discopotato03

A GT2835 Pro S is also available as bolt on kit but ups the anti to a much better turbine/turbine housing/dump pipe than any bolt on GT28XX system uses . This is where the price hike comes in mainly because their turbine housing outlet is totally unique for a GT30 turbo and needs a unique style of dump pipe . Their system is as good as it gets for a single scroll GT30 IW turbo IMO . You could possibly do a little bit of smoothing at the dump pipes turbo end flange but its a long way ahead of Garretts GT30/35 OEM Ford based IW housings in std form . I think if people intended to upgrade computer/fueling/intercooling/exhaust systems this would be an appropriate bolt on model specific turbo kit . If all combined properly you could have lots of fun with this one one a daily basis and not have to use high revs all the time . A GT3037 is getting a bit more serious on an RB25 and its getting into the grey area of losing that nice lower end torque . They use a larger family of compressor than the 2835 and the turbine is the full sized 60 x 55mm GT30 in 84 trim . This is what it takes to pump 300+ Kw's worth of air into an RB25 so if thats the ask this one can do it . If turbine lag concern's you then there are limited ways to tone it down a little but that begins to defeat the purpose of having a turbo of this ones capacity . I haven't had any feedback on how a GT3037 Pro S in 0.68 A/R performs so I don't know how comparable it would be to a Garrett marketed GT3076R IW in 0.63 A/R . So thats about the size of it , small/med/large . Small being the mild inexpensive (for HKS) upgrade . Medium I think the best broad ranging user friendly (and more expensive) option . Large - for those that are prepared to compromise the user friendly every day performance for more mid range to top end . Its not one I'd use for a mostly suburban car - in Sydney anyway . Cheers .

Hi Cubes , I don't think you'll see a GT3076R/GT3037 with a 0.70 A/R compressor cover and its hard to imagine one needing it . Just to keep things on track the 76.2mm GT 37 series compressors used in the above mentioned turbos have T04"E" series comp covers , the 7/14 blade T04S and GT40 compressors (ie GT3582R) use T04"S" series comp covers . There is such a thing as a 0.70 A/R T04E comp cover but its an ugly thing with the same sized inlet/outlet as a 0.70 A/R T04S comp cover . If you dig through T04E compressor wheel specs there are 76/76.2 and 82mm OD versions and I think the 82mm ones used the larger 0.70 A/R covers at times . Cheers A

Hi Cubes , I'm curious to know why the Jaycar simple voltage switch has issues . I guess the question is do you set it to switch from an rpm or an airflow meter signal . I'm thinking if its workable from the MAF's load output voltage you could make it work a bit more intelligently than the std computers engine speed signal - if thats how the std system works . Cheers A .

I think its very easy to run around in ever decreasing circles trying to nut this one out . I can throw my opinion in but the question you should be asking yourselves is "what do I want this car to do " . HKS basically caters for three distinct levels of power - actually I should really say three states of tune . For the : I'm impatient and I want spin the wheels everywhere so need boost from cranking revs - GT-RS . For the : I want to be able to drive this thing normally , have more squirt and overall usable power - GT2835 OPro S . For the : I want lotsa grunt and don't care if it comes on hard at 3500 + - GT3076R/GT3037 Pro S . I know everyones gonna say BS my 3076R/3037 makes pressure under 3000 revs (RB25) but a lot of people say I don't want to "idle" it around everywhere at 3000 rpm just to get a push in the back when I want it . Honestly I can only recall once hearing anyone say that a 3076/3037 came on too soon and that one had the tidliest exhaust housing HKS do (0.61 A/R) so its not surprising . The HKS housing everyone loves on 4 cylinders (for a 3037) is their 0.73 A/R one but I don't think they ever made them in T3 flange . Bad planning really . What pay and what you get : A GT-RS is designed to be a basic bolt on easy upgrade for a bit more squirt without the Japanese telephone number mechanics bill . It fits the std manifold/dump and just needs plumbing basics . Gotta run more later , cheers A .

