discopotato03

I will search again but my understanding of a mass air flow sensor is measuring air temperature from which density is known . I think the only difference the size of the duct makes to the sensor is that more flow equals more air to affect the cooling at the heated wire . It's the regulated current required to keep the element at a set temperature that gives the sensor output voltage . From memory the circuitry is known as a Wheatstone Bridge and there should be info out there on this system . Also manufacturers know how much air a given MAF meter will flow with atmospheric pressure behind it . The only variables will be atmospheric pressure and temperature and these aren't hard to allow for . Things that do change are engine and bay temperatures especially in warm weather and with stop start running . The inlet tracts ie manifolds heat up and the slow moving air absorbs this heat more easily . Everything now has oxygen and knock sensing so the EMS can compensate for slightly more extreme conditions , computers also self learn these days attempting to stay within fairly narrow ranges for emissions reasons . IMO the reason why some OE engines have Mass and air temp sensors is because continuous full load running heats the engine and its bay to temperatures a production car would never normally see and slightly leaner running kills things eventually . It's not hard to see why say a GTR has a basic air temp compensation sensor where GTSTs don't . Nissan and no doubt other manufacturers have moved to better air flow meters than they used in the 80s and 90s because they are all chasing accuracy and ever tightening engine controls - and its driven by emissions and consumption legislation . I reckon hats off to a MAF sensor where you can remove/replace the element without pulling the ducting apart , its made things easier for the aftermarket who can make a larger body and use the OE element . A .

With regard to these Walbro E85 pumps are people having issues with them circulating too much fuel and getting hot fuel and tank pressurisation as a result of it ? Just curious to know what happens in warm weather and traffic driving . Also does anyone have pics of one mounted to an R33s bracket ? Lastly noise , my 25T is not particularly noisy and I can hear my 33 GTR pump whining away . I run E70 and don't think I'd ever see more that 320 kw , Nismo is probably the easiest and quiet but you pay for it . Cheers Adrian .

What I meant was using an RB25 Neo turbo head and it's inlet manifold . It's not an easy job grafting a RB26 inlet system onto any RB25 head and if driving conservatively much of the time I don't know why you'd bother . To me there is only two reasons anyone would ever go with an RB26 head and they are the shim under bucket lash system and the six throttle inlet manifold . The aims being valve train reliability at very high revs and sharp throttle response . Big revs is not a consideration for normal road driving and single throttle inlet systems work fine in these applications . So basically yes I think an RB30DET based on the Neo turbo head would be easier to get better consumption from - particularly if you can get the static CR around 9.5 to 1 and run it on something better tan basic E10 or 91ULP fuel . I'd also consider using a taller diff ratio like say 3.7 or 3.9 because doing close to 3000 revs at 110 km/h won't help consumption . A 20% larger engine can in theory pull 20% taller gearing which works out to be around a 3.29 diff ratio , not hard to see how that's a bit extreme so if you halved that to 10% it works out to be a 3.7 final drive ratio . Lighter VL Commodores with RB30Es (SOHC 9.5 CR) from memory had a 3.45 ratio final drive and something very similar to an RB20DET gearbox inc ratios . A .

I don't think you'll get that in the burbs with the 26 inlet system , I'm not sure if you'd see much advantage of that if mostly driving around at smallish throttle openings . On the open road at fairly consistent engine loads and throttle openings it may not make much difference . I tend to think that since Nissan made the last revision of the RB cylinder heads in R34s the changes they made would have been to do with running leaner mixtures and not detonating on the sameish available pump fuels . At that ultra low emission vehicle (ULEV) point many manufacturers had to revise heads so that their engines could perform acceptably using lean mixtures . They had to have better cooling around exhaust valve seats and ports and having less chamber surface area (more compact chambers) means less area to absorb combustion heat . What I think they were trying to do was remove more of the heat via the exhaust gasses than the engines cooling systems - also helps keep heat in cat converters . I don't remember there being any changes in the R34 RB26 chambers and ports though someone here would know . GTRs were not really designed with economy in mind (IMO) and as long as Nissan got them past the emissions standards they probably didn't care that much about economy . Having all round reasonable performance and better consumption would have been the realm of the GT and GTt and the latter was a step up from the R33 GTS25T . I think it's safe to assume that had Nissan produced an R34 GTt with an RB30 it would have used the Neo turbo 25 head and inlet system and only minor rejigging . It would have had more part throttle torque everywhere and probably longer diff gears to take advantage of the extra soft pedalling torque . I think if you want the best of both performance and economy you should consider the last revisions of what the factory did because they were after these same things , but limited themselves to 2.5L . A .

