discopotato03

So ah how do we get the GTR PFC to work in a single turbo R32 ie 26 head on RB30 . I don't feel real good about two parallel AFM's in front of the turbo . If one was to get more air ie better duct filter etc the others half of the engine would run lean right ? Also isn't the R32GTST PFC a modified 32/33 GTR PFC ? Cheers A .

I reckon Garrett will sell it because there is sufficient market to make it worth their while . The modified 56.6mm GT30 turbine is manufactured by Garrett and found in some of the turbos they sell too . GT-RS vs GT2540 , try buying a 2540 that isn't old stock . Read the comparison article (Zoom or HPI) . Development costs don't have to be high for a product to work well , just need to be close or right the first time . Now you want 250Kw for your FJ20ET . 250Kw = 333.33Hp , working off 11Hp per pount of air = 30.303lbs . I add 10% so as not to fall off the RHS of the compressor map so 33.3333lbs air . Working off my theoretical 55-65% of compressor end flow to get turbine end corrected flow , I'll use 65% this time = 21.66lbs . Now to the maps . As I think I said to you before I thought the GT28RS (GT2860RS) would be very close . I'll show you the maps and you can see for yourself , by the way I am not playing games by working the numbers backwards either . Now from memory you've said in the real world you don't reckon its enough . I have said to you here and elswhere that the GT2871R 48T is the next small step up - compressor flow only not turbine flow , actually turbine flow drops because of the reduction in a/r housing from .86 to .64 as you can see on the turbine maps . If you know how to make more air in for more restriction on the way out make better torque and turbine response for equal thermal load you are a rich man . I have also thrown in the turbine maps from Garretts GT3071R "waste gated" turbos because they use the cropped GT30 turbine . Pay no attention to the efficiency number because these use the bored out and butchered GT28 turbine housings . They are a GT30 based turbine that needs a GT30 based turbine housing like what HKS has made . Also those 3071R WG's use again the larger 56T 71mm GT35 compressor wheel . I've not mentioned this here before but its important to realise that the jump from GT28 to GT30 turbine involves a jump to a very different style of turbine . The GT28 (NS111) is a 9 blade 76 trim where the GT30 is a 10 blade 84 trim UHP (Ultra High Pressure ratio) . The blade forms are different , the GT28 is a higher exhaust temp petrol engine turbine while the GT30UHP was designed with cooler exhaust temp Diesels that work over narrower rev ranges hence the large trim . This is why at times people make the GT28 to GT30 jump and find the thing laggy . HKS knew that ages ago and opted for smaller trim compressors to get around it . What Garrett could have done is make a 76 or 78 trim version but then its not so good for Diesels which are the bulk of their sales . The cropped GT30 turbine has no GT30 based housing from Garrett , is still in 84 or 90 trim . HKS had to get their own housings made which cost a lot more that buying an off the shelf item if it existed which it doesn't . So 180BFJ you are going to have to fit something to get a result and from that work out which way to go from there . Could be wrong here but seem to remember you saying you had one of the GT30 based TO4S turbos . These are hopeless because the arguably very free flowing GT30 diesel turbine does not have the trapping efficiency at the low revs that the dinosaur TO4S compressor starts to pump and load the turbine at . What you do is up to you , asking 20 different people will probably get you 20 different answers so you take one of their opinions or form your own otherwise you will ponder for ever . Cheers A . GT2871R_Turbine_Map_..bmp 84_Trim_56.6_mm_turbine_1_..bmp HKS_GT2835_84_T_2_..bmp

All things considered the GT2835 Pro S would probably come the closest off the shelf . This is not a cheap option but you can at least ask others on this site who've got them what they think . Actually do a search , lots of old threads on the HKS GT2835 Pro S . It is possible to change turbines from GT28 to GT30 because the shafts have the same dimensions . I would do it this way because I prefer the full sized GT30 turbine to the cropped one in the 2835 series . BUT I would use the smallest trim 71mm compressor that gave me the airflow I needed . I should add that modifying a Garrett cartridge would be a cheaper basis than a HKS ! I was told recently that its difficult to get much more than 300Kw (400Hp) to the ground with reasonable street rubber (2WD) . If you work on ~ 10-11Hp per pound of airflow the 48T 71mm GT35 comp is good for 390-430 Hp . So either GT30 turbine into 2871R ( 48 or 52T) or 56T down to 48 / 52T comp in the real GT3071R . One way will be cheaper than the other but both give the same end combination . I really hope Garrett is doing their new T3 flanged integral gate exhaust housings in .63 as well as .82 a/r as it would make a responsive unit . The 2835 Pro S uses the slightly cropped GT30 turbine (56.6 vs 59.9mm) in a .67 a/r housing . I reckon the 59.9 in a .63 housing would be pretty passable particularly with the smaller 48T compressor . Talk to Brett if your serious , nite all ...

