discopotato03

From reading more in that site it seems that the reason they and we ended up with garbage grade E10 was because of tax credits and in their case minimum levels of oxygenates in their fuels . The interesting thing is that while in general peoples fuel consumption drops between straight petrol and 10% ethanol (E10) it tends to climb back up as the percentage climbs to a point anyway . In that site someone reckons the American EPA has tested and approved E20-E30 in non flex fueled cars but their manufacturers have said nothing . Avoiding potential claims ? I gather all their ethanol fuel blends include garbage grade base stocks as the petrol component and no one seems to have tried home brewing E70/E85 with premium fuels . It would be good to find that 98ULP mixed with enough E70 or E85 ie 20 to 30% ethanol gave as good or better fuel consumption to the straight 98ULP - and a potential performance boost as well . Interesting times , cheers A .

I found another thread that looks interesting but don't shoot me if it turns out lame because its from a Green looking site . http://www.greenhybr...u-should-16411/ I don't know where my time goes , cheers A . Edit , this one is a link to a technical paper looking at optimum mid level ethanol fuel blends (greater than E10/less than E85) to see what works best - or as well or better than straight ULP anyway . http://www.ethanol.org/pdf/contentmgmt/ACE_Optimal_Ethanol_Blend_Level_Study_final_12507.pdf I noticed people saying in the first thread above that E10 is useless because there only enough ethanol to screw things up and not enough to do anything positive . I guess we also have to remember that most of these blends consist of ethanol and cheap mouthwash substituting for ULP . If it was 95 or 98 ULP outcomes may be different . A .

Interesting , thank you . Trent how do the 25-45% ratios look compared to E50 ? I should add that if your into modest turbos like say GTRSs and cap at say 1 bar of boost this may not need lots of "help" above 98 ULP to keep the timing where it needs to be . I suppose the more pulp you run the better the normal use consumption should be . I have heard about United 100 E10 but not used it so far . Are we to assume they add ethanol to 98 PULP to get it up to the 100 octane ? If so a splash of E85 or Eflex would easily get everyones favorite Ultimate 98 up to or over the ton . 10% of 55L is 5.5L (ethanol wise) which is a hair under 8L of EFlex or 6.5L of E85 . Even easier if you could lay your hands on 5.5L of E100 and only the very lazy would claim that pouring in 5.5L is too hard . Jeez I can easily get easily get 11L into some of my "10L" fuel containers and it would be a snap to make a tank of 98PULP + E20 . Is it possible to buy E100 in Sydneys south side ? Cheers A .

Thanks all , the plug in is a lot more affordable than the Extreme or V88 and looking more attractive all the time . Cheers A .

Quick question , can we confirm that both Link and ViPec Skyline plug in ECUs are flex fuel capable please . I though someone once told me only the up spec Extreme or V88 could do it . Thanks , A .

I'd like to see some comparitive results of E50 vs E85 if you have them Trent . What sort of difference are you finding power and ignition timing wise ? I don't suppose you've blended anything lower like say E40 ? For me I can be bothered and because I'm no stranger to fuel containers its not really any extra effort . Fuel prices piss me off no end and range is important - to me . I'm also interested to see what you think of the E50 for round town type driving . Thanks , A .

