discopotato03

I suggest you get water from the block not the radiator and return it to the head somewhere near the top rad hose barb . Water can only bypass the thermostat if you plumb it to do so . My FJ20 got it from the blocks drain bung hole and retured it to the heads thermostat bowl area , we drilled a hole and tapped it for a brass barbed fitting . If you access water on the wrong side of the thermostat the water pump draws water through the new water line plumbing . With an RB that has the thermostat at the bottom hose you would use the std water source at the back of the block or go looking for a lower drain bung hole if it was an early non turbo spec block . The water plumbing does not have to be vertical it just has to slope uphill , what you are avoiding is a trap (think toilet S bend) where air can sit in a hump or high point that isn't the top end of the plumbing . A .

These are 17" wheels not 18 - 17 x 8.5 x 30 .

No it grew a GTRS 256 Tomeis and larger exhaust valves . Handling aside from traction is is unchanged . Does anyone here run 255 40s on 8 1/2 inch wheels ? I found they are Rays Nismo 5 spoke LMGT4s and that makes them +30 offset . A .

If you can move your cams around with adjustable pulleys you can change your ovelap timing . Uh , not really sure what you expect to achieve with more overlap because thats more a scavanging thing than a cooling thing . Generally turbo engines don't like a real lot of overlap timing because the static compression ratio is often lower than NA versions and you have an exhaust manifold and turbine housing designed to get a turbine up to speed quickly . Until a turbo actually does something it acts like a small system restriction on the exhaust side and a low engine speeds and loads (low exhaust gas velocity and pressure) mostly all wider valve overlap timing does is increase exhaust gas reversion back into your cylinders . Hot gasses going backwards before the exhaust valves close and shut it off . The other thing wider overlap timing does is decrease you cylinders "trapping efficiency" at low revs which reduces your dynamic or effective compression ratio . Any engine and moreso a turbocharged one is a "system" meaning a certain combination of components achieve a good overall result . Things like static CR cam timing ITBs exhaust manifold and turbos turbine sides all have direct affects on how the system works . Changing one thing can mean the system is now incomplete and does not work as well as it should . Manufacturers change things and alter others to compensate to get the good overall outcome . All this aside you obviously have concerns over piston temperatures and it would be good to know whats raised these concerns you have . If its to do with running std or even std NA pistons there are ways to make them better but they have to be removed and coated and it could be easier and cheaper just to use new OE turbo pistons . Again generalising but OE Nissan turbo pistons are pretty good but hardly F1 standard and mostly don't need to be . The thing with turbocharging NA engines is doing everything you can to reject more heat because the NA system was not designed to do this . Better radiators and particularly oil coolers are a must and do anything you can to eliminate detonation . Warmer cams are about making an engine breathe better and make power at higher revs than standard . OE turbo cams are about making a lower CR engine have acceptable power (and economy/emissions) off boost and good mid range torque with boost . Using OE turbo cams with NA pistons isn't always the answer because again they were not designed to work together as a system . I would think that slightly warmer cams would be Ok on a NA+T engine though a little less hotside restriction would help too . My old Subaru RX Turbos EA82T has NA cams in it but its running a tad higher CR and a much higher flow turbos hot side and manifold than it originally did . Needed all the breathig help it could get and NA 256 cams were better than the std I think 248s , I don't think the few extra degrees of valve overlap did anything significant for it . A .