Correct me if I'm wrong but doesn't the Neo turbo head have chamber volumes about the same as the RB30 NA SOHC head ? And wouldn't that make the static CR about 9.5 to 1 . IMO having an adequate CR is where part throttle torque and economy is because it has a big say in the dynamic or throttled CR . The GTRs six throttle inlet manifold was all about sharp throttle response because you could open the ports up to a big inlet tract . Trouble is that when you let lots of air in you have to hose the fuel in to maintain acceptable AFRs so the transients tend to be bad consumption wise . Yes and the variable inlet cam timing makes for better low end torque and consumption - better overall compromise . I think what you seek is a torquey engine that doesn't need a lot of throttle to get around in style , everything about a GTR is open it's lungs and go for ratshit fuel economy - it's not something Nissan gave any real consideration to . I can't think of any homologation specials from the 80s and 90s that had good fuel economy-especially turbo ones , things like RS500 Sierras Evos GTRs etc . On paper a Neo turbo engine makes 206 Kw where I think a std R32 RB26 made 209 , the Neo would have been a simpler cheaper engine to make with one throttle and one turbo and in theory its power output wasn't far short . It's power delivery would be more user friendly for a road car and it should have got better normal use consumption . If it were me I'd use turbo Neo heads on a fresh std RB30 NA or turbo because it's the best compromise for a road car . CR will be better and if the car was a single throttle one you get to use more of what it came with . Freshening up a standard late RB30 NA - std pistons rods water pump - shouldn't be to exy though a turbo oil pump like maybe a 25T one is probably a good idea . IMO you only need the collar etc if you are going to rev to 7 and beyond or bounce off the limiter much . Your call cheers A .

I reckon he would get the dampers checked on a shock dyno and go from there , he knows what readouts he gets with his valving and will probably advise what to do . I believe springs are a bit more difficult and the delux option is a coilover conversion with Eibach springs . I'm not sure that Whiteline make the SK "Works" kit springs anymore so anyone that has them , like me , is at a dead end if you have problems with them . The conversion is a little exy but not difficult and you get access to a huge range of springs and easy height adjustment . Actually he told me the other day that my rear springs are not the exact rate he wanted but it was what was doable with a std configuration (not rate) spring . Bottom line Billies are great because they are serviceable and if you can get into easily available springs there is no dead end . Others would disagree but I don't like the bling brightly coloured aftermarket coilovers with spherical joints when the above mentioned system can go in and work really well with the std rubber in the strut tops and bottom eye mounts . You don't want spherical joint rattles and a hard as nails ride in a road car - or the NVH roar that drives you crazy . SK stuff is great when you want it to work well and be liveable . I really like mine cheers A .

I've had the Shell Rotella T6 Synthetic 5W40 in my 33 25 for a few changes now inc right through the winter . It never rattles on start up and never comes out milky either . I just have the std oil pressure gauge and it never points to doom and gloom , also using genuine filters BTW . My engine never runs filthy rich on E70 but if some peoples engines do then I imagine you'd get more oil contamination . Also if your oil runs hot enough it should boil any water condensation off and send the vapours back through the breather system . Oil temp is going to come into this and I reckon if you drive your car for any distance and the oil temp is only 70C then you have a cool oil issue . When my Lap top is plugged in the Vipec shows the coolant temp is from 83-87C and since I run the std oil cooler/heaster I reckon the oil temp should be mostly slightly above water temp though I have no gauge set up to check it . As for oil coming out like water if its hot and synthetic I'd expect it to anyway . A .

I reckon the easiest way is to pop the pin from the relevant wire out of the plug and elec tape it to the loom . It doesn't take much longer and is reversible , not that you'd want to but why butcher something if doing it this way is so easy ? A .

There were a few other things they did after the weight was increased and boost level limited . I will ask but I think one was increasing the static CR but can't remember the other . They didn't get all the power back but enough to reduce the loss . A .