sarahB the problem is that the turbine is a bit small in diametre - blades/vanes are not long enough radiating out of the turbines hub to generate sufficient leverage or shaft torque to power the 71.1mm compressor esp in its mid and large trim .

This topic is about the GT-RS and my opinion is for it , have less time for the 56T version . What I said about the 48T version I stand behind for these reasons . Everyone at the time (me included) wanted to know what was the next small step up from the GT28RS (GT2860RS) in Garretts GTBB range . The GT28RS is good for ~ 35-36lbs compressor flow and the 48T GT2871R is good for ~ 39 . From memory the 52 and 56T versions do about 44lbs - the energy required to power a 44lb capacity air pump is significantly greater than a 39 or 35 lb one . ALL of these turbos use THE same 53.85mm 76T turbine . Because the GT28RS's compressor is a very good match for this turbine it works very well - in a .86 a/r turbine housing - on a 2L four . I would not take this turbine past the 48T GT35 71mm compressor because I don't believe it can drive it properly read efficiently . The GT2835R starts to look much better than the 2871R because it has more turbine to drive the 71mm or GT35 compressors with . The modified turbine in the GT2835R is larger at ~ 56.6mm in 84 or 90 trim and developes more shaft torque for the same exhaust gas energy . The GT-RS was the answer to the ultra lag HKS GT2540R , that doesn't make it perfect just less of a compromise . You people really should be testing the turbine inlet pressure and comparing it to boost pressure downstream of the throttle/s . You also should go to the maps for compressors AND turbines to get an idea how efficient the turbines are or are not . A turbine with an appropriate compressor is always going to be more efficient than the same turbine with a bad ie huge comp hanging off its shaft . Don't believe me ? Go back to turbobygarrett and have a look at the turbine map for the GT2860RS . Now flick over to the turbine map for the 52T GT2871R . This is the exact same turbine but its efficiency is pathetic don't you think ? The reason for this is 1) the diametre mismatch 2) its lack of gas flow capacity particularly in a .64 a/r turbine housing . It is critical when specing turbochargers to compare the turbine/housing combinations corrected flow capacity and compare it to the compressor/housing's choke flow capacity . Now somewhere in the 55- 65% region of turbine to compressor flow seems to be ok , its a hell of a juggle with wheel trims and housing's a/r's but that's as broad a generalisation as I can work out . The best compromises seem to be 60%+ but you start to trade boost threshold for efficiency under full load full boost . If I was going to work with FJ20's again (not) I would use a GT30 turbine or better still the 60mm NS111 turbine from Champ Car type turbos . In a perfect world my GT30 turbine would be 76 or 78 trim not the Diesel 84 trim and the compressor a GT35 71mm 48 or 52 trim . With a bit of stuffing around it would have more grunt than mine did with the GT28RS and no more chance of choking on its exhaust and melting down . Custom GT BB turbos can be had if you know where to look but they are expensive and the success of them depends on your understanding of what makes a good one tick . Out of time cheers A .

