discopotato03

I personally think if you had money to burn go all out on a 25 Neo Turbo head casting . Smallest chambers and better piston crown design . Granted a bit harder to get 26 spec inlet manifolds on but at least the variable inlet cam timing is free . Correct me if I'm wrong but I don't think the RB 26 head castings changed much if at all from R32 in 1989 till the last of the R34s in what 2001 ? The piston crown design is quite basic - big decked plateau across the middle to get a barely acceptable static CR . 8.5 is really low by todays standards and a bit pathetic IMO with ethanol fuels . I seem to remember the GMS engines being more like 9.6:1 particularly with restrictors and later less boost . They were not slow by any means . I think the formula is smaller capacity chambers with a flatter piston crown design . I reckon if Nissan had the money to develop the 26 right through the 90s it would have ended up more like a slightly stroked Neo 25T with the 26s externals and maybe bucket over shim valve train .

Don't forget EFR do the 6758 in the same 0.80 AR T4 TS IW turbine housing . Just for the record Geoff did say that 7163s tend to like engines with high volumetric efficiency whereas others are a little less fussy . Probably something to do with reasonably big wheels for the housing sizes . It may pay to look at the rated power of these two EFR turbos and base your wants on what they can do .

Modified PULP map and I don't do the 4500 + . The reason the light load areas are so advanced is because that's where it seems to make best part throttle torque , on E70 . Not spiking now . I will agree the timing is mild around 1 bar but that is dyno tuning territory in my opinion . I think the PULP tune was pretty tame and until I added a fair bit of light load timing felt quite flat . I have heard this engine rattle twice in 10 years and 88000K so I highly doubt it'll go bang . Bores looked good at 90 and ~160K . At idle no breathing out the oil filler hole at all . Like I said lets see other peoples E70/85 timing maps , and AFR target tables .

AFR Target and timing looks like this . It probably could use a bit more timing at 1 bar but I think this is better sorted on the rollers .

Yes the Tech Edge reads in Lambda not AFR . Personally I think 0.77 Lambda is ridiculous but I'm not a trained tuner . I think the Tech Edge refuses to read lower than 0.7 and just says RICH . Is there a way to have the ViPec Target AFR read in Lambda ? Looks like Dale was right with AFRs but the difference feels like more engine torque rather than big increases in turbo excitation in the 2500-3500 area . I think the sad truth is than RBs will never have good consumption no matter what you do to them .

Well its now richer in the 2500-3500 area and dipping from mid 9s lambda to mid 8s and occasionally down to 7.7 . A bit more positive pressure timing too . Next is to wind back the accel sensitivity to something more sane like 30 . Just for the record I'm just playing with someone elses PULP mapping by increasing the main fuel multiplier and trying to dial things around that with no rollers . All road stuff . Also Insight said both times they had it that my Tech Edge WB3A2 reads very close to their gear and yes its running the reasonably current LSU 4.9 probe . I'd like someone to throw some timing numbers at me for the 100 kpa (atmos pressure) to 200 kpa area . I doubt you could hurt this thing on E70 provided it didn't run stupid lean but I'd like to hear what people typically run at 1-1.3 bar on this or E85 .

Well I get side tracked because I have a life to live . I couldn't get phone to link with this lappy earlier but reg looks like this . And that L shaped elbow . Yes officer than an factory engine and turbo . The 52T GT3076R . Until everything else is right its hard to give it an honest appraisal . At different times it has felt better and worse mainly because the tuning pre boost has to be right . Last night I was watching lappy WB02 and revs and the dryer didn't offer a real lot of urge under about 3500 revs . This not to say it doesn't add positive manifold pressure lower down but not much of a shove in the butt dyno . Being again on E70 the part throttle torque is better than 98 PULP and the idle manifold pressure even creeps down slightly lower than on PULP . Problems I'm having is trying to get this engine to return to a consistent idle and no matter how I tune this thing feels like its got a fuel lag as soon as the throttle is opened . I'm using the ID supplied dead time corrections and hoping they're right . I'm double checking everything for vacuum leaks and next replacement is the 21 yr old PCV grommet and hose . Probably pull that IAC housing off again and clean it and the screw adjuster Going to be too busy again next week to do anything but hope that intercooler turns up . I need to speak to Insight and organize the flex fuel gear and look further into Emtron . A .

