discopotato03

Its hard to put a number to it so if I had to guess probably around 450 , more interested in average power . The car will almost certainly be 2WD and have to live with production gearbox ratios , also don't know what I'm doing with rods yet so maybe SK's 475Hp may be the ceiling . Its doubtful if a road driven R32 with street rubber on sane rims could harness even this . So a free reving torquey engine with good throttle control is the aim . I want to use a reasonably tall ie 3.7 final drive with 16" wheels and tune the thing to make best mean part throttle torque because I think that feels good and pays off at the bowser . I don't think making good power with this kind of engine will be difficult but getting a smooth transition from cubic inch power to forced induced power may be interesting . Cheers A .

In more recent times some turbos have been optioned with turbines closer to the compressors major diameter or if thats not possible smaller trim compressors . I think this is done to minimise exhaust restriction and concentrate on moving lots of air but not at high boost pressures . There are lots of examples of HKS optioned GT BB turbos with mid trim compressors while Garrets nearest equals have the big trim comp . Many say HKS turbos are optimised to work at higher boost than their Garrett cousins but I reckon they are simply optimised to be a good balance when loaded up rather than a hell fired attempt to find a couple of pounds of boost at cranking revs . So from some of their examples we can learn that lag and response can be moved around in a couple of different ways . The old standby if a turbo was a bit lazy was to throw on a smaller a/r turbine housing to wake it up earlier . I think the better way to do it is to reduce the compressor trim which takes some load off the turbine and for same exhaust energy input can spin up earlier in the scheme of things . This is all fine and well as long as the smaller trim compressor still has the pumping capacity required . To the GT3540R , finally they say ... These turbos use the 82mm GT40 compressor of the BCCW18C family in 56 trim . From some sniffing around I found 50 , 52 and 54 trim wheels of the same family as well . The HKS GT3040 uses a GT40 50 trim as does the bush bearing GT4082 . The bush bearing GT3782 uses a 52 trim and finally HKS's GT3240 uses a 54 trim version . Interestingly the HKS's use a .60 a/r TO4S comp cover except for the GT3040 optioned with the largest 1.12 a/r turbine housing (thanks Fantasy) while Garrett plugs on with the larger .70 a/r TO4S cover . What I have in mind is to use a 50 or 52 trim GT40 compressor on a GT3540R to optimise whats probably a Diesel cartridge for a petrol engine . I don't need 650Hp's worth of airflow when 500's worth will do nicely . Now Brett from GCG tells me that the 52T wheel is available though from over seas and would require machining operations so it could fit . The comp cover is also around but as a new component is a tidy sum . So it seems that the only "easy" way out is to somehow obtain a "cheap" or damaged HKS GT3040 and rat it for the compressor and comp cover . Even then the wheels centre hole would need to be drilled as the GT30 turbine shaft is smaller than the GT35's . If anyone has one of these for reasonable money can you let me know - remember its just the wheel and housing I need . It it eventuates it could be called the GT35RS . How much better it would work than a std GT35R is hard to say but I'm sure it would suit my purposes and close the gap between GT30R and GT35R enough while having no less exhaust restriction . Opinions ? Cheers A .

Hi all , I've been looking at Garretts GT3540R for a while now with the idea of using one on an RB2631DET low mounted . Peoples experience with these things seems to show that the 82mm GT40 compressor in 56 trim is often a bit over the top for realistic power goals so what to do ? I don't like the idea of the GT3040R's , either 50T (HKS) or 56T (Garrett) though the 50T is the better of the two . I believe the GT30 turbine is a little small for a 3L anyway so it wouldn't matter what compressor you hung off it , a reasonable alternative may have been the GT32 turbine but Garrett don't offer it in any ball bearing cartridge I know of . I think HKS had Garrett crop their GT35 68mm turbine down to ~ 64mm 84 trim for the GT3240 - so had a "sort of" BB GT32 turbine . That turbo had a 54 trim GT40 comp but more on that later . Essentially the GT3240 is a bit like a GT3540R with an in between sized turbine (between GT30 and GT35) and a slightly smaller trim compressor of the same family . It seems to have been an effort to have more wind than their GT3040 and a bit more exhaust flow for a bit more squirt . They are being used in single form on high performance fours such as Evo Lancers the odd Toyota 3SGTE and in twin form on Nissan RB26 drag specials . Back to my situation . I think when HKS were having their GT BB turbos developed there was less in the way of wheels around than there is today and anyhow it was 90's thinking . More very soon , cheers A .