Abo Bob I had a look around to be sure of the facts . I only found two versions of the HKS spec GT-RS . The first is the SR20 version which has the S14 style comp cover on the std GT-RS cartridge . The second is the RB20/25 version which has the straight snout version of the TO4B cover with a kind of port shrouding . It also has HKS's own custom .64 a/r T3 flanged GT28 exhaust housing specifically for RB's . Interestingly Garrett is just about to release a version of the GT2871R in 52 compressor trim and the pic is identical to HKS's GT-RS for SR20's . The turbo no is 472560-15 and its cartridge no is 446179-67 . Its turbine and compressor spec is identical to the GT-RS . Because I'm a kluts and don't know how to copy links its at turbobygarrett/products/turbos and see 2871R 472560-15 . The turbine map is woeful as you would expect from the 71mm comp 53.85mm turbine mismatch . Because I'm away with work (foreign computer) I cant post pics of the RB specific GT-RS but they are available at - Unique Autosports Online Catalogue - Skyline GTS-T Turbo , third item down . I think this turbo in any version is a POS and you can do better . Sure the compressor may push enough air for ~ 400 Hp but the 53.85mm turbine in a .64 GT28 housing - very sceptical . HKS claim 300 wheel PS out of their own demo Silvia - they would claim more if they could .... If you played around enough with some sort of GT30 turbine based CHRA with VERY careful compressor and housings selection you could do better . The real GT3071R with the right compressor or as I said small trim GT30R/3037 52 trim could do it and be reliable . Cheers A .

I would be asking Brett at GCG to build me a GT30R but with the 52 trim 76mm GT37 compressor and .50 A/R TO4E comp cover . This is essentially a GT3037 52T and with one of the soon to be available GT30 T3 flanged integral gate housings would be a good package for an RB25DET . The smaller trim comp makes a 3037 spool 500 rpm lower on an SR20 and still makes nearly 400 at the wheels . Cheers A .

No they don't because Garrett develop their turbos and have the maps under wraps . If you can find the wheels type size trim and A/R generally they turn up on line . Many of Garretts maps are available and they often use the compressors HKS specify but in different combinations of turbine and housing style and AR . I give you a hint - look through the Garrett bush bearing turbos at turbobygarrett/products/turbos . Another hint - try to place the point of greatest efficiency at the torque peak not the redline . Cheers A .

The std GT35R in twin form could easily do 1000Hp and more . It sounds like they use the GT35 cartridge with their own turbine housings . There's lots of mention of them but no specs or pics that I could find . It would be nice if they did make turbine housings with T3 flanges though getting the thousand through two T28 flanges could be done . Cheers A .

Thanks Chris , its good to know the integral gate and housing can pass the exhaust gas at 400Kw on an angry 4L 6 , the torque must be pretty good . Latest information is that the GT35R's turbine shaft will fit in the GT30R cartridge , apparently the GT25 through to GT35 BB turbos all use the GT25 BB centre section/bearing cartridge/shaft BUT the journal where the compressor mounts is different/larger on the GT35R turbine shaft . So this means it can work but the GT30R's compressor bore needs to be enlarged to suit the shaft . Cheers A .

Hi all , seen these mentioned but can't find any specs . Someone said something about a GT35R cartridge with the 102mm GT42R compressor and housing . Anyone know for sure or have links to info on these things . Thanks A .

Low mount and max 3" engine pipe . Out of curiosity what size HKS gates are those and what tube size for the gate ? For the one that is plumbed back do you have expansion and contraction problems ? Thanks A .

Corky Bell in his book Maximum Boost shows pictures of the "Aerocharger" which is no longer made . From memory the Aerocharger used an actuator not unlike an integral gate actuator which could work with boost signal pressure , though not quite the same as electronic control . Cheers A .

[200] I'll save you the trouble . HKS GT3040 Turbine is GT30 (60 x 55mm) 84trim . Compressor is 82mm 50 Trim GT40 HKS GT3240 Turbine is GT35 cropped from 68mm to ~ 64mm still in 84 Trim . (~ 64 x 58.8mm) Compressor is 82mm 54 Trim GT40 Many spec sheets for the GT3240 turbine show 54 x 58.8 which is a misprint and leads many to believe its a slightly modified GT30 turbine which its not . Will have to look into HKS 3540 and Veilside GT3540 because they're new to me . Note Simon Gisgus (sp?) uses large singles on his I6's , I would not think there's anything groundbreaking about them except their size . Note that Simon in the past was using blow off valves to vent the compressor outlet rather than using a wastegate to bypass the turbine to control turbine/compressor speed and boost . Also note the torque limit of the XR6 engine was capped at I think 800 while the rev limit was raised to 8000 . Without being insulting I am curious to know if this was done purely to reach the Hp number ie Hp = torque x engine speed . Cheers A .

