discopotato03

I'm only guessing but surely that run was done with an engine dynomometre . Its easy with a well set up one to create the sorts of engine loads that are impossible to sustain in the real world . High figures would not be hard to get with that engine at a constant rpm/load ie no acceleration losses . Just on HKS's T51R series turbos , don't forget their GT42 turbines use a smaller trim than Garrets same family turbos (GT4294R/GT4202R) ie 76T vs 84T though the housings are very different . Other turbos such as Garretts GT4088R and the more recent GT4094R are getting up with the T51RKAI anyway . Ask Full Race Geoff what he gets out of GT4088R's . Cheers .

Sounds real laggy to me , TO4 "P" trim is getting large and heavy for a road driven 2.5L . Also a bit vague with the compressor ie T62 and TO4E and 3.5" , rather large on the compressor outer diametre . A dinosaur bush bearing victim turbo I think . Cheers .

V band fasteners are compact and convienent . Was not from a trader add . Mods : Do I get in the poo from ripping other sites pics ? Cheers A .

Hi all , I stumbled across these pics at a US site . Interesting for some . Also the first pic gives a good view of what the real GT3076R's port shrouded compressor housing looks like . Note the 6 blades , 6 full height and 6 splitter blades . The machined step towards the middle is where the bell mouthed inlet that HKS fits locates . The three holes in the outer boss is where the fasteners (roll pins - I think) lock it in place . Someone recently had a link to an E Bay site where some mob is selling the insert piece . Cheers A .

1) Need to see it to assess it . 2) Yes . 3) If its the T3 flanged RB version sort of . Will bolt to manifold and dump pipe but water/oil fittings different .

I put up a string recently about the GT3076R/GT3037S 52T turbo which is suppsed to be available in March 07 . Its basically a HKS GT3037S 52T but with a Garrett GT30 IW exhaust housing and minus the bell mouthed inlet insert that port shrouded HKS turbos usually have . The ported shroud compressor housing should deal with any surge issues caused by using smaller than ideal exhaust housing AR sizes . The slightly smaller compressor trim (52T vs 56T and 55mm vs 57mm inducer diametre) costs about 30-40Hp according to HKS but still could easily top 400Hp , 450Ps according to HKS figures . Speaking purely turbocharger wise three things about this unit could potentially pull down its boost threshold . I have to assume that most things engine wise are optomised at this point . Firstly you should have the option to use the smallest Garrett GT30 IW turbine housing which is .63 A/R . HKS also produce a .68 A/R T3 flanged turbine housing which many think have a better nozzle and passage form . Extrude honing any turbine housing helps clean up the volute passage because the abrasive goop flows like a fluid so optimises things for the also fliud like gas flow . Secondly the slightly smaller 52T or mid trim GT37 compressor will have a little less bite into the atmosphere so for the available turbine power would get a wriggle on slightly earlier . Thirdly the port shrouded compressor housing . If you look closely at a properly designed housing with this feature you'll notice that the leading edge of the compressor wheels lower or spliter blades line up just below the radial slot . Logically there will be times when the airs pressure is higher or lower in the area between the heights of the upper and lower blades . Obviously if is higher the least path of resistance will be out through the slot and returned to the area in front of the boss . If its lower it would pass through the housing and on to the engine . Everyone who's tried the plain and then shrouded compressor housings says that the shrouded ones want to pull up into boost revs earlier . My guess is that the air bled off means the compressor workload the turbine see's is less so more energy to accelerate it to positive pressure type revs . I know I sound like a broken record but I still think the ported shroud is way to go . HKS uses it often and even goes to the trouble and expense of custom compressor housings that have it for surge prone small capacity sixes like RB20's . Just incase you missed it I'm told the unit will retail for ~ 2G . I have been asking in the States for a comparison of the real GT3071R and this 52T GT3037 but no one seems to have tried them back to back . I have not seen a compressor map of the GT3071R with the optional .60 A/R port shrouded compressor housing so its difficult to compare maps with the 71mm and 76mm (GT35 and GT37) compressor families . So untill we see the results of similar engines with these two turbos all we can do is speculate . I believe Mafia is in the process of fitting a 56T version of the GT3076R/GT3037 (.82 A/R IW housing I think) and I'm keen to see the results of that one . Based on how it goes we will get an idea of its power characteristics and be able to judge if its just right or want a bit more downstairs . Cheers A .

If it came with the HKS cast low mount manifold its a TA45S .

Just the RB25 type Hitachi exhaust housing on that VG30 turbo would wake it up a bit or the RB25 turbo as it is std .

I thought someone dug up ages ago some sort of twin plate thing for grafting the whole RB26 inlet manifold system onto the RB25 head . Not sure which one ie R32 or 33 RB25 heads but I think it was some Japanese aftermarket item . Can anyone explain why the 2JZGTE can make seemingly huge power from a single forward facing plenum style manifold yet no one can do as well on an RB25 ?

