3t starlet Posted July 24, 2011 Share Posted July 24, 2011 ok ive got a c33 laurel factory rb20e auto. motor has been changed to a rb30e from a vl small problem is its running the injectors from the vl, size is fine think its 250cc but the impendance is not low impendance vs high impendance ecu.. This seems to be causing big fuel consumpution, ive found this out when i took it for a tune. still running rb20 afm ecu etc including tb,been told you do this so you dont need to change the loom so what im thinking of trying is running rb20e injectors which are high impendance 270cc think they are,any thoughts should fix fuel being so close cc whys.. should also mention car runs fine and goes hard..for na anyway Quote Link to comment Share on other sites More sharing options...
HighLUX Posted July 24, 2011 Share Posted July 24, 2011 Fit a resistor pack to the injector feeds? Quote Link to comment Share on other sites More sharing options...
3t starlet Posted July 24, 2011 Author Share Posted July 24, 2011 Fit a resistor pack to the injector feedsnot sure id know how to wire up,set of rb injectors is cheap well na ones away as most people upgrade and turbo Quote Link to comment Share on other sites More sharing options...
efp0wa Posted July 24, 2011 Share Posted July 24, 2011 Why would you take a sohc rb for a tune? lol Fit a resistor pack. Google is there is info all over the place more than likely. Quote Link to comment Share on other sites More sharing options...
barf Posted July 25, 2011 Share Posted July 25, 2011 don't use low impedance injectors unless you have an ECU designed for them! putting a resistor pack on low-Z injectors does away with the benefits they offer anyway. high impedance injectors have different control systems (simple FET switch) while low-Z injectors require PWM control with peak-and-hold to operate correctly. Quote Link to comment Share on other sites More sharing options...
3t starlet Posted July 25, 2011 Author Share Posted July 25, 2011 Why would you take a sohc rb for a tune? lolFit a resistor pack. Google is there is info all over the place more than likely. it went for the tune up to see why it was using lots of gas eg 25dollars to the 30 to 40 k mark seems a little bad to me..and thats nt frying the tyres everywhere .. this is how i know the injectors are not right,they are low impendance injectors and my ecu needs to have high impendance.. now would fitting a resistor pack increase or decrease the impendance,or can you get one to increase, and another that will decrease?? Quote Link to comment Share on other sites More sharing options...
3t starlet Posted July 25, 2011 Author Share Posted July 25, 2011 don't use low impedance injectors unless you have an ECU designed for them! putting a resistor pack on low-Z injectors does away with the benefits they offer anyway. high impedance injectors have different control systems (simple FET switch) while low-Z injectors require PWM control with peak-and-hold to operate correctly. my ecu supports high impendace,but its got vl low impendance injectors. so rb20e are high impendance injectors but are a little biger 270cc i think,, aways thought i could just change out the vl ones and was hoping the rb20e{high} ones would go straight in?? Quote Link to comment Share on other sites More sharing options...
Mikewazowski Posted July 25, 2011 Share Posted July 25, 2011 Fitting a resistor pack will increase the impedence. Quote Link to comment Share on other sites More sharing options...
barf Posted July 25, 2011 Share Posted July 25, 2011 Fitting a resistor pack will increase the impedence. and do away with the benefits of having low-impedance injectors, such as the faster opening times. resistance and impedance are subtly different things you can exchange high-Z with high-Z injectors but putting low-Z injectors into a high-Z system is opening a can of worms. you'll need to create an 'equivalent circuit' using the low-Z's with the same electrical characteristics as the high-Z's the ECU is designed to drive. while that's not impossible, you can use a resistor pack, it's more complicated than just using the correct high impedance injectors which can safely be driven in open-circuit style. low-Z injectors need current limiting circuitry which is why a resistor pack would be needed. honda actually tried this for a while and had problems with transistor junction temperature in their ECUs causing premature failure. Quote Link to comment Share on other sites More sharing options...
keltik Posted July 25, 2011 Share Posted July 25, 2011 I thought the faster opening times were a product of peak and hold control method. So wouldnt apply since this ECU doesnt use that. Slam in the right injectors and make it work good. My Cynos ran like arse with wrong injectors in it. Resistor packs are too much fucking around if the correct injectors are available. Also things like deadtime and pulse width are likely to be closer to the right values with the high impedance injectors compared to the low impedance ones with a resistor. Quote Link to comment Share on other sites More sharing options...
barf Posted July 25, 2011 Share Posted July 25, 2011 I thought the faster opening times were a product of peak and hold control method. from what i can gather, low-Z injectors are typically higher-performance and have higher flow rates, shorter opening times through better construction and it's the low resistance of the solenoid windings which mandates the requirement of PWM and current limiting circuitry, primarily to avoid overheating, which leads to insulation failure. you can peak and hold high-Z's but that doesn't improve their operation over simple switched open-circuit driving. Quote Link to comment Share on other sites More sharing options...
keltik Posted July 25, 2011 Share Posted July 25, 2011 That makes more sense, as you were.... Quote Link to comment Share on other sites More sharing options...
3t starlet Posted July 25, 2011 Author Share Posted July 25, 2011 i got the car like this,with low imp injectors already in it.. the ecu supports high imp being the ecu is rb20e.. so putting in rb20e injectors should fix the problem/using heaps of gas..everything else is working fine been tested proformance wise it goes really well. or will for some reason rb20e injectors not work,as people say i need a resistor? why do i need it.?? ecu =high rb20e injectors=high perfect match correct.. Quote Link to comment Share on other sites More sharing options...
Mikewazowski Posted July 25, 2011 Share Posted July 25, 2011 It's been covered above, but yes if your ecu is set up to use high impedence injectors then it makes sense to use high impedence injectors. You can use a resistor pack to increase the resistance (subtly different to impedence as mentioned above) which allows you to use low impedence injectors. If you have injectors that will suit the application then it makes sense to use them instead of mucking around with resistors. From what you have said using the RB20E injectors should be the go, at least from an electrical point of view. Note: I am not an expert. Quote Link to comment Share on other sites More sharing options...
3t starlet Posted July 25, 2011 Author Share Posted July 25, 2011 It's been covered above, but yes if your ecu is set up to use high impedence injectors then it makes sense to use high impedence injectors. You can use a resistor pack to increase the resistance (subtly different to impedence as mentioned above) which allows you to use low impedence injectors.If you have injectors that will suit the application then it makes sense to use them instead of mucking around with resistors. From what you have said using the RB20E injectors should be the go, at least from an electrical point of view. Note: I am not an expert. think ive got it sorted now,gona use rb20 injectors, and intake if i have to,everything else is r20e tb afm etc,dont think i the guy i got it from knew putting vl injectors would cause problems,only other problem there may be would be afm,to small maybe,sure i could probaby sort that out aswell.ill keep u guys posted as to how it all works.. im not expert thats for sure,this is my first rb powered car lol... thanks for your insight.. Quote Link to comment Share on other sites More sharing options...
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