ninjette.org - View Single Post - Fuel injected 08-11 ninja250r help

DannoXYZ · February 16th, 2020, 03:21 PM

FPR should be connected to plenum after throttle-body so it sees vacuum and lowers fuel-pressure under non-boost operations. That's because tip of injectors will experience vacuum and pressures differential between inlet and outlet of injectors wIll be higher than 43psi. Same thing under boost, injectors will have pressure at their tips forcing fuel backwards. FPR should increase fuel-pressure in-step with boost to maintain 43-psi differential across injectors. This makes fuel-calculations much, much easier because 5ms pulse-width will end up squirting exact same volume of petrol at 15-in.Hg vacuum or 10psi boost.

Wastegate should get control signal from charge-tube between intercooler outlet and throttle-body. This will then allow signal to incorporate pressure-drop through intercooler. That drop is not constant value and most people mistakenly tap into turbo's compressor outlet before intercooler. Result will be dropping boost-curve as RPMs increase since pressure-drop across intercooler increases with RPM and boost. Even Porsche made this mistake on some of their cars.

Due to variable signal required going to wastegate just to maintain flat boost-curve under WOT, you can't connect charge-pipe line directly to wastegate diaphragm. This signal should actually decrease as RPMs increase in order to maintain flat boost-curve due to exhaust-pressure pushing on wastegate valve. As RPMs increase, exhaust-pressure increases and diaphragm pressure needs to decrease in order to maintain same boost (especially if you want low-boost with weak spring). Solution is to use boost-controller between charge-pipe and wastegate diaphragm. I've got extra BoostSciences Reliaboost1.PDF I can send you. Just PM me your address.

Finally, BOV should be configured as CBV in recirculation configuration. During shifts, this diverts pressurised turbo compressor outlet back around to compressor inlet and keeps turbo spinning for minimal lag during shifts. Otherwise in BOV config, it dumps all pressurized air to outside. Turbo inlet is forced to compress unpressurized outside air and this stops turbo dead in its tracks since there's no exhaust pressure to drive it during shifts. Then turbo has to spool up again after shift and you have classic turbo-lag.

BOV also really messes with MAF measurements in draw-through systems as metered air is dumped and never makes it into engine. Even with common plenum, you'll find that MAF load-sensing is much, much more accurate than MAP or alpha-N blended MAP+TPS.

February 16th, 2020, 03:21 PM	#7
DannoXYZ ninjette.org certified postwhore Name: AKA JacRyann Location: Mesa, AZ Join Date: Dec 2011 Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C Posts: A lot. MOTY - 2018, MOTM - Nov '17	FPR should be connected to plenum after throttle-body so it sees vacuum and lowers fuel-pressure under non-boost operations. That's because tip of injectors will experience vacuum and pressures differential between inlet and outlet of injectors wIll be higher than 43psi. Same thing under boost, injectors will have pressure at their tips forcing fuel backwards. FPR should increase fuel-pressure in-step with boost to maintain 43-psi differential across injectors. This makes fuel-calculations much, much easier because 5ms pulse-width will end up squirting exact same volume of petrol at 15-in.Hg vacuum or 10psi boost. Wastegate should get control signal from charge-tube between intercooler outlet and throttle-body. This will then allow signal to incorporate pressure-drop through intercooler. That drop is not constant value and most people mistakenly tap into turbo's compressor outlet before intercooler. Result will be dropping boost-curve as RPMs increase since pressure-drop across intercooler increases with RPM and boost. Even Porsche made this mistake on some of their cars. Due to variable signal required going to wastegate just to maintain flat boost-curve under WOT, you can't connect charge-pipe line directly to wastegate diaphragm. This signal should actually decrease as RPMs increase in order to maintain flat boost-curve due to exhaust-pressure pushing on wastegate valve. As RPMs increase, exhaust-pressure increases and diaphragm pressure needs to decrease in order to maintain same boost (especially if you want low-boost with weak spring). Solution is to use boost-controller between charge-pipe and wastegate diaphragm. I've got extra BoostSciences Reliaboost1.PDF I can send you. Just PM me your address. Finally, BOV should be configured as CBV in recirculation configuration. During shifts, this diverts pressurised turbo compressor outlet back around to compressor inlet and keeps turbo spinning for minimal lag during shifts. Otherwise in BOV config, it dumps all pressurized air to outside. Turbo inlet is forced to compress unpressurized outside air and this stops turbo dead in its tracks since there's no exhaust pressure to drive it during shifts. Then turbo has to spool up again after shift and you have classic turbo-lag. BOV also really messes with MAF measurements in draw-through systems as metered air is dumped and never makes it into engine. Even with common plenum, you'll find that MAF load-sensing is much, much more accurate than MAP or alpha-N blended MAP+TPS.