discopotato03

My opinion is that the longer it takes the spark plug initiated flame front to reach the end gasses the grater the chance is that heat and pressure will light them up . TC RB heads are a production compromise so things like valve angles will never be ideal in a competition application . To be ideal a TC head needs to be tall enough to have a narrow included valve angle inlet to exhaust and to have high inlet ports and an ideal port shot at the backs of the valves . To see stuff like this look at the old Nissan LZ twin cam heads or Cosworth BDA ones . Narrow valve angles means shallow compact chambers and you don't need lumps of aluminium on the piston crowns to get high compression ratios . From what I heard GMS used higher than standard CRs on their RB26s particularly when boost levels were dropped . Are there any pics available of the piston designs they used ? A .

The usual practise with competition engines , not Hemi POS designs , is to have as compact a combustion chamber as possible so more of the volume is in the piston crown for better combustion efficiency . The idea is to compress the charge into a small area near the spark plug to have shorter flame paths . Part of the reason why dated designs detonated was because the end gasses , last to be burnt , were further away from the intended ignition point and the The longer it takes for the intended burn to reach the end gasses the greater the chance of heat and pressure igniting them . AFAIK there was SFA development in RB26 head castings from beginning to end of production . RB25 heads went through a number of revisions from R32 GT25 to R34 GTt , I think it's significant that the chamber size shrank and the piston crown was redesigned to give the same 9.0 static CR as a 33 spec RB25DET . Granted RB26s have different dynamic compression characteristics but I think the Neo is a better design . A .

If tuned for E70 and had to use E85 it's simple to toss ULP in to make it E70 . Its a 15% difference you can work out based on an almost 60L tank . Works out to 2.25L of petrol to every 1/4 tank so 2.25 / 4.5 / 6.75 and 9 litres . I'm sure 3 5 7 and 9 would work fine and if you have a wideband wired it would compensate enough for normal road use . Just don't bugger it up watching the dollars instead of the litres or carry a clean dry 10L container in the boot . A .

My take is that static compression ratios are worked out from physical volumes but they're never achieved real world because rings and sometimes valves never achieve a perfect seal . Also its virtually impossible to have zero loss throttling though GTRs are better off than other RBs here . I would look into engines that run really high boost pressures and see what they do to get around detonation issues . I think you'll find that a lot rides on the hot side because that has a lot of say how an engine rejects heat which is mostly out the exhaust . Note how some competition engines seem pretty big on exhaust manifolds turbines gates exhausts etc , not necessarily huge but big in relation to the cold side in some areas . To me the fact that higher tech turbos like the EFRs have quite large turbines for their compressor size tells me that less restriction is part of why they can make good power . Actually thinking about it big truck diesels often use large turbines and turbine housings and diesel compression ratios are higher than the petrol engine norms . This would be about have a good pressure balance across the engine from the torque peak to maximum power / revs , and keeping it up for long periods of time . I think the only reason more conventional car turbos have smaller turbines is to increase their response with less revolving inertia . Manufacturers want heat through the cats ASAP for cold start and running emissions compliance . If you could get RIPS in NZ to talk to you he should know about super power RB30s and exotic fuels , may not want to give his hard earned experience away because he had to learn through trial and error . Lastly if spending big you could consider going a bit larger to 32-3400 ccs and having a less extreme state of tune . A .

My train of thought was to have the fuel supply and return as a manufacturer would and enough have banjo fittings if they enter and exit the ends of the rail . The way I see it the head of a Banjo bolt is a lot tougher than an aluminium barb or bend and better supported . If the Banjos outlet went back over the nose of the rail it would be simple to connect it up with the standard hard lines and park a reg where the damper is on a standard R33 . Same at the back with a hose over the rail leading back into the standard return line . Some RB25s had a steel line clamped to the std rail rather than the fixed one brazed in at the back like my S2 one has . You can't get more factory appearing than standard parts so the more you use the less molested it looks . A .

If it were possible to have a banjo fitting with a 90 degree tube facing back along the top of the rail it would look standardish to uneducated eyes . Trouble is most rails have those O Ring Boss female sockets and I'm not sure if there is suitable banjo fittings for them . I looked at Weber carburettor ones but the sticking point is their 14mm threads . The drama is that the aftermarket wants to sell gear that looks like race stuff - all pretty anodised for those who want to stand out . Stealth takes a bit more effort to find ways that look like OE . I'm really surprised rails aren't made to suit commonly available plain looking banjo fittings because slipping on and clamping fuel hoses could be so easy . A .

