discopotato03

I did some searching around to to see if thats right about S14 or 15 diffs bolting straight into R33 GTS25Ts . I need to update my information on these later short nose R200 diffs . It seems there are differences in the half shaft adapters and these can be 5 or 6 bolt , sounds like R33s are 5 bolt . I looked at lots of pics and another difference seems to be ABS/non ABS because of the pinion sensor . Is the difference a slightly longer nose needing a slightly shorter tailshaft on ABS cars ? Also , this is a link to a site showing a pic of a couple of short nose R200s and note the size of the front mounting "ear" holes . http://forums.240sxone.com/showthread.php?t=3880 I suspect the small ear hole one is an S13 diff and the big hole one next to it takes bushes to reduce NVH on S14s ? It sounds possible to coble together a 3.7 or 3.9 R200 that will bolt into a GTS25T but the agro involves the half shaft adapters and ABS/non ABS differences . Just for the record my Skyline is a 96 GTS25T without ABS and I assume has a viscous LSD which seems to work fine . So I guess the go would be to try to find a non ABS S14 diff that had 5 bold half shaft adapters - and the same nose ear hole sizes . Thoughts , cheers A .

I'll have to ask Stewart Wilkins if there are suitable crown pinion sets with the right sized crownwheel bolt sizes that will go int an R33s housing . Generally dramas surround getting the pinion height right and backlash within spec . He may also know if suitable speedo drive gears exist to make that straightforward . The earlier long nose R200s from R30 R31 and various Zeds were easier to get suitable ratios and they mounted off the same nose and removable rear cover housings . A .

No first and second are very slightly different , The big box 1st is 3.2 vs 3.3 and second fractionally shorter . Things like Aus spec 260Zs had a 2.9 1st and my Evolution 6 is 2.75 , admittedly with 4.5 diffs , in 1st . Obviously its easier to change diff gears than individual gearbox ratios . For the record what do aftermarket close ratio gearsets use ratio wise ? A .

I seem to remember the RB25/26 turbo gearbox ratios being slightly better than the eariier smaller NA 5spd boxes . An annoying thing Nissan used to do was to have a big jump first second in those NA6/4cyl boxes - something like 3.3 - 1.91 and I think that had a lot to do with people wearing out or breaking 2nd syncros if they slammed 2nd gear all the time . It used to shit me up the wall 20yrs ago when I was playing with Bluebirds and stroked L series donks with sidedrafts and later FJ20ET engines . I had Stewart Wilkins build me a 5spd based on Aus spec 260Z ratios converted to Warner (brass) syncromesh . First second was 2.9 - 19 and that was really good .To me the 25T box feels like is was designed to be short 1st to 4th and a bigish jump to that 0.759 5th . Actually thinking about if a heavier R33 GTR with 70 more lower CR ccs can get away with 4.1 diffs you'd think a 20% larger engine pulling 100+ kilos less could pull slightly taller gearing . I can see what your saying about JDM cars and their speed limits and traffic volumes . They probably don't cruise interstates at 110 for hours on end very often . Ultimately gearing is a trade off of street drag vs overall usability and for me I'd like to lean towards usability , I think with an RB30 you can do this if the engine is not a high rev drag screamer . I'm not that interested in traffic light drags or going flat out everywhere , to me a bigger engine is all about doing everything more effortlessly basically same performance with less revs or more performance with the same revs as the standard size engine . Anyhow I think 3.9 or 3.7 would suit me for how I drive most of the time in Sydneys suburbs . A .

Um no , limits to how fast you can drive a street car particularly a traction challenged one . No my thoughts were about being able to use the extra capacity to make my car easy to drive under all conditions - more flexible as in can pull any gear at just about any engine speed . I'm actually trying to guess what Nissan would have done had they used an RB30/25DET in an R33 Skyline . I have a feeling it would have been the 3.7 or 3.9 based on more torque at low revs than an RB25DET . Anyway my aim wouldn't be 350 Kw if I went down the RB30 road , probably more like 270 (Gt3076R) but able to be flexible and strong without having to wind it up . Sort of larger almost NA like power delivery . Lower cruise revs at 110 would be good and I reckon a 30DET should be able to go most places at 26-2700 revs provided its static CR was in the 9-9.5 range and it had std or something mild like 256 Poncams . Back to Factory I think slightly lighter VLTs had 3.45 diff gears with admittedly wider gearbox ratios and our porky R31s had from memory a 3.7 or 3.9 Borg warner diff . A .

