discopotato03

I'm starting to get what I think may be some missing at large throttle openings and on boost so need to look at new plugs and if its still there possibly coils . I think the Sk33 had red Super Spark coils in it and they seemed to work well . Pita job but am wondering what the sock strainer looks like on the 33GTR pump in my tank . If I had to replace that I'd look at Tomei or Nismo direct replacements . Just on coils is the coil loom available through Nissan here ? Cheers A .

They say necessity is the mother of invention but the real question I believe is how much does the OP want to spend . Its all possible and its his money and responsibility to use it usefully . That aside there was an interesting thread here a few years back where someone welded up the inlet side of a Neo 25 head so it could accept an RB26s inlet manifold complete . IMO if you want an RB to breathe well and have rapid throttle response the 26 inlet and a non hydraulic valve train is the way to go . The complete 26 top end is easiest to bolt on and probably the best from valve/bucket innertia and revs point of view . As we know variable inlet cam timing is the complication because 26s never got it std . To me an RB25DET can be a torquey flexible engine and VCT would be a part of this . Going to 3L I'm told just pulls everything down 500 revs compared to the 25 and that must make them a really nice road engine . I'm suggesting a 20% capacity increase probably does more than a bit of inlet cam movement does for low end torque and flexibility so the lack of VCT is possibly no issue for an RB30 . I look at the RB26 as a complete system from airbox to cat including the front intercooler and ducting via the drivers side . Possibly the OP needs to consider how he wants to package everything in an old HD Holden and take into account the air/intercooler layout he wants to use . Something else to work is the overall weight this thing will be because a std HD is probably lighter than say an R33 coupe and less for an angry twin cam 30 to pull around . If it were me and money was in any way a question a good runner RB25DET with a bit of bolt on help would be a good start . Your call lets hope the HD shell can take three to four times the stress of a turbo RB compared to an Olden grey , or was it a red ? Cheers A .

Yep 446179-xxxx are bal bearing cartridges . Something is a bit screwy about the lists I've looked at because they show units with 53.8 /53.9mm turbines as being GT28 turbine based units . They show the turbine as being 62 trim and if its od is 53.8/.9mm then that wound indicate the smaller trim version of the NS111 turbine . The compressor details are 60mm 60 trim . Also BTW the specs I've seen for the BB GT2556"CR" which is for Nissan are turbo number 702987-3 using cartridge no 446179-42 , I assume these are the OE R34 GTR turbos . One more to check , cheers A .

I decided to try the RB25DET defaults maps and with the Z32 and injector trim alterations it runs quite reasonably . I would not hesitate to try this if you had enough injector and pump and had access to a Datalogit . I wouldn't thrash the thing without a propper tune but to just get around its quite reasonable . I didn't have the wideband in at the time and consumption looks a little higher than with my maps but I'm about to plug it back in and have a look at the Lambda numbers . A .

Single Z32 ceramic BB turbos used the same compressor housing as most RB25 ones though they were profile machined for a slightly smaller compressor wheel . They won't go over a std 25 compressor and I know because I have both and tried it . The housings side by side are dimensionally the same . A .

I'm interested to know what the firmware differences are and if Datalogit can talk to it . I wouldn't replace an existing PFC with a new one because more recent plug ins probably offer more for not a lot more money though that would depend on what these new ones cost . A few more goodies like a map sensing option and air temperature sensing wouldn't go astray - sort of L Jet D Jet options in one box . Maybe a bit faster processing and updated injector drivers/IAC control . A .

The easiest thing to do is buy a new cartridge and stick the GT Pro housings on that . Provided the housings are undamaged you'd have effectively a new turbocharger . Sadly in a BB or any cartridge the bearing housing and turbine seal grooves are wearing parts and if they're stuffed the only practical fix is to renew the cartridge . Cheaper than buying a new turbo and particularly a HKS spec one . If you can post the ID tag numbers I can probably tell you the cartridge part number . If the turbo is a GT2835 Pro S the cartridge number is 700382-3 meaning the cropped GT30 turbine with 56 trim 71.1mm compressor . A .