I wouldn't hesitate to fit an adjustable exhaust cam pulley on an RB25 if doing the belt etc . Another option exists if you are going with a T4 flanged manifold and that's the twin scroll IW EFR turbos . All the blurb I read suggests that those lightweight Gamma Ti turbines make a significant difference because they have less mass to accelerate . If you went with an IW TS T4 flanged one you eliminate the need for external gates so less bulk cost etc . These EFRs have long turbine housings compared to most turbos but they make things easier in other ways . Just a though cheers A .

Yes I think the same of the stainless 1300s and if demand is there they may do the short 850 GMs and 1000s as well . I can see where 1000s could be limiting on a 4 cylinder but 6s get an easier time with similar power outputs . It's logical that a good injector sized properly will make the best of a more basic computer . A .

For a cheap E85 engine 9.5-9.7 static CR should work out pretty good for a roadie , always provided the turbo wasn't too small or boost too high for the NA pistons . A .

Yes went there with no real positive results - needs to be done on a dyno I think . I've been experimenting with a couple of the accel settings sens and decay . The sensitivity was set at 30 and I kept getting rich spikes on uneaven road surfaces because my foot was bouncing on the loud pedal . I'm down to 23 ATM with no drivability issues and more consistent "steady" throttle AFR . Was spiking from ~ 0.94L to 0.87-0.85 . I will try slightly increasing the decay and its up 2 from 30 ATM . Be interesting to see if it improves consumption , cheers A .

Don't they run a single fuel line to the rail and no return from that point ? A .

Do some research on 7MGTEs and head gaskets . They are I believe prone to not clamping the fire rings very well and people who raced them reckoned they could tell how many times they loaded it up by the number of times it moved and marked the head face . I know of one fella that drag races a 7MGTE in an old once 2L 6 MK2 and he got it to survive using a rare HKS head gasket . I believe the issue is that the head casting isn't real rigid and doesn't like to seal in high power loads . I think the 7M was the last and largest of that engine family and Toyota kept increasing the capacity by making the stroke longer and with the 7M the block taller . Not trying to be a killjoy but doing a bit of research may save time and money in the long run . Best of luck cheers A .

I did look in your sig before I asked the question and wasn't going back a dozen pages to check what you run . Does anyone here have a 7064 on an RB engine ?

Brad is your 7064 mounted on a standard RB25 manifold and if so can we see some pics of it . It'd be interesting to see a bolt on one in an R33/34 engine bay . Cheers A .

This was what I asked two weeks ago . Since then I found out about those Pilot Sport AS3s but I'm now out of rear tread so can't get them out here in time . I also found out that one of my rear Bilsteins was history , NS one leaked gas and oil and the thumping was the oil piston bottoming on we reckon a jammed gas piston so short only about 2 1/2 inches of travel ... Both replaced with new ones and now the rear height is not even with the circlips in the same height groove both sides . That troubled NS must also had it's spring settle more than the OS which would explain wear and traction issues . I like Michelin performance rubber and the only 255/40/17 available in the Pilot Sport range is PS2s which as I said are too soft and fast wearing . I am resorting to PS3s in 245/45 because I need tyres NOW and sorting the rear suspension should help with grip and wear . Just as a note the feller that designed a tested these suspension kits likes Michelin so I got to like them and his SK kit too . A .

Isn't that the truth . A .

My experiences so far with the GTS25T . Bought with G Grids , noisy and 225/45s stretched on 17 x 8.5" wheels ...... Replaced with Michelin Pilot Preceda 2s in 235/45/17 , not bad all round and wore evenly . Replaced with Michelin Pilot Super Sport same size , good handling but average drive traction - though did have rear suspension issues , rears wore out but fronts plenty of meat . Can't find a 255/40/17 I like in time so getting Pilot Sport 3s in 245/45 to replace the dead Super Sport rears . I will be interested to see how those Pilot Sport All Season 3s go overseas and may get some in next time if I can't find anything I like . A .

