comp cover from a truck turbo (I think a GT3576 on an Isuzu) because it has a .65AR port shrouded comp cover though not sure about for which wheel trim 52 or 56 . It may just get a little more from a hard worked GT3076R compressor side . Garrett rate the thing at 500Hp though they don't mention turbine housing AR . To give some idea the turbine map shows maximum turbine flow with the .63 turbine housing of ~ 20.5 lbs flow at 2.5 PR or 1.5 bar (22psi) . The .82 housing ~ 23.5 lbs flow at 2.1 PR or 1.1 bar (16.2psi) . The 1.06 housing shows ~26.5 lbs flow at ~ 1.85 PR or 0.85 bar (12.5 psi) . 1) 0.63AR Max flow 20.5 lbs at 22.0 psi . 2) 0.82AR Max flow 23.5 lbs at 16.2 psi . 3) 0.06AR Max flow 26.5 lbs at 12.5 psi . This shows very clearly how maximum exhaust flow in corrected pounds mass or weight goes up as pressure or resistance to flow in psi drops . Its interesting how the flow has risen approx 20% while the resistance to flow has fallen almost 50% . Never done this before thanks guys , cheers Adrian .

Personally I'd rather keep the static CR up around 9:1 because mega boost pressure is not everything . IMO thicker head gaskets are a poor way to decrease CR particularly if the engine is being built up and you have some say in piston type . Lifting the head higher off the piston crown will increase the chamber volume but its not ideal around the quench or squish zones so may not be any more detonation resistant . The higher 9:1 with the 100 oct Shell pump fuel should work out well enough . Having low CR and high boost would be ok if the engine lived in a boosted environment all the time but they dont , and they do feel like a soggy breathless boat anchor off boost because of the low dynamic compression pressure . High boost pressure does not always guarantee high airflow , far better to remove where possible the resistance to flow to get a greater weight or mass of air into the chambers . Doing this with less boost also means lower fuel pressure requirement/less energy to recover from exhaust gass (meaning less resistance to flow through turbine/housing) / ignition timing optimised around burning efficiency rather than detonation supression . My 2 cents spent for today , cheers A .

I would stay right away from that thing if I were you , wrong turbine housing for a start (T28 flanged GT28 housing) and the 9 turbine blades usually means a 54mm GT28 turbine . Its hard to tell which compressor it uses but the comp housing looks like TO4S .70AR and too big and bulky . Too many people buy dog turbos like that and the financial burden of replacing it with a good one is often too much . You are far better off doing some research and spending your money on something more appropriate . If the guys feel this topic is a string of repeats PM me because its only a bit of time on the keyboard , but you'd hate yourself if you went and bought a "Victim Turbo" on mates advise . Plenty of clued up victims try to sell on the sows ear and make the loss someone elses problem . For your own sake DON'T get sucked in by that thing ! Cheers Adrian .

Lots of things affect where a turbo comes on boost . Examples are good vs average exhaust manifolds , tuning namely ignition timing , dump pipes , exhausts , static compression ratio , cam timing and lift , head work yada yada . Its too simplistic to expect just the turbocharger specification to have all the say . All else being equal (except optimal timing and AFR's) you can expect a GT3076R to be more responsive than a GT3582R because its gas passages are smaller and its wheels have less pumping capacity on one side and more trapping capacity on the other . Also you cant really look at a GT3082R as a scaled up GT3076R because the ratio of turbine to compressor is slightly better on the larger turbo compared to the smaller one . I believe this is why the smaller trim compressor wheels work so well on the GT3076R/GT3037 . No one I know has tried the smaller wheel trims on a GT3582R so still a final fronteer . I reckon a custom backplate/adapter ring to mount the plain bearing GT4082's 82mm 50T compressor wheel and .58AR port shrouded comp cover would help make the torque mountain but probably better suited to an RB30 . The increased difuser diametre over the TO4S cover/backplate I think makes for wider islands at low pressure ratios so more inlet flow for less boost provided the engine can take advantage of it . Using an unmolested Garrett comp cover means factory clearence on the compressor blades and a ported shroud that is proven to work - many machined in by turbo vendors do jack shite . Cheers A .

