discopotato03

What everyone does with RB25/30 hybrids in R32's . Remove the engine to block mounting brackets and slot (or redrill the holes) longer/higher . This will sit the engine lower and give some room up top . Or if you want the best fit the RB26 head and inlet manifold with forward facing plenum .

Actually there is a Garrett Ford style integral gate .82ARR T3 exhaust housing . ATP offer one as well thats supposed to be like a GT30 on the inside .

KamikaziR33 I do remember one Jurasic turbo that seemed to work on an RB30ET . It used a split pulsed (twin entry) T3 flanged 1.00 ARR T4 housing/Ptrim turbine . The compressor was a 60-1 in its native cover and back plate . The word was it tore up the pavement at 10 lbs boost . The std exhaust manifold had a fitting welded to it and a 42mm external gate . The single cam motor used a stage 3 camshaft and idled like a chaff cutter . This was about 6 or 7 years ago .

Some of that is right and some a bit controversial . You can't really separate the turbine and housing and say one is more important than the other , they are a matching pair working together . The whole GT28BB is better than T3 thing is because the light weight high speed rotating assembly can move the same or more gas wth less exhaust energy and restriction while being more compact . The ball bearings have less drag losses , particularly at low shaft speeds , but far better shaft support and longer life . Compressor trims for the GT wheels are mostly between 48 and 56 and turbines 62 and 90 . 76 to 84 seems to be the sweet spot . Garrett list 6 six bladed 60mm T3 compressors from 35 to 60 trim . There are so many variations in what people loosely call T3 turbines that its not funny . Its safe to say that GT BB turbos are generally wider range devices but if badly speced or sized don't expect top shelf results .

You have some conflicting information and there are lots of variations in the 2835 series . You describe it as a 56 trim compressor while its ID tag reads 52 trim . There are 3 HKS turbos listed using the 700177-0002 CHRA . Generally the variations are housing style and ARR . From what I can tell the compressor covers on all HKS2835 series are .50 ARR T04E . What they call GT2835 have 70mm (2.75") inlet barbs and 50mm (2") outlet barbs in 380/400/410 PS versions . The GT2835 "Pro S" and "R" versions are 100mm in and 50mm out . HKS lists your version as using a T25/28 flanged GT30 external gate exhaust housing in .61/.73/.87/1.01 and 1.12 ARR's . The .86 ARR housing you mention should be a T25/28 flanged GT28 integral gate housing . Garretts engineers don't like the GT30 based turbines when used in bored out GT28 housings and prefer them in GT30 housings . That turbo on offer would be a really good thing if it had HKS's GT Pro S integral waste gate exhaust housing on it . I'm curious to know what a good deal means ie good price or good sales pitch . The choice of exhaust housing will make or break its effectiveness and if it has the wrong flange for your manifold the effort to make it fit is not cost effective . To get the best out of it on the RB's exhaust manifold it needs that housing which has the necessary T3 flange to bolt up . Good turbo "deals" often go sour when fortunes are needed to hang them off the engine . So if its a $1000 turbo (yeah right) I'd grab it , it its a $2200 turbo I'd ask them to lightly grease and ....... Cheers A .

Look into the compressor inlet , if you see seven blades (seven full and seven splitter blades) its not a GT series compressor and won't perform like one no matter what housing is put on it . I'd be asking the retailer to swap it or pay the difference in price for the real one . Garrett specifically calls it the GT30R so if they won't play ball demand you're money back and go elswhere , you did not ask for a GT30/T04S so why did they sell you one . This problem keeps coming up because any turbo wearing a GT30 turbine and ball bearings gets called a GT30R , I can think of 14 different cartridges that do and probably 6 of them are good on petrol engines . Cheers A .

If its not going to fit take it back and ask for what most people consider the most suitable "GT30R" . Yes it will have the .60 ARR T04E port shrouded compressor cover and the propper or GT series compressor wheel . The turbo part no to ask for is 700382-12 which uses cartridge (CHRA) no 700177-7 . This is the better version Garrett retails . HKS (rebadged Garrett) sells a version of the GT30R (they call theirs GT3037) with the same GT series of compressor but in 52 or 56 trim and with a .50 rather than .60 ARR compressor cover on the 52 trim version . This version is supposed to come on boost 500 rpm lower than the 56 trim version on an SR20 so better but at what cost . Its cartridge no is 700177-6 , may be out there somewhere 2nd hand . Garretts GT3071R (CHRA 700177-23) is supposed to do a similar job but I don't think anyone's tried it with a .63 GT30 exhaust housing on an RB20 . It uses the same compressor cover as the 52 trim HKS GT3037 and is about as compact as they come . Cheers A .