As I said I think it was a base line to demonstrate how different fuels react to increasing compression ratios and nock . I think it may be some time before we see static compression ratios that high and I reckon there would have to be a lot more high ethanol fuel available and being used . The trouble is that at the moment few vehicles here are OE flex fueled ones and those that are were not designed to specifically use E85 , I think it was mentioned that engines set up for straight ULP/E10 give poor consumption with E85 because they can't take full advantage of its usefull properties . I sense consumer resistance here to garbage grade E10 and its hard to promote something that decreases your fuel consumption and makes your engine run slightly lean . Its easy for people to think that if 10% is bad how bad must 70-85% be . If their Engines were designed to burn straight ULP/PULP and are getting a bit tired they are not going to give any worthwhile returns with E10 or possibly E anything - particularly without any retuning . Later model cars designed to cope with at least E10 and have some ability to self learn via wider band 02 sensor will cope better especially if their static CRs are on the high side . I get the feeling that direct injection holds some answers but thats beyond what most people here have or can probably tune anyway . There needs to be more E85 marketed and engines designed to properly use it before it can take off in the market place , because there is no easy transition strategy its going to be a long drawn out process . Its not like when unleaded fuel came in and every car after a certain date had to use it by law . Most people are not that concerned with the green aspects of Ethanol fuels and will only voluntarily make the change if there is something it it for them - meaning some cost incentive . People tend to remember the increased consumption more than the power they gained in something like their "Spark Ignition Direct Injection" Commode Door and if they weren't specifically focused on the power aspect having to fill the thing more often is a drag in their busy lives . Why would they bother . If they were a bit of a car nut and wanted to play with different blends of say 98ULP and E85 it could be interesting but I doubt thats your average Commodore buyer . Ultimately some car nuts and a few bent greenie rat bags are the small number leading the ethanol wave , the rest prefer it in glass . A . If I was setting out to build specific E85 engine it would have a higher static CR ie 9.7-10:1 and possibly the typical 1-1.2 bar boost that many use in road cars .

Well I think it was a good datum to start with 91 ULP though in our measurements I think thats more like 95ULP . Correct me if I'm wrong but I though their 87/91/93ULP was similar to our 91/95/98ULP . What I read out of that paper is that for any meaningfull engine speed and load there is an optimum AFR and timing setting and if for whatever reasons you have to retard the ignition timing the torque falls and exhaust temp rise . With higher compression ratios the temperature and pressure in the chamber increases the chance of detonation and with real high CRs only high ethanold content fuels resist detonation and nock retard . I think its more a case of running the optimum timing than running any extra over that . For our less sophisticated RB engines it's probably a case of working out how often you end up running a lot of boost and how much the extra anti nock properties of high ethanol content fuel are worth the cost and set up hassles . I'd say any worthwhile amount of E100 you could throw at 98ULP would make it more nock resistant but lower amounts are easier than higher amounts particularly if you didn't need much help to make the 98 workable . A .

Yeah wouldn't have a problem with that if I could buy pure fuel grade ethanol in Sydney , is that possible ? I'm just not convinced that some gain a lot from the short range disadvantages of E70 -E85 , on the street anyway . There would be a sweet spot trade off of ethanol percentage for daily road use but I don't want to make a guess what that is at this stage . I've only had one day of HippE50 and I can feel positives with no negatives . All the right down low running is more torquey IMO and it makes me think the lower heat value of ethanol in high percentages is a disadvantage here . My guess is that you can't get the same combustion temps and therefor pressures when an engine is using bugger all air and throwing in more ethanol doesn't seem to make up the temp difference . I think my car has some issue when running on boost but it tries to boost earlier and harder for the same throttle positions on HippE50 than wth pump e70 . Its certainly going through less juice with it and I'm looking forward to seeing over 100 Km for the first quarter of a tank . Something thats probably not possible to know is what United and Caltex are using for the petrol content of their E85/E70 . I have been reading that Australia has been recently developing standards for "E85" so that there can be some degree of quality control . Standards reckoned that until recently these fuels were unregulated and its hard to imagine the producers not leaning their own way with things like "base stock" used as the ULP component . Its worth reading up on vapour pressure and why ULP and Ethanol blended fuels are altered seasonally . Actually one thing thats made the Americans sit up and take notice is the regulating bodies in states like Callifornia making the standard flex fuel blend E51 I think due to vapour pressure reasons . Do a search on that one . It probably doesn't work out too bad provided the other 49% is something better than cats piss . Somewhere in one of those American threads someone quoted that a lower ethanol blend was getting them less range than ULP but more economical running from a cost point . It may have been ~ E30 , can't remember . Anyway I'll run this E50 through and then brew up a tank of HippE40 and see what happens . I'd rather be doing this with United E85 than EFlex E70 because less of it is the whatever but there's only EFlex close to here . If someone here can tell me where to buy fuel grade E100 in Sydney for reasonable money I'd try that . Cheers A .