There is a simpler way to get the static CR up and it's as simple as using an RB25 Neo turbo head - smaller volume combustion chamber . It involves changing manifolds or fixing points but if you want super power it can be done . I agree that extra fuel octane is great but the point of it is to have the optimum ignition firing point for most power rather than finding the limits of the fuel . As per boost thresholds I'm not sure higher static CRs will bring them down , more likely increase the pre and just post positive pressure torque . My mentors taught me that there are two benefits of high static CRs . First , the only way to increase an engines power other than FI revs and capacity increase is the static CR . second , it's the way to reduce the torque loss (reduced dynamic compression) on an engine with long duration cams . Thing is that really high cylinder pressure and power loads means having the engine structure more like a diesel though if anything they are worse off because they make comparatively big torque at low revs . It may not be silly to search what Nissan did to RD28s to make them a reliable diesel . A .

The problem with flex tuning is having no way to measure the petrol parts octane . To be totally "safe" you'd have to start off with E85 and increase the 91 ULP content until it was all 91 . You could imagine what would happen if you flex tuned using only 98PULP blends , some goose gasses it up with straight 91 or 95 and rattle rattle bang - DOH . A .

Something else to think about is what takes an engine closer to detonation ie heat and pressure . If you choose to run an engine lean for any reason a few extra points of octane may make the difference between detonating or not . Granted if you ran it really lean it would lose power but detonation is generally the biggest baddest wolf . When I was doing 50/50 E85/7Eleven 98 I screwed it up once with too much E85 and while it carried on a bit it still ran and showed some out there Lamda numbers . From what I read leaded Avgas was designed to be run in aircraft cruising with lean mixtures for economy - range . The slow burning high octane characteristics suit lean running without detonation though they have heat temperature measurement so they don't seize valves in guides and fall out of the sky . Just on E85 I get it from near Potts Hill but occasionally from Ingleburn , I noticed the latter stuff looked different but I was topping up because the price cycle lunge is due any day . I think the petrol octane number becomes more important as the ethanol content drops so 98E30 should work better than 91E30 . No doubt the fuel suppliers will do what earns them the best returns so 98E85 is probably dearer than 91E85 . If the ethanol content floats around 90% then anything that's flammable with no water would probably do . We really need an octane/ethanol blend standard to sort out the mess because with alcohol percentage on one hand and petrol octane on the other it's BS . A .

From pics I've seen that looks like what some mobs put up as a compliance cat . What I did was have the dump made up in 3.5 inch and used the XForce cat as a reducer . By this I mean bought the cat as a 3" generic (flangeless) and had the 3.5 flange fitted further up the inlet side cone . I use a 200 CPI one because I didn't want the exhaust to stink , even then it did on 50/50 PULP/E85 but on straight 85 it's ok . A .

Just as an added extra people used to power these cold start air valves off the fuel pump circuit say with a relay . The idea being that if the ignition was on for any length of time without the engine running the valve wouldn't be heating and closing up . As mentioned most engines had these valves mounted somewhere where they got coolant heat early in the warm up phase so that if the power feed failed they'd still heat up and close . How does the Neo system work . A .

There is a version of the GTRS that is a bolt on for RB20/25 , fits the std manifold and dump and inlet hose . A .

I think you can safely say that a GT30 turbine in a Garrett 0.82AR GT30 turbine housing is not restrictive at your power levels . Too many other people have made good power with this hot side combination to doubt it . If there is a restriction elsewhere it won't help the cause . I personally don't like split dumps because they are difficult and expensive to make properly and I think the gains aren't there with these turbine housings . The flat valve is set in its own well so when it cracks open it isn't going to be firing gasses sideways into the turbines outlet stream anyway . IMO grab a decent XR6T flange and get a dump made from there . Mine is 3.5 inch back to the cat and my exhaust is not noisy . Bell mouth is much easier to form , basically weld the tube to the flange and make a fillet back from the gates side . Simple neat functional . What remains to be seen is if you have to spin the compressor faster to get boost at lower revs , after the exhaust and tuning the only other place to go is the turbine housing . It would be interesting to know the AFR and timing numbers you have in the low to medium rev area when it starts to boost . I'd like to think that the tuner isn't retarding the timing where it doesn't need to be and giving you high EGTs because of it . Some people have strange ideas about tuning turbo engines in the light to medium load/rev areas - that get used every day . Biggest can area straight through mufflers work and can be quiet if properly designed . Mine are Redbacks and while its hard to get a centre muffler that takes up all the available space (Skylines a bit unique packaging wise here) mine is plenty quiet . A .