Someone here PM'd me just the other day saying they really like their HKS GT2835 Pro S 0.68 A/R on an RB25DET . The full kit may look expensive but they give you everything to make the turbo fit like all lines a dump pipe etc . The call was that its very similar to the std pea shooter turbo right down low but comes on reasonably quickly - like a road car turbo should . This person thought through someone else experience that the 0.87 A/R exhaust housing option cost that nice low-medium range squirt and for the small amount of top end it wasn't worth it on an RB25 . The guts of it is that the 2835 Pro uses a slightly larger trim version of the same compressor family as the GT-RS uses . Turbine wise its a little larger and a different family to the GT-RS's one . Exhaust housing wise the Pro S one is a MUCH better design and with the 2835's turbine will make more power for stuff all difference spool wise . Like with any change to a turbo engines breathing abilities you HAVE to tune it properly to take full advantage of the upgrade . This kind of thing is a bit beyond what the std computer wants to deal with and dito for the std SMIC . Sounds like a real nice can live with it everyday road car option to me . Cheers A .

Too small IMO , a HKS 2510 is just a 2530 with with the more spool friendly - and restrictive - GT25/28 turbine . Aside from a few more recent HKS options ie GT-RS much of the HKS Garrett GT turbo range have been around a while . One of the best all round in its turbine size range is the 2530 IMO . Your call but with what you've done to your RB20 to make it breathe the last thing it needs is a restrictive turbine to choke it up . My vote goes to an RB specific 2530 . Cheers A .

Nup , T04Z's are not my thing . Too much T4 dinosaur technology in them . GT4088R's kill those if they're set up propely , exy but they do the trick . Boy has HKS got y'all in with the drilled port shrouded comp covers ! BTW this does nothing for you if the compressor doesn't actually surge , it can be a step backwards .

It would be interesting to know why CRD had the water crossover pipe and the rads water inlet on the nearside insted of the std offside . Must have been to get around something on the offside behind the radiator ? Cheers A .

Thanks Cubes , the viewers at home will be able to plainly see the difference in the size and location of the turbine outlet hole . Just in case last night was a big one look at how close the outlet hole in in relation to the sealing groove on the 3037 Pro S (right hand pic) . It really drives home the difference in exducer size between the cropped and standard GT30 turbines . I really would have liked a good second hand 3037 Pro s housing in the smaller 0.68 A/R size but can't locate one for reasonable money , and thats why I'm looking at 2835 Pro S housings and the cropped GT30 cartridges in smaller than 56 compressor trims . At least the 2835 IW housings are availabe 2nd hand from time to time . As a heads up Geoff Raicer (Full Race in the US) sent me a message yesterday about a twin scroll GT3071R (-23 version) he supplied to a "drift professional" along with his manifold and gates for an RB25 powered R33 . The customer had been using a GT3582R on some form of HKS manifold but was really wrapt with the spool response and torque of the new components . Geoffs been asking for dyno graphs but has none yet . Anyhow great news but no use to those not wanting to spend lots or use external wastegates . Cheers A .

Hi all , was going to tack this onto the real GT3071R results thread but sort of OT - sort of . I mentioned recently that I'd like to look into these cropped turbine GT2835/GT3071R turbos but in a slightly different variation to those sold by Garrett or HKS . Basically the gap between the GT25/28XX BB turbos and the GT30XX ones is a significant one and it tends to force people to accept limited top end or a trifle limp low end . I think HKS tried to bridge the gap between GT25 and GT30 with their "GT2835" series which as we know uses a GT30 turbine cropped (clipped in US speak) to an in between diametre ie 56.6mm vs 53.85 and 59.9mm . They screwed it up with their version of this turbo using GT25/GT28 turbine housings because the over boring of these housings stuffs the nozzle section inside them . HKS also does T25/T28 (same) flanged GT30 housings profile machined for these cropped GT30 turbines and they seem to work because internally the housing is designed for the GT30 turbine family . The best news is that they also make the GT Pro (Pro S) turbine housing in T3 flange and IW to suit RB20/25 DET exhaust manifolds . The general feeling is that these GT2835 Pro S turbos are good for ~ 280+ Kw probably in the larger of the two available A/R sizes - 0.87 A/R , the smaller one is 0.68 A/R . I've said in the past that I think HKS went a little big on the comp trim size at 56 but thats the only way they sell the 2835 ProS . In other applications they did make the 2835 with both 52 and 48 trim compressor options so the cartridges do exist . I think if I could find or get one made and locate a HKS 2835 Pro S IW turbine housing it could form the basis of a fairly responsive turbo that would bolt up easily to an R33 GTST . I don't think it would make mega high horsepower but for some its the overall result thats more important than a maximum figure . I'd probably also think about using a T04B comp housing for the 52T compressor or even the std RB25 one with the 48T wheel because both are more compact than the T04E cover HKS and Garrett use with the 56T wheel . If a few people with 2835 Pro S's in both 0.68 and 0.87 A/R could let me know how these turbos respond on internally std R33 RB25's I'd appreciate it . If there are any characteristics that people don't like about these turbos that would be good to know too . Cheers A .