Hi guys , I would not be ordering a small parallel brass bung from Japan with a 1.5mm (60 thou) hole in it . If you are lucky the basic OD of the thing will very likely be a std brass rod size and only need drilling to size parting off and de burring . Any machine shop could make these for you very easily though you may want more than two to make it worth their while . Actually just had a thought , Nissan L series engines use a similar type of in block head oil restrictor and its just possible that it could fit and work if the ID/OD is suitable . We have the technology here cheers A .

Variable Area Turbine Nozzle exhaust housings are still being developed but will probably be specific to a set state of tune . The theory is to keep the exhaust gas speed up over the engines total operating range and be able to achieve a large enough effective a/r to prevent the VATN turbo from overboosting at the redline . I think its another gimic (sp?) to get around the I want /need positive pressure from idle all the way up . The ones I've seen in bits have small turbines in relation to their compressor and the turbine housing is always a bulky cumbersom heavy thing . The future will tell but I see the next turbos having more modern turbine and housing forms and wider ranging compressors as well . The diesel turbo is heading into higher pressure ratios and the turbine sides that can drive double sided compound compressors to achieve it . The manufacturers are screaming for higher outputs without greater engine capacity which well developed diesels with better engine controls can do . The VATN turbo is a problem for petrol engines because their higher exhaust gas temperatures do nasty things to the VATN housings intricate vanes and if they lock up overboost can kill . Even if they can get round this its debatable if the compressor can make serious boost over a wide airflow range read engine rev range . The sad fact of life is that the rotary compressor is not a perfect thing , when it works over a variable speed range its pumping efficiency also varies and this has to be lived with . The turbochargers chief limitation is that it has to balance out exhaust energy against a rotary compressors limitations and turbine efficiency/flow against compressor efficiency/flow neither of which is linear . Cheers A .

T3/T4 hybrids , hundreds of possible combinations of compressor/turbine/housing a/r's . Easy to screw together , even easier to build unworkable combinations and ultimately limited by bush bearings and the dinosaur plate/collar thrust bearing - and thats if the wheels are a good match . Cheers A .

Up to you but when running twins of this size I would lean towards the HKS versions because their detail changes generally better suit a model specific application . Their variant of the GT3040 uses a smaller trim compressor than the generic Garrettt version . The GT3240 is a real orphan , GT35 turbine ground back from 68 to around 64mm and a 54T GT40 compressor . Only one turbine housing (.82 T28 flange) available for its unique turbine . Both of these are slightly compressor flow biased but when used in pairs on 2.6L they need to be this way to "spool" south of the redline and not go backwards at gear change time . Really need to know its intended use because even a drag car has to have a usable rev range where a dyno queen could run near the redline and have its maximum torque output at this point . Just on the subject of twins/singles do you really have to have twin turbos as there are singles capable of feeding 1000Hp . If this project got to the trial and error stage and you had to fiddle housings to get the power where you want it a single is far cheaper and easier to "tune" if you see what I mean . I reckon std GTR's are a plumbing nightmare but when the turbos grow .... It could be worth looking into Garrett GT42R/T51R turbos as something of this nature is almost certainly going to be lighter/more compact/cheaper/simpler . Cheers A .

Been thinking about compressors and housings again for the mythical perfect GT35R turbine based turbo for an RB26/31DET . After much research into small ie 50 trim GT40 compressors it turns out that the larger trim ie 56T GT37 76mm wheel from the real GT30R and 3037 56T has similar pumping capacity in a more compact TO4E type compressor cover . I need to go back and compare the maps specifically the speed lines of the maps to see if they're similar enough to work at same-ish shaft speeds . If so I then need to ask Brett if a GT35R turbine can fit up the guts of A GT30R turbo with its heat shield so that the cartridge seals in the front of the turbine housing . If it worked it technically makes it a GT3537R or GT3576R . I also need to find out if the 50mm outlet is large enough to feed a 3L up to 300Kw and if not are their .60 or .70 a/r versions with the larger 60mm outlet . Does anyone know if the XR6's turbo will go 300Kw + because this would answer some of these questions . I really would like to see its comp map but being a local development probably unlikely . Cheers A .