After reading SK's comment on Mercury CDI coils I'm curious to know if the PFC can be made to work with any kind of multiple strike CD ignition system . I don't know anything about the HKS Twin Power but could it work . Also for SK , what mods if any are needed to fit the Mercury coils on an RB cylinder head . Any means of more complete combustion interest me but like everything there's a financial limit . Cheers A .

If its what I think it is the boost threshold will be high and transient response only Ok . Have a look at the numbers on the tag rivited to the bearing housing , would one of them be 700177-12 or -15 ? The 7 blade compressors are not GT wheels . To get these in a proper GT30R use turbo no 700382-12 , though probably still pretty big for an RB20 . The GT3071R (CHRA 700177-23) in small .63 housing form would be the most responsive GT30 based turbo . Even the larger capacity GT28 based turbos can be lagy on RB20's , what sort of power curve are you looking for ? Cheers A .

Nope Racespec your wrong , go and have a look at the old Garrett Cataloge PDF . Cartridge or CHRA no is 700177-23 . Its also shown in the new cataloge (turbobygarrett) BUT only in the comparison sheet . Its the third of the three GT3071R types listed as 420 , 425 and 450 Hp . This is a generic cartridge that you option housing kits for if it comes from Garrett . ATP will sell a complete unit with optional housings . No one has offered it yet but there's nothing to stop you using the comp cover off the GT2871R 56 T which is .60 ARR T04B . 700177-13 is GT30 turbine + 76mm 60Trim T04S compressor . 700177-14 is GT30 turbine + 82mm 56 Trim GT40 compressor . Cheers A .

I'd say you hit the nail on the head Cubes , if a turbine side is causing a major restriction uncorking it pays off . It makes me wonder if the small turbine and housing combination had some emissions benefit - sort of heat and a little forced EGR . Notice how at times larger ARR turbine housings pull the cork out and unleashes a few ponies with no change to the compressor or cover . I guess it comes down to how well the sysyem was designed in the first place and its aims . The combination I always wanted to see on an RB20 was the 25 exhaust housing on an otherwise std turbo , how much gained compared to how much lost . At least it should all fit and look standard . The GT3071R (-23 CHRA) is biased toward exhaust flow turbine wise so may not need big housings to make it work depending on the desired state of tune and engine size .

That was all about non std wheel offsets and spacers . Why would you want 3" studs ? Nissan did have an issue with short std studs and alloy wheels but the R31 GTS studs fixes this .

Another thought , those sexy Nissan four piston calipers are not exactly the bees knees - even the R32 GTR ones . For their bulk the pistons are not very big . I have seen VT floating calipers on an R30 that worked very well and it was using 304 x 28 disks with 24 offset 16 x 7's . A very cost effective upgrade for no compromised bling bling ...

Sorry I should have been more specific , need rims with the right offset that clear the calipers . Most late style rims are like this . RTA hates spacers and long studs because they make the wheel put higher side loads into the ball joints and wheel bearings . This is because the track changes by the total thickness of the spacers and also screws up geometry of in this case zero scrub offset . Bump steer is also not desirable . People have a bad habit of wanting to "fill" the arches and often with over width wrong offset wheels . Also this "dumping the front or nose on the deck" ride height stuffs it all up . This look the part mostly wont work the part but it does show up the wallys , sorry if this offends but I will never compromise function for looks . The manufacturers are not as silly as many think .

Hi Cubes , how do the numbers run for the manual VLT ? I think the final drive was 3.45:1 but it used a 3.6 1st wide ratio box and 205/60/15 ? Also how does the weight stack up compared to a typical RB30DET R32 2wd ? Cheers A .

I doubt R30's have Australian compliance for them .

Easiest is the R31 GTS studs , about 1/2" longer and not dear . At least you can say they're factory parts .

Guys that HKS GTRS is really just a GT2871R with a 52 trim compressor . Comes on song at 3700 on an SR20 ? My US SR contacts claim the larger HKS GT3037 52T spools at 25-2700 rpm and would easily out gun a GTRS . The 3037's are using the T25/28 flanged .73 ARR HKS GT30 exhaust housing and usually the RNN14 GTiR exhaust manifold . That GT3071R at the GCG site is not the same as the one from ATP turbo in this string . The only way to make it work properly is with the HKS GT30 style exhaust housings . All the ones using GT28 exhaust housings are dogs - wrong type of turbine housing for the turbine . Cheers A .

Walking on thin ice guys , spacers and stud mods are illegal . I wouldn't want to crash it and get caught because you'll wear everything . That aside the effective wheel offset changes with spacers as does the track . The most common dramas are heavy steering and bump steer . There are wheels out there with the right offset that clear the brakes though 7's are the sensible limit on the front of an R30 . I lucked out and got the right wheels on my DR30 .