Hi all , I've looked a few times and not seen anyone come up with a way to get a 3.9 or 3.7 ratio gear set into a GTS25Ts diff . A few threads I chased quoted about 120-130 revs difference per 1000 revs at 100 km/h between 3.7 3.9 and 4.1 . I imagine an RB30DET with a compression ratio of around 9-9.5:1 should easily pull 5-10% taller gearing since the 20% increase in capacity in theory should give 20% more torque . SKs way of explaining the capacity increase is to say that everything happens 20% earlier in the rev range than a 33 25DET . Anyway has anyone found a way to get 3.7 or 3.9 gears into the back of their RWD R33 and is their speedo drive pinion gears to suit ? Also I have to work out the slight difference circumference wise with 235 45 vs 245 45 17" tyres . The 245s were always more exy because they appear to be a less comon size . I should also check 255 40s to see where the rolling diameter is . Thanks in advance , cheers A .

Sorry still OT but I believe those GT3076HTAs have a lot of potential even on larger than 2-2.4L fourbangers . The GT30 turbine gets a big increase in exhaust flow capacity with even the 1.06 AR T3 flanged turbine housing and FP has already upsized to the larger 0.70 AR T04S compressor housing on this turbocharger . If I ever built an RB30 and wanted to spend money on turbos this is what I'd use and it'd be on an IW GT30R turbine housing in 0.82 or 1.06 AR . Anyway back to the GT3788R and GT3794HTA I reckon some of the gains would be from the turbine living in a housing designed for it rather than a GT35 turbine bashed into a bored out GT30 turbine housing a la GT3582R . Hopefully in time Garrett will make available to the public the large frame ball bearing GT35 turbos using the GT40 turbine housings intended for that turbine . A .

Yes I'd like a copy even in Japanese too if possible . Cheers A .

If its a locally built one with that 5 link rear end ... You may want to be sure that a 5.7L engine into a normally 3L car will get approval because I don't think allowable upgrades are based on the weight of the car any more . A .

Poor choice of words , what I ment was lacking compared to a GT4294R . From memory HKSs sollution was to use a T51 turbine and a slightly smaller trim 94mm compressor . It may be possible to buy the T51R/94mm cartridge through Garret and source you own housings . A GT4094R is just a 4088R with a 94mm compressor in a housing intended for an 88mm wheel . The 94 and 102mm compressors usually have larger housings and I think HKS had their own made up for T51R KAi and SPL . A .

That AWD Motorsports claim of this GT3794HTA being on the GT35R "footprint" is a bit interesting . I suspect they may mean the same mounting flage footpring because the BB GT37 turbos are all larger center section things than a GT3582R/X/HTA . I hadn't thought Garrett would put together a BB spec GT37 turbine with their GT94 compressor wheel . They did do a GT4094R which people I know of thought was a bit lack luster . Forced Performance seems to be doing quite well with their HTA compressor and port shrouded housing upgrades on Garrett cartridges . Not knocking what people are doing with these things or GT3788Rs but a little while back David Buschur cranked out from memory 600+ from a stretched 4G63 on E85 with a GT3076HTA , not sure which turbine housing though . Sorry if slightly OT but there are also 3 variants of the GT37BB series and the mid comp spec one uses the same compressor wheel as the smaller frame GT3582R . http://www.dieseltru...ew-t288434.html http://www.completeturbo.com/Dodge02.pdf http://store.forcedp...TGT3794HTA.html A .

The point of what I posted above was to point out that the GT3582Rs are a compromised bitzer , basically bigish wheels in a smallish cartridge using non family housings . Me personally I'd be using a GT4088R on upwards of 3 litres though probably need 3.2 to 3.4 to make it truly responsive . I can't see any big frame turbo beingw what I'd call responsive on an RB25 particularly on the street . My opinions only cheers A .