Virtually all engine blocks have a water drain plug near the lowest point in the blocks cooling jackets . Simplest way is to remove this plug and drill it out so you can braze a water or fuel line barb fitting in it . This becomes your turbos water supply line . It must run uphill all the way to the turbo . It works best if the turbos water outlet line runs uphill to a point close to the engines main water outlet near the top rad hose The logic in this is that your engine is hot enough at shut down for the thermostat to be open . The trouble with picking up water at the radiator is that in some circumstances the engine wil draw water through it bypassing the thermostat and running you engine cool at low revs and light loads . As was said the reason to water cool a turbo is that oil flow stops after shut down and the turbo has considerable heat energy stored in the turbine housing - and exhaust manifold . IMO if retrofitting turbo water cooling I wouldn't worry about finding ways to have the cooling system pump water thriugh it for running cooling purposes . The critical time is just after engine shut down and the turbos water cooling system has to thermosyphon because the water pump has stopped so isn't moving any coolant . Thermosyphon means hot water rises (hot water is less dense and lighter than cooler water) and the rising heated water draws cooler water behind it . You MUST ensure turbo water lines run uphill because if they go down then up steam bubbles can form a vapour lock and the water flow can stop . If this happens and your turbo boils all the water out of its cooling jacket you are back to square one meaning no cooling . If you set it up right and can hear a boiling gurgling sound from your turbo after shut down don't panic , this means its working properly and the boiling water exiting the turbo is doing its job by transporting the heat elsewhere ie up and hopefully out to the radiator and in my old FJ20ETs case the overflow bottle . I wouldn't waste money on fancy braided lines , for Garrett BB turbos I get 2nd hand SR turbo water lines and banjo bolts and run steel lines far enough away to escape radiated heat . Then I link the system up with good quality EFI fuel hose because its more than good enough to withstand cooling system heat and pressure . Simple cheap and works , A .

I bought this car must be 5 years ago (I think) off a member here and he'd just had the full SK Garys Whiteline Bilsten kit fitted new and its done ~ 11000 Km . Tyres wearing evenly and it drives straight too . I have no reason to believe any settings have changed back or front . It was set up to Garys spec and while I speak to him occassionally I can't remember his numbers off hand . My guess is that its partly that dryer and its ability to make good mid range torque . Its not impossible that these tyres have gotten a bit harder over time and for much of the time with me this car did very few miles . I must ask Gary if they used the GTR diff stuff in their R33 which saw a bit of track use . I think I'd prefer a CLSD to the S15s torsen and I like the idea of the larger stubs axles and hubs . I run my tyres at slightly higher pressures than most ie ~ 36 hot because I find they wear more evenly and give less rolling resistance . Could try them back at 32 33 and see what happens , cheers A .

Feeding unburnt fuel through an engine achives nothing . The only way fuel could ever cool anything is when it evaporates and you get a charge cooling effect . When you burn fuel you generate heat - thats its purpose . Heat = thermal expansion = pressure rise to push the pistons down on their power strokes . In theory a rich mixture burns cooler than a lean one but thats a simple rule of thumb because too many other factors ie ignition timing play a part in combustion temps . If you were paranoid about piston temps you could ceramic coat the crowns and use oil squirters to transfer some of the heat to the oil . I'm guessing that you have read about running slightly richer mixtures under load to reduce combustion temps . I reckon the point is an engine with a closed throttle (over run) has a very low dynamic compression ratio because the throttle is literally strangling it and the cylinder filling efficiency is obviously very low . Because its so low the mass of air going through the engine will be also and the AFR to get even a reasonably rich ratio ie 11 to 1 is going to take stuff all fuel . The piddling amount won't have the capacity to absorb much heat so I think it would achieve SFA . I think the best over run cooling idea is to have no fuel at all because reasonably cool air goes through the engine unburnt meaning no combustion heat what so ever and the engines cooling systems are still operating so for any significant amount of time the engines internals will cool further . Most will tell you that the highest temps occur in modern engines at part throttle cruise because of the lean running conditions . Turbo engines manufacturers style typically run reasonably rich under load beacause they are not intended to run at full load for any length of time and the extra cooling adds reliability . The question I ask is how often and how long do you expect to have your engine in over run mode ? If you can tune your computer by all means richen it up on over run , I think all it will do is cough and fart and foul you plugs , and make throttle response a bit wooly until it cleans itself out once on throttle . You may also risk slight bore washing and some extra cylinder/ring wear plus a bit more fuel contamination in your oil . Your call , A .

Are you willing to sell the rear hubs shafts and stub axles without the diff ? DPO3 .