I imagine the R31 GTSR engine was designed to make power at revs so low down torque wouldn't be its strong point . That manifold would have been part of a system to achieve a desired result . The mid 1980s was a learning time for all turbo road car manufacturers including Nissan . If you look at their other 80s engines eg L20a/28ETs/Z18ETs/FJ20ETs/RB30 ETs the pattern is similar . Lowish compression ratios and no intercooling except or the later FJ20 powered DR30s . They had to keep the exhaust side flow up and boost modest to avoid detonation . And whilst using pretty agricultural turbochargers . Power came at revs except for the larger L28 and RB30 engines . The tide turned with the later DR30 FJ20 where they reduced the inlet plenum volume / compression ratio up from 8 to 8.5:1 / turbine housing down from 0.63 to 0.48 . AND had smaller inlet tube plumbing with a side mount intercooler vs no IC . Maximum power was up and boost threshold came down , I had one of those cars around 15 years ago . AFAIK the R32 RB20DET was the best all round version of that engine , it lost all the TVIS style BS and had a more modern BB turbo with better engine management . The things to keep IMO are the native manifolds because they are sized to keep the gas speeds up around where they need to be with those small 330 odd cc pots . If the cast iron RB20 and RB25 style manifolds were garbage there's no way they , esp the 25s , could make the power they do when modified . Just on this I did once see SKs cracked RB20 exhaust manifold and they are smaller bore than any 25 one I've ever seen . If you think you can make a twin scroll T25/T28 work go for it , all I know is that if the housing doesn't work with the turbine turbo performance suffers . It doesn't have to be out by much to push the boost threshold up . Any waste gate should have zip to do with turbo response because it will be shut until rated boost pressure opens it . I'd be trying to keep this thing as simple as possible . RB20 manifold and turbine housing and fit a small Garrett or whatever BB cartridge into it . Or ask Hypertune to develop something that will come on sooner than the complete OE RB20 turbo does . Restricted Rally style turbos sometimes had quite small looking compressors but they still made strong low to mid rev torque . I'd be looking at Garretts GT2554Rs and GT2854Rs and crunching the numbers based on low to mid rev torque rather than high end numbers . All this is attempts to work around what Nissan fixed with the RB25 . The RB20 really is an orphan based around the bore and stroke of the old L20a six . I don't think you can compare the RB20 with any other RB because of that small 78mm bore size . All other RBs were big bore and even Nissans poverty pak RB24 was a destroked 25 not a long stroke 20 . Really major works are not an economic reality with an RB20 because no matter what you do that small bore and lack of capacity will eventually paint you into a corner . The engineering solution is greater capacity and less extreme mods . I would go so far as to say that a really well done RB25DET Neo could convince you that the eventual dirty 30 may not be needed . Your call I know what I'd do . A .

I pondered this for an hour this morning and ended up deleting my thoughts because they all point towards ways of a trying to fix something that's avoidable/replaceable .I reckon I can see too much effort and money going into something that's dimensionally same as the 2.5L version . I don't reckon I could live with a 20 even in a 32 GTST when things like Neos fall in and have way more potential .

Twas just some thoughts for the OP Lith not a shot at you .

I would be looking at trying something with standard RB20 BB turbo sized housings or at most the HKS 0.64 AR one in T3 flange . These don't look too big but they will keep the exhaust gas speeds up . You cannot compare a small bore short stroke 2L six to a 2L four , too many differences . With Mitsubishi they were trying to compete within the restrictor Group A regs and they knew it was going to fall flat on its face at 5500 revs . What they often did was actually reduce the compressor wheel size to a 15G and tried lighter materials like titanium alloy turbines and in a few cases magnesium compressor wheels . IIRC the Evo VI TMEs made peak torque 300 revs earlier than GSRs but the real RS2 based TMEs were lighter cats too . More later .

The ethanol sensor is part of a grander scheme with better management , atm I need that IC delivered so the pipework can be sorted . Mine may need to be slightly different because I'm using a Plazmaman rail and the reg is off to front and left of it where the cold side pipes sometimes run . Also waiting on an aerial unit and fan hub from Kudos . Want a real fan hub which isn't cheap but will out live the car in theory .Back in a sec .

I don't have the P98 one , I think I had a pic of it ages ago but M.SD card in phone died . Once the IC is in I want an ethanol content sensor and possibly a bypass because I'm not sure they flow that well . Can anyone show how they get around restrictions with these things . Also depending on how things shape up I may consider a turbo upgrade , EFRs sound nice but some later GT30 based thing like say a gen 2 3071 would at least be an easy swap . No great hurry with this and I'd like to see more results with them . The existing 90 deg bend off the compressor housing is the old GTRS kit one and it looks terrible , a smooth 2" elbow shouldn't be hard to get . Gotta like the smell of ethanol - at the filler and and out the back , not as good as Jamisons but much better than ULP . A .

