discopotato03

No the pic I saw had two throttlebodies bolted to the cam cover side of the plenum chamber . The Neo DE idea looks good but they didn't do it with the Neo turbo variant and there must have been a good reason for that . A .

Interesting point , off hand whats the Lambda number for that . Damn I wish Datalogit would let me set target AFRs . Lowest manifold pressure would indicate the strongest induction pulses and its probably as good an inicator of a "strong" idle as any . Not being a pro tuner I'm always trying to find ways of making the fuel tables settings do most of the work and minimising the accell bit so having the idle a tad richer and the cells below load wise the same probably helps out a bit here . I still run into that split second rich spike when the throttle is closed at times . Yes I also wondered about doing the idle learning after the tune was complete to tie up loose ends . Thanks , cheers A .

Looking at the hicas dash light is getting old and I don't want to have to explain the process at rego inspections . I searched and found this thread which reckons you go to the Hicas computer (R33 GTS25T) under the rear parcel shelf and cut the Green wire with the White trace . http://www.skylineowners.com/forum/showthread.php?t=105358&page=2 Has anyone tried this here and found it works . If so it has to be easier than stuffing around under the dash to get rid of the light . Thanks in advance , cheers Adrian .

Well if the factory one does a better job than some and only slightly worse than the best then it looks pretty good cost and effort wise . Hard to fathom how the single throttle on the side of the plenum does it . I did see a pic of two throttles on a standard plenum but not sure if that was photoshop job. A .

Well with a little luck it'd be a cheaper option provided it bolted to the head the same . Are the plenum ports and bolt patterns the same as R33 ? I did read somewhere that the lower section has longer runners so they obviously changed a few things as part of a package . If a complete Neo engine fits in an R33 bay then this manifold must be usable . A .

I never had much time for the hand controller and only had it plugged in with Datalogit when I first bought that . I think the hand controller froze and has been gathering dust ever since . I reckon some sort of Lap Top interface is the only way to go . Cheers A .

Hmm , do you think by any chance that the Neo RB25DET inlet manifold and plenum section has any advantage over the R33 RB 25 pair ? It sounds like the lower section has longer runners and that the plenum was different possibly for packing reasons in an R34 bay ? I know there are differences with the R34s secondary TC throttle but not sure if the R33 TB can be substituted . Also isn't the IAC housing different , not sure if its electrically different . Possibly a lot to hope for but factory engineering can be hard to beat sometimes from a later slightly higher performance version of a given engine . A .

This is on a 96 S2 GTS25T . Had troubles filling the fuel tank and noticed the flap missing , the flap has fallen down the tube a caught in the bend . I can probably get it back up with a telescopic magnet but can I get it or the filler surround out to remove it ? Id actually like to have the std OE fuel filler pipe that the compliance people used to remove when we still had leaded fuel here , are they available ? A .

The feeling I get is that large single throttle plenum inlet manifolds are all about getting the maximum airflow through the system for high rev only drag race apps . They are simpler cheaper and have 1/3 of the setup issues the original RB26 throttles have . I don't aim to put words in peoples mouths , but it often sounds to me like there is a myth that RB30s are huge and the tamer of long cams and big turbos . They are really just a squarer version of the 25 or 26 with a taller block and longer rods . I don't look at RB30s as a long stroke motor - more that 25s and 26s are short stroke ones . Having ~ 20% more capacity than the short stroke motors should in theory give up to 20% more torque at the same revs , but if they (30s) have long period cams with more overlap timing the cylinder pressures tend to be lower and the torque can be less - at the same revs . It obviously can be a self defeating exercise if what the user wanted is more low to medium rev grunt (torque) in the first place . Years ago there was a boy racer cam profile for the old L Series engines which basically had significantly more valve lift but not much more duration than a warm road cam and it worked really well . It b reathed better because it opened the valves further but didn't have them opened terribly long . The result is high volumetric efficiency and good trapping ability because the valve open time wasn't long nor the overlap timing very wide . It is harder on the valve train because the valves have to open very quickly and close the same but it works performance wise . If it can work well on a daggy old two valve SOHC rocker engine in can work as well or better on a four valve cam lobe on bucket valve train . With a single throttle manifold all the inlet ports obviously communicate with the same plenum area , if long cams are used you will get reversion issues because the valves open too early and close to late to give good cylinder "trapping efficiency" at low to meduim revs and part throttle openings . Most long period cams are timed to have a fair bit of overlap valve timing because the aim is to spin to high revs and have the thing scavange the cylinders in the overlap phase - at high revs . What ITBs do is block the reversion pressure waves at part throttle so they tame down camminess noticably at lower revs . I think it was SK that quoted years ago that the std RB26 inlet system was good for ~ 600-650 Hp and better plenums on the std throttles push this up to I think 700 plus ? Thats possibly as much or more than the OP wants and theory suggests should give a better all round result in a car thats often driven at normal speeds and not just a WOT drag car . Just my thoughts , cheers A .

