paulr33

800km/h

so fix the stock bov so it doesnt leak or change to twin gtr stock bovs the purpose of the thread, as far as i can see if to find out if there is any myth to compressor wheel failure, why are bovs factor standard, what does flutter mean and so on

right, and so what have you learnt after doing that (not stalling with an atmo bov). what have you achieved ?

ok now lets forget everything we know about turbocharges and various components. what advtanges do you have by not using a BOV? what do you hope to gain by not using one?

1a) depends on how the bov was setup and if it was in recirc or atmo mode or half half 1b) depends on how the bov was setup and if it was in recirc or atmo mode or half half it has NOTHING to do with how much power you make or how much boost. if its on full AMTO and you haven't tuned around the brain-dead stalling then it will stall. think about it. pressure is building up, the throttle body closes, instantly you chear a chop chop chop flutter sound, just like if you talk into the back of a pedestal fan. whats the likely conclusion? the pressure has bounced off the throttle plate, collided with the compressor wheel and basically done a sonic boom on itself. people when they insist on modding the stock bov or fitting an aftermarket bov that runs in ATMO that doesnt stall, they all report much more lag or turbo lag response, as it has to wind up from scratch again instaed of re-using the built up air velocity (reused in recirc mode)

could be right, anyone else have any supporting material they are ball bearing? anyone know the CHRA no#'s

i could tear all those comments to shreads, each of them is full of flawed of comments (the ones from the so called expert)

the powerfc has a self idle learn procedure which is executed when a user does a DATA INIT or when the unit is shipped as new from the factory. the self idle learn simply learns the car's optimum idle point by what i suspect is looking at the sensors and picking a varyation of paramters to get a constant idle that varies with say 5% and doesnt hunt up and down. there is no self tune feature, self adjustment or anything else. it is purely so the FC can out of the box run on almost any car setup and idle properly. nothing worse than shonky idle out of the box. other ecu's that run a self tune use a wideband sensor and basically dial in or out AFR"s on demand based on what target or ideal AFR you give it. it reads what the wideband sensor says and decides if it needs more or less fuel. it can only be done with a wideband sensor

that is all complete frogshit, i dont care what magazine or what he does the facts; blow off valves were designed to prevent excess turbocharger failure. without a recirculating blow off valve the compressor wheel experiences violent surges and also it hampers turbocharger response. a side affect of this is you get the VL turbo chop or "flutter" sound. this can be replicated by talking into the back of a desktop pedestal fan. it will chop your voice as you talk. when the introduction of blow off valves was done on the nissan range, nissan altered their turbocharger servicing internals on the turbocharger from 50,000k's to 100,000k's turbocharger reliability is of very high importance to a car manfacturer so there would be no risks taken at any cost. hence why the r32 gtst and nissan oem's have a bov. so in summary; a bov provides the following features; 1) protection against compressor wheel surge or chop on throttle body closure (usually associated with gearchange) 2) helps increase turbocharger spool up, as the already processed air is reused without a bov you will experience the following 1) compressor surge / chop / flutter when the throttle body closes 2) reduced turbocharger compressor lifespan if you have an atmo bov 1) it will stall as the AFM has measured the air and tells the ECU 100 units of air is present. as soon as the ATMO bov dumps this air there is only say 10 units of air in the manifold but the ECU is still told there is 100 units present so it adds the corresponding amount of fuel to suit 100 units and because there is only 10, the mixture is way off, overrichens and stalls instantly the bov ore recirculation valve has NOTHING to do with emissions

its a wives tail, you wont gain anything i dont reckon 1) turn car off 2) undo ground wire for battery 3) pump brake pedal, all power should go off 4) reconnect 5) fang

yeah i was just fiddling i wanted to go back to base maps for a bit of a laugh so i just dialed out -9 using tmp adjust theres a massive difference on base ign timing it feels flat and theres like no engine respone or "zest"

oh the unit has a vaccum line on it? how odd. ok cool yeah carl is spot on then, my bad

i see my stocker dial in before 3k on my 25t its funny i jump onto IGN / INJ dial out -9 degrgess timing and the turbo seems to wind up nice and quick. the engine doesnt give much zing but the turbo comes on nice

ETC SENSOR SW / CHECK what items are black? do you have the boost kit turned on or off? (are u using it) have you preformed the self idle learn procedure? is this a new powerfc install ?

get the vl jatco box, it will be stronger, cheaper and doesn't need ecu signals to change gears. so you can use any ECU you like. most ecu's are manual only and dont support signals to auto box such as the r33 auto box as it needs signals from ecu on when to change

we are looking into a few options, stay tuned

gcg have plain bearing hiflows as well, just so you are comparing apples with apples

whilst over ecu's certainly would handle the map sensor implentation better the powerfc simply uses (that i can see) the map sensor signal and nothing else to decide "load" on its load axis. still a great topic of dicussion either way

fark rob's doing a BIG reply (im scared)

anyway im gonna give up im in way over my head and i dont even know if im right or not no one seems to be supporting so its likely im on some other tangent or have gotten it wrong. all good map sensor it up croat

croat: have a read of http://www.skylinesaustralia.com/forums/in...pic=80162&st=20 that covers relocating the airflow meter

maybe im reading this all wrong but heres how i see it; a car tyre has 40psi of pressure a truck tyre has 40psi of pressure given the map sensor method both tyres have the same air volume in them. if you were to let all the air in each tire via a hotwire airflow meter i would bet the truck tyre would have more air in it

i still fail to see why a djetro ecu would make more power? what makes power, airflow. there is no magic to making more power. the only way i would see it (the djetro) making more power if one of the following was true; 1) airflows meters in use were being maxed out, hitting ceiling limit and not able to show any more air to the ecu 2) airflows becoming a physical resctriction in either case upgrade to larger airflow merters or fit an additional one

i have seen the pvrt theory and i still believe the djetro PFC simply uses MAP sensor signal and nothing else to work out what load axis to jump to on the maps. i see no other supporting items to influence the LOAD axis on the djetro. datalgoit shows me a LOAD axis calibartion and for AFM its purely AFM voltage and for map sensor its simply map sensor voltage there is no calibration or table reference for TPS, volume, revs or anything else 3d'd onto the MAP axis. * when air that has been measured doesn't go into the engine (i.e. blow off valves venting to atmosphere) so use a correct blow off vavle system, its there by default so it must be there for a reason. there is no need for ATMO bov. it didnt come atmo from the factory so nissan would have had to have been fairly certain the recirc idea was useful * when the hot wire gets fouled by oil that may insulate the wire from the air so clean the AFM. this would come under normal maitenance and would only take 5 minutes with some contact/carby cleaner. no different to cleaning your air intake filter or pod filter * the delay between measuring on the inlet side of a compressor and actually entering the engine (especially on big intercooler volumes) i dont understand this at all, once the air is in, its in and nothing more. i am unsure on this "delay" thing * the fact that generally there is no account (or even measurement) of manifold air pressure or temperature. Both of these properties can vary even at a given AFM output. the pfc ljetro supports airtemp correction. air temp correction with measuring how much air directly comes into the system is the ideal way to work out how much air is coming in. there is no other better way than to measure how much air is coming in. dont get me wrong im not against everyone or anything i just dont see why one would move to a map sensor system, there are no benefits

see diagram for relocated AFM