I couldn't bridge the operating system gap 7/XP and I normally run Datalogit from XP because I couldn't get Win 7 to work with the USB converter cable . Nowdays I just use a Serial cable because it never locks up or blue screens . I'll get around to trying the serial with Win 7 soon . Anyway it occured to me that the Datalogit comes with various RB startup maps and I had a look at their RB25 ignition table which is along similar lines to mine but different in a few areas . Also their water temp enrichment and accel enrichment tables are slightky different to mine and I'll give them a go too . On the fuel side they are a bit leaner than my figures at light loads and richer at high loads and I'll try theirs if the timing figues work out ok . I had my Evo out recently and you forget how much petrol stinks compared to E70 and the same with petrol exhaust fumes , consumption and tuning antics aside the high eth stuff is nicer to work with IMO . A .

I think you'll find that extract was from the first time he put United E85 in his car ar Rozelle and then uploaded a map he made from pure estimation . I'm not sure he ever showed any of his timing or fueling maps on this site . From what I remember him saying he was increasing the whole timing table by a sizeable amount and pulling back the extremes by probably similar amounts ie the idle and part throttle light load areas . The other thing is that an RB30 is a 20% larger air pump than an RB25 is so you would expect it to make cruise type torque at small throttle openings and lowish revs . He had the advantage of being a more experienced tuner than I am with access to a dyno which I don't . He would have had better petrol mapping and I'm sure thats a big advantage when you change fuels and in my case just upped the injector trims 30% . Adding this extra fuel across the board just allows for the difference in the heat value of the new fuel so you in theory end up with very similar lambda numbers . As I said before with a PFC a Datalogit and enough injector making the change to E70/85 and having you car run acceptably is childishly easy - provided your petrol mapping was good . Mine was just sort of Ok and thats why I've been tapping down the road with a walking cane . Obviously I need a propper tune on a chassis dyno with an educated operator . Also before doing that I need something a bit better than a 34 SMIC and that was someting Guilt already had done . I'll see if I can cut and paste my current timing map , A .

I have to go out now but will get back to this in a while . My timing table looks very different to that , is that from a PFC as I've not seen load reference numbers like that . My finding with E70 is that it's very easy to advance the timing past the point where you get maximum torque and going beyond is effectively going backwards performance wise . I'm not sure going much higher than 40ish does much at light loads as in enough to drive rather than just coast on a feathered throttle . My experience is that very low revs and light loads don't like lots of ignition advance probably because with low cylinder filling and low fuel requirements make it easy to time the combustion pressure spike later in the cycle than it needs to be . People have to realise that its this timing thats critical and different fuels burn at different speeds sp a slow burning one needs its fire lit earlier than a fast burning one to get the thermal pressure rise where it needs to be . I think the charge temperature advantage is purely one of more fluid evaporating and reducing the temperature of the air going into the cylinders . A .

It appears to be an RB20s turbocharger , the compressor wheel and housing is smaller than an RB25s ones and the turbine housing will be slightly smaller internally. The real give away is the "Nissan" etc cast into the 25s comp housing . Its in bolder lettering and also 25 turbochargers have an anti reversion groove machined into the compressor housings inlet boss . The last thing as you found is that the adapter that bolts to the comp housings outlet is larger on the common RB25/VG30 comp housing casting . The threaded holes are also on a slightly larger pitch circle diameter than the RB20 type compressor housing . You need to change it for an RB25 one . A .

Depending on the condition of the engine and what you want it for you could replace the bent rod provided its exactly the same centers length and replace the bearings with the same size the originals were . Being fresh they should work fine and obviously did from the factory . Really a glance at the crank journals and used bearings will tell you if its forked or not , low oil pressure could be another indicater of worn bearings . I don't consider RBs "weak" from the factory and if you're not asking for much more than std performance fancy bolts and 26 rods won't do a lot for you . If the engines worn out or damaged by water or the lock it needs a rebuild but if it wasn't and is ok the budget option is to fix whats bent and leave what isn't . If this is for a Patrol you should be able to use an RB30 short though the conversion takes a bit of time and money . A .