I came across this article when searching for info on lower ethanol fuel blends . http://delphi.com/pd...010-01-0619.pdf I have not had time to read it it all but what looks interesting is the table on page 5 and how the octane rating and knock resistance of E85 and E50 are very similar . Whats more interesting is the stoic AFR which means in their tests they think E85 and E50 (US fuels) do much the same thing , only you'd use less E50 which would extend your range . As I said I have not read it all but if interested in ethanol blends its worth a look . Cheers A .

For better or worse I tipped in 15.3L of Ultimate 98ULP and topped up with EFlex so I should have something close to E50 now . I reckon EFlex is a pretty forgiving fuel and it'd be simple to start with 15L of 98ULP and the rest EFlex , provided the pump numbers were reasonably accurate and you were not tuned to the bleeding edge its probably good enough for road though monitering with a wide band would be good . I guess if you use less ethanol the percentage variation becomes less of an issue and the PULP you add is more of a known quantity/consistancy . I'm not sure if its known what United and Caltex use for the other 15 to 30% of their FF blends and it probably doesn't have to be anything brilliant in those percentages . This would be one area where drum E85s should be a known quantity . Not something for everyones garrage ... Anyhow as luck would have it my current best EFlex maps were just starting to give more acceptable consumption and that was from getting the shits with chasing better range and going for better drivability and performance . Anyhow the fuels mixed in reasonably quickly and I drove for about a km before the wide band indicated richer in Lambda and I uploaded a map with different injector trims to suit with Datalogit . I went from 65.0 to 60.7 though its still a little rich so will fiddle again later this morning . It will be interesting to see if performance changes at all which is unlikely for a "light tuned" roadie and if my range increases which it should . If all goes well I may be able to up the ratio to 60% PULP (E40) and see where that takes me . Not that too many care but for the record 40% of 55L is 22L and 31.5L of E70 in theory has 22.050L of ethanol . Whats life without challenges

I cant remember the exact details but I did speak to Gary about these Nissan V8 MAFS and he reckons the difference is the element inside them . If I have it right some of these elements can "interchange" and thats the primary difference between say an 80mm R33 GTST MAF and the 80mm Z32 TT one . He thinks that its a similar situation with the 90mm V8 ones and obviously the one to have is the 90mm body with the insert/element that the Z32TT one has . With care it may be possible to transfer the guts to get the right combination but its always preferable to have the right one brand new where possible . A .

Actually if you could get a graduated container or something that filled to virtually the same exact amount and used it for the E70/E85 fuel component I reckon you could get a repeatable blend . In that seciond link I posted above they speak about how the Ethanols octane rating is not an accurate one and it isn't a good indicator of a fuels knock rating anyway . Someone in the thread these links come from reckons that in concentrations at/above 50% the actual octane of the petrol content becomes less critical . More later , cheers A .

This is an interesting if time consuming read into fuel standards in the US . http://ethanolrfa.3cdn.net/dd9e74ce1c454a97cc_rbm6bdgh3.pdf If at all interested in fuel I suggest you read it Cheers A .

The answer hit me a couple of hours ago . Making the assumption that an E70 blend needs 30% more fuel than ULP then E50/E70 = 0.714 times my 30% = 21.428 . Because my Nismo 740s are twice the std 370 size I use a 50% correction factor which means I cut above 21.428 in half (10.714) as well then add that to the 50 to get an injector trim figure of 60.714 - 60.7 . Mine is a pure road car and I have no interest in bouncing it off its rev limiter . When you consider that the majority here are probably using 98E0 , 95E50 or 98E50 in the right AFRs has to be better . A .