Yes I do understand what Lambda is but learing how a PFC learns is my learning curve . The big disadvantage with Datalogit is that we still don't have enough access to whats going on within the silver box because things like this idle learning is something shat should be visible and recordable . Now for the record I innitialised mine and reloaded my dat file even though some say all you have to do is change idle speed or FC settings to drive it back into "learn" mode . I was reading a thread from the RX7 board last night and I think they mentioned that changing fuel tables in the first 2-3 load and speed sections does the same think . Actually no that was from a Rex site somewhere . I think they said that the learn business starts at 60c coolant temp too . Anyways I went to start the learn process and was about to stick the Tech Edge WB probe back in but though no stuff it leave the std narrow band one in and enable 02 feedback . I let it warm up to around 45 deg and reset and reloaded my dat and let it idle for 10 min , AC on for another 10 min , demist plus parkers on for another 10 min . Yes everything is smoother now though it does take some seconds to drop back to my target idle speed at full running temp . At that stage I started a log and went to the monitor page to double check the closed throttle TP voltage which was 4.15 . At a slightly cracked opening the timing stil retards from 15 to ~ 13 for no apparent reason and picks up slightly up the rev range . I moved the TPS to a closed setting of 4.5v and left it at that . I realise that I have made a change and possibly need to relearn again but I'm still not convinced that my TPS is 100 % so I'll enquire how much new ones cost . A couple of things I learned from the moniter page are that giving the throttle a very shallow rapid tap , barely enough to make the engines note change , shows no increae in TPS voltage so this is either too fast for PFC to read or ? Also this very slight throttle retard business only happens one way ie slightly opening the throttle not getting beyond the retard point and very slowly returning to idle . I'm wondering if the second lower plugs idle and WOT switches , if that what these sensor use , are doing weird things its sendig squiff signals to the PFC . Just lastly when I next do a idle reset I'll have the headlights on as well because I think it needs greater electrical load to give a better overall result . Datalogit shows from memory 14.3 volts with no load and 14v with AC demist and parker lights on . Anyway idle light load and drivability is better now and I'll be staying away from parameters that upset this dedicated idle zone . Surely this is something thats easier on later computers like the ViPec plug in , cheers A .

Yeah well its not impossible for a split outlet pipe to work but the extra effort and cost is hard to justify for what you gain . The simple effective way is make the open one and not be shy on tube size . A .

Something that could possibly be thought about is running higher temperature coolant thermostats like the R34 GTts use . From memory they are 82 instead of 76 and that could have an effect on oil temp and warm up times . I certainly would not be using lower temp ones eg Nismos in a street car let alone an E70-E85 fueled one . A .

Big cams are not the thing to make strong low to mid range torque with , they are all about opening the valves further and for longer to make upper end power . That inlet manifold isn't going to be the thing of low to mid range torque if its a large plenum single throttle job either . They actually make an engine worse in this area that has big cams . You call but I'd be refitting the whole stardard RB26 inlet manifold inc plenum and using a pair of mild cams . I tink the difference would be night and day . A .