Food for thought .

I believe the cartridges are Garrett GT42R's with the 94 or 102mm compressor options , HKS ocassionally get Garrett to fiddle with the turbines ie 2835's and 3240's . Housing and a/r development helps a lot as well . Cheers A .

For Cubes hot off the press , Brett tells me there is an 82mm 52 trim BCCW18C compressor (59.1mm inducer) available . Just have to figure how difficult it is to fit and if HKS's idea of using the .60 a/r TO4S cover for 50 and 54 trim 82mm wheels is the go . The amusing part is that with these GT40 compressors the inducer sizes are as follows . 50T = 58mm 52T = 59.1mm 54T = 60.3mm 56T = 61.4mm So only 3.4mm the difference 50 to 56T though its supposed to make a very real difference in the way they load up the turbine particularly initially . As I have mentioned before the difference between a 52 and 56T GT30R is 500 rpm . Cheers A .

I think it may have been Davis Craig or Natra that were supplying viscous hubs but don't quote me . I've always had great results from Southern Suburbs Radiators near the Blakehurst end of King Georges Rd . Kyle and his dad are very helpful and try hard to please . I'm sure they could advise you on hubs as well . Another thought - it may be worth looking into the temperature probe as when they lemon out you get all kinds of strange readings . A long shot but happens at times . Cheers A .

I'm using the SWR type with Nolathane bushes and works well , my experience with spherical joints on road cars has not been good . No compliance and plenty of road wheel noise and vibration transmitted into the shell/cabin area . Rose joints are not a high mileage item which is not an issue with dedicated race cars . I chose not to modify the std rods because its debatable if the steel is up to it . The SWR rods are made from 60T steel and larger than the std ones . They come with the tube that the bushes locate over (+ nylock nuts) and std Nolathane bushes can stretch over them with no probs . Fit set forget . Cheers A .

If you decide to use HKS's GT3037's I'd give serious thought to using the 52 compressor trim version (cartridge no 700177-0006) . They work out to be a better balance of compressor load to turbine power and if the SR boys can get nearly 400 Hp out of them in single form its more than you probably need in twin form . Also from memory HKS did a 48 compressor trim version but I don't think anyones ever seen one . HKS do T28 flanged housings for them in .61 and .73 a/r as well so my guess would be .73's . It still seems a lot of turbo for the 600 odd Hp , what do twin 2530's get you if the manifolds and turbine housings are cleaned up and good dumps and cams are used ? Would be a lot cheaper and use a bit more of what you already own if its enough . Also glad its not me paying for the driveline to support it ... Cheers A .

LOL , don't know ATM . The turbo is a long way off yet but with some recent research into GT3240's and some of Garrett's GT bush bearing turbos it seems there are 82mm GT40 compressors in 50 , 52 and 54 trims . I feel the 56T on Garretts GT3540R is a little big for the power or I should say torque I want so its a waste of turbine energy spinning something thats never going to achieve its potential . Far better to use the compressor wheel trim that suits my needs as it should be more responsive and increase turbine efficiency a bit . The $64 question is can the wheels be bought and is the back of the wheel the same as the BB version ie flat back or tulip shape and so on . Brett from GCG tells me they can drill/bore the centre hole if necessary so if the bush bearing shaft is smaller its not a problem . If I'm lucky and it bolts straight up I'm laughing . Another thing to look into is this extrude hone process , the Americans say that noticable gains are had from extrude honing the turbine housings . This is not so much from a making the passages any larger but smoothing them out which aids the flow rate but not at the expense of gas speed . Its supposed to give a few more points of measurable turbine efficiency . Some of the turbo sellers will do this in the US at an extra cost so its an option if you buy from them . It could be done here but the set up cost is not cheap and I have seen the result of just a bit (lot) too much taken out . I was told about these C117 compressors about 18 months ago , like the later GT40R has , and there is supposed to be new turbine designs on the way but when is anyones guess - they may already be out there in truck turbo's . So I can wait and when the car eventuates the goodies get stashed away as turbo technology marches on and it all comes together . I hope I can resist the temptation to play with the RB20 - maybe just an rb25 turbine housing - see I'm hopless ! Cheers A .