That thread I linked above digs some pertty deep holes when it comes to the petrol quality that could be going into these E70-E85 type fuels . That aside can some mathematically minded person come up with some sort of formula that would allow us to work out injector trim numbers for diferent Ethanol content fuels ? I use 740s which are double the size of the std 370s so my PFC trims would be 50 for petrol and 65 for E70 - assumes I need 30% extra fuel because of the different heat values of the high Eth content fuel . Just trying to calculate what E50 would need in the way of injector trim numbers . Thanks in advance , cheers A .

Hi all , I was crunching some numbers to see how difficult it would be to make an E50 blend just to try . I'm not totally convinced that ethanol ratios of 70-85% are necessary in a medium powered road Skyline and I did some searching to see what others think of this . I found this American thread and it was most interesting to read about "blender pumps" that can make up varying ethanol blends overseas . http://www.dsmtuners.com/forums/tuning-engine-management/418047-using-lower-percentages-ethanol-e20-e30-e50.html I haven't gotten all the way through that thread yet but it was mentioned that even when the octane rating of certain blends matched straight petrol the ethanol blends tended to be more detonation resistant . I guess its the evaporative cooling of ethanol at work here . Just for the record by my calcs and assuming an R33 has a 55L fuel tank you could possibly add 39.3L of EFlex which is 27.51L ethanol and top off with 15.7L of petrol to get your 55L of E50 . It may be possible to go even lower in Ethanol than 50% , with the right AFRs , and not have to pull too much timing losing burning efficiency and torque . The one big variable is the octane rating (detonation resistance) of the ULP being used in these potential blends . It would be interesting to try 95 and 91 ULP just to see how far the still higish percentage of ethanol can supress detonation . I realise this is a bit of a screw around and you'd need to be carefull to keep the blends accurate , sounds like an ethanol content sensor and read out would be the safest bet . Something to think about , cheers A .

This is a tread I found with one persons views on this . http://www.8thcivic.com/forums/hondata/189947-injector-latency-explained.html If this is the case then I have a better understanding of what this Latency means in relation to compensating pulse widths to allow for the time taken for the injector to react in relation to the electrical signal sent to it . I can see where having the Latency constant wrong may alter pulse widths across the board and change mixtures accordingly . Anyway from searching in the early hours it seems the std R33 RB25DET 370cc side feed injectors have a Latency or time lag of ~ 0.528 ms where the 740 Nismos I use are 0.66ms so the settings should be 0.132ms . I can change this easily enough from 0.14 to 0.13 and fiddle my fuel table to suit . Sorry for my injector timing assumption . A .

GTS boy I am aware of what goes into calculating injector pulse width and why . You should have read my whole post because then you have some idea where my questions are - not just blatently brush me off . A .

I will agree that there is a fixed time between injector closed and opened but I don't agree that applying a set correction has to be cast in concrete . How would we know why Nissan set up their sequential injection timing where they did with standard parts . Anyway obviously moving the correction number around changes the injection timing which in turn can change the AFR - mine did any way . I think the reason why Apexi allow corrections is to make the altered injectors partially mimic what the standard ones do as in the start or finish of the injection pulse . I mentioned before that I played with an Autronic SMC years ago and moving the injection timing around made changes , I just didn't know how much because I didn't have access to a wide band 02 reader like I have now . I suspect that the part of the injection pulse that we are correcting for is the closing phase or end of pulse because that is the part in the engines cycle when all the fuel has been added . To me it makes sense that a larger injector will be open for a shorter period that a smaller one to inject the same amount of fuel and if the end of pulse occurs at the same point in the 720 degree cycle (four stroke two complete revolutions per cycle)then the effective AFR should be the same . What I want to know is why the AFR changes with injection timing , particularly if the pulse width (injector open time) remains the same . Logically if this occurs at idle the injection timing must have been wrong to start with . You would think that moving the injection timing around so that the least pulse that gave the intended AFR should be best - why inject any more fuel than necessary to achieve the desired result . Without meaning to sound insulting it looks like some fiddle with correction numbers but may not have the means to see whats actually going on except noting the engine running rough or lumpy from the mixture going lean or rich . I think an idling engine has to have everything right to idle well as in ignition timing injection timing and obviously AFR . Its being literally strangled by the throttle/s and its effective CR is very low , to try to have efficient combustion with such little air probably creates narrow windows of opportunity to inject and fire what mixture it has . Anyway AFAIK injection timing in sequential systems seems to have the greatest effct on the slowest engine speeds and the accuracy advantages fall away with increased engine speeds . In fact I believe some computers are designed to revert from sequential to batch fire above a certain engine speed because its no longer important - and injecting twice per cycle in batch mode rather than once per cycle in sequential mode can reduce the need to use large injectors to start with . All this aside I found a not insignificant fuel leak below my fuel filter yesterday and having fixed that I should get better consumption figures ! Being on the pump side of the reg it may have in some small way affected fuel pressure and more so at elevated manifold pressures . I reckon I can feel some slight differences and the Tech Edge is showing slightly richer mixtures under load . Always a worry to find fuel pooling under your car , cheers A .

