Correct injector sizing

[markwt]

I have a 2005 busa with stage 1 turbo, 8 psi. I have an walbro 255 pump and 1:1 fmu. Sounds like there are several routes to go with pro and cons
Use stock injectors and rail: Don't have to change injector but will push duty cycle limits at high rpm
Replace injectors with larger: Lower c.c. injector will be an upgrade from stock and will handle duty but will need to run a 3 bar map sensor
Replace injectors with larger 650 c.c. injector: Will handle anything I add down the road but hear you have to have a really high idle to keep fuel atomizing with such large injectors.
Planning on this mostly being a steet bike and want reliability and a reasonable idle. I am going to keep my 1:1 fmu and get ecu reflashed. I just want to see what you all have experienced with different c.c. injectors. I do not want to under or over do it for my application. My instinct is to use something middle road like a 440 c.c.
Please let me know your thoughts, appriciate any help

 

[Quiksilver]

What are your horsepower goals and current horsepower? I have a 2002 stage 1 with 370cc injectors, begi rising rate fmu, and pc3. Can't recall the name of the fuel pump. I changed the turbo so I need a new tune, but the bike rides fairly well. I'm sure with a new tune it would ride even better. My bike is mostly a daily driver with the occasional trip to the strip. I've been told by a few on here to get secondary injectors. So I'm most likely gonna get factory cc primarys with I'd1000 secondarys along with a microtech. I'm sure someone with more info will chime in.

 

[Boosted Cycle Perf]

Mark, what year bike is this for? Depending on year the answer could go 2 different ways.

 

[POWERHOUSE]

Mark, what year bike is this for? Depending on year the answer could go 2 different ways.

Rob, this is a Gen 1 so there are only two ways he can go IMHO: four injectors with an FMU, or he can run secondaries with a Microtech, or something similar. There is no way a 1:1 regulator will be able to supply enough fuel, regardless, if he is only intending on using four injectors. If he goes 60 pounds or better, he should get his ecu flashed to compensate the fuel tables. And there is a third option: standalone.

 

[Boosted Cycle Perf]

Pretty much exactly what I was gonna say frank. I was just trying to spare the typing for both generations.

 

[markwt]

I have a 2005 Murdered. Sounds like if I do the 650 c.c. and get MPS to flash ecu with the map they have for it I will be good. Frank, so it sounds like the ecu flash for bigger injectors that compensate the fuel tables will solve my concern of going with too big of an injector and having a high idle to keep enough fuel thru the injectors.
Thanks guys

 

[OZBooster]

650cc are much bigger than you need with 8 psi and 1:1 reg , i would expect about 250 odd hp at that boost level and a 440cc injector would have fuel to spare at that hp
depends if you see more boost in your future

 

[B-12]

just to compare
I have a messured set of Blackbird injectors. They deliver 268-270cc
and a messured set of S2000 delivering 342-348cc

are plug and play to GEN1 and ECU reflash

 

[markwt]

I argree that 650 c.c. is way more than I need for the boost range that I will be in. With the 330-440 c.c. injectors and ecu flash, are you guys using a rising rate or you using a 1:1 regulator.

 

[POWERHOUSE]

I argree that 650 c.c. is way more than I need for the boost range that I will be in. With the 330-440 c.c. injectors and ecu flash, are you guys using a rising rate or you using a 1:1 regulator.

This was already answered . . .

. . .this is a Gen 1 so there are only two ways he can go IMHO: four injectors with an FMU, or he can run secondaries with a Microtech, or something similar. There is no way a 1:1 regulator will be able to supply enough fuel, regardless, if he is only intending on using four injectors. If he goes 60 pounds or better, he should get his ecu flashed to compensate the fuel tables. And there is a third option: standalone.

 

[smithabusa]

id personally not go with 650cc's on a streetbike, going to be a ton of tuning to get it to part throttle well, especially if you don't need them. if you do need them for increased hp, to me the better, easier to tune route would be secondaries.