David Vizard one said wire mesh restricts airflow and doesn't filter . If you can afford to rebuild your engine all the time don't use a filter . Parts suppliers will love you . Cheers A .

Would be very interested to know if any RB30 block used piston oil squirters . Cheers A .

HKS and Garrett TO4Z's use the same cartridge or CHRA (740759-5002) . The HKS turbine housings are only divided for a very short distance inside the turbine housing flange or inlet . They are not a true divided housing because the divider ends before the volute section starts and the nossle that feeds the turbine inducer blades is not divided or split . My theory only but its a remarkable coincidence that the bush bearing HKS TO4R used a split TO4 flanged housing and their TO4Z would make a lovely upgrade . A few have mentioned that they use the Garrett marketed TO4Z with single entry T3 flanged turbine housings and get good results . I think low friction ball bearing cartridges have removed the need for twin entry or split pulse turbine housings , if you look at the turbine maps at the turbobygarrett site you'll notice how much faster the BB versions get going compared to bush bearing maps . You will also notice that virtually all their BB turbos use single entry housings where many bush bearing types seem to need split pulse housings . My private theory is that a free flowing exhaust path is critical to todays emission/consumption/cat light up and volumetric efficiency requirements and a must have at lowish revs . At times split housings have a bad habbit of cracking around the divider , probably because they were designed for Diesel apps with their lower exhaust gas temperatures and don't tend to cope as easily with petrol engine exhaust gas temps unless material spec is changed to suit . There is no problem with running a single entry housing on a split pulse manifold , all VL's and most RB sixes do it like this . Its interesting that you found a HKS single low mount split pulse manifold with the TO4 flange , I thought they used the T3 split flange like the RB20/25 version does . There is a bit of controversy surrounding Garrett GT40's and GT40R's . A couple of years ago Garrett releasd a BB GT40R with I think an 88mm 52 trim BCCW series 6/12 bladed compressor like the bush bearing GT40 has . These were only on the market a short time and in very short supply - soon dried up . Then not too long ago it reapears but this time with the newer design C117 7/14 blade compressor in 88mm 52 trim . The map looks quite good but it gives no indication of how responsive the turbo is in the real world . The turbine in bush and BB form is a 77mm 78 trim UHP design . TO4Z's use an 84mm 63T TO4R compressor thats supposed to max out at 75lbs flow compared to the late GT40R's ~ 68lbs flow . This wheel has good anti surge properties which is a bonus . As to which is better ? No one seems to complain about the TO4Z's abilities , most reckon its really good and up to 750 odd Hp difficult to beat for its response . I don't have any feedback on the GT40R , I can say its getting pretty heavy and bulky for its capacity so that has to say something . Cheers A .

Hi all , there are soon to be some new Garrett T3 flanged integral gate exhaust housings in .63 and .82 a/r for the GT30R/GT3540R ranges . They are to be available in April 2006 but no details yet . This will help those who want to use GT30R's and GT3540R's but without the external wastegate . The rumor is that the dump side will look something like the Fords XR6T's GT3540R housing . More soon I hope , cheers A .

I reckon give another viscous hub a go , for the four bolts/nuts its a quick tryout if someone has one lying around . The debate about pressure before and inside the engine bay is interesting but airflow through the core is whats needed . I'll always stand by the engine driven fan as it pulls air through the core (and engine bay) whilever the engines running . As for the overheating L24 , even without the thermostat its getting halfway so either the rads RS or its not getting enough air through it . I'd be getting it hot and giving it a free rev and seeing if the fan is pulling much air (free hand in front of core saves hands/fingers ) . If he likes the car he should not have a problem with getting a new or good second hand hub . If it still overheats then Id get help with the rad . All this assumes that the head gasket is not blown or ignition timing way out or AFR way too lean . MR30's in good nick don't have cooling problems so std parts in good condition will do the job . Cheers A .

