injector size calculated from BSFC?
#1
injector size calculated from BSFC?
Ok, here's my question:
My current goal for my car is 400 HP. people have been telling me that for that kind of power, I need 1200 or 1600 cc secondaries.
someone please correct my math here:
stock TII injectors = 4*550cc/min = 2200 cc/ min. or 2L/min, assuming that they dont really flow 550.
at 400 hp, with BSFC .56 for turbo rotary,
fuel consumption= 400 HP*.56 HP/lb/hr= 224 lb/hr
224 lb/hr = 1766.5 cc/min.
1766.5 cc/m < 2000 cc/min
so im getting that stock injectors could support over 400 hp??
wheres my mistake?
pat
My current goal for my car is 400 HP. people have been telling me that for that kind of power, I need 1200 or 1600 cc secondaries.
someone please correct my math here:
stock TII injectors = 4*550cc/min = 2200 cc/ min. or 2L/min, assuming that they dont really flow 550.
at 400 hp, with BSFC .56 for turbo rotary,
fuel consumption= 400 HP*.56 HP/lb/hr= 224 lb/hr
224 lb/hr = 1766.5 cc/min.
1766.5 cc/m < 2000 cc/min
so im getting that stock injectors could support over 400 hp??
wheres my mistake?
pat
#2
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A couple of things I see:
1 lb/hr = 10.5 cc/min (the so-called standard)
most people use a conservative 80% for duty cycle
My site has a pretty good calculator for this.
Gordon
WitchHunter performance
fuel injector cleaning & flow testing service
1 lb/hr = 10.5 cc/min (the so-called standard)
most people use a conservative 80% for duty cycle
My site has a pretty good calculator for this.
Gordon
WitchHunter performance
fuel injector cleaning & flow testing service
#3
OBEY YOUR MAZDA
Originally Posted by patman
Ok, here's my question:
My current goal for my car is 400 HP. people have been telling me that for that kind of power, I need 1200 or 1600 cc secondaries.
someone please correct my math here:
stock TII injectors = 4*550cc/min = 2200 cc/ min. or 2L/min, assuming that they dont really flow 550.
at 400 hp, with BSFC .56 for turbo rotary,
fuel consumption= 400 HP*1.56 HP/lb/hr= 224 lb/hr
224 lb/hr = 1766.5 cc/min.
1766.5 cc/m < 2000 cc/min
so im getting that stock injectors could support over 400 hp??
wheres my mistake?
pat
My current goal for my car is 400 HP. people have been telling me that for that kind of power, I need 1200 or 1600 cc secondaries.
someone please correct my math here:
stock TII injectors = 4*550cc/min = 2200 cc/ min. or 2L/min, assuming that they dont really flow 550.
at 400 hp, with BSFC .56 for turbo rotary,
fuel consumption= 400 HP*1.56 HP/lb/hr= 224 lb/hr
224 lb/hr = 1766.5 cc/min.
1766.5 cc/m < 2000 cc/min
so im getting that stock injectors could support over 400 hp??
wheres my mistake?
pat
with 0,56 you willactually divide instead of multiply.
400x1,56= 624
#4
OK here is my figures, using witchhun performance's help
400hp
4 injectors
.56 bsfc
80%
735 cc per injector
X4
2940
-880 (2 550cc injectors you already have with 80% dutycycle accounted for)
2060/2 = 1030cc each (increase the size 20% to give some room for error)
2x 1236cc injectors
so 1200cc will do it (if your other 2 injectors are 550cc's)
go with the 1600cc's because i think you will be looking for rwhp and not at the fly
400hp
4 injectors
.56 bsfc
80%
735 cc per injector
X4
2940
-880 (2 550cc injectors you already have with 80% dutycycle accounted for)
2060/2 = 1030cc each (increase the size 20% to give some room for error)
2x 1236cc injectors
so 1200cc will do it (if your other 2 injectors are 550cc's)
go with the 1600cc's because i think you will be looking for rwhp and not at the fly
#5
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Join Date: Feb 2001
Location: Charlottesville, Virginia, USA
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I think that a .56 BSFC may be a bit optimistic. I have heard that a stock TII is somewhere around .64 BSFC, but I have been unable to confirm this, although it sounds about right to me. I don't know how you tune, but from what I have seen on this forum, most people like to run an insane amount of boost and then run an overly-rich mixture to be "safe". This practice can bump the BSFC into the .70 to .80 range.
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