The real GT3067R's CHRA or cartridge number is 700177-0007 or -5007 . The cartridge number does not change with the integral wastegate version . Garrett could possibly change the turbocharger assemby or unit number if they sell this turbo in IW form . They normally sell this turbo without a turbine housing and the buyer gets to choose which one they want . Also no I have not seen a GT3076R surge on an RB25 though the port shrouded compressor cover tends to widen the map islands in the upper LHS - sort of takes out that semi circular dip so to speak . I've been spending some time sniffing out GT3037 specs and HKS seem to rate the three comp trims ie 48/52/56 as being good for 420/440/470 PS though it would also depend on the turbine housing AR ratio . Garrett I think is rating their 56 trim comp version (GT3076R) at ~ 500-530 Hp . People are getting into the 270-300Kw region with the GT3076R even though its 56T compressor/housing pair is good for ~ 50-55lbs flow in the 15-22 pounds boost area . So the compressor is easily capable conservatively speaking 500-550 Hp worth of air . To do 400Hp (300Kw) means 40lbs of air is needed and with 10% leeway 44Lbs . The 52 trim compressor fits in about here and would allow you to make the power but with a tad more shaft/wheel speed which is not a bad thing because turbine inlet pressure drops . The downside is that 48 and 52T compressor versions are only sold by HKS (ouch) but compressor wheels are available (from Garrett GT bush bearing turbos GT3576/GT3776) being 76.2mm 52T , 55mm inducer , 5.45mm tip height and 7.40 mm threaded bore style centre . It would not be the end of the word to do the machine work to make it fit a GT30 based cartridge designed for a GT30/TO4S (76mm) or GT3076R (76.2mm) compressor . That compressor wheels part number is 434441-0003 . Just because - details of the 82mm GT40 compressors from bush bearing GT turbos that use them . 48T 82mm 56.75 inducer 5.50 tip height 7.4 threaded bore Wheel Part No 448856-0019 . 50T 82mm 58.00 inducer 5.75 tip height 7.4 threaded bore Wheel Part No 448856-0016 . 52T 82mm 59.15 inducer 6.00 tip height 7.4 threaded bore Wheel Part No 448856-0009 . 54T 82mm 60.25 inducer 6.00 tip height 7.4 threaded bore Wheel Part No 448856-0013 . Am trying to get a damaged/dead GT3582R cartridge to gut and measure up for alternative compressor wheel trims . The housing would be one from a TO4S and reprofiled for the GT40 wheel . I hate unnecessary lag almost as much as I hate exhaust manifold pressure thats higher than boost air pressure . If I wanted a GT30 based turbo for an RB25 this is what I'd use , a bit more effort and money than an off the shelf GT3076R but better transients and no doubt fuel consumption more than make up for it . Late Edit - I've seen mention of HKS selling a 48T GT3037 for the Subaru WRX EJ20 and this is possibly because the flat boxer four with long manifold runners and arguably weird pulsing from opposing heads makes them a little laggy at lowish revs . Out of fingers cheers A .

I owe , I owe - more grave yard shift . Back in the morning but a taste - you CAN get GT30 turbine based turbos to spin up on an RB25det under 3500 but you have to have the right compressor options and good manifolds and tuning . Nite all .