Seriously this not dial up 5000 revs and "drop" the clutch kiddy style , this is take off at part throttle and increase to almost WOT and somewhere about 3800-4000 just spins and gets a little trampy at least in first . Second is sort of similar but watching the road so guessing similar sort of revs . Also I'm talking about that smoothish hotmix road surface not that gravelly secodary road type stuff . It did it to me out of a two lane roundabout recently in second and the road wasn't quite straight , that 96K old VLSD is doing somethink because it never single spins like open diffs do . It got a bit out of shape and needed hauling back into my lane . I would have thought that Michelin Pilot Preceda 2s were reasonable things and they don't have much more than 8-9000 on them and plenty of tread depth . As I said 235 45s on 8 1/2" wheels and the rims look wider than the tyres . Theres a chance that 255s would sit outside the bodywork and thats not acceptable . Wheel offset escapes me ATM but I think its the same 34 as my Evos RPFIs have , exact same dimension all round actually . I think I remember looking at 245 45s when I bought those tyres and they were considerably more expensive in the same type of tyre . I gather 245 45s are a bit of an odd size and lower volumes make them more expensive . I researched the GTR diff bits into RWDs and if I could find the bits for reasonable money I'd give 1hat a go . I'd just swap centers and fit the rest outwards from there . I reckon one of these CLSDs set up to std specs would be livable in a street car , not really interested in hops skips etc round slow bends driving in citizen mode . Cheers A .

Story is this , have mild RB25 just GTRS and R34 SMIC SK Bilstein suspension Rays 17 x 8.5s with 235 45 Michelin PS2s and I can't get this car to hold its feet in the dry when it comes on boost with the boot in - in at least 1st and 2nd . Not sure how much of this could be from that VLSD or just Skylines less than even weight distribution front to back . To save me finding out the expensive way do mechanical LSDs and bit more rubber make a worthwhile difference or not really ? I suspect 245 45 or even 255 40s would go on 8.5 inch wheels but does it make much difference ? It kind of defeats the purpose of having more than 2.5L if the std capacity donk makes more power than these cars can use . So , is this a my car thing or just the nature of RWD Skylines ? Cheers DP03 .

From my research there are two differenf nose lengths on "short nose" R200s . The one with the cross wise sensor in the nose is about 3/4" longer than the ones without so for a bolt in I think you need one with that sensor to match your tailshaft length . The diff and tailshaft are matching pairs length wise . The alternative is to remove your std diff assuming its ratio is right and swap the hemisphere for something better and get the side stubs to suit you inner rear joints . A .

Hi all , can someone link me to a Nissan service manual on R32/33/34 R200 clutch LSDs please . I'd also like to know if any or all GTR R200s used solid pinion bearing spacers because these make it a lot easier to change inlet drive flanges if you use these diffs in cars with RWD style tailshafts . It would have been good if all short nosed R200s used solid pinion bearing spacers but I think the ones in S platforms had the crush type ones instead . Also for the record were there any significant changes to diffs stubs axles or hub bearings from R32-R34 GTR clutch type LSD rear ends - aside from the 34s ratio ? Cheers A .

I haven't had time to read right through this thread http://forums.hybridz.org/index.php/topic/64241-short-nose-r230-and-r200-info-and-why/ but it looks to have useful info on some late short nose USDM R200s and R230s . It probably answers the questions about the larger stub (6 hole) and axle size used in GTR spec R200s and I'm guessing Z32 TT R230 diffs . A .

GTR diff in S13 Link . http://w3slide.blogspot.com.au/2011/09/gtr-rear.html A .