Garretts "GT3582R" is a variation of what they produced for HKS in the "GT3240R" . Both these turbos use the same series turbine and compressor but the HKS spec one has a cropped turbine and a slightly smaller trim compressor wheel . To me it looks like Garrett wanted something they could market without dramas with the HKS technology tie up . The "GT3240R" , technically in todays speak a GT3582R , is in the same situation as a "GT2835R/GT3071R right down to the cropped turbines . The trouble with the 32R and 35R is that the turbine and compressor wheels have been pinched from larger framed turbos and squeezed into smaller housings never intended to work with these wheels . With both versions they simply machined out GT30 turbine housings and bashed the 35 turbine into them and its a compromise . The compressor wheels are the same 82mm GT40 (BCCW18C I think) and both have T04S compressor housings on them . From memory T04S and TB41 compressors are 76mm major diametre with the diffusers set up for 76mm wheels . And to the center section . Garretts BB units from GT2554R to GT3582R use a centre based on a modified (for ball bearings) T25 bush bearing centre and its not exactly huge . It does Garrett credit that they can use big wheels in them without hand grenading but the GT3582R is getting close to the edge and they will bend turbine shafts if pushed hard enough . It goes without saying that they destroy themselves when they do . The large frame BB units are based on a BB conversion of Garretts GT bush bearing centre section and are longer larger in diametre as is the turbine shaft . The T series wheel versions like T04 60-1/T04Z/T51R have the four ears machined off the back of the bearing housing to form a flange so they can clamp up to T series turbine housing with crab plates - like T series bush bearing turbos do . These big frame units in GT format can only mount large frame GT40 type turbine housings which is why you tend to see them with large T4 International flange style twin scroll turbine housings . Some have single or twin entry "T3" mount flanges but they are hardly an ancient T3 or GT30 based housing . Same with the compressor side . The compressor back spacing is different small to large frame and Garrett modified GT40 compressors to get them in GT3582Rs . Housing wise big frame units tend to use GT40 comp housings and if they put modest wheels in them they just use a smaller AR like say the 0.58 one lifted of a plain bearing GT4082 . The BB GT4088R gets a (from memory) 0.72 AR compressor housing . Garrett does do larger frame GT35 BB turbos for Hino and Isuzu and they use the larger GT40 housings both sides . I have a plain bearing one somewhere and it is more bulky than a small frame GT3582R even though its turbine is the same dimensions . I know some here regard the GT4088R as dated and not the highest performance thing for a big framed BB unit , I think it tried to be a big frame replacement for a GT3582R but its harder to use because of it greater bulk and that TS T4 flanged turbine housing . Also its larger turbine even in 78T would take a bit more driving than a GT3582R . The $64 question is how would it go with the 82mm 56T GT40 compressor that is an option on the GT37BB series turbos . With the right comp housing it should all screw together but I doubt anyone would ever do it . Big frames/big turbine housings/significant lag on "smallish" petrol engines . Your calls .

The issues I see are that electric fans seldom pull enough air through the radiator and obviously a fan not running does SFA . I believe there is a reason why Nissan stuck with the viscous hub belt driven fan and thats because they pull a lot of air through the core all the time . I think many don't realise that for a cooling system to operate (read regulate) coolant temperature properly there needs to be a reserve of cooler water in the radiator , this is what allows the system to work as the power (heat load) increases . For the radiator to reject a lot of heat it needs to have a LOT of airflow through it and many elec fans just dont have enough air pumping capacity to do the job . True performance cars are different with cooling systems because they are intended to be worked hard for extended periods of time . Your average production road car is expected to be leaned on to get up to speed and then loaf along in consumption mode . The big engined car like a Falcon doesn't generally work that hard and at low loads they don't have the same heat rejection requirements as a hard worked RB26 . True race use cars should have a gale venting on their radiators because they in theory spend a lot of time well above 100/110 km/h . I believe the effective compromise is to have a large mechanically driven fan with a shroud than allows it to draw air through most of the cores area . RB is an S series is something the factory never had to find a fix for so you're on your own there . A .