Hi all , Mafia two of those turbine maps you have there are not from what I call the REAL GT3071R turbocharger . You will note that those maps show turbine housing AR or area to radius ratio as .64 and .86 , those are the bored out or re profiled T28 flanged GT28 turbine housings not the propper GT30 turbine housings . Just on this compare the maximum efficiency of those two compared to the one on the second row which is the GT3076R turbine map - huge difference real world . So basically these (pic 1 and 3) are the dreaded GT3071R - "WG" turbos that I try to steer people away from . These have the same cropped or ground down turbine as you have in your turbo . Where there seems to be some confusion going on is comparing similar turbine housing AR ratios but with different families of turbine housings . 1) GT28 Turbine housings - designed for approx 54mm major diametre turbines . 2) GT30 Turbine housings - designed for approx 60mm major diametre turbines . I you held a GT28 and a GT30 turbine housing of the same AR ratio the GT30 would be larger and bulkier because the area and radius are larger/greater even though the ratio is similar/same . As a rule of thumb housings with .64 or .86 on them won't be GT30 housings , Garrett got away with calling the GT3071R - "WG" a GT30 based turbo because the turbine (although modified) started out as the normal GT30 turbine . Its name has nothing to do with the butchered GT28 turbine housing they come fitted with . Also to clue people up on the compressor housings . Virtually all GT37 76mm compressors (like in the GT3076R and all GT3037's) come from Garrett with TO4E family compressor covers and usually in .60 AR though occasionally on GT3037's in .50 AR and non port shrouded . The TO4S compressor cover is generally found on turbos with either those nasty TO4S compressor wheels or the 82mm GT40 compressors ie Mafias turbo (TO4S comp) or the GT3082R or GT3582R or HKS's GT3240R which use a variety of trims of the 82mm GT40 compressor family . I don't know if anything with a 76mm GT37 compressor uses a TO4S comp cover . Back to the real GT3071R and GT3076R . The first one is more responsive purely because its compressor is a 71mm 56 trim vs the seconds 76mm 56 trim . It takes more turbine power to drive the 76mm wheel than the 71mm so for the same turbine power it kicks the 71mm into life sooner and accelerates it up to positive pressure type revs more easily . The maps show you that the 71mm wheel is good for around 440 Hp worth of air and the 76mm about 520 . IMO its better to have a little excess turbine flow than compressor flow because you can tune it to a degree with various AR ratio turbine housings . If the compressor is too big you lose response and generally cant use its capacity very efficiently so you lose the lower mid range for no good reason . Now that Garrett has the new GT30 integral wastegate T3 flanged housings there is no excuse to buy the GT3071R "WG" turbos which having the T28 flange won't bolt up anyway . Also as I mentioned to Mafia its not a very good idea to use the .63 GT30 housings on Garretts GT3076R mainly because it has the big or 56 trim compressor wheel . Its this big comp trim that makes these turbos a bit laggy (ask SK) and using small or .63 turbine housings makes for higher backpressure and increases the chance of compressor surge . Garrett did manufacture this turbo in 48 and 52 compressor trim but only High Kost Spec (HKS) market them . The 52 trim version is rated at similar power to the GT3071R , no one seems to know much about the 48 trim version . I'm making some enquiries through Jim Wolf Technology in the US who seems to discount thius kind of thing so people can get an idea what the damage is like . Last I hear a couple of yrs ago was ~ 1600 USD . The fellow in this thread could tell you what his real GT3071R cost and its probably a more reasonable figure . For those that don't know the real GT3071R's cartridge (CHRA) number is 700177-0023 or -5023 , Garrett don't sell it as a complete turbo . You buy the cartridge and add one on the three available AR GT30 turbine housings (.63/.82/1.06) then one of the three available compressor housing kits . These are TO4E and there is one available with a port shrouded snout . Firms such as ATP Turbo in the US market them as a complete assembly with you choise of housings . So for an RB25 my guess is the .82 housing but for an RB20 the .63 . These combinations would get you similar results to HKS's GT2835 Pro S turbo but with a little more turbine and a little lower turbine housing AR ratio ie .63 and .82 vs .68 and .87 . Fingers falling off cheers Adrian .

The Garrett GT28RS (GT2860RS) is the disco potato turbo , HKS's GT-RS is a GT2871R 52T in their housings . Cheers A .

To a large degree the jump from a 60mm to a 71mm compressor is going to affect the boost threshold because you have essentially the same sized turbine and housing with the same exhaust gas velocity trying to spin them up . Lots of people ask me what is the next step up from the bigger trim 60mm compressors ie 2530's 63T or the high tip height 60mm 62 trim from the GT28RS/2860RS . So next up in Garretts GT range is the 71mm wheels (GT 35 comp series) which my list shows three sizes . 1) 71mm 48T , 49.25 inducer diameter , 4.75 mm tip height . 2) 71mm 52T , 51.20 inducer diametre , 5.00 mm tip height . 3) 71mm 56T , 53.10 inducer diametre , 5.00 mm tip height . The larger trim and exducer tip height wheels have greater pumping capacity but it comes at a price , moving more air for the same wheel rpm means they need extra power to drive them . If the extra shaft power is not available then we need more engine revs giving more exhaust gas velocity to power the turbine/s . Basically the big trim/tip height wheels with the same turbine force a slip loss effect of the exhaust gasses round the turbine blades . Its a lose lose lose situation because boost threshold goes up , exhaust restriction goes up , detonation threshold comes down - backpressure if you like forces exhaust gas reversal back into the chambers in the overlap phase so charge dilution and preheating as well as pumping losses . All biggies . Note in (1) above that the 48 trim 71mm wheel has obviously a smaller inducer diametre size AND lower exducer tip height . This is the next incremental step up from the 60mm GT compressors and will generate a bit more airflow (maybe 3-4 lbs) but have the least negative side affects of the three 71mm compressors . I don't think I'd go past this stage if at all on a standard capacity RB26 because its already starting to turn laggy and getting a bit hot and restrictive on the turbine side if really pushed . Probably more to be had from porting and cams with less trade off . 2860's and 2530's seem to be the sweet spot and after that really need larger turbines to compliment the larger compressors . This then really pushes the boost threshold up and increased capacity is the only way to help bring it back down . Cheers A .