My vote goes to keeping the 8.3 to 1 , a minimum really these days with fuel prices being what they are . Detonation should only be a problem if thermal issues are not sorted , choking the exhaust with improperly sized turbos promotes detonation . Mafia it occured to me that there is one slight help for your turbo response probs but its not a ten cent option . Port shrouded compressor covers make the wheel cycle some of the inlet air so would tend to reduce the load on the turbine to a degree in the spool up phase . I have not seen the early HKS style covers with the centre insert removed but it should not be too difficult for a competent machinist to recreate . My opinion only but the increased capacity of the 3L makes the turbo choice much easier , the engine has enough torque to get the thing moving in style without boost so the turbo can be sized to enhance power further up the rev range . Turbos to suit engines of this size are closer in specification to the aftermarket offerings so you can get away from the Garrett makes it but only HKS sell it price scenerio . Something in the GT30R - GT35R range should work well and the XR6 style GT35R is at least convienent with its integral gate and air in/out pipe dimensions . Its 1.06 turbine housing would help stave off detonation on a 8.3 - 8.5 CR engine and It should not need heaps of boost to steer it on the throttle . If the budget could stretch to a HKS cast manifild they're better and give the option of an external gate if you ever choose to go that way . Cheers A .

I've got a Bluebird box kicking around here somewhere that had Stu's Aust spec 260Z/warner (brass) syncro conversion done to it . Good ratios , pity about the narrow gears and small syncro hubs . Cheers A .

Fair enough , the map I was looking at shows ~ 62lbs airflow at ~ 23.5lbs boost . Output would vary with different engines , tuning , state of tune . The 7/14 blade GT40's 88mm compressor map shows about 68lbs flow and the word is that the 84mm TO4R does 75lbs of flow . My preferences only , 88 GT40 more blades than is good for response and turbine efficiency + requires huge comp cover , 84mm TO4R wheel pumps more air and can use more compact comp cover - AND 6/12 blades good for reasons already mentioned . Everyone that uses TO4Z's (same comp) can't sing enough praise for its compressor and its non surging characteristics . Cheers A .

I was once in that situation and the fix was actually very simple . Provided the banjo bolts are too long you can selectively shorten them with a bench grinder so that they clamp the copper washers to the banjo and bearing housing . If you do grind them make sure you clean up the threads before screwing them in . If you have access to the gas torch heat the copper washers carefully and quench them in cold water , this will soften them if they've been work hardened and help them seal . DO NOT guts the bolts when doing them up , those production banjo's can easily deform and never seal . Hope this helps cheers A . I had one worse that that also , had a turbo built from a new bearing housing and one of the bolt holes was not drilled/tapped square to the spot facing - a little late to be finding out .....

I'm glad its not my money ! From other peoples hearsay the TO4Z would be a straightforward single solution and far cheaper than twin turbos - particularly twin HKS's . If you want more or don't like TO4 P trim turbines there are a couple of alternatives in the US , firstly the GT3567R From Full Race.com and secondly the 4067R from I think Precision Turbo . The GT3567R is basically a GT35R with the same compressor (TO4R 84mm 63T) as the TO4R/Z turbos . The GT4067R is a GT40R with the same compressor as the one above . It also uses the large TO4 flange as can the TO4R/Z . I think either of these would be more responsive than a GT35R with either the 94mm or 102mm compressors from the GT42R/T51R KAI/SPL . If an 84mm big trim compressor can push the air you want why chase a larger 94 or 102mm one ? Actually just had a sticky at the maps - a GT35R might just about get there depending on turbine housing a/r and drive line losses , the 3567R should romp it in . Cheers A .

For Dennis , there is a chance that the wide gear set with the big syncro hub/ring/fork 1-2 (basically FJT set) may fit the "stubbie box" , the main changes were the rear extention housing and mainshaft length (obviously) selector rods as well . Provided the mainshaft gear bearing journals are the same it may be possible to get tougher bits onto the "stubbie box" mainshaft and if she's worth it even the larger lower front bearing . It would at least look original ! Cheers A .