Welllll I guess an RB twin cam is not really keeping the classic dream alive so I though I'd point him in the hallowed direction to keep him honest ! Cheers and good will to all , Adrian .

Yep ditto all , don't bend yerself your licence or your ride . Cheers from Planet Potato !

I think I'd just find a usable injected L28 and plonk it in . Spending on dying cars is not real good in my book . You're probably better off trying to find another acceptable MR30 and buying one cheaply . Cheers .

Thanks fellas , I guess its a case of a trial fit in the end . I remember asking ages ago for pics of the 3037 Pro S exhausting because the turbine size difference (compared to 2835 version) would not have worked . From the pics I'd say the people who machined these housings off set the turbo slightly and it shows when you compare the two turbine outlets in relation to the sealing groove . Adam how do you find the power characteristics of that 3037 56T with the .68 A/R housing ? Depending on how much off boost urge I can find I was thinking of using the .87 . Cheers Adrian .

Not everyone agrees on this one but I feel my R33 could do with a slightly taller final drive not so much because I want to have taller overall gearing but because I'd like a bit more load on the engine at round town speeds . I find myself short shifting this car all the time but then my style of driving is probably different to most . I like the idea of more load on the engine so throttle is opened a little more and dynamic CR a little higher . By using V power racing 100 pump fuel and tuning the engine exclusively for it both consumption/power AND throttle/boost response should improve . For the twenty someting cents a litre over power kero gade unleaded I can live with this . I might add my car is not daily driven either , have a nearly dead roller skate for general use . Cheers A .

The go would be to buy the turbo with the external type GT30 exhaust housing if you are already running a manifold mounted ext gate . I did ask Brett about the non gated housing option and I doubt it would be a problem for him to fit one but he's the one to ask . Bolting a plate to the manifold is not difficult to do if you go for an integral waste gate . Integral gates are never going to be as simple as externals because of all the bits attached to the turbo make things fiddly in crowded places . I just have my doubts about getting away with externals if the cops go looking for non std bits . With a bit of effort the integral can be made to work and not look too life threatening . The trick is to make everything look as OEM as possible . Size wise yes the GT3076R 52T fits just over half way between the GT2835 Pro S and the GT3076R/GT3037S 56 trim . A bit more turbine flow than the first and a bit less compressor load than the second . It certainly has the makings for a good 2L four or 2.5+ L six , IMO anyway . Cheers A .

Hi all , as usual trying to make things easy if I can ... For all you people who have HKS's GT2835 Pro S or GT3037 Pro S , I need to know a couple of things about clearance between the compressor housing and the std RB20/25 exhaust manifold . From specs I have both these turbos use TO4E .50 A/R compressor housings and I'd like to think they clear the std manifold by a reasonable margin . I have always liked HKS's turbine housings because they are biased a bit more towards performance that Garrett's offerings ie the volute passage and nozzle is a better shape . There is a chance that using a real GT3076R (the one that looks like a GT3037S but without the trumpet mouth inlet insert) with Garretts IW GT30 housing that the comp housing may be where the exhaust manifold lives . I'm wondering how I would go with the Pro S turbine housing on this GT3076R 52 trim turbo thats in the wings next year . If I can luck out with a better housing design and clear the manifold it makes life easy . Just on the Pro S housings , the waste gate vent path looks like it had some serious thought put into it (flat valve not small either) and the dump pipe should not be difficult to re create if its expensive/impossible to get . Another thought was trying this combination out on HKS's cast low mount exhaust manifold though I have a feeling that the engine mount may get in the way . Thoughts - particularly from that fella with the 3037 Pro S on the RB25 . Cheers Adrian .

I'd think very hard before using that engine . People here are trying to stop you painting yourself into a corner with the early R31 spec RB20DET . It would make more sense to save a bit longer and buy an engine that not only works better everywhere , is easier to get parts for and comes standard with better manifolding/turbocharger and engine control electrics . Just to get the non std engine and gearbox into an R30 is going to take a bit of effort and money so why go with a known problem child . Cheers A .

R33 GTR fuelpump if you can get one for reasonable money , suppose to fall in as a direct replacement and not too big . This will be the last addition to mine before the PFC goes in , didn't like the idea of tuning the thing around an inadequate pump and have to do it again . Cheers A .