No VVT RB26 in factory trim . The only RB25 without it is the NA one from the R32 RWD version . The head/block water passages are the same as the RB30 and fit without mods though need extra tensioner on the block and a different cam belt . See the Forced Induction section of this site .

I just had a quick look at the HKS GT3040 which uses the 50T 82mm GT40 compressor in a .60 ARR cover (quoted as 500 PS) unlike the Garrett GT3540R with its 56T comp and .70ARR cover . On ya HKS , free development work through online specs - I like it . Cheers A .

I'd say the largest ARR cover will offer the lowest gas speed for a given wheel speed . The lower ARR covers will pull the optimum gas speed down the compressors flow and speed range . I was asking a fellow who used to do lots of custom turbo work years ago about this , he said the larger ARR covers make the turbo hit hard when the gas speed gets up where the lower ARR ones tend to be more progressive . Note HKS's GT3037's , the 52 trim version uses a .50ARR cover , the 56 trim version uses a .60 . I'm guessing the gas speed is similar but the ARR goes up with the higher flowing 56T because of the greater mass flow . In my perfect world I want the 50T GT40 82mm wheel with a T04S .50 ARR cover because I think it would put the ideal air speed where in the engines speed range I want it , not where a 6L GM/Detroit or whatever needed it to be . Sadly HKS (they optimize things for petrol engines) didn't option a GT3540R . I basically want the same sort of result that WilliamsF1 got but with 3.1L and one turbo .

Quote : Compressor Design . The centrifugal compressor consists of three elements which must be matched to each other for optimum efficiency : The impeller , the diffuser and the housing . The compressor impeller rotates at very high speeds and accelerates the gas passing through it to a high velocity by centrifugal force . The diffuser acts as a nozzle in reverse , slowing the gas down without turbulence . This causes it to increase in pressure and , unfortunately , in temperature . The housing around the diffuser is used to collect this high pressure gas and direct it to wherever it is used . He also goes on to mention static and total pressures , a static probe into a compressor cover is not affected by the velocity of the gas . A total pressure probe measures the static pressure plus the velocity pressure of the gas . A static pressure tap could be a hole drilled at 90 deg to the direction of flow through the housing eg waste gate actuator pressure supply . A total pressure tap could look like a small "L" shaped tube with its hole facing the direction of the moving gas . In this book its called a pitot tube . Aircraft use them in the wings leading edge I believe to measure air speed which differs to ground speed . So my understanding of the real world comp cover ARR is that because of the larger passage size of the higher ratios all else being the same the gas speed will be lower out of the cover . I reckon a set volume of gas moving at a higher velocity has to benefit our humble piston pump (engine) more than the same volume at slower speeds . With the Foulcoon Ford were not looking for really high performance so for the lowish boost pressure (4-6) , the GT40 compressor is not working very hard and compressor efficiency does not need to be brilliant at the flow rate required . The GT40 82mm compressor is usually found in T04S covers and back plates but I think its the larger diffuser area from the "S" cover and back plate that becomes critical at higher boost pressures . It would be interesting to know if Garrett make smaller ie .60 , .50 ARR T04S comp covers for the 82mm 56T GT40 compressor . That way you could get the best of both worlds ie the larger diffuser area and some control of the cover velocity to get decent total pressure . If you look at the specs of the GT40R it uses a fifty something ARR comp cover but I think its for an 88mm compressor - more searching needed . In Corky Bells book Maximum Boost he quotes some figures for gas speeds that he feels should not be exceeded for exhaust and inlet air , I don't have time to find it now but maybe later . Please do not take my ramblings as gospel as its only my current thoughts and not based on experience . Cheers Adrian .

There is a section in Hugh M's book on turbocharging that describes the workings of the comp cover . My understanding is that it sort of the reverse of the turbine and exhaust housing . Its about converting high velocity to high pressure without turbulence in the diffuser . I think its safe to assume that the larger the AR the lower the gas speed will be for a given mass flow . More tomorrow cheers A .

Cubes if your not sure wait for some results . Your own experience shows what happens when the restrictions were removed from the exhaust side . If it makes you feel any better I know of one RB30DET that uses a GT3540R that has the compressor side of a GT42R grafted into it (102mm comp wheel) and it spools at around 33-3400 rpm . The F'n Orrible Rusty Device is a late emission engine with drive by wire throttle and all sorts of torque limiting devices . Your R32 (probably 400 Kg lighter) and tuned for performance should eat it . By the way have you put taller rear gears in it yet , that should make it feel better . Cheers A .