paulr33

all that happens when the AFM is maxing out is that the AFM can show anymore airflow increase to the ECU. which is basically the same as MAP sensor style. it will shoot across the horizontal access from the point it maxes at 5100mv. you can make upto 250rwkw on the stock AFM if you can deal with the maxing out. even maxing it out 3500rpm, simply means from then onwards it will shoot across as apposed to diagnoally down.

yes the load points are not linear, that is they are not 20 eqaul load points. as load increases so to do the scale of each load point

mines were somewhere near 600hp stock fuel rail and stock plenum

hey ben, have a read of the djetro vs letro conversation currently happening. you will realise why one tune drops to load point 15 and others drop to say 18 or 19 and vice versa. a very good read

second hand GTR intercooler or 450x300x75 intercooler, hybrid, garrett, any chinese brand is likely to do ok and be satisfactory.

all apexi powerfc's use the airtemp for airtemp correction, that is IGN correction for airtemp INJ correction for airtemp this applies for ljetro and djetro versions (and pro). they influence more or less IGN/INJ for given airtemp values but won't affect load axis placement. the R33 GTST is one of the only PFC's to have broken airtemp implementation, that is the factory car does not come with an airtemp sensor so it doesn't work. SW20 customers can purchase an additional sensor and connect it up to the PFC loom for working air temp sensor support depsite the car not having a factory air temp sensor

mines use the stock fuel rail and plenum, i guess they were ok with it and their power target. they probably just dialed in the highest flowing injector into #6 and maybe did a slight trim like busty2k said

its already been covered i thought. put highest flowing in #6 and least flowing in #7 and it should balance out the fuel issue.

this point of this thread wasn't to prove anyone right or wrong. it was merely to clear up a few myths and post up the actual mathematics behind it. ive often wondered why most stockish gtst only max near load point 15 and ive also often wondered how you strectch or bend the afm load points, now we know, use the load ramp table and rescale, which in turn affects the final load bearing

map sensor tuning becomes more difficult on multiple throttle bodied engines such as the Rb26 and the SR20 GTIR version as they have individual throttle bodies. the djetro doesn't utilise an extra air temp sensor. the RB26 has a factory air temp sensor in the plenum for air temp correction, but this won't affect load placement on the load map. on my R33 when i hit target boost in 3rd gear just near 3000rpm my AFM reads 3100mv and slowly increses to 5100mv just near 6000rpm. so for the AFM vesion the load keeps increasing until we peak the engine's efficiency near 6 grand. on the map sensor version my load would have remained static from 3000rpm until redline as the air pressure would have never changed.

what turbo's are u using? you should have twin bov's and a joiner pipe between the intakes to balance out the pressure difference. have a search for compressor chuffing shuffling, as it sounds like that

i dont believe in any supernatural or ghosts for a second. its likely to be a set of events that however unimaginable have occured. just a big bunch of conincedience is the likely answer.

r32 and r33 have different oxygen sensors. r32 is itanium and r33 is some other format. front and rear sensors have different plugs in both models i believe. r33 gts/gtst can use falcon el sensor, its just a generic 3 wire 02 sensor but its easier to ask for ford falcon el than R33 gtst at your local parts dealer. nowadays its not such a big problem. NGK website has part #'s for BNR32 sensors with matching plugs

there is nothing to prove here. all the information is in what i have posted and how the load axis calculations are different from the normal and djetro versions. do you honestnyl think if i change my PFC to a djetro version i would magically make another 20rwkw on my 194rwkw gtst? of course not. this thread simply puts down the exact method used for load axis calculation. there is no 3rd dimension for the djetor load axis. even I thought TPS was the 3rd dimension, but its not.

motec is basically a racing use ECU. it has many many features that an average bog stock skyline or even high powered skyline wouldn't use. it is simply not cost effective for a customer to use, given they can go for $1000 ecu and get 90% of the features they need. some of the features include 2 lambda sensor input drive by wire control rev limit per gear down shift rpm matching for gearbox 3d map tables choice of firing for upto 8 drivers temperatre input/correction for air temp, oil temp, water temp 8 aux outputs for gate control, idle up, warning lights porgrammable inputs (speed control for pits ie: lock speed to 50km/h) full logging basically rally cars and v8 supercars run motec as it has the features they need and use. gear logging for each gear and so on.