After going backwards consumption wise I'm getting better results with slightly richer and more advanced settings at around town revs . I am curious to know if anyone worked out the ideal injector lag time because searching gives all kinds of numbers ie from 0.08 from the SR people to 0.20 from some RB people . Mine is currently at at 0.14 but I did try 0.08 at hot idle and it sent the mixture leaner , 0.16 made it rcher . I would have thought that anything other than injecting more fuel that made mixtures richer was a step in the right direction because it sounds like what fuel going in is being burnt more efficiently , could in theory go this way and inject slightly less fuel for the same mixture result ? I always though sequential injection and having control over injection timing only made a difference up to say 3000+ revs and then the speed of the cycles and inlet air overcame any injection timing differences . Also something else and yes I did search forst . Are the battery voltage corections in the sample Datalogit RB25DET dat file the right ones for 740 Nismo side feeds because that could be one variable that people may not be taking into account . Datalogit shows that my running voltages are mostly between 14 and 14.2 volts but on a log it once spiked to a 14.6 max . Any help appreciated , cheers A . Actually one more I entered 10 10 and 8 in the retard from coolant temp settings and I think its warming up faster because of this . I may try 12 12 and 10 next .

Yep I go with velocity over volume and with a bit of research you tend to find that often high rev race engines don't necessarily have huge ports . Going back a bit but Cosworth BDAs didn't have big ports but they could turn quite high revs with bigish cams and induction . Don't want to go too deep but I see an engine as a piston pump and the velocities and pressures are critical to have the gasses coming in one side at the right velocity and out the other at the right velocity . The pressure balance becomes critical particularly with forced induction because you are attempting to force a given engine to breath and perform like a larger one - usually without larger engine gas paths . It also has to have acceptable performance in un boosted and boosted states which is a big ask . With RB26 heads I'm guessing the design didn't change much if at all and nissan got more std performance from them with different turbos possibly cams and management . I don't recall seeing that R34 GTt heads have larger exhaust valves than earlier 25 and 26 heads , although valve ratio size exhaust to inlet 25s/26s appear to be a little short changed on exhaust valve size than the ideal formula . I reckon this was done to help with emissions (EGR effect) and possibly help spool std turbos on engines that were not large capacity wise for the weight of the car they had to drag around . It is really easy to fit 0.5mm oversize exhaust valves into RB25/26 heads and the gains don't seem to be compromised with any negative aspects . Manufacturers are not stupid and mostly have good reasons for everything they do . A lot has changed engine design wise since the late 1980s and change has mostly been driven by emissions consumption and manufacturing economics . Had Nissan designed the RB26 from scratch in the late 90s it probably would have had a smaller bore and a longer stroke or more likely more capacity . I think single or twin VCT would have gotten a serious look in too . One day someone will find a way to make or remanufacture the inner section of the RB26s inlet manifold to suit RB25 heads , that will be the day when the potential performance difference between the two disapears . Much as I like the I6 layout the trend has been V6s almost certainly for packaging reasons . A .