Technically speaking Geoff is right , a propper "TO4E" turbo uses a T4 turbine and T4 turbine housing . For the record so does the TO4Z turbocharger which has the TO4 "P" trim turbine and any T4 turbine housing profiled for the P trim turbine wheel . If you had a TO4E with the P trim turbine its housing would interchange with a TO4Z turbo/cartridge . Where TO4E turbo's got confusing is that small shaft TO4 and T3/TB31/TA34 turbines all use the same basic shaft dimensions and so the T3 etc/TO4E hybrids grew out of interchangeability . Mind you just because they fit together doesn't mean they work very well , sell yes , work maybe . TO4 P trim type turbine housings are availabe in single and dual entry T3 , T4 and T4 International stud/flange pattern . HKS's unique housings are large T4 twin entry (though open to single entry not far inside) housings with a particular V band size . Garrett makes TO4 housings in a variety of outlet styles including four bolt , six bolt , V band and slip ring type . Basically what the feller that started this needs to ask himself is do I need a 700 odd Hp capable turbocharger or would a 500 Hp one do the job required , that's the real issue here . Cheers A .

I think the point with high octane fuel is being able to run more advance timing so that we can light the fire at a point in the cycle where the heat (thermal expansion) energy can give the greatest benefit to us per unit of fuel . A "throttled" engine such as petrol fuelled one ends up with a reasonably low effective or dynamic compression ratio so there is a large benefit from lighting the mixture earlier before top dead centre to give the burning mixture time to develop its highest cylinder pressure when the piston is not too far past TDC . The trouble is that the air fuel mix wants to auto ignite because it is exposed to hot piston crown/valves/ chamber and reaches fire point before the plug arcs or before the spark ignited fuel and air is all burnt . Normally the last defence against detonation is to light the mixture closer to TDC because the power drop is preferable to piston (or whatever) damage . The only performance you'd get from less that allowable timing with high octance fuel is the lighter wallet power to weight ratio . Cheers A .

I managed to find out the final spec of this GT3076R 52 trim turbo . It will use the same cartridge as HKS's 52 trim GT3037 and GT3037S so CHRA number 700177-5006 . It will have a port shrouded TO4E .60 A/R compressor housing and one of Garretts integral (internal) waste gate turbine (exhaust) housings . The ask is going to be ~ 2G which while not chicken feed is not too bad considering you get the ported shroud comp housing , a propper integral waste gate turbine housing with T3 flange , and the waste gate actuator and mounting bracket . The closest thing would be a HKS GT3037 Pro S which would be considerably more expensive and only available with the 56 trim compressor wheel . I dug up some power (potential power) figures from HKS and they quote 450PS for the GT3037S 52T . Interestingly the slightly different "S" varaint gains 10PS from its port shrouded compressor housing which is the main difference . So if PS is approximately the same as Hp then Kw potential equates to 337 . I would have thought a bit over 400 and 300 but I'm conservative . One unknown at this stage is will this unit require a spacer plate between the std RB20/RB25 exhaust manifold so that the compressor housing clears the manifold casting . If anyone has a "real" GT3076R with the Garrett IW exhaust housing on the std exhaust manifold can they let us know if it fits with or without the spacer . Brett at GCG expects to have these turbos here in March 07 . BTW they have available now an exhaust housing thats dimensionally the same as Nissan RB20/25 in .70 A/R for those that want a bolt on style housing for some of Garretts GT BB turbos . Cheers all , A

The manual and PFC solved some issues then . Did you do any thing with diff ratios or are they ok ? A/R I wouldn't like to guess because its not my money involved if you don't like the result . Its the same situation with RB25 Hi Flows and RB25 vs VG30 exhaust housings . Latest info to hand , will use same cartridge as HKS version. Cheers A .

Tired or dirty idle air control valve ?