The Skyline pattern is more like Euro T4 , or what most call twin scroll T3 . It's wider than single outlet T3 to allow for the dividers width . The bolt pattern is same as T3 buts any similarity with Garrett T3 turbos ends there . Everything else about the cartridge and housings is different except maybe the inlet air boss size . Nissan did use T3 cartridges in 80s era engines like Z18ET FJ20ET L28ET RB30ET but Nissan provided the turbine housings which is why their dumps and IW outlets were different to Garretts own patterns . Terrible turbos because they used the smaller diameter T3 series turbine and when you machined the housings out for larger ones it all turned to shit . The breakthrough came when Garrett developed the IW GT30 type turbine housings so everyone could use "bolt on" GT30R and GT35R turbos on their "T3" pattern std manifolds . A .

I gained my experience from elec fan cooling an FJ20ET in a Bluebird , bulky engine in a car that had cooling issues with the single cam carby L20B in it . I was using the DR30s factory radiator and fans and later an R32 GTR radiator in that car . The only reason I didn't run a belt driven fan is because it wouldn't physically fit . OT but the factory system in R and S series is very effective , if it wasn't the world would be full of dead and dying Silvias and Skylines .

There is a logical reason why many people get the elec fan switch points wrong and it's basically this . For a radiator to cool an engine the water available from it must be below the temperature you want to run the engine at . Basically the water thermostat regulates the engine temperature but only if it can let cooler water in than the block and head have inside them . If the water coming in is the same temp then the engine temp will rise . I believe the stumbling point is that people measure the temperature of the coolant inside the engine (head or inlet manifold log) and use that as a basis to set elec fan thermostats . The problem is that the fan/s are cooling the water in the radiator not the engine and the water thermostat is attempting to regulate engine water temperature . You can have a situation where the water thermostat and fans electrical thermostat fight each other and temperatures can go all over the place . I think if you must run elec fans regulate them from the radiator not the engine water jackets because then the water thermostat does what it's supposed to do . The standard mechanical fan system works so well because it drags lots of air through the radiator core creating a reserve of cool water which the water thermostat lets in when needed . With no fan running average radiator temps are generally higher so the reserve of cooler coolant often isn't there , it won't be because the elec fan control is looking at engine temp not radiator temp so as the engine temp rises so does the radiator temp . By the time you decide to hit the fans they have to drag the heat out of the whole cooling systems volume not just what's inside the engines jackets . A sensor in the bottom radiator tank would be the go because the temperature difference top to bottom can be considerable and its water from the bottom that goes into the block as the water thermostat opens . If as you said you were cruising on the expressway the radiator should be doing its job and water low down in it should be low so the elec fans mostly won't run . It's this coolant reserve between the top and bottom tanks that makes all the difference and why the factory system is so effective when it functions as Nissan intended ie belt hub fan shroud . Optional opinion , I reckon most late north south engine cars have elec fans because emissions regs are so tight , particularly at cold start , that the manufacturers are forced to do everything possible to have the least load on the engine and run them as lean as possible . Things like low friction multi rib belts and PCMs that lower alternator charge rates to minimise parasitic losses for emissions and consumption reasons . Longevity isn't what it once was and longer maintenance schedules ensure most garden variety cars today won't be here in 15-20 years time . I don't think manufacturers give a rats what their creation is like beyond a certain age and mileage because they want cars to be consumed thrown and replaced . Obviously new ones can stand up to less than ideal circumstances for a time but beyond warranty period tough luck . An R33 is now 17 to 21 years old and IMO over engineered in some areas compared to many of todays "cars" ... A .