By Quaife do you mean a Torson gear/worm type mechanical LSD ? Very interested to see details if thats the case . Cheers A .

Series 2 R34GTR 322 x 22 - interesting . So did Nissan use different rear calipers or change the rear uprights to move the caliper out ? Thanks Adrian .

If your going to transplant any RB I would start with an RB25DET , they make a lot more torque than an RB20DET and are dimensionally almost the same . If you want to build hybrid RB30DET's thats fine but to do it properly is expensive mainly because the compression ratio is a bit low at ~ 8.3 to 1 . Also there are limits to how much you can get out of NA RB30E pistons . I'd forget about the RB20DET in a car as heavy as an R31 . Unfortunately you will also come up against handling limitations with strut front and unequal length trailing arm/panhard rod controlled live axle rear suspension . Without major mods you cannot stop the rear steer effect and even if you get around that the unsprung mass makes axle tramp an issue - thats without very expensive competition grade dampers . Power beyond handling limitations and traction is a waste - a hard and expensive lesson to learn . Thinking about it I would try to enhance the RB30E with the GTS cam/computer/Nismo extractors and have a bash at driving the thing rather that doing major feats of re engineering . You may get to have a lot of fun without spending all your money and time working on it . Cheers A .

If you look at your second picture you can see the restrictor in the oil inlet hole . Its the hollow mushroom shaped gadget that needs an inverted flare fitting . All these GT25 BB centre sections have them , actually its the stem of the restrictor that does fore and aft location of the bearing pack itself . If its not there the turbine and compressor try to shunt backwards and forwards depending on which side has the greatest thrust load at the time driving its opposite wheel into its housing - not good . I guess two restrictors can't hurt but I'd rather have the one only in the turbo because it has unrestricted flow to within a couple of cm of the bearings . Cheers A .

Hi all , searched for ages for side by side pics of standard R33 and R34 ceramic turbos because I've seen them here before . Getting conflicting information on the size of the compressor cover , I know the exhaust housing is larger like the VG30 BB turbos is but the comp cover ? There is a small posibility that there were changes across the R34GTt production run as well . SK I think even once had a pic of an R34GTt turbo with a Garrett comp cover on it to suit GTt plumbing ? Any help and pics appreciated , cheers Adrian .

Yes the GT3037 56T and Garretts GT3076R use the same cartridge/wheels so compressor must be 56 trim . Turbo number should be 700382-12 and CHRA no 700177-0007 or -5007 . In the first pic the tag was badly stamped "30037" - should read 3037 . The second pics says 700382-11 because of different housing options used by HKS . Cheers A .

Hmm , I don't think Garrett or HKS made any .9x exhaust housings for the GT30 BB cartridge . Do you have any pics of it ? Cheers A .

Can you tell us which exhaust housing your GT3037R has please , sounds like a HKS version and I'm curious to know the exhaust housings AR ratio and mount flange style ie T25 or T3 . Also the 3037 was available in three compressor trims of which the 56T is common and the 52T not so common . The 48T version must be rare as . The highest spec version will be the 56T and HKS's exhaust housings went up to 1.12AR ratio . As I said recently I'm not sure if they still sell non gated exhaust housings in T3 flange but the T28 flanged ones are still available . If your not using the larger/est housings available you won't get the most from a GT3037 . Some of the response problem with the GT3582R is the extra innertia to overcome from the larger diametre turbine but its needed to drive the larger diametre compressor . The only other available non hybridised off the shelf turbo from Garrett is the HKS specific GT3240 , this is a modified GT3582R , its had its turbine cropped and its compressor trim is 82mm GT40 in 54 trim vs the GT3582R's 56 trim . I've only ever seen them with a .87AR T25 flanged HKS exhaust housing , these will be an expensive option but is money is no object .... Cheers A .

Agreed .

And finally the GT2860RS that worked so well on my FJ20ET .

And the RB20 turbo that replaced it .

In the days of green potatoes we had this frankeinstein built , HT18S turbine in T3 wet core with TO4B -24 compressor in an RB25 comp housing . Don't copy this one because its a surging unit with very average performance . Both the RB25 comp and turbine housings had the number 2 inside them , in the inlet on the turbine housing and the outlet of the comp housing .