Yesterday evening went out on the expressway with the medium load range mixtures a bit richer to see what butt dyno said . It didn't really achieve anything and it makes me think an issue with E70 etc is that it allows you to run richer advanced settings without drivability problems though best torque isn't there . I made up maps with a little less advance and leaned some areas out a bit to see if its a bit torquier in those areas and I'll try that today . My car really needs a dyno tune so its known exactly whats going on in controlled conditions and everything is measurable . I think a problem with Ethanol in high percentages it that it allows wide variations in mixture and timing without the engine really acting up . I guess with experience real tuners get to know what different engines like and have the dyno gear to dial it all in . A .

I think you missed the point with the neo 25 . Obviously Nissan intended it to be a petrol rather than E85 engine and they changed things like chamber volume and piston crown design and used different cam profiles . Late engines tend to run better on lean mixtures than older designs , part of this is making them more detonation resistant so they don't have to retard the timing as much to make it reliable . Stop start traffic driving is never going to give good consumption no matter what you do . If an engine is an efficient design , combustion wise , it doesn't need much fuel for small throttle transients . I don't know too many people that would deliberatly set this area lean enough to have drivability problems because that often increases rather than decreases consumption . I do understand what you are saying about how you drive and consumption b ecause big fluctuations in throttle opening mean extra fuel hosed in just to maintain acceptable AFRs . I believe that if you can run best torque timing and the engine is capable of efficient combustion it should make good torque at fairly small throttle openings and thats good enough to get around town much of the time . I stuck a reasonable amount of extra fuel into my PFCs table tis afternoon to see if I could get it to show rich on the Tech Edge wide band but it doesn't seem to show much richer lambda numbers . It makes great part throttle torque and the lower end drivabilityis really good . I topped up my tank which I don't like doing at more than 1/4 just to see how the fuel usage will be . It seems to fire up with the temp gauge on the peg first go atm . I had a think about fuel trims and PFCs and I'm not sure they change anything accel enrichment wise so I again raised the increase and sustain and it seems to like that as well . Anyway to round off with the limited tuning I've done over the years I find that mixtures lean enough to cause drivability problems make consumption worse not better . I think its the steady state mixtures that have the most say consumption wise and particularly at smallish throttle openings . This always assumes you don't boot you car everywhere ans stupidly expect good consumption figures . RBs are not exactly a modern engine but they are not really agricultural either . They escaped out of the late 1980's and engine design has changed quite a bit in the last 22 years . Also 90s era Skylines are not exactly light for their size . A .

Yeah I was just curious to know what Nissan actually achieved with the Neo 25 differences . A bit of extra power is always good for marketing when releasing an updated model ie R34GTt and if they can get a bit better consumption thats good too . Cleaner emissions would have been a must and not something Nissan probably had much say in . I am still interested to see if adding a bit more fuel in places will get me a little more performance and same or better consumption . A .

Well for whatever reasons my car fires up fine even cold when the PFC has the settings it likes . I found a thread here started by Joeyjoejoe about his E85 Tuning Adventures and it mentioned a few interesting things I didn't know For example I think either Paul33 or Cubes mentioned that R33s have 55L fuel tank where I thought they were 60 and typical GTS25T mileage was ~ 400 on PULP and possibly 300ish on E85 ? I think the figures worked out to 14/100 and 18/100 . I don't suppose anyone knows any difference mileage wise with a Neo RB25DET compared to the R33 version ? Joeys power numbers also looked pretty good at 320Kw on a 0.68 AR GT2835 , someone else mentioned numbers like 270 odd on a GTRS too . http://www.skylinesa...ng-adventutres/ Woolverine as well must have cottoned onto something good with the 2835 Pro S and the ethanol seems to make them very streetable . I guess these kits come up second hand in good condition at times ... Cheers A .