Someone was always going to ask that one and its its a good one because these two wheels in theory are good for about the same sort of airflow . The real GT3071R is not a bad thing but when teamed with the GT30 turbine its a bit of a juggle getting the wheel speed right to put the pumping capacity where you want it in relation to engine speed . This turbo is good example of being biased a bit more turbine wise than most . You will have noticed that this turbo does have an optional port shrouded compressor housing available but you don't tend to see it in this form probably for cost reasons from a suppliers point of view . The available compressor map shows that to get the most from this turbo takes a bit more shaft speed and the area of highest efficiency begins and ends a bit higher than the 76mm GT compressors do . I'm pretty sure this ties in with the compressor housings A/R ie .50 vs .60 and the fact that the 76mm GT wheels use ported inlet shrouds . One of Garretts engineers once mentioned that this real GT3071R was sort of a production based version of Garretts competition TR30R but IMO that one used a 60mm version of the NS111 turbine (same family as GT2860RS/GT2530) and if it was in 76T a better thing - very open bladed light weight compared to 84T GT30 . That turbine with the 71mm GT compressor in 52 trim would have been very likely better than the GT2835 52 trim cartridge and similar but slightly better than the GT-RS . Garrett should be shot for not using that turbine more often . Back to GT3076R 52T vs GT3071R 56T . Provided you can get the required airflow the mid trim size usually gets the best efficiency with compressor wheels . Larger or smaller trims are there to tune the wheel families pumping capacity to suit the engine . Production economics step in at this point and turbo manufacturers who use a common wheel/housing family often try to have the same part/s used in different units to keep costs down . Market trends also dictate what sells in volume and sales are what its all about . In this case the demand for the GT3076R/GT3037 in 48 and 52 compressor trims has not been high so the aftermarket section of Garrett North America went with the larger 56 comp trim version . Very probably a moores law thing - more air guys , more power . Also more boost lag ... Anyhow I can keep on spieling on but the bottom line I feel is that a GT3076R in 52 comp trim is a better road car turbo that a real GT3071R in 56 comp trim . I can't show back to back test results because I don't have any . Somewhere in the mists of wheel tip speeds and compressor housing design there will be reasons why the 3076R/3037's map is better . This is not to say that with a bit of mucking around you couldn't get something similar out of the 3071R but without the maps its a case of spending money and hoping it works . As I said before HKS has opted for mid trim compressors and ported shroud type compressor housings on some their successful turbos and they appear to work very well . Its also important to note that they used a cropped version of the GT30 turbine in their GT2835 series turbos (very similar to real GT3071R cartridge) probably to keep the wheel speed up a bit at the expense of top end exhaust flow . That is a workable formula provided the turbine housing is GT30 based because the GT28 housings bored out stuff it all up . There have been interesting reads at SR20 sites where they have compared the GT3037 56T to the GT3071R 56T , they did not find the 1000 rpm lower boost threshold that ATP was claiming in the US . Another significant thing is that the Sentra mob (Sort of Pulsar 4 door sedan B15 rather than N15 as we have) race transverse front wheel drive cars and there are limits as to how much torque you can feed through the wheels that drive and steer their cars . The ones that can get their hands "on pretty much any turbo they want" like the GT3037 52 Trim . Surely its a throttle response vs boost/torque response thing here . I will put it to them and get back on this . Turbine housing and A/R ratio . Again the real GT3071R is a bit particular here so don't know about the .82 on this turbo on a Stagea . They are rather heavy and being automatic probably thrive on low down torque depending on how the stall speed of the torque converter is set up . Engine management is an issue for them and Gary SK is probably the one to ask about Stags . If I had to make the choise for an RB25 it would most lilely be the GT3076R/GT3037 52T .63 exhaust housing and the port shrouded .60 A/R compressor housing on an R33 spec engine , if I had the luxury of an R34GTT spec RB25 (I wish) I'd be brave and opt for the .82 because the variable cam timing and better aftermarket cam profiles available (slightly shorter duration and a little more valve lift) would probably pull up the off boost and low end torque . If and when these things land here hopefully the supplier will be keen to test both housing sizes which is to their own benefit because a happy customer is great advertising - grape vine shakes and reaches far and wide . Cheers A .

Anyhow the upshot is that the larger A/R housing can pass the gas off the compressor at peak revs a little more easily than a smaller one if flow capacity of the wheel is reaching its limit . Note that with std RB20 and 25 turbos the compressor housing grows markedly for the same wheel size . Depending on what you read into it , HKS USA's website shows their GT3037 as having a .60 comp housing with 70mm inlet boss and 50mm outlet boss and claim 440 Hp potential in 52 trim . The next up HKS GT3037"S" 52T shows 100mm inlet boss and 50 mm outlet boss and claim 450 Hp . I think they may have made a typo in the first instance and meant .50 A/R and plain or non shrouded housing . They don't mention it but I've never seen a GT3037S or GT3076R without the 100mm inlet boss and port shrouding thought HKS always use the trumpet mouthed insert probably to cut down the "jet turbine whine" that ported shrouds often produce . What this feature does do is widen the maps particularly in the upper left hand side of the graph (in other words high pressure at low gas flow rates which is what turbos with small turbine housings do when boost rises sharply at lowish engine speed - low airflow rate) . For your SR20 the .50A/R housing should not be a problem because often four cylinders are less likely to surge than sixes - the pots are of greater capacity than a similar capacity six so can get away with slightly larger A/R turbine housings without being too laggy . The small inlet boss/plumbing is also easier to house in tight spaced four pot engine bays particularly front wheel drive ones . For an RB six I'd prefer the ported shroud and .60 A/R ratio particularly on the 2.5 litre engine because its probably going to windmill fairly fast if the turbine housing A/R is sized to bring the thing on in the 2500 + rpm range . If it had the .63 A/R housing and you floored it at low revs the ported shroud should just about cope with surge issues but thats only a hunch . A bit wide that .63/.82 A/R gap , the HKS GT3037 Pro S .68 A/R housing is probably a little better sized for street 2.5L . Time will tell , cheers A .