Exhaust gas recirculation is a cheap nasty way of reducing combustion temperatures that are high enough to create NOx emissions . In certain circumstances it can also help prevent detonation but its probably the worst way to go about it . 80's era EFI systems sometimes resorted to these methods possibly because ULP and Cat converters were not as good as they are today . Also the sophistication of engine management systems with true wide band 02 probes and nock sensors means they have much tighter control over what happens in the combustion chambers . I also suspect some of the late truly variable VCT systems are programmed to do their own internal EGR thing . Cheers A .

Those garrett GT30 and GT35 IW turbine housings are made here in Australia so we know where they're getting them from . Many of them are playing with reprofiled Ford Garrett "T3" IW turbine housings because they available and cheaper - result is cheap and nasty . Up to you but talk to those using the propper housing in original form making high power , the problem you have may not be the IW and if its not then it won't solve much . Also larger flat valves have greater face are for exhaust pressure to work on so don't be surprised if you need a slightly higher rated actuator to maintain your desired boost pressure . Turbine inlet pressure is a PITA but can be beaten if approached properly . Cheers A .

Sir racer as far as I'm concerned the inlet manifold is part of the engine so if you can avoid it then so much the better . Really anything that transfers heat to the coolant (ie turbos/water oil heat exchangers etc) really needs to have as direct a path as possible to the radiators top tank because you want to transfer the heat input to the radiator not the engine or its externals . I think the reason Nissan went the way they did was to simplify the overall package and makes life easier on the production line . Also they know what the thermal output of their engines is and cater to that plus a margin for reliability . Honestly the best system I know of is the one I described before . Find water at the lowest point in the block you can get and and plumb water through the turbo and on to the engines water return to the radiators top tank . That pic from RIPS clearly shows his turbo coolant return to the engines water outlet though if you wanted to make work for yourself a tube bewteen cuts/shut in the top hose and a barb for the inlet wold work as well . Actually if you were having an aluminium radiator fabbed you could spec a barb fitting in the back of the top tank on the near side to avoid running the water tube across the front of the cylinder head . Just thinking about high mounted turbos for a sec , if they are above the highest point in the engines cooling system then its going to require an even higher mounted water header tank to work reliably at all . Cheers A .

Hi all , I'm trying to find the turbo cartridge numbers for these turbos which is hard because not to many seem to use them . I was wondering if anyone has them and can check the ID tag for the numbers . I want to look into using one of these in a 0.68 A/R GT Pro S IW turbine housing for my R33 . Cheers A .

Not for me to say what you should do but some interesting facts . Firstly , I doubt very much they use the actual motorsport compressor used in the RS500's turbo and it was just a tarted up Garrett compressor modded to make it hang together at high revs for extended periods . It would not be a responsive thing in a road car . Secondly , the RS500's turbo is a dog . The only thing thats any good (and only if you use a TA34 style turbine) is the turbine housing because of its redesigned integral wastegate and vent path . Your calls but I'd be trying to find the HKS T3 flanged IW GT28 turbine housing , they were fitted to 2530's , 2540's and the RB specific GT-RS . Once you have that any of the better GT25/28 BB cartridges will bolt on . Cheers A .