 

[markwt]

Im following what yall are saying, thank you. Sounds like I wouldn't need 650 c.c. injectors at my boost level nor would it be a good idea as just having them as primaries. Having a rail with secondaries and controls for it sounds like the best case scenerio but not looking to go that far yet. The guy that I bought my turbo off which was installed and tuned on his bike has blackbird injectors flowed to 42#, which I bought his power commander 5 off him with the map this setup was tuned for by Johnny Turbo in Florida. He was using a 1:1 regulator with 3 bar map sensor wired into his 5V analog input. With the 3 bar map I am guessing it is adding the boost ref. from the power commander and processed to the ecu. He also had his ecu flashed. The 1:1 would not provide enough fuel but guess he was getting by with the 3 bar map sensor to compensate. Since I have the map for this setup, I was hoping to have a good starting point to tune from. Trying to make sure I understand all my options and what works best. I need to get ecu flashed and buy larger than stock injectors either way, just want to make sure I get the correct setup. If I understand what Frank is saying a 1:1 regulator with 4 injectors will not provide enough fuel which I am not doubting, I am just confussed how he was running this setup and keeping a good afr at full boost. Sounds most logical to go with a rising rate around 8:1 but I assume that would make the map I have worthless?
Sorry so many options and questions, I am sure there will be varying answers and different ways to achieve a good result. Can never learn enough and really value all the experience you guys have. I need to pull the trigger on something, want to get injectors ordered and send ecu to be flashed. Side note who is the best to send ecu to for flashing?

 

[POWERHOUSE]

Im following what yall are saying, thank you. Sounds like I wouldn't need 650 c.c. injectors at my boost level nor would it be a good idea as just having them as primaries. Having a rail with secondaries and controls for it sounds like the best case scenerio but not looking to go that far yet. The guy that I bought my turbo off which was installed and tuned on his bike has blackbird injectors flowed to 42#, which I bought his power commander 5 off him with the map this setup was tuned for by Johnny Turbo in Florida. He was using a 1:1 regulator with 3 bar map sensor wired into his 5V analog input. With the 3 bar map I am guessing it is adding the boost ref. from the power commander and processed to the ecu. He also had his ecu flashed. The 1:1 would not provide enough fuel but guess he was getting by with the 3 bar map sensor to compensate. Since I have the map for this setup, I was hoping to have a good starting point to tune from. Trying to make sure I understand all my options and what works best. I need to get ecu flashed and buy larger than stock injectors either way, just want to make sure I get the correct setup. If I understand what Frank is saying a 1:1 regulator with 4 injectors will not provide enough fuel which I am not doubting, I am just confussed how he was running this setup and keeping a good afr at full boost. Sounds most logical to go with a rising rate around 8:1 but I assume that would make the map I have worthless?
Sorry so many options and questions, I am sure there will be varying answers and different ways to achieve a good result. Can never learn enough and really value all the experience you guys have. I need to pull the trigger on something, want to get injectors ordered and send ecu to be flashed. Side note who is the best to send ecu to for flashing?

You didn't say this bike had a PCV with the boost referencing setup and map sensor, although that does not make a difference in regard to the injectors and the 1:1 regulator, which could not have possibly fueled the bike properly. POWERHOUSE can flash your ecu for the features you need to take advantage of. Yes, you would need to entirely revamp your fuel system using the new-style FMU (without shims), which we have in stock, and yes, you will have to get it remapped properly on a dyno with somebody who know wtf they are doing . . .

 

[markwt]

Frank, I sent you a pm, please let me know if you got it. Says that I have 0 sent messages.

 

[POWERHOUSE]

Frank, I sent you a pm, please let me know if you got it. Says that I have 0 sent messages.

I got it and replied, thanks.

 

[arthur39]

You didn't say this bike had a PCV with the boost referencing setup and map sensor, although that does not make a difference in regard to the injectors and the 1:1 regulator, which could not have possibly fueled the bike properly. POWERHOUSE can flash your ecu for the features you need to take advantage of. Yes, you would need to entirely revamp your fuel system using the new-style FMU (without shims), which we have in stock, and yes, you will have to get it remapped properly on a dyno with somebody who know wtf they are doing . . .

just wondering why this setup would not work properly? PCV with boost referencing with a gm3bar and 1 to 1 with larger injectors .... ??? older versions would be, pc3, multi funtion hub, gm3bar and 1 to 1 regulator with larger primaries, flow rate should still be there with proper injector pulse widths and right pump.

 

[gsxrdan2]

just wondering why this setup would not work properly? PCV with boost referencing with a gm3bar and 1 to 1 with larger injectors .... ??? older versions would be, pc3, multi funtion hub, gm3bar and 1 to 1 regulator with larger primaries, flow rate should still be there with proper injector pulse widths and right pump.

I use a PCV and a 3 bar map sensor with a RCC rail and MPS 62# injectors.Bosch 1:1 reg for fueling.Works great on the street and it was mapped to 400hp with a RCC stage 1 kit.I bought all the stuff from Richard and he supplied a map.Almost forgot I used his ecu flash.