Overdue update , went back to E70 from P98 last night mainly to get back into Ethanol tuning . Took about 3 goes and 10 minutes to get acceptable running from my dino juice tune . Still using the Tech Edge to monitor AFRs . Was on the rollers last year after the head refresh and to get P98 maps reasonably close - for road and with ID injectors . Not surprisingly the max power went slightly backwards from the original GTRS/E70 tune but only by 3 kw . I thought the 3076 would do a little better on PULP but I think the Blitz return flow woes had a say here . I have the IC Stao likes on order with a wait time of 6 weeks and should hear back about it soon I hope . Aside from the shorty ID850s also using a 33 GTR Nizmo fuel pump . A .

No my 271 RWKW figure was on E70 with that GTRS . I highly doubt the head work valves or Poncams did much for it because that poor little GT28NS111 turbine and 0.64AR turbine housing was a big limitation for a 2.5 liter engine . It got to 17 pounds of boost but fell off to 14 higher up . The Blitz return flow IC replaced the R34 SMIC just before that tune . Not an ideal turbo for an RB25DET but still better than the OE ceramic Hitachi . I maintain there is no mid sized turbo out of Garrett because the gooses still have that big gap between GT28 and GT30 turbines . The cropped GT30 or GT29 as it's now called is a total waste of time . I kid you not that GT30 UHP turbine has been around since about 1991 when it appeared in HKS spec Garrett turbos like the 3037 . I used to argue with their production engineers that the aftermarket was screaming out for something like the larger 60mm NS111 turbine . But no the morons instead glitzed about with billet wheels on prehistoric turbines . They know the problem they refuse to fix it . That aside E70 or 85 will allow you to push ignition timing numbers and get sort of reasonable looking power numbers from restrictive turbos . Not the best way to go but I suppose choking on exhaust is better than detonating to death . A .

Just for the record the IC Tao uses is shown in P550 of this thread . I didn't go back far enough initially but chased a link to it from elsewhere . I'll be ordering one Monday and looking into the 100 C cat as well . Also my IAT sensor is in the back of my cast X over pipe and I'm wondering if it is heat soaking because of it . A .

That R33 does have neat simple pipework and clears everything . With a bit of mucking around I suppose a decent OE style recirc vale could be adapted to it , something like an Evo one . Will look at the recirc plumbing on mine . Tao says he uses Plasmaman pipes so they must still be available , possibly to special order . I'll ask Alex what they can do and if they can make it with a fitting for a recirc valve . This would be the only fiddly bit I can think of . A .

Tony I also like the pipework in the yellow car but that's not going to clear the airbox snorkel like with the black car , I do like that airbox BTW . I have the basic Turbosmart reg on the front of my fuel rail so need a bit more space if the cold pipe goes up over that . It could still do a 90 into the cast crossover pipe and clear the airbox and snorkel , probably means custom stainless tubing . A .

Laughs , no didn't lose the moonshine love but did get tired of really pathetic consumption which eventually turned out to be worn exhaust valve guides and not very hi tech side feed injectors . Changed to a Plasmaman rail with shorty ID750s , and better reg , and had the head off for a freshen up . Couldn't work out why it idled badly but occasionally seemed to fix itself . Leak down test sed do something about it because valves sometimes lined up - and sometimes didn't ... Last tune was on PULP because I got tired of having to store fuel and splash blend . I think you really need a brain box that has knock control to safely do flex fuel . I don't think you can get close enough to the detonation threshold on PULP safely . Also a challenge to get 300 or so on commonly available pump fuel , pulp makes you work harder to get everything flowing nicely because you end up knock limited if you don't . The tuner had very conservative timing in this thing and it really kills low boost torque / throttle response / consumption .I fixed that but I don't want to kill an engine doing higher load road tuning with no knock sensing . The right setup E70/85 would possibly get an easy 340-350 wheel wasps . I can't remember the exact capacity of the 52 and 56 trim 76Rs I think approximately 47 and 50 lb/min , either should be easily good enough if everything flows properly . That poor little GTRS originally went from 17 to 14 pounds of boost so the ethanol is a valid cheat but it's because things can get restrictive/hot without necessarily lethal detonation . You can use some pretty crazy tuning numbers with E70/85 and not burn anything short term , not so with dino juice and a 168k old standard bottom end . I'd like to be able to use most/all of the 52T 76Rs capacity and to get it there the exhaust has to have low restriction and the intercooler have minimum restriction . I agree that E70 and this dryer would have done better but I want things working properly particularly the intercooler . Tao's shown what doesn't work and it would be good for the current and future Skyline fans to get what they want from a known path . The Silver Ghost is 20 years old now and I want to remember getting what I wanted out of it afterwards . A .