Cubes and Mafia both have IW GT3076R's , Mafia up north and Cubes down south - or was that South Aus ? Anyhow depending on where you are you could ask them where they got theirs . All you have to do is insist on the 700177-5007 (sometimes marked as -7) cartridge (CHRA or centre housing rotating assembly) . The real Garrett IW GT30 turbine housings only come in three sizes so 0.63 or 0.82 or 1.06 A/R ratio (area to radius ratio) . If you are really unsure or untrusting get them to send you a pic of the turbos ID tag and exhaust housing . Just looking up the GT3582R with 0.82 A/R non gated turbine housing . From Garretts online catalog that turbo is 714568-2 . For the 0.63 A/R turbine housing version 714568-3 and the 1.06 version 714568-1 . They all use the same 706451-5 cartridge (CHRA) . If you wanted it in the propper GT35 IW exhaust housings you could talk to Brett Lloyd of GCG or Garretts franchise in Sydney at Chipping Norton . Personal opinion , a GT3582R is a lot of turbo for an RB25 and way too much for me . I think its significant that some are using GT3076R's on RB30DET's and really like the results , to me this says that even this turbo may be a tad big for what many are realistically going to need on a street RB25DET . 95% of my time and some money is going into another project ATM but when I get to the R33 I think I'll look into the cropped GT30 turbine based turbos (GT2835/GT3071R) but in smaller 71mm compressor trims ie 48 and 52 . These were only ever HKS options though the cartridges are starting to become available I'm told . It urks me that Garrett won't do anything serious with GT30 turbine trims or make propper turbine housings for the cropped turbine but at least HKS make nice GT Pro S IW turbine housings for it and they are more common 2nd hand than the 3037 Pro S IW exhaust housing . I would also lean towards a T04B rather than T04E compressor housing with small and mid trim 71mm GT compressors because they are a fair bit more compact and would tend to keep the gas speed up with a smallish compressor . For what I want this is the easiest way to go about it with conventional components , I'm not overly concerned about how many Kw's it could crank out because I don't have a need to go flat out everywhere . Outa time , A .

I was just about to say the same thing ... LOL .

So many workable ways to skin the cat , just need to find the simplist most cost effective one . I think you need to draw up a list of the pros and cons of a twin turbo setup vs a single twin scroll (split pulsed) one and then cost it out . Actually even before that I think you need to think seriously about what your trying to achieve here . It may or may not be an easy task to take on the GTR's , sure you should be lighter but will that make enough of a difference ? Weight works for and against a GTR , for when it comes to weight on the driving wheels but against when it comes to changing direction and stopping . There was a bit of history made with the Ford Cosworth Sierras and in their case it was mainly bad . With local oposition only being the Doors and Cans they did quite well , light weight and a fair bit of admittedly peaky squirt . When the R32's came along they had to push harder to stay competitive and thats when they found that they couldn't keep rear tyres on them . In the dry and on the straights the DJR Sierras could just about stay with the GMS R32 (1992) but in the courners and with wet greasy surfaces forget it . I've got the tape of Bathurst 92 and I think it may have been that year that Dick Johnson blew a rear tyre at something like 270 on the way down conrod and and spun the thing I don't remember how many times . Very lucky to drive it away . Anyway that was a case of more power than traction and the legal tyre sizes couldn't hack it . If I wanted to seriously take on the GTR's with a view to winning I'd be looking at Evo Lancers because they've become arguably a superior package particularly with chassis balance and weight distribution . They have the electronic smarts just not available to Nissan in the late 80's and suspension development is a never ending thing . Please don't think I'm being totally negative about your plans but if you don't achieve what you want its a bitter and expensive pill isn't it . To sink 30-40G into building and maintaining a race std R32 makes a not too old Evo seem affordable , you could just about do wheels/tyres/pads/fluids and have a bit of fun in that . If its not for you I think you'd turn it into more moolah than a 3L 2WD R32 . Food for thought , cheers A .