It sounds like the HR30's use a similar/same box as the MR30's . Could be a simple cheap fix if you found one for the right price . Cheers A . Forgot to add , if you change that lower front bearing to the smaller earlier type the "L" bellhousing should go straight on . I think my hybrid FJ/RB20 box was like that after its innitial build . It was in and out 2 or 3 times trying to get it right . For the 130 KW you may not need the hassles of the big front bearing conversion , FJ20ET's made 143/147 Kw (early/late) and they did not get the big lower front bearing and don't seem to eat them in std or mild state of tune . Bye .

If it were me I'd be checking exhaust manifold pressure as you already know what boost pressure is . Provided there's no actuator signal leaks you could check the integral gate bypass flat/flap valve to make sure it actually opens as it should . You could try disconnecting the actuator rod from the gates lever arm and see if it still boosts - it should not . I have heard of tales of less than well manufactured dump pipes restricting the valves travel and this can defeat its ability to open/bypass so it cannot control turbine and therefore compressor speed . If all else fails and you can narrow it down to the turbo (IF) , there is a slight chance it has the turbine housing off an RB20 although the chance is slim . Always try the simple tests first , can save a lot of time effort and money . Best of luck cheers A .

Hi all , don't want to lock swords with you Dennis but its the Turbo RB25 box that needs the different yoke because of its larger mainshaft and splines . Jacko and I found this out years ago when we were playing with Bluebird/DR30 and RB20DET boxes . The input and output shaft splines are the same both ends for all three as is the approximate length of these boxes . We know this because the last box he built me for the FJ Bluebird had a full set of RB20DET guts inside FJ DR30 casings which externally are same dimensions as L20B Bluebird box - except different bolt pattern for FJ block . I will never do this again because there are many differences between early and late selector mechanisms which can be hybridised but the shift quality suffers . To get an RB20DET box behind an L series is straightfoward , basically ditch the RB bellhousing and bore the lower or layshaft bearing hole in the L series bellhousing to suit the larger RB style bearing outer race . You need to use the RB's larger front bearing cover/input gear support because it suits the larger lower bearing . Now it will bolt together using std bits as per normal . From what we can see the RB71C is the last and strongest evolution of the 71 series gearboxes . It has the wide gears , the larger syncro hubs/baulk rings ie 1-2 and 3-4 . It has the later shift mechanism and all large size selector shafts . Nissan would have gone beyond these to support higher torque loadings because there comes a time when the only way to strengthen a box is to use larger diametre gears/shafts/bearings hence the larger box used behind RB25/26 turbo and N/A/turbo VG30 four cam engines . The VL-T also has a variation with slightly wider ratios which is good because you can buy a yoke to suit these big boxes that uses rebuildable uni joints . Cheers A .

It seems the emotive thing surrounds these cars in this country particularly since they blatently wiped the big eight's out in Grp A , the nuckle dragsters failed to accept what they're eyes told them in 93 hence the crowd boo fest . If I had real money to spend on cars it would be difficult to resist the temptation to own a GTR though as pointed out you'd need money budgeted to fix an old performance car . No doubt people bought cars like these to use them so its unreasonable to expect them not to have been driven enthusiastically , unfortunately the Japs don't tent to maintain their cars like some of us do and it shows in wear and tear . Sophisticated cars will have an expensive maintenance regime if not serviced properly early in life and GTR's are incredibally labour intensive because so much is crammed into a limited amount of space . I saw an R32 import being transformed into a club race car and the time that went into basically making it an N1 copy was staggering . That car went bang first time on the track , I suspect oil pump failure and trashed its bottom end ie leg out etc . Having seen this I decided I could not run the risk of buying an expensive car and having the feeling that the engine was a time bomb . Its a sobering thought that in the club race scenereo the Evo Lancers seem to trump el GTR so the truth of the matter is the icon can be beaten . Some people can't hack the feeling that Godzilla can be bettered by a two litre single turbo four but then the V8 brigade felt the same about the I6 TT GTR . So for me its to be a 2wd R32GTST which is affordable to buy and reasonably light , an RB30DET will go in to make good grunt and I'll have to live with less traction . I figure with the more sophisticated methods of revenue raising these days it will be more than good enough to drive on a daily basis if necessary . Like many I got to look round and under a brand new R32GTR but the 114,000 price tag at the time was fantasy land material . Such is life .....