300 Plus from RB25 for street Hi all , I'm starting this thread to keep the Hypergear one for Taos Turbos and development . Ok well many streeters start out looking for 300 + RWKW and with a fairly typical bolt on build often get to the upper 200s and hit a power wall . As Tao said with the wrong combination of bits in pipes , exhausts and inlet tracts , getting beyond 280 odd can be difficult . Bigger turbos and big wastegates don't often help because they aren't the limiting factor . People understandably try to keep their engine bays stealthy to avoid defects at the roadside lids up debacle . This is where the return flow intercoolers seem good because there doesn't have to be aftermarket pipework . Just recently there have been pics of engine bays with standard looking pipes and claims of 3-400 RWKW . I'm not sure how that works but I'd like to know . Also Tony posted pics of his GTt with the air dam off and a conventional FMIC but with a 90 deg bend and a return tube behind the IC . That tube looks very low BTW , and I'm curious to know what sort of power you made on which fuel . I have the Blitz return flow and my last run on the rollers got a whole 268 on PULP . The previous run a few years back got me 271 but that was with E70 and a HKS GTRS turbo - on its knees . Between tunes I went to the 3076R IDs and a better fuel pump , plus flicked the Jap exhaust for a custom made one with straight through 3" mufflers . Front and cat are 3.5" but I'm beginning to think the 200 cell core was a bad idea so looking at a 100 cell version . Anyone have any idea how much of a real world difference this makes ? Back to Intercoolers . There's a few variations on the cold side pipe and I prefer the one that joins to the standard crossover pipe and lets you keep the std recirc valve . The one with the U bend over the cam covers is set up for aftermarket fart valves which don't interest me at all . If I could find a way to return the flow from a crossflow IC that would be good but I'm a bit concerned about the return pipe being too low . ATM I'm hoping a 100 cell cat and the PWR 300/600/81 IC will get me past 300 wheel wasps with the 3076R on ~ 17 pounds of boost . And on 98 PULP . Maybe better turbos can come later but the groundwork needs to happen first . Any feedback would be good in the exhaust and intercooler/pipework areas , particularly with integrally wastegated builds . Thanks in advance cheers A .

So as not to clog this thread starting another , 300 Plus from RB25 for street . A .

OT , 270 on 98 .

Alright have the diagrams from PWR so for those that want to know everything . Core 600 x 81 mm Tanks 93 width x 70 horizontal length , barbs 76.2 (3") 80mm center above base height . Threaded mounts on 500mm centers top and bottom . This is interesting in that it uses the same sized core as the 33GTR one but a little longer . The tanks are generic and the mountings much simpler than the model specific 33 GTR one . Think I'll go with one of these , thanks Tao .

Just off the phone to PWR , they don't know of any 600 x 300 x 89mm intercooler . They do an R33 GTR one Pn PWR 154641 600 x 265 x 81 rated at 1000 Hp . Has swept back 80mm in/out . Tao is this the one you mean or do you have a different part number . Cheers A .

Hi Tao , I will contact PWR today about their 600 x 300 x 89mm intercooler . I went back looking for your posts and noted some dated 18.8.2016 (P 587) where you bought another R34 GTt and tried the typical Blitz return flow and a flawed Japanese exhaust . You were trying to prove to a customer that his setup was the issue not your turbocharger . I think I'm ok exhaust wise and that 0.82 GT3076R is a reasonable thing but that Blitz return flow has to go and I just want to hear you say that your 3-400 RWKW results have been with PWRs intercoolers and generally Plasmaman pipes . I realize the higher numbers usually come from using E85 fuel . Don't suppose you have pics of these PWR Intercoolers ? Would you consider stocking them . Also what do you recommend for an R33 as cold air intake . I have Scottys intake pipe plumbed into a Z32 AFM and the std air box and snorkel . When everything else is "right" I'll look at turbos again . Thanks in advance cheers Adrian .