The problem 2630GTS is that most cam profiles for 26 heads are speced for the twin parallel turbos which would give noticeably lower exhaust manifold pressure - once you start using them with single scroll single turbo hot sides the reversion demon may make life difficult . I think I mentioned somewhere here that just to stay even with parallel twins a twin scroll single is mandatory otherwise exhaust manifold pressure characteristics change and very likely won't suit the the rest of the engines setup ie valve timing/static compression ratio/inlet side airflow characteristics . The way I see it RB26's are a bit of a bastard because of the ways Nissan went about getting power from it . Nearly EVERYTHING was an attempt to have high flow rates at lowish pressures (unrestricted) because thats what works in a limited capacity 4-8 rev range engine . Don't get me wrong its all good (low exhaust restriction and creamy inlet system) but if you want to alter its state of tune everything that affects air and exhaust has to be considered because they all affect one another . If you look at the setup in an RB25DET its very different to an RB26 , obviously still a performance turbo twin cam six but its based on one turbo and a single throttle valve plenum inlet manifold . Now because people like Mafia don't give in easily we know that 300 Kw can be screwed out of a reasonably std RB25DET if you try hard . If that head was improved a little and plonked on a three litre block it should romp it in - with a single scroll single IW turbocharger and std inlet manifold system . Its the cost of the externals thats so much lower doing it this way than with an RB26 top end . At the end of the day it hasn't got four paw traction so extreme states of tune will achieve zip - as in unzip your wallet and nothing falls out when it comes to having a life . Now I don't know how deep you are in here as in what you you already have and whats its cost so far . Need an update I think . Cheers A . Just for the record that HKS housing being sold is not mine , someone else here .

From what I've seen all the "KAI" bit means is that a 2530KAI has housings to suit an RB series six cylinder . By far most GT25/28 series BB turbos use a GT28 turbine housing (meaning a T28 flanged one) . The HKS is the wild card being a T3 flanged GT28 turbine housing intended specifically for RB20's and 25's . The reason I know the guts are the same is that the cartridge numbers are all the same - 446179-21 or -5021 . The turbo assembly part numbers I have are 472560-4 and 472560-11 . There are only three variations I'm aware of being SR/CA type , RB20/25 type , RB26 type . Their housings are unique to the intended engines layout . If you look at HKS's (Garretts actually) GT-RS all they are is a Garrett cartridge with HKS's model specific housings bolted on . If you buy a GT-RS specifically for an RB20/25 you'll get a port shrouded compressor housing on it , HKS obviously found out that using a compressor of that size with a reasonably small A/R turbine housing would drive its compressor into surge on an RB20/25 . If you buy a GT2871R 52T from Garrett (same cartridge/wheels) you'll get a T28 flanged turbine housing and a non port shrouded compressor housing because its intended for an SR20 . So basically the RB version is in effect a "KAI" . Mount flange aside you may so what ? Well the difference is that an SR20 has ~ 500cc pots and its cylinders are phased 180 deg apart . An RB six has either 330cc pots (RB20) or 410 cc pots (RB25) and their cylinders are phased 120 deg apart . Basically a 2-2.5L six is more likely to drive a GT28 based turbo into surge with a bigish compressor . Unlike Garrett HKS only do one turbine housing A/R size - 0.64 , Garrett do 0.64 and 0.86 A/R ratios but only in T28 flange . Cheers A .

If you buy the HKS version of the GT-RS (GT2871R 52T) with the port shrouded compressor cover (meaning the RB 6 variant) it shouldn't surge . If you get the SR version and put either the T3 flanged housing from HKS or std RB20/25 on it then yes I expect it would get compressor surge . Truthfully the hardest bit to find is the HKS T3 flanged exhaust housing , once you have that then any GT28BB turbo with the same turbine can be bolted up . If your talking about the price of a new GT-RS vs a bargin GT2535 then I'd take the 2535 . That way you get the good exhaust housing , can play with the 2535 cartridge and put a new GT2871R 52T in it if its not to your liking . The better turbo suppliers/machinists can port shroud a T04B comp cover easily enough . Your call .

IMO a good factory RB25DET and bolt ons/plug ins . Up to 300 Kw which is still lots more than an R32 GTST can get to the ground . Or just hunt around for a reasonable R33 GTS 25T and bolt/plug . Still won't get traction . Many find out over time that the car with most of what they need fitted std ends up being cheaper overall . I think a GTR is different because they are expensive to buy and mega expensive to upgrade . Your call .