I've done a quick pro's and con's of each (my comments are marked as PR). These are the most debated ones Ljetro Pro's -> Out of the box, works great, plug and play nothing more to add/change PR: This is suitable for the majority of customers -> Supports factory airflow meters and larger models PR: This is suitable for the majority of customers and tuners (less fiddling the better) Cons' -> Some tuners/owners believe the airflow meter is a restriction PR: Turbocharged cars have a restriction after the compressor outlet, not before. -> Once you max out the airflow meter it can't show any more useful load to the ECU PR: Once you max out a given airflow meter, move to a larger unit with higher resolution. If you stay with an airflow meter maxing out (stockish GTST customers) then you basically have the same load bearing as Djetro customers. Once you peak or reach max airflow (the most the AFM can show) then Load doesn't increase anymore. This is dead obvious for stockish GTST customers who do a map trace. Djetro Pro's -> No air intake restriction PR: Turbocharged cars have a restriction after the compressor outlet, not before. -> No airflow meters in pipework PR: This can be helpful for large twin applications. It may also help avoid chuffing or compressor shuffling. With correct pipework and bends you should be able to run twin MAF's or even a big single MAF relocated in the after FMIC pipework -> Can't max out airflow meters PR: This is a valid Pro. But once you max out any airflow meter simply change to a larger unit or more scalable unit. Con's -> You loose load point resolution once you reach target boost (horizonatal shoot across, as pressure never changes) PR: This would be my main caveat of moving to map sensor system, the lack of tuning points, as the map isnt a 20x20 useable map anymore.

turbocharged car's don't have restrictions bofore the turbocharger. the restriction lies after the compressor outlet so it wont be an intake restriction. and even if you or the tuner deems it a "restiction" move to a bigger or larger unit. moving to a map sensor system isn't the solution