I was speaking to SK recently about RB26 manifold flange differences and his reasoning sounds logical . So I'm told Nissans earlier experiences with R30 and R31 Skylines was that all the boy racers in Japan bought the more mundane versions and bolted on the good gear from the high performance varients - because everything bolted on or plugged into the poverty pack versions . He reckons Nissan didn't want smarties tossing GTR bits on GTSTs so they made GTR bits different enough to not fit without major re engineering . RB25s could very easily have been the same water passage and manifold pattern wise but that was obviously not Nissans intention . Head casting wise I'm not sure if the R33 or R34 RB26s were any different to R32s and I suppose if they got by performance and emissions wise it probably wasn't justifyable to develop a better head . It sounds to me like the Neo RB20 and RB25s were the last of these RB engines to see any developement at all and that was probably aimed at meeting later more restrictive emissions standards and having a bit more usable torque as well . My best guess is that the RB 25 Neo head would be better than an RB26 one if you could get a six throttle inlet system on it . Also it may pay to see if the 25 Neo uses the same length and height valve guides and same diameter bucket bores because RB26 valves and buckets may fit straight in . I reckon small as in compact chambers are good chambers particularly in a 4 valves per cylinder head because you don't have that silly plateau on the piston crown to make the static CR acceptable . A compact chamber with a flat or slightly dished piston should have better quench characteristics and if the head was from a late ULEV era car you'd expect it to have better water jacketing to better cool hot spots , think lean = hot and detonation prone , and lessen ignition retard from trying to control detonation . From memory on paper an RB25 Neo cranked out 206 Kw where I think early RB26s on paper had 209 kw , they used an 82 deg C thermostat as well . I think by the time R34s came to life GTRs were old news and Nissan weren't so concerned with the copy cat issue . They obviously found ways to get almost GTR power with one turbo one throttle and that little ole R34 GTt SMIC . Lots of subtle differences in the Neo RB25DET obviously helped like a few Kw here a few Nm there . Ultimately a much cheaper engine to make than an RB26 . Gut feeling is that there is more to the humble Neo turbo head and valve train than meets the eye . A .

An RB26 would be very different with its individual throttles because the rise in manifold pressure would be fast and you need to toss a fair bit of fuel in to keep a reasonable AFR . Its take a bit of getting head around but these computers have a unique idle setting state if you did the idle learning properly and you don't seem to get access to this even with Datalogit , not sure if you do with Apexis software . I'm finding that you need to play around with the injection and timing tables just off idle where it changes to these map settings . Its interesting to watch Datalogit in log mode so you know exactly where the engine is live . I think its a juggle of how much innitial fuel comes from the accel settings and how much from the fuel table . ATM I have things a little richer in the 400 800 1200 areas while further up I leaned out the upper cells and pulled a bit of timing out to stop it popping on the overrun . I find the more you can get using the fuel table the better the consumption tends to be but don't forget to play around with timing settings as well . I think there's limits to what can be done without a dyno and someone who knows what these engines like where timing wise . A .

I'm not an RB26/GTR person but I'd look at it like this . HKS effectively replaced the old "GT2540s" , which in todays speak are actually GT2876Rs , with turbos called GTRSs which are a GT2871R in 52 compressor trim . People here say that it takes a specific combination of parts and good tuning to make GTRSs work on an RB26 and they actually use smaller but more modern compressor wheels than the old 2540s . You could try all kinds of ways to work around those turbos but at the end of the day they are not a well though out turbocharger and you can do better . Simply too big a compressor for the turbines to drive and thats what makes them lazy . I think the designed for the purpose GT2859R (GTSS) are the go because they make boost and torque in the rev/speed range you can use in a street GTR . Pretty sure you'd still make 300+ Kw but you'd drag the power range down possibly 1000 revs if not more . So your call , either GTSS or inaptly called GT2530s I think . A .