A Hotwire Mass Air Flow sensor does take into account ambient conditions - provided the box/filter gets air at ambient temperature . Air changes mass with density - temperature basically and thats where the mass in MAF comes from . Its also the reason why most MAF sensed engines don't use an air temp probe and compensations . In the past alternate load sensing devices such as the vane/flap AFM and MAP sensed systems NEED an air temperature probe so that the computer can attempt to calculate air density from air temperature . This is the reason I loath MAP based systems and rate them last of the three main alternatives so hotwire gets the biggest tick in my book . As to why the RB26 gets its air temp probe I'm not sure . I do know that various race and rally teams found out the hard way that high performance turbo engines (manufacturers style) have changing requirements when run at full load for extended periods of time . I'd say that most manufacturers take it for granted that their customers won't drive their factory hottie that hard for that long without giving up either their freedom or their ass . Its no secret that Nissan put a huge effort into developing the Skyline GTR so possibly put it down to an air temp facility as a diagnostic tool or possibly some Grp A homologation requirement . Personal opinion I suppose .

For my money it would be a 56 comp trim GT3076R based on the 700177-5007 cartridge (real GT3076R) . It would be your call on which A/R GT30 turbine housing to use but if you want it to be reasonably free reving with reasonable response probably the 0.82 housing would be a good starting point . IMO but with good reason you should only really use Garretts GT30 turbine housings in non IW single scroll form . If the 0.82 is a tad restrictive (unlikely IMO) and you could live with an IW go the HKS 3037 Pro S one in 0.87 A/R - someone here is trying to sell one ATM BTW . Some people put GT3582R's on those engines and wonder why they feel a bit lazy , I think its a bit pointless using a 600 odd Hp capable turbo when 450 is the ask . I think its better to have a turbo thats run almost to capacity than one that may never reach it . Cheers A .

Tripe yes I can understand that . Sorry the broken record - when you remove parallel twin turbos and replace them with a single scroll single turbo technology wise you've taken a sizable step backwards . Parallel twins operate exhaust wise very much like a single twin scroll turbo . With twins its 123 - front turbo , 456 - rear turbo . With the TS single its 123 - front nozzle , 456 rear nozzle . If you bolt on a single scroll single turbo its 123456 - single nozzle . I'm running out of ways to explain this but one more time . When all six cylinders communicate with a single passage exhaust housing the average pressure within the housing WILL be higher . Any pressure rise down stream of a performance engine is THE enemy . Splitting the exhaust plumbing on an I6 as mentioned above means each cylinder firing event alternates between the front and rear groups because the firing order is 153624 ie front back front back front back . Now because the front and rear groups can't communicate (till the gasses enter the turbine blades) the time between the firing events is double for each group . Because the time gap is greater the pressure in each passage is lower just before the exhaust valves crack so there is LESS resistance for the firey gasses between the exhaust port and the nozzle . In other words more of the thermally excited expanding gas velocity is available to drive the turbine . Also because the next exhaust event is via the other group the current cylinder has longer to blow down to a lowish pressure in this same are before the current group get its next blast of exhaust . The overall result is high manifold pressure when it needs to be high - exhaust gas to drive the turbine , and low pressure when it needs to be low - best situation for the next exhaust event . Roy , that RB26 manifold has larger passages than the 20/25 version and the outlets are probably too large for a split T3 (T4 Euro actually) flange without copping a pressure drop . If you want to run a T3 or split Euro T4 then the 20/25 version will work better . The 20/25 version is a sort of hybrid because it has the split Euro T4 sized outlet ports and stud hole pattern , the flat pad they are in is actually the big T4 size . In other words it can be converted to true T4 size where the 26 version is already the big size , your one was designed for a TA45S turbo which is basically GT4088R dimensions . The 20/25 version was designed for either a full sized T04E or T04S , by full sized I mean T4 turbine and housing . Dimensionally those two fall in line with a GT3076R and a GT3582R . Also as I sure you know the head side stud patterns are different RB20/25 vs RB26 , I smell a sleeper here somewhere Roy ... 300 kw 26/30 ? A set of 2530's would breeze in 300 Kw you'd think . Boost threshold ? Hard to guess but assuming a std capacity RB26 gets on song at say 4000-4200 , if you put 20% more capacity under it then in a simplistic way could you expect it to load up from 20% less revs ie 32-3400 rpm ? So many variables . Twins would be convenient because the two integral gates are part of the package , the twin scroll single chains you to an external gate or two if you go the most effective TS route . So unless you have lots to spend twins have a bit going for them , they can look very std too . Look at the time , I'm outa here .