mellonman Posted July 10, 2015 Share Posted July 10, 2015 i'm not sure but the aim of the ecu could be holy crap i have been making that much boost at stoick i need to cool s#it down lol.Like i have said i cant tell if its 100% duty but its alot ask any mapper on the forum . yes your right afr will be richer at 4k the lower the boost you have from what i can tell but 10 afr is the richest mine reads finish your single turbo build and drive up the road then come back to this thread when you have some experiance of how it acts and see if you say the same thing , I'm sure you will change your tune disclaimer it could be auto related Quote Link to comment Share on other sites More sharing options...
Scott Posted July 10, 2015 Share Posted July 10, 2015 i'm not sure but the aim of the ecu could be holy crap i have been making that much boost at stoick i need to cool s#it down lol.Like i have said i cant tell if its 100% duty but its alot ask any mapper on the forum . yes your right afr will be richer at 4k the lower the boost you have from what i can tell but 10 afr is the richest mine reads finish your single turbo build and drive up the road then come back to this thread when you have some experiance of how it acts and see if you say the same thing , I'm sure you will change your tune disclaimer it could be auto related Stand alone though bud so I won't have any of that. Quote Link to comment Share on other sites More sharing options...
nihontoman Posted July 10, 2015 Share Posted July 10, 2015 My JDM supra is like that. it came with a single turbo garret ta45/hks t04s hybrid. with stock fueling/stock ecu :/ though it does have additional injectors in the intake (3 to be precise, 550c densos, which would ideally translate to about 710cc per cylinder). thing is, at 0.9 bar, the car makes 320 at the wheels on mustang dyno. didn't get the chance to see what it did on another "mode" set on HKS EVC - 1.3 bar as additional injectors dumped fuel and there was problem with ignition (faulty spark plugs). as for 4000rpm thing, the turbo starts spooling at around that point... Quote Link to comment Share on other sites More sharing options...
Ian C Posted July 12, 2015 Share Posted July 12, 2015 Jaysus how did I miss this thread the first time around Things that deffo get you out of closed loop: Rapid throttle opening Rapid throttle closing Going over 4000rpm Low coolant temp I don't think boost pressure is one of them. There is a fuelling strategy table somewhere in all the PDFs but I can't find it at the moment. Closed loop or "self learning" can't compensate going from 440cc to 550cc injectors on a J-spec ECU as that's precisely what happened to me years ago when I spent months tracking down an overfuelling and stalling problem - turned out the Apexi AFC wasn't altering the airflow signal any more. Fuelling below 4000rpm when in open loop is mapped for 13:1 AFRs. This is for a tiddler turbo pushing 0.6bar tops, and is where the big risk comes in when mickey-mousing on a big turbo with no fuelling work. Once you reach between 3500 and 4100rpm the fuelling has a bipolar switch in attitude due to the sequential transition, and tries for 11:1 AFRs upwards, depending on how close to 1bar of boost the ECU sees. The exact point it changes is still a mystery, but you can map around it with an E-Manage, it just takes a lot of time and almost half the map resolution for this one area - that's the tricky bit when using a piggyback on a MkIV. Do not confuse the increase in fuelling at the sequential transition point with the 100% duty cycle that running close to 1bar gives you in BPU. If you are mapping a single turbo with a piggyback and you still get the BPU 100% duty cycle issue then you're doing it wrong Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted July 15, 2015 Share Posted July 15, 2015 my brother's tt got stuck in closed loop and the car poured out thick black smoke, it was doing circa 5 mpg, it sooted up both turbos. This was caused by a garage having the car for respray and other jobs for three weeks and they kept jump starting the car and damaged the ecu, After trying several experts in our area of preston in lancs the car was taken on a flat bed to chris wilson who sorted it, had to clean out all the sooted intakes and turbos, and i think he had to replace the ecu and other software. I would never let anyone jump start my car unless they know how to do it safely to avoid transients. Quote Link to comment Share on other sites More sharing options...
Supraleeturbo Posted July 16, 2015 Share Posted July 16, 2015 I ran my hks t51 on stock fueling and ecu and it was a blast I turn the boost down to 0.5 bar, kept an eye on the afr gauge and away I went and was running perfectly. The yanks do have the 550 injectors and would advise to have these but no a must Quote Link to comment Share on other sites More sharing options...
mellonman Posted July 16, 2015 Share Posted July 16, 2015 I ran my hks t51 on stock fueling and ecu and it was a blast I turn the boost down to 0.5 bar, kept an eye on the afr gauge and away I went and was running perfectly. The yanks do have the 550 injectors and would advise to have these but no a must the reason you got away with it lee is because you have a 70mm turbo that doesnt have masses of boost before 4k ,if you was at part throttle you just couldnt make any real boost to cause an issue with the closed loop fueling 14.7 , and if you went full throttle from the dig spool vs air flow of the larger turbo in open loop would just be rich down low maybe between 2500 and 3500 and making real boost past 4k when both stock turbos would have been on line anyway so fueling would be more matched with a capped boost.( but its still capped boost fueling of the stock twin air flow so no power gain apart from maybe cooler charge). it is do able on stock ecu with a large turbo running the way you did but still not correct , but a small fast spooling turbo of today would just make to much boost pre 4k and would be running the fueling and timing of a single stock toyota turbo maybe you could get away with this in the open loop stuff ? but in closed loop you would just make too much boost at part throttle being carefull enough you could maybe manage to stay in closed loop and make over 1 bar . So would have to cap the boost again at a lower level , if you had a decent boost controller you could maybe limit the boost pre 4k then open it up . but whats the point? It would still not be as good or as fast as a bpu supra which its been mapped for correctly. piggyback or standalone is the only real way to make the car anybetter if bolting on a single turbo !! Quote Link to comment Share on other sites More sharing options...
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