I'm a little curious to know why you would do a strut conversion to an R32/33 . A .

I haven't seen inside a VQ but I imagine being a later design its burn characteristics are a bit different to most RB25/26 engines . Except for Neo 25s I don't seem to remember the 25/26 chamber design changing much if at all . I don't think they were intended to be ultra low emissions engines and probably don't cope super well with lean overall mixtures . Obviously Nissan put some extra development into 25 Neos to get them to run reliably as a ULEV engine . Big plug gaps tend to like very high voltage ignition systems and thats probably what it takes to fire lean mixtures reliably , always assuming the engine doesn't detonate with the higher associated combustion temps . I have limited experience with these high ethanol content fuels but from what I can hear and feel ethanol fires quite easily . Perhaps the greatest difference between E70-85 and 98+ octane petrol is that its a higher octane fuel but unlike high octane petrol its not hard to light up . The detonation resistant properties of high octane petrol actually work against it when it comes to lighting the fire . Anyway back to my goals , economy at all cost is not what I seek best torque at all engine speeds and loads is . My aim is to not use any fuel beyond getting the most torque I can everywhere . A .

Well my most recent experience shows that being lean was not economical and adding a bit more fuel in certain places gave it a tad better consumption and it runs better too . I don't think ethanol burns much like petrol at all and the fact that it can run lean and not detonate (speaking same Lambda numbers petrol/E70) means lean with less heat and pressure and I reckon less torque and agro because of it . It would be real interesting to compare EGTs with both fuels running the same Lambda numbers to see if high ethanol content lean means lower combustion temps by comparison . We know a lean running diesel has lower combustion temps where petrol engines tend to have to a degree higher combustion temps when lean and I reckon high eth content fueled engines are a bit more like a spark ignition diesel in some ways . I can see the difference in the turbo not spooling as early or as easily when mixtures have been lean in these areas , throwing in more fuel makes a noticable difference here . Turbos are driven by thermally driven exhaust gasses and generally if the gas is not as hot it doesn't have as much energy (velocity) to drive the turbine with . I'm not splitting hairs but I'm not really sure how a wide gap would make any difference to the end of the burn phase . Outa time cheers A .

No what I was looking for some sort of Lambda reference to petrol AFRs which had some meaning for me . I'm not interested in being any richer than does any good in the light load areas because that costs money for zip . I can tell you that leanish mixtures under load feel weird with this fuel and not really like a leanish petrol situation . No cough spit or rattle just a torque fluctuation from probably low combustion temps and pressures . Being able to read EGTs would be great but how many normal people have access to the gear or even know what the ideal temps are ? Yesterday I put more fuel back into the low medium load areas which helped made more torque and put the Lambda numbers up to what I now think they need to be . Later today I will do the same a bit higher up the engines rev range because I'm getting to know what leanish mixtures feel like to drive with but the wide band will show for sure . I think this is going to be one of those times where adding more fuel in the right places gives better consumption because lean isn't always economical . Also going to have to resort to a serial cable because this laptop is doing blue screens with Datalogit when the engine is running , seems ok with the ignition on and the engine not running with their supplied USB converter cable . A .