Hi all , firstly I did search but need a little info anyway . It seems the humble PFC tries to relearn its idle suff if you alter (I think) the first 4 x 4 box area of the fuel or idle tables , or if you change your idle speed and decel fuel cut numbers . It also tries to relearn of course if initaised . Now it has been mentioned in other recent PFC threads that these computers use a form of closed loop to chase the target idle speeds as in with timing and narrow band closed loop 02 sensor feedback . I'm curious to know what AFR it would chase with E70/E85 or if you'd have to untick the 02 feedback and set a suitable AFR some other way . I'm beginning to think that this strange off idle retard I'm getting is because I change settings so often that the PFC keeps attempting relearns but doesn't get the right proceedure each time . Something to try today , cheers A .

Well from what I can see I'm beginning to think they create as many problems as they solve for a pure roadie . I just fixed that mongrel turbo return water line behind the head (drivers side) and I can olny imagine what it would be like to spring a leak under a Gready or Plazma setup . Probably not going to fix it by the side of the road and if your Skylines like mine its an effort to get at the sump plug let alone coolant hoses . I can sort of understand why people used to attempt to remodel the std upper section because at least you can unbolt the thing from the top if all else fails . Actually thinking about it maybe Oyay , or however he spells it , could consider a different version of his plenum that has long bolts accessable from the top . Crush tubes through the thing may not look sexy but at least rusting bolts/studs wouldn't flake into your engine and again you can get at the fasteners easly to pull it off for service work . One of my golden rules is that I never do mods that make servicing difficult to impossible . Really the only difficult part in getting at the coils and plugs is getting that damned cover out from under the crossover pipe . As we know its those two small steel pipes and how they mount to the cross pipe that causes all the grief . Just to cover all the bases how difficult is it to get at the snake pit under a GTRs inlet manifold ? I don't intend to adapt this system to my 25s head but it would be good to know anyway . You can thank Nissan for making the flange patterns different because they clearly did it to stop us doing the logical thing . Probably the most complete legal way if you want a fresh engine that isn't the original is to bust the bank and build up an RB26 or maybe a 26 head on an R32 RB25 block to avoid the front water hole issue . Dunno if the various roads authorities are smart enough to tell by block numbers if you had a 32 25 block in an R33/34 GTST/GTT . A .

I either forgot RIPs did one or didn't know . Must search to see how they are . Plazmas ones are supposed to be exy but whats access like under those ? They use the std lower section of the factory manifold don't they . A .

Does anyone know of any correction setting in a PFC which would retard the ignition timing to zero in the 11-1200 rev area and drop out at guesses 15-1600 plus revs ? I increased the idle and FC numbers slightly and made each pair the same to see if I had things wrong way round but makes no difference . I really need to know if this is my PFC screwing up or some other thing screwing it up . A .

I was hoping that things in and around the Greddy would be easier to get at and the water plumbing nightmare easier to deal with . Can you explain what you mean by not as straight as the GTR system . A .

Of late I've been working on , around , my RB25s inlet manifold and TB inlet pipe and its all a right royal PITA . Coils and plugs are hard to get to and fixing the turbos water return hose behind the head was something else . Life has to be so much easier with some alternative to the standard inlet manifold . Obviously most people who make a change want the throttlebody pointing vaguely in the same direction as a GTRs plenum inlet does so they can use a cross flow intercooler again GTR style . The choice seems to be the GReady or Plazmamans and I'm curious to know if both give equal access to water plumbing etc . Also I'm curious to know if they are an automatic defect should unwelcome eyes get a look under the lid . I am told that if you use the factory through the inner guard tube gadget from the same series GTR there is no loss of strength in that area . The easiest is probably the GReady style inlet and it possibly gives the impression of being more standardish to look at anyway . A .

Sorry my bad , 0.52V . Something I did noticw was that the WOT voltage didn't rise with the increase in closed or base voltage if you like . I would have thought that the whole range shoud have risen not just the base voltage at Idle . Fixed the water leak , bastard of a job though . A .