I'm sorry now I didn't post another link to a pictorial of a GTR diff/axles/hubs conversion into an S13 . They just removed the S series bits and bolted the above GTR bits straight in . The only mods are because S13s have the small plain front diff mounting holes and GTRs have the later rubber bushed system meaning larger holes in the front diff mounts to fit these bushes . Other than this and the GTRs unique companion or front input flange it just about falls in . Its good to see that the steel uprights or knuckles if you like take the larger spline size GTR hub bearing assembly and I certainly wouldn't be changing to the aluminium one in a road car . Can't see the sense in having to do rear struts just for the ally knuckle . Its seems obvious than a late R200 is an R200 is an R200 . The only major things that are going to trip you up are the nose lengths (front ABS/non front ABS) and the stub axles because they have to suit the diff centers splines/lengths and obviously your choice of half shafts . I cant see anything stopping you using a GTR mechanical LSD in any of these diffs provided you use the matching stubs half shafts and big spline hubs . What will limit your choice in a 4WD car is available front diffs to match the rears ratio to . For a RWD R33 using GTR bits seems easy because 99% of it looks like it goes straight in - well to a non ABS car like mine anyway . If you found a non ABS diff in whatever ratio you like I reckon a GTRs LSD center would go straight in and then you just work out from the GTR stubs to the hubs . Your choice of ratios and in fact if you used your own diff as a basis it all goes together by the look of it . A .

I thought it was possible if you could get the R32GTS4 diff bits . The reason is I'm not into street racing and I don't drive street cars flat out everywhere . Also as I keep saying these cars are traction limited and what I like is high average torque everywhere . I'm not so sure a 400Hp Rb25 is going to pull well down low , some will but a lot depends on how you went about getting 400 and what that did to its low down performance . Same for the 600Hp RB30 . I think with a bit of thought an RB30 designed to pull from nowhere revs will have strong part throttle torque and acceptable full throttle power . You do realise that a 5% difference is 50 revs per thousand so 150 revs at 3000 . A .

Thanks for your input jet , what do you think was the best general purpose diff ratio you used? Part of the basic question for me is can I better use the torque my engine has if I load it up a bit more for the same road speed . What I find is that both the Evo and the GTS25T make good torque but at part throttle with even low revs in low gears they seem to go nowhere unless at WOT , so the only option is to short shift them everywhere trying to find enough load to use the good part throttle torque they have . The idea behind slightly taller gearing is to have a bit more load on the engine from a little less gearing reduction , its not about moonshot speeds at the redline in 5th gear . I understand the bit about having slightly improved traction control when the engine comes onto boost and the torque multiplies over a narrow rev range . If the gearing is taller the process should take a little longer and I think its because the torque multiplication not ganging up as quickly with the gearing reduction and overwhelming the available traction . I'm not Robert Godard and I think the potentially better fuel consumption comes from a slightly more open throttle at highway speeds at lower revs - a bit better cylinder filling meanig a slightly higher dynamic CR . If your 5th gear is going to be a real overdrive its probably not realistic to expect it to be usefull at less than highway speeds - meaning 80-90+ . Anyway unknown to me but I find it impossible to believe that a 20% increase in engine capacity for a 5% (3.916) or 11% (3.692) increase in gearing wouldn't be better everywhere than the std RB25 4.11 combination . Should have more torque everywhere and 5-10% more load for the torque to push against . Actually if you crunch numbers compare a 2L R32s 4.363 gearing with a 2.5L R33s 4.111 (25% bigger engine) the gearing difference is 6% so if you follow the trend its likely a 3L R33 would have had 3.916 (+5%) gearing at least outside Japan . If you want to compare any two diff ratios divide the numerically smaller into the larger and mulpiply by 100 ie 4.11 / 3.916 x 100 = 104.95% . My suggested three litre 3.916 ratio is 111.34% - 11.3% taller than the two litres 4.363 diff ratio . Had the comparison been 3.692 to 4.363 the increase is 18.2% for a 50% increase in engine capacity . I wonder what the final drive difference is between a 3.6L and a 6.2L Dunnydoor , cheers A .