I think its more a case of knowing what they mean as in elec load vs no elec lod load fuel resumption revs and elec load vs no elec load idle speed . I had the Tech Edge wide band back in mine today and as I thought it was running a little lean in the light load low to medium engine speed areas . I richened up the very low engine speed areas when loaded ie 400 and 800 rev colums at higher airflow rates . Thhis makes the idle torquier and less likely to stall with very small throttle openings when moving off . With the fuel resuming at 12-1300 revs nothing I did fixed the bucking kangarooing problems I had . ATM I'm idling at 1.01 - 1.02 Lambda but it can go lean towards 1.08 at hot restarts which doesn't give any drivability issues . Light load cruise is around 0.98 to 1.00 L . As the load ramps up its falls to 0.95 and around boost it gets into the 0.92 to 0.85 range . If I go WOT as it comes on boost it gets to 0.80 L and I had to look up petrol L/AFR to see what it equates to . To save you looking the tables I found show this Lambda .....Petrol AFR .... E85 AFR 0.75 ...........11.03 ............. 7.32 0.80 ...........11.76 ............. 7.81 0.85 ...........12.50 ............. 8.30 0.90 ...........13.23 ............. 8.79 0.95 ...........13.97 ............. 9.28 1.00 .......... 14.70 ............. 9.77 1.05 .......... 15.00 I'm getting a better handle on what the E85 Lambda numbers mean but I had to go back and search for some petrol Lambda numbers to see what the corresponded with in petrol AFR . I did go to start a new thread on Lambda vs AFR but I didn't think too many would be interested a didn't post it . Something I would be interested to knoe is Lambda numbers with E70 because most of the tables and calculators only show E85 and Lambda = 1 or 9.77:1 AFR . Logically E70s chemically correct mixture would be a slightly higher AFR number because of its higher petrol content . The difference wouldn't be huge but if we could gain a slight consumption edge thats not a bad thing . Just on cost I love paying $1.15.9 for Eflex when its cheap compared to Ultimate 98 at $1.70.9 when its not . I think in rough terms I'm paying 2/3 the price of Ultimate was a while back and getting 3/4 of the consumption I used to get though my petrol tune wasn't real good . Eventually I will go back to Ultimate just to clean my petrol tune up but overall I prefer the Eflex E70 . Ongoing , cheers A .

If you have Datalogit change your fuel cut resumption settings to lower revs . I think the problem is that the engine tries to "come alive" at that resumption point and the IAC and small throttle settings fight for control of engine speed . If the engine gets no fuel down to say 900 revs with the throttle shut it wouldn't matter what the IAC valve did because theres nothing to burn in the cylinders . I was finding my RB had reasonable pull at 1300 revs especially when I didn't want it to . I still have to stick the wide band back in to look at the mixtures because I had been trying different things with timing and fueling in this 8-1200 rev area thinking is was something else . I have to read through the Co Pilot thread here to see if its worth looking into . Cheers A .

I set the fuel cuts lower because I was getting a bucking kicking thing going on when the injectors resumed at 11-1200 revs . I have a lightened flywheel and I was blaming some of my issues on that though now I think its not the case . My car had an annoying habit at very low revs of going crazy because it wouldnt drive and wouldn't stall and it could get quite violent backlash in the driveline . I wasn't quite sure about the four settings above as in were some of them cold idle ups and or fuel cut resume speeds . Anyway after searching I found through wiki of all places what they were in a Skyline L Jet PFC so now I can set up as I like . Also my car idles fine at 700 and if anything the no elec load fuel resume could possibly be set even lower ie 800-850 because it works fine for me even with the light flywheel . A .

I notice one thing people never do with GTSS turbos is experiment with the next size up compressoe housings . I don't remember exactly the dimensions of the GT2859R compressors but they are not exactly tiny in the GT25/GT28 world . I think Garrett intended GTSSs to use a housing very similar if not the same as std turbos and it was intended to help make these turbos wind up early - or earlier than your typical GT2860R turbo . GTSSs use the same RB26 specific (compact type) 0.64 AR turbine housing as most Garrett 26 type bolt on turbos and the main hot side difference is the 62 rather than 76 trim size of their NS111 turbines . Once you step up from an RB26 specific GTSS to a GT2860R type turbo you get the larger compressor housing and the larger trim turbine . Something to research is the four cylinder version of the GTSS because it uses the big or 76 trim NS111 turbine but its compressor is a 60.1mm 60T rather than the 62/63 trims of the GT2860RS/ "GT2530" compressor wheels . A .

I had a minor driveability win today when I found out what the PFC idle speed parameters meant , the main one was the fuel cut revs for electrical load and no load . My idle speeds load/no load are 850 and 700 and the fuel cuts are set to 1050 and 900 . I'm curious to know what others are using for their GTS25Ts , cheers A .