The ceramic RB turbos were intended to be throwaways meaning no factory (Nissan) rebuild option . The ceramic turbos are not really suitable for an RB30 because they are too small on the hot side , better off high flowing the standard RB30ET T3 turbo given a choice . Long story short Nissan used Hitachi ceramic turbine ball bearing cartridges or centre sections in RB20/25/VG30 turbos and like with earlier T3 turbocharged Nissans provided their own housings - hence "NISSAN MOTOR" cast into them . RB30s even the single cam ones make more low down torque than RB20 or 25 so turboing is easier , don't need small turbos to pull up the bottom end torque - especially in a lightish VL sedan . You can probably even skip ball bearing turbo centres for an RB30 provided the turbo isn't too big . Rebuilds . The simplest fix is to buy a new cartridge for a turbo if the housings haven't been hacked up by damaged exploding wheels provided cartridges are available . Basically remove the housings from the old and refit to the new and you have essentially a new turbocharger . Hypergear would be good to talk to because they hi flow lots of turbos many which have Nissan or alternative housings on them . Basically the old Garrett small shaft T3/T4 centre section is very similar dimensionally to the Hitachi ones so with a bit of machining and re profiling of the housings to suit different turbines and compressors you can make a package that looks and fits much like the standard turbos . I think even the water banjo thread sizes are the same . I know people new to turbos think any centre section can be rebuilt but the problem is that the bearing housing itself is a wearing part in all of them inc the ball bearing ones . Sadly the turbines piston ring seal spins in the back of the housing at considerable speeds and eventually chews it out . It the turbine shaft has any significant wear replacing the turbine and centre gets exy and for the effort buying a replacement ready to run cartridge makes things quick and easy . That T3/T4 centre is a true broad minded person amongst turbos and a huge range of compressors and turbines can be made to fit them . Hypergear has gone further with them than anyone I know of in Australia and has made many unique wheels to dial them in . Constant development is a great thing . If you tell them exactly what you like and hate I'm sure they can brew up something that won't cost multiple thousands . A .

Possibly rewiring my S2 33 headlights next weekend . I have the main engine bay loom and interior fuse box back to where I cut it adjacent the drivers seat from a wrecker . Basically there are two power feed wires running from the rear fuse box to the headlight combination switch on the steering column . From there two pairs of wires run to RHS and LHS headlights . The earths run back up the loom to flick knows where - haven't had time to follow them out of that spare loom yet . Everything tells me that R33s have no headlight relays and power is sent from the rear fuse box to the lights via the combination switch . From the body wiring diagrams I've seen it looks like the lights are positive switched and run to ground to complete the circuits . I think the simplest rewire would be to open the loom adjacent the under bonnet relay box and use the relevant wires to switch new relays with power sourced from the alternator side relay box bolt . Would need a diode to stop the high beam relay/s staying on when switching from high to low . I know everyone reckons headlights are earth switched but the earths at the lights are black wires with silver bands and they don't go back to the combination switch . To be earth switched the switch would need to be between the lights and body earth ? A .

Well IMO 4-500 kilos does make a difference , how would the Stag go if it was more like GTt weight ? With wheels it isn't just matching gearing because their physical mass and revolving weight make a measurable difference . Your typical fourby wheels are ship anchors compared to decent road car ones and I hope yours aren't those chrome plated cast iron pieces of ship . Anyway if you want the thing to feel reasonably sprightly you need torque down low and if it's from forced induction it needs to work in the ranges you drive it . I don't think for normal use a 3076R/3037 is small for 3 litres though that's not exactly healthy capacity for a 2.2 tonne car . Plenty of people reckon R33/34s should have had 30s standard and they are more like ~ 1400 Kg or 800 less than your Patrol . Anyway I'd use a GT30 over a T04E and size the turbine housing around the rev range I used 90% of the time . If you can't low mount then non gated GT30 housings aren't hard to get . Just remember if you get this wrong with turbo size and go too big you could end up with a 2.2 tonne R32 GTS4 . A .