My GTS25T had the SK Bilstein kit fitted all round in 2005 , not long before I bought it , and the rear Billys were changed out today . One was perfect where the other had leaked it's gas and oil though still had a perfect shaft . I wouldn't fit anything else to a road Skyline even if it was going to do the odd track day . I think some people reach for the bling coil overs without realising that direct replacement dampers and springs can work real well without the dramas of spherical tops etc . Your calls though the SK spec Bilsteins springs etc can still be bought new I believe . Those rears had an extra top circlip groove machined upwards because I can't stand real low road cars , mine are set two up from the original std Bilstein groove and can go up one more if necessary . I started to get a few tyre rub issues when I went to 245/45/17s after running 235/45/17s and when Gary measured my car it was a tad front low compared to how it should be . Originally this was done because people didn't like the front height with the front circlips where they were supposed to be and these cars settle about 8mm in the first 1000 od km . You were supposed to come back to have the front raised one groove but my cars previous owner must not have done this . I aim to raise the front 16mm (two circlip grooves) and if it can be done in time have a couple of extra higher ones machined in just in case . I believe a road Skyline can be too low and the suspension geometry can suffer because of it , for example if control arms angle upwards to the hubs the roll camber change is probably wrong and roll resistance not as it could be . Will find out in time , cheers Adrian .

Late getting back to this and Geoff Raicer in particular .<br />There are limits to what you can use on a standard exhaust manifold and I reckon if there were suitable TS IW T3 flanged turbos available the standard manifold mob would be better off .<br />I'm particular and I can't have everything as I'd like it even with a single scroll IW turbo . At the end of the day I probably need more cubes so I can have the stronger low down part throttle torque and less reliance on FI to do the job properly .<br />

What I did was this , I run a Vipec and Tech Edge Wide band BTW .<br />My car was tuned on Caltex Eflex because that was what I could easily get in three localish servos at the time . Now United E85 is close to where I work so I'm trying E85 with 15% BP pulp to home brew E70 with at least 15% "real" PULP .<br />I worked out that 8.25L Pulp in a tank of E85 makes E70 so not hard to do .<br />My ECU has a target AFR table so it can chase set AFRs at part throttle loads provided the variation isn't too great . My car didn't like going from E70 to E85 so obviously the approximately 15% less petrol was a bit lean for it to cope with , it was very quickly and easily fixed by adding 5 1/2L of PULP in a nearly full tank .<br />I don't know if the effect is as noticeable going from E85 to E70 because a tad rich rather than a tad lean probably isn't felt so much . My tuner said to me that my engine probably isn't making enough power to really hurt it if I got it a bit lean though I never play with the full load settings only the up to positive manifold pressure stuff . I would like to have an ethanol content sensor and readout so I can see and the computer can monitor though people should be able to tell themselves if their car feels a bit flat or flat spots under normal acceleration transients , I can .<br />My computer can have flex fuel tuning though if I ever did that I reckon I'd only have it cover E40 to E85-90 . I think there is too much variation in what we call ULP particularly octane wise and it clouds the whole flex fuel thing if the tuner has to cover increasing petrol percentages AND a variation in petrol octane ratings . Obviously the higher the petrol percentage content is the greater the importance on ULP octane becomes . I guess if we could have a petrol octane sensor as well as an ethanol content sensor an ECU/tuner could cover the whole fuel content range but I don't know if this is possible .<br />Anyway I think asking a tuner to start out with say United E85 or preferably E90 then add more of whatever octane ULP you normally by say in 10% jumps down to E40 or E50 would be quite workable . I think this would make the tune vs ethanol availability wide enough to get by without adding the straight petrol with who knows what detonation resistance vulnerability . The ethanol content sensor would tell you which way to go to stay inside the 40-90% range and you could tailor it towards performance or extended range with the higher potential petrol content . Maybe not totally flexible but flexible enough .<br /><br />Sorry if I've gone a bit off the OPs track but it's all food for thought , cheers Adrian .<br /><br />

I know of someone that tuned a car with a 6758 and really liked it , they also I think played with a prototype 7163 and it was good as well . I'm told EFRs are generally wide ranging things and I believe they are aiming at compact though they don't look that compact to me turbine housing wise . I think it's difficult to make IW particularly TS IW turbine housings reasonably short and have the waste paths flow well enough . Garrett and Mitsubishi have done it but not with clockwise rotation "T3" flanged turbos . Sadly there is a market for T3 flanged TS IW turbine housings but not much is being done about it . Hate to say it but I think single scroll and VATN will be the reality once the moving vane assembly becomes reliable on petrol engines . Meanwhile I am interested in EFR 7163s but I don't see one on my car . A .

Depending on flange size if you didn't want anything too expensive / exotic a GT3582R can probably get you there and be a bit more modern wheel wise that your T series BB Z turbo . A .