Sigh , I didn't want to look at GTR rear diff parts but you chase enough Nissan forums and the R vortex soon drags you in . I don't know if this deserves its own thread but I suppose stronger/est rear diff bits goes with RB30 territory . So far I've read that GTR R200s are short nose diffs without the ABS sensor and slightly shorter (for short nose R200) non 3 chanel ABS snout . The main difference seems to be larger splines and stub shafts , and the 4 channel speed sensors on these stub shafts . Also the output flanges are 6 individual hole ones . People say these can be fitted to S13/S14 and I'm guessing R33 GTS25Ts if you use GTR half shafts . Theres also talk about GTR alloy hubs which I think must be uprights that use larger rear wheel bearings . Do RWD R33s get these too but with 5 hole stub axles ? Anyway I think it may be possible to graft a GTRs hemisphere into a GTS25Ts or S14s R200 but you have to change stub axles half shafts and not sure what else out at the knuckles/uprights . Thoughts , cheers A .

Another article from Zilvia Net in the US . http://zilvia.net/f/s-chassis/200226-shimming-r200-j30-vlsd.html I would NOT do this viscous hub "overshim preload" business because I think its a cheap rather than a long term way to have a partially locked diff center . The reason I'm posting the link is because it shows in pics how to remove the carrier from a short nose R200 and how to open up the hemisphere to get to the viscous hub . Also on the second page someone posted an exploded diagram from a WSM of a 350Z short nose R200 . I must have joined Zilvianet and was last there 5 1/2 years ago , I searched "R200 VLSD" in the S platform section and have about a weeks reading to do . I really want to open our world up to these later R200s because most Aussies don't seem to know all the variations and what can be cobbled together to suit everyones needs - like a 3.7/3.9 VLSD bolt in for R33s . Or even aftermarket LSDs . A .

The only std Torsen diff center I know of came in S15 200SXs . This is an interesting article someone put up in an American 240SX forum , USDM S13s and 14 came with KA24E and KA24 DEs just in case anyone didn't know and as is mentioned they had a 4.08 R200 std . http://www.ka24development.com/vlsd.html Note the second pic shows two nose lengths used in "short nose" R200s , the 3/4 inch longer one has a speed sensor in the nose and uses a shorter tailshaft . I'm guessing this was for 3 chanel ABS and later 4 chanel ABS had sensors on each half shaft adapter ie 5 or 6 bolt bit . My R33 is a 96 non ABS car and it'd be good if someone can confirm if ABS GTS25Ts used speed sensors in the front or sides of the diff . Fingers crossed its the sides because then the case lengths and tailshafts will all be the same - manuals anyway . Again to try and sum up I think it works like this for "short nose" R200 non GTR diffs . 1) I think all short nose diffs use 12mm crownwheel bolts . 2) Half shafts are 5 or 6 hole . 3) Viscous LSD units have different length half shafts . Open center ones are same length and same spline as long nose R200s . 4) There are two lengths of short nose case and pinion , front sensor ABS and the shorter non nose sensor type . 5) The critical thing to find is the ratio you want and the correct nose length , see point 4 . It occurs to me that once you have the desired ratio and case length the half shafts and carrier from your standard diff should transfer in easily enough which gets around the spline and half shaft compatability issues . I've been here before years ago and compared to H190s R200 are easy to pull the carrier swap crownwheels and drop the assembly back in . 200s are easy because the spacing/preload spacer shims are outside the carrier bearings outer races and you can select fit them with the bearing caps off . The only unknown is any carrier offset differences which exist in some diff families to work around the diameter differences in pinion gears . If ratio differences are set by the crown tooth count rather than big differences in pinion teth numbers/diameters the carrier offset problems aren't as great . A .