I'd basically forget about all the Skyline RB30 stuff because a Patrol (GQ ST ?) is a far cry from a Skyline in every possible way . The Patrol is going to be heavier and geared to suit an RB30S carby job if the RB is OE . In the interests of simplicity I'd have used the RB25 exhaust manifold and an IW gate turbine housing . Ages ago Cubes had a GT3076R on a non VCT 25/30 and he said it started making positive pressure from 1500 revs . For a truck a GT3076R would be the largest I'd go on an RB30 because you want reasonable part throttle torque at low revs and torque from boost not too much higher in the rev range , particularly with a truck ratio gearbox . I'd even look at the 52 trim version of the 3076R because you aren't after high rev high boost performance so anything you gain down low without any avoidable exhaust restriction would be a bonus . If in your case you get positive pressure at 1500+ revs and strong torque from 2500 then it should work quite well . What happens after 6000 revs is irrelevant in a truck that isn't raced IMO . A .

Does your car have the original coils in it ? A .

Twice the current draw from a battery that's sometimes not real close to the alternator . I haven't looked that closely into the fuel pump control modules , basically they are like a ballast resistor with a fancy relay to bypass it when the computer says so . With GTRs the FPCM has two stages or resistors and the usual bypass . Nissans like the Q45 V8s in the US use the same type of thing and at one of their sites they have pics of them opened up and in various stages of melt down - literally . Their purpose was to minimise the amount of fuel doing circuits at low revs and loads and to shut the pump up to a degree . The upshot is that the standard wiring won't appreciate more than double the fuel pumps normal current draw which is why the bolt in Nismo pump works with the standard system . One feller many years ago reckoned an easy way is to leave the std or similar pump in tank and run an external pump to do the hard stuff . A standardish pump should easily cope feeding into the external because its not creating the rails pressure head on its own . . And its not like either pump can run away speed wise because all the fuel is going to the same place . External pumps make the wiring easy because there's no fuel tank to feed/seal wires into . Bonus is they're easy to change if you mount them in an accessible place . In a way running pumps in circuit is like running several in tank because logically the fuel all goes to the same place . The difference is that running them in series rather than parallel means they share the work load and if primary isn't a gorilla pump it doesn't matter . If the external tries to pump more than the in tank its flow increases because the effective pressure ahead is less . A .

Mr Mafia is that the R33 GTR or GTS25T Nismo pump ? Personally I think an EFI pump that draws 18-20 amps on its own is hardly current tech electrics . I think the GTR Nismo is advertised as drawing 8 or 9 . A .

Subjective is it with any GT30 based turbo on a std manifold RB25 . Not quite sure what a 0.84 turbine housing is , typo 0.82 ? My experience with the 52T version is that drive round power is very adequate but tuning even on E85 is critical in the rev/load ranges used every day . If the fueling timing spark is a bit how ya goin then it will feel lazy and it isn't necessarily the turbo causing it . My take with the 0.82 GT30 hot side is that you can tune it to run better than with std or GT28 based turbos because the engine breathes out better and you can take advantage of that if you or your tuner tries . And this is with little or no boost . I think it's a fact of life that you aren't going to get 10 pounds of boost at 2000 revs with one of these (first three gears anyway real world) and you wouldn't like it if could . But if you have an RB25 in good condition even a mechanically standard one it can be more than adequate on the street . The more I think about it many of their physical characteristics are the reason why they don't pull like a Patrol at 2000 revs and if you want all that's available small turbos aren't the way to go about it . The issue is can you make enough part throttle torque for your liking and can you accept that it won't pull like a locomotive till somewhere in the mid 3000s . If you want it all you have to have good tuning and absolutely the most accurate fueling injector wise you can get because I think it does affect the part throttle lowish torque . I wouldn't have a 34 Neo Turbo without EV14s unless it was stock as a rock . To run E85 to 300 you obviously have different injectors and pump and they won't be small . Big injectors often struggle to spray well at low pulse widths and if yours is a dribbling mess like mine possibly is then the basic engine won't give its best at light loads and the pre spool area . Basically to me its how well you can get your engine to run up to the point where the turbo boosts and FI takes off . A .

The way I see it there isn't an ideal point to mount it on the manifold and the throat of the turbine housing is the largest area downstream of the six passages merging . Even then the mount angle sometimes isn't ideal but if you want part of the gas stream to change direction its easier to do that where the passage is larger . For the work involved go the turbine housing or use an aftermarket manifold if you want the gate/s on it . A .