Well personally given a choice a twin scroll with two external gates would give the best results I reckon on an EJ25 . The four cylinder has a very different dynamic to a straight six and it literally revolves around the 4s flat plane crank vs the I6s 120 deg phased one . Its a trade off of fewer larger cylinders vs more smaller ones with power strokes closer together . I'm not a fan of flat fours even though I own an L Series with an EA82T . Both are so far apart across the banks exhaust port wise that it screws up the exhaust manifolding and cylinder scavaging so for best results they need twin scroll headers if anything more so than an inline four cylinder . Having 2.5L to play with means more capacity for torque off boost but the cars going to be heavier as well than say a GC8 Impreza . Best most seamless system is twin scroll because it allows the engine to make more torque off and once on boost . I'm not going to ask why 440 Kw is the ask because I'd be more interested in how much torque you can get in the engine speed ranges you want to haul at . IMO the best it ever gets is torque just below which the driveline can withstand everywhere and that assumes traction isn't the limiting factor first . Anyway that aside a GT3240 is a dated thing and a compromise even in its day . Cropping a turbine is never a great way to do it because it means you have a heavy hub (innertia) for the blade area . Personally I'd look at what David Young is doing at FP with the HTA version of the GT3076R , I think Garrett may be on the wrong foot using the TO4E compressor housing on the GTX3076R and Robert must think the larger TO4S one port shrouded works better . You could look into retro fitting a TO4S comp housing on your GT3076R/GT3037S though not sure about the port shrouding without machining and welding mods . If your here in Aus you could speak to Mark at GTPumps because I think he has ears at FP an d may be able to built/modify a GT30 into a HTA version . David Buschur I believe got quite high numbers from the 76HTA on on a Mitsy 4 which you can read about if you search Evolutionm.net . A .

Thye only RD part I was checking out was the crank but its not really suitable for a 25/26 block . The stroke is really a bit long and the crank pins I believe a bit small possibly needing custom con rods . Its much easier using an LD28 crank in an L6 block because dimensionally everything is much closer to an L28 crank - except the stroke . Not that anyone cares but LD28s use FJ20 turbo rods too . Possibly easiest if the numbers are what eyes are expecting to see . Don't they all come like that ? Of course if you don't drive like a fool or venture out in packs to the known hotspots the probability of the Sky falling in would be lower .

http://www.skylinesaustralia.com/forums/topic/58134-rd28-diesel/ I read this some time ago but couldn't remember where . A .

Don't know about the crank didn't ask . The person I know that had a bit to do with race use RB30s said better with a 25 block to do a 2.7L conversion . Otherwise as mentioned . I'm sure RD28 cranks were not found to be usable and if I search I'll probably find out why . A .

Shame there isn't a 3076HTA for comparison . They are supposed to be the cats wiskers torque wise . A ,

I'd say the story is if you have to ask and it isn't a factory option you go through the mill . I suppose its not easy to make a 30 block "look" like a 25 one . My guess is that many just do it knowing that a number check is not part of the yearly safety inspection in new south cactus . Provided you didn't make a target out of yourself by driving like a lunatick it could go unnoticed forever . Insurance is probably the issue . Anyone know the current pricing of liners and spacer plate for 25 block , Harris thinks it maybe 5G and can't use an OE 30 crank . A .

Turbines and their housings are always a compromise , where you gain at the top you lose at the bottom . AFAIK Garrett and HKS only made RB26 specific turbine housings in 0.64 A/R and its questionable that porting them would make much difference . I think the way to make an RB26 wider ranging without increasing its capacity is to give it some form of variable cam timing and play with fuel octane and static CRs . Ideally more cubes but thats expensive to do as well . A .

Sounds like a deck spacer 25 "tall block" is the only sneaky wayto fly under the radar with a legit engine number .

I was just wondering if this was a way around the legal minefield to get a 30 twin cam into an R33 coupe - in NSW . I think the OS method uses very thick removable liners where I was asking about thin walled ones . I did ask one blue slip place about 30s in 33s and they said no prob based on the cars weight , not sure if thats legal in NSW these days . A .

I've been contemplating RB30s again but I don't want all the BS dramas with engine numbers etc . So I'm curious to know if its practical to bolt a spacer plate on top of an RB25 block and bore both for thin walled liners . It may look obvious to an informed eye but at least it has an RB25 number on it . Curious , cheers A .

I believe the theory behind metalic head gaskets is that they support the fire rings better if the engines sees very high non standard cylinder pressures and or detonation . Usually with HGs the fire ring moves or splits and when it does you lose the seal between the block and around the chambers . I can't see the point of overkill on a std engine especially when OE headgaskets out of Nissan are usually very good . A . Yes should try to find out what killed the original HG first .