Apexi PoweFC - Ljetro VS Djetro For some time this debate has gone on with various opinions and ideas with no real concrete evidence/proof or logic to back it up. There are two distinct differences between the LJetro and Djetro PowerFC (and presumbably other LJetro/Djetro ECU's) and we will discuss them as this is a hot topic. Having since worked out the mathematics behind the Load axis calculations for both the Ljetro and Djetro versions of the PowerFC I can show you how they are both calculated. First we should look at each base model and how it works; Apexi PowerFC Ljetro Version Uses standard airflow meter 20x20 Load Map Other addtional supported airflow meters (selectable on menu) Apexi PowerFC Djetro Version Uses optional supplied Apexi Map sensor 20x20 Load Map Other addtional supported map sensors (selectable on menu with correct voltage and offset) Both units are scalable upto 1100bhp with supported modifications, sensors, injectors etc. i suspect the ljetro version was created first, and then Apexi following demand added the Djetro version for some select cars as they found customers were migrating to other ECU's to map sensor support. Ljetro Vs Djetro Load Axis: Both have arbitary values for Load indiciation, Djetro has higher RPM as its from RB26 Djetro Airflow Meter Ramp: Voltage Ramp for Airflow meter load signal. Infinitely scalable, as we can rescale any given airflow meter. The most commoin airflow meters are supported out of the box, Z32, Q45 and Apexi Power Intake. Seemingly all the Apexi Power Intake does it alter the ramp values, which should yield slightly higher airflow load values, which should drop them on the map 1.3rows if that, ever so slightly. Map Sensor Ramp: Voltage Ramp for Map Sensor. Each sensor has a single Offset and nothing more. Fixed offset value Optional Map Sensors include GM5bar map sensor and Denso unit's also. The Apexi one is in fact a Denso unit. The only map sensor supported out of the box is the optional Apexi one (denso rebadged). GM 5 bar and other sensors need their scale and offset placed into the PowerFC to work. Apexi Ljetro Load Calculation: LOAD = CORRECTION * (16384 * Airflow lookup(MAFSV) / RPM) Airflow is proportional to RPM so this is why we are divisible by RPM. We obtain MAFSV from our running environment. We lookup the Airflow value from the Airflow ramp table (viewable by datalogit) and use this value. We lookup the CORRECTION value from the Airflow corretion table, for 4.48v and higher my correction is 84% See ljetro-data.txt LOAD = 0.84 * (16384 * 3598 / 4950) The answer gives us 10003.57 and we can see for load point 14 we have an Load value of 9642. The load value for point 15 is 11571 so we place our load axis on 14 with a value of 10003 As we can see here the load will always increase as the engine speed increases. More and more air comes into the system and thus airflow load will always keep increasing until redline. There have been doubts over this as many people see bog stockish R33 GTST's drop to load points 15 and shoot across. This is due to the fact they are maxing our the airflow meter at 5.10 or very close to. The reason it drops to load point 15 is because the majority of them have airflow % correction somewhere near 80% for 4.48v and higher. Apexi Djetro Load Calculation: LOAD = Map Sensor Offset * Map Sensor(PIMV) We lookup the Map sensor offset and use this value (viewable by datalogit). We obtain PIMV from our running environment See djetro-data.txt LOAD = 3289 * 1.95 The answer gives us 6413 and we can see for load point 8 we have an Load value of 5938. The load value for point 9 is 11571 so we place our load axis on 14 with a value of 6681. As we can see once pressure is fixed or doesn't increase any more, the load value doesn't. This will result in a horizontal shoot across method once target boost pressure is reached. This is because the Djetro version uses air pressure and runs a guesstimation method to calculate airflow. As the engine speed increases more and more air comes into the system, pressure remains the same and the load axis remains the same. The Djetro has two additional features which are; IGN vs TPS correction INJ vs TPS correction These are there presumably to assist in correction for the throttle position sensor. These will have an affect on the output figures but don't appear to adjust the load bearing. These are much like Airtemp correction or water temp correction, they affect values but don't adjust load bearing. So that's it in summary, a few myths cleared up. Im glad to have finally worked it out. ljetro_data.txt djetro_data.txt

no i still dont believe it will magically make more power there is no phyiscal way possible. the differences between ljetro and djetro are simply the load axis is determined by different methods. one uses a hotwire airflow meter to measure the air directly the other uses a pressure sensor and based on pressure guesstimates airflow. there would NO reason why car a and car b would have different power output, there are certainly a few differences between the two but none of which would add more power

there would be no logical reason why a map sensor over AFM would make power. its simply not possible. do you think if i fitted a hks vein pressure conveter on my r33 gtst in its current state and changed to map sensor its going to make an extra 20rwkw? of course not. airflow makes power.

n1's will be too small i think. if you wanted 2530s why did u just buy them the first time ?

there is no reason one ecu would make more than another it would come down to the state of the tune.

powerFC Faq shows how to correct ECCS wiring thanks to some guys from here. it covers what wires need to be in tact and a diagram. with it setup incorrectly you are likely to encounter what you are seeing on the dreaded read only PFC mode where any changes you make are lost when u power the car off

5100mv is the absolute max of the airflow meter. i would suggest turning off the AFM warning under ETC as it will just keep flashing and mistakely alert you, when you may think its knocking. my max load IGN timing is near 19deg on full load. the reason its running across the 15-16 load axis is because for 3.84 4.48 and 5.12v brakets cor airflow correction you will have something like 80% or thereabouts, which affects the final plot point for engine load. if they were all 100% it would drop near 18-19 on the load map.

agreed it should be SAU only