Try punching 2838 revs into that table above and you get 110.2 something revs in 5th gear , I was just going by what my gauges said which looked like 2900/110 . I'll try the table again with the 3.9 and 3.7 and see what comes up at 110 . Partly what started me thinking about expressway cruise was driving an XR6 back from Goulburn recently and it was sitting on about 1750 revs at 110 by it gauges . I realise that these have a 4L engine and late auto but its not a lot of revs to cruise most places at 110 . The trouble is I've never had the RB30DET experience so I'm only guessing how much extra torque they'd make in the 1-3000 rev range . If I did one I'd want every Nm I could squeese out of it in this range because getting more further up goes with the territory . I think a 30 to my 25s spec but with a slightly higher 9.5-9.6 static CR should feel significantly stronger at part throttle which is where my car spends 85% of its time . With all else being equal I think unintentional traction loss would happen more often and its already a slight issue and thats just running off actuator pressure , actually I tkink the FC was set at 12 for the OE dryer . Obviously I'm different from most SAUers in that I'm not looking for a million Hp just more average torque , I doubt I'd ever track this car and just want something strong enough to get in and out of the traffic and breeze down the highways . As I said it would have been interesting to see how Nissan would have done a 33 30 combination . The closest thing I can think of is the 2JZGTE Supras and I'll search their gearing as well . A .

Interesting to plug a few numbers into that table , the differences are greater than I thought though the 3.9 ratio diff puts me about where Id like to be based on revs in 5th at ~ 110 - about 2700-2750 vs around 2900 . I just find my car feels undergeared and I'm always short shifting it and it pulls 4th and 5th around at low revs really easily . If an RB25 can do this then an RB30 should be able to do the same or better with slightly taller gearing ie a 3.9 . My RB25 isn't factory and the things done to it were intended to make it a bit stronger everywhere than std . Things like its head was cleaned up by Harris and has oversized exhaust valves and was decked to give ~ 9.3 static CR , 256 cams and a GTRS . You accelerate out of corners in first and second with less than full throttle and it wants to spin the first two gears in the dry as soon as it makes any meaningfull boost . PITA if the road isn't straight and it wants a bit of someone elses lane as well , ole' goat like me gets strange looks driving one of these things when it gets a bit out of shape ... Anyway my next searches are going to be for info on R200 crown wheel bolt sizes , I think Skylines used the larger 12mm bolts at least in GTRs all /R33s /R34s . I've seen some peope posting that S13s use 10mm bolts and the S14 and 15 turbos 12mm bolts . If I do start playing with a short nose not ABS 3.9 R200 I'd like the larger bolts so that nothing is a backwards step strength wise compared to my std one . Cheers A .

Yep I can understand that , I screwed around with H190s in 3.9 and 4.375 with the FJ Bluebird years ago . The trouble is you virtually end up with a four speed gearbox and a low speed crawler gear - 1st . I should look up USDM S14 240SXs to see what diff ratios they used . Obviously more torque down low than an SR20DE/T cranks out so I'm going to predict a 3.58 or a 3.69 . Will search later , cheers A . Actually speedo drive gears for the larger 25T style box , whats available ?

This is an interesting thread I found over as NS.com re R200 diff ratios and diff swaps . It seems S14 and S15 diffs may be the answer with a bit of stuffing around but sounds easier than changing crown wheels and pinions . The Silvia people are trying to go to shorter (numerically higher) diffs and using R32/R33 bits to get into 4.1 and 4.3s . http://www.nissansilvia.com/forums/index.php?showtopic=337751&st=0 The thing I don't know is about the drivers side stub shaft adapters (5 or 6 bolt bit) as in the above thread there are pics of these stub shafts in two different lengths . I think I remember reading about these in American Nissan forums years ago and the longer stub/half shaft was a viscous center thing . Fingers crossed S type and R type viscous diff half shafts are the same length internally . Also the crownwheel bolt diameters . I know there are two sizes in H190 and possibly long nose R200s and the crossover was probably 4 cylinder to six cylinder . Lastly note that in the NS thread they mentioned that JDM S14s had shorter diff ratios than ADM ones , I think it was 4.1 vs 3.69 . This makes me think that had R33s been sold here they probably would have had 3.9 or 3.7 diff ratios std - for our slightly higher average speeds ? Thoughts , cheers Adrian DP03 .

Would it have to be a non ABS S14 diff to suit a non ABS GTS25T ? Also do the S14s have the same viscous hub LSD as an R33 , and the larger crownwheel bolts ? And lastly whats the story with S15 LSDs , is the helical center a Torsen LSD ? Cheers A .