Moving the TPS makes no difference between 0.41v and 5.2 volts , at a certain speed the timing retards often back to zero and after the revs climb a bit jum up to 20 + . Bigger fish to fry as I found a coolant leak in the turbos return line and I can't get at it behind the head . Its a HKS GTRS and where the braided lines barb meets rubber hose its leaking I think under a wormald screw clamp . After much screwing around it looks like all the heat shields around the turbo have to come off so the banjo fitting can be undone to pull the line high enough to get at the problem section . Great . A .

It may not suit me personally but for easier power and less regulating issues the mid sized turbine housing may have been a better choice for you . I feel the big issue with most integral gates is that its hard to get the exhaust gas to turn 90 degrees and flow out the port when the gas speed is high . The larger the housing AR the lower the gass speed is through the housing for a given output . Externals if located properly make life a lot easier because they tend to be larger and flow better when open - if located properly . You occassionally see externals plumbed to an IW housings std outlet and you have to ask if its much better than the original flat valve . Just on those XR6T hybrid GT3582R/GT3576Rs . Ford went with the larger 1.06 AR turbine housing - and like all Garrett IW T3 flanged GT turbos - used a GT35 turbine in a GT30 housing . They went bigish on the hotside and smallish on the compressor housing because it was intended to be a low boost pressure sollution for a reasonably big 250 Cube/4 litre I6 . I reckon the later versions went back to the 76mm compressor because the overall package better suited their needs and boost control was probably easier as well . Anyway at over 300 Kw they are supposed to pull fairly hard in a guesses 1800 odd Kg barge . That same Ford spec GT3576R could be an interesting turbo to try on a street RB30 with the right sorts of things done to it . A .

Thats why I want to fill it 13.75L , 1/4 tank , at a time to see what my gauge reads . A .

My issue with "split dumps" , particularly for these IW Garrett turbine housings . is that the fabricators often merely holesaw a round hole through the flange plate and weld the seperate tube to that . This is my theory , the gasses out of a turbine housing are hot and getting real hor by the time the waste gate was to open to regulate turbine speed/boost pressure . Hot gasses want to expand and don't like a passage opening up and then closing particularly into a round hole with sharp edges , a bit like a non matching manifold/port flange . I think to make a propper split dump you need to have a matching sized and shaped hole through the flange plate and the tube/duct then needs to grow in section to handle the gas flow rate . I honestly can't say through experience but logic suggests that any restriction between the waste gate and where the seperate duct meets the exhaust down stream will limit how much the waste system flows and if it doesn't flow enough it won't control boost .A restriction doesn't have to be the waste gate itself and you should view the waste section as from the valve to where it rejoints the rest of the system . If you go the seperate tube particularly with a modest AR turbine housing I think this is somewhere that a little overkill size wise is a good idea . I don't want to reignite the split vs bell mouth dump debate but with these Garrett GT30 IW turbine housings you already have a partial divider between the turbines outlet and the waste gates valve so the waste flow won't go straight into the main outlets path IMO . The bellmouth with give a large area for both to vent into and you shouldn't get any pressure rise higher than what the turbines outlet has , if you did with the split duct then you're behind the eight ball boost control wise anyway . A .

I'm going to find out for sure how much fuel I can squeese into my R33 this afternoon because ATM its low enough for it to lose power because it was nearly out . For some silly reason the the spring loaded fuel socket flap fell into the tank a week or so ago and this time around the low fuel light didn't come on . I must have driven 60 or 70 km below the E line and was part way down the E itself before it gave signs of starvation . I was carrying some E70 in containers because one thing you can't do is get low on this fuel when it isn't available everywhere . At least I know now how low I can get via the gauge and that will help me estimate what mileage I'm getting . I'll check it at 1/4 1/2 and 3/4 to see if the gauge is accurate , 55 divide 4 = 13.75 so the quarters shoud be 13.75L - 27.5L - 41.25L and 55L . By my estimations I've been getting around 14/100 which is sort of ok in a car thats not properly tuned and has some sensor issues . This is mostly around town driving too . A .