Hi all , have any of you mounted an external wastegate down close to the engine pipe rather than up on your manifold away from disapproving eyes ? I was thinking this would look a bit less agro but still work as it should . The problems may be supporting the weight of the gate and dealing with different expansion rates of main and gate outlet pipoes . A friend once suggested using a smallish exhaust pipe flex joint to give it room to expand and contract - sort of a soft point . I've no idea how cuddly a single turbo R32 GTST is down around where the 3" engine pipe would go but is there any chance of it fitting ? Also have an old Turbonetics catalog that shows a "Deltagate Maxima" which is basically a throttle valve in a piece of pipe with V band fittings . It has a diaphram on the side with a sort of short rod integral actuator style linkage . If it does weigh 3lbs and is not too huge it could work in this situation . Any feedback appreciated , thanks Adrian .

Out of curiosity what sort of airflow and power potential is a T88 33D good for ? Cheers A .

These are supposed to work well but are really a TB31 meaning T3/TO4E small trim like 38-39 . They use a .58 a/r T3 flanged turbine housing with V band outlet and integral wastegate . Cheers A .

I'm not sure what kind of fleas they put in ThermoTech wrap but the itch spans days . Its like its full of glass fibres and they nip whatever part of you they touch . Don't want to be visitin the loo in the middle of this job . They do a kit of the wrap , the spray on stuff and stainless clamps to feep it in place . It looks costly but cheap compared to fire risk alternatives . Gary is your turbine cover blanket the stitched type or the "bag type" ? Also good to know that the retained heat from the insulation is not a problem for the turbo and within the capabilities of the water cooling system to prevent coked up bearings . Thanks everyone for the input , cheers Adrian .

Roy turbo water cooling was explained to me as follows . Water is a very useful coolant because it takes a lot of heat energy to boil it . What we want the coolant to do is absorb the heat from the thermal mass of the turbos bearing housing and some conducted heat from the turbine housing and take it elswhere . Generally there is not a lot of material in the bearing housing casting so it can only absorb and temporarily store so much heat energy . The danger period for the turbos bearings is hot shut down because oil and airflow ceases . If the turbos heat is enough to cook the oil in and around the bearings it will kill itself . What I did with the old FJ20 was to add water cooling that was not standard , the BB turbo had it so with the cost of the things it made sense to use it . The fellow who used to run Road and Rally Centre set it up so that it would thermosyphon when shut down and do the heatsink thing for the two or three minutes it took to get the core down below waters boiling point . FJ20's like I suppose most iron blocks have a coolant drain bung low down on the exhaust side so he figured this as being the most convienent place to find a water supply . The bung was drilled and had a short piece of steel fuel line brazed into it for the water line (EFI hose) to clamp to . That bottom hose actually scribed a "U" shape so it would prime and not form an air trap . I ratted up the required banjos and bolts to fit the turbo . The turbos water outlet must run up hill and mine re entered the cooling system on the head side of the thermostat (FJ20's have the thermostat on the heads water outlet not the blocks water inlet like an RB) . So the water path started low down where its cool and dense . When the engine was shut down the water in the turbos water jacket would start to boil and the steam bubbles would gurgle up the pipe to the head and out through the thermostat and via the radiator cap to the overflow tank . Because the hot water flowed up out of the turbo it was replaced by cooler water from low in the block . When I say water boiling in the turbo I don't mean hammering and banging violently like a cooling system in melt down mode . It was all very gentle but entertaining to listen if it was quiet (this was in the pre riot days) . So it was really set forget and automatic . The crucial bit is that the hot water MUST be able to flow uphill to the head so no highest point before this or it may form a gas trap and not self syphon (thermosyphon) . I also stay away from any other water lines ie heater hoses because they don't always flow in the desired direction . I wanted it to be an independent system to make sure it worked . The lines can be 5/16 or 8mm so don't need 1/2 " lines to cool a small thermal mass . I've put this idea up on other sites though people have hysterics as soon as they hear "water boiling in turbo" for some odd reason . Its really not an issue if the hoses are routed properly and works very well . Two more cents spent , cheers A .

I remember seeing the footage live and it was a heart in the mouth run . I would like to own a copy of it so if anyone knows where to find it please do tell . Cheers A .