boost psi before fuel pump runs out of puff?
boost psi before fuel pump runs out of puff?
Follow up question would then be how much horsepower can I expect from that level of boost?
el_bandido
15-02-2021, 01:08 PM #1Anyone know roughly how much boost can be run with the usual plugs/injectors/black box (or emanage etcetera) before the fuel pump can't keep up with demand?
Follow up question would then be how much horsepower can I expect from that level of boost?
I.e. Normal injector size, then max injector duty, and fuel pump rating per hour.
I only know standard FPR is static at 3.5bar
So for mine instead
550cc say if I maxed them to 100% duty at max 4.5 bar fuel pressure
At base pressure 3.5bar
550x6 = 3300cc in a minute.
At boost of 1bar it the rising rate FPR adds:
550/50 x 14 = 151cc x 6 = 906cc extra
906 + 3300 = 4206cc = 4.206litres per minute x 60 = 252.36 litres per hour, and I have a 255lph pump.
But then again you never ever take an engine that far, normally you'd stop at 80%
As for power there is various calculators on the net that work that out.
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Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
Sparkystav
15-02-2021, 02:25 PM #2Need to know a few details first
I.e. Normal injector size, then max injector duty, and fuel pump rating per hour.
I only know standard FPR is static at 3.5bar
So for mine instead
550cc say if I maxed them to 100% duty at max 4.5 bar fuel pressure
At base pressure 3.5bar
550x6 = 3300cc in a minute.
At boost of 1bar it the rising rate FPR adds:
550/50 x 14 = 151cc x 6 = 906cc extra
906 + 3300 = 4206cc = 4.206litres per minute x 60 = 252.36 litres per hour, and I have a 255lph pump.
But then again you never ever take an engine that far, normally you'd stop at 80%
As for power there is various calculators on the net that work that out.
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
I will mess about with some injector sizes and work out what I need.
el_bandido
15-02-2021, 03:43 PM #3Thanks mate, that's exactly what I was after. I've made myself a spreadsheet to calculate power projections since the original post anyway.
I will mess about with some injector sizes and work out what I need.
for 310cc injectors (yellow 2zz-ge) I'll need to flow 90 litres per hour for an 80% cycle, which will be 4 litres per hour above the calculated fuel pump capacity, so I think I'll end up maxing out before that.
Messing about to work out how much horsepower this might be, as the BSFC changes when turbocharging is involved.
el_bandido
16-02-2021, 03:19 AM #4Right, doing some rough calcs for the stock set up on an IS200 assuming 240cc injectors running constantly at 100% duty cycle, the fuel pump must be at least 86 litres/hour. At 80% I only need ~69 litres per hour, which gives me a rather astonishingly bad brake specific fuel consumption figure of 0.71, which is ridiculously inefficient. Not a great surprise the IS200 has such terrible fuel consumption and low horsepower for a 2 litre.
for 310cc injectors (yellow 2zz-ge) I'll need to flow 90 litres per hour for an 80% cycle, which will be 4 litres per hour above the calculated fuel pump capacity, so I think I'll end up maxing out before that.
Messing about to work out how much horsepower this might be, as the BSFC changes when turbocharging is involved.
Does this correlate well with peoples practical experience messing about with the IS?
el_bandido
16-02-2021, 03:49 AM #5right, assuming FI gives a better BSFC (which is does/should do) I think 310cc injectors will max out at around 280hp on an 80% duty cycle, which equates to 11.5 psi (roughly) on the is200. Assuming the IS200 has a 90L/hr fuel pump. this will be pushing the absolute limit of the car's capability to deliver fuel.
Does this correlate well with peoples practical experience messing about with the IS?
i am not as good with the calculations as you are but i have now some experience with 310 cc 2zzge injectors.
I am now running a 155mm pulley on my supercharger setup with 310 cc injectors.
I can tell from the numbers that i get from my aem air fuel ratio meter.
that, i am running 0,6 bar manifold pressure near the rev limit.
the air fuel ratio is 12.0 till 4000 rpm with wide open throttle
the air fuel ratio goes from 12,0 to 10.0 from 4000rpm till 6400 rpm
I am still running the patrick blackbox. Wich is not ideal because it is a bit too rich in the higher revs. But as i can see from the numbers it can deliver more then enough fuel for 0.6 bar.
If you look at Dimis project threat. He runs 2azfe injectors wich i am not exactly sur how big they are but his fuel pump was maxing out with the 160 mm pulley. and he now has an upgraded pulley
hi
i am not as good with the calculations as you are but i have now some experience with 310 cc 2zzge injectors.
I am now running a 155mm pulley on my supercharger setup with 310 cc injectors.
I can tell from the numbers that i get from my aem air fuel ratio meter.
that, i am running 0,6 bar manifold pressure near the rev limit.
the air fuel ratio is 12.0 till 4000 rpm with wide open throttle
the air fuel ratio goes from 12,0 to 10.0 from 4000rpm till 6400 rpm
I am still running the patrick blackbox. Wich is not ideal because it is a bit too rich in the higher revs. But as i can see from the numbers it can deliver more then enough fuel for 0.6 bar.
If you look at Dimis project threat. He runs 2azfe injectors wich i am not exactly sur how big they are but his fuel pump was maxing out with the 160 mm pulley. and he now has an upgraded pulley
In the real world this probably equates to a bit less than 0.8 bar, I imagine it also depends on pressure drop through the intercooler and intake temperatures etc for a horsepower figure so take what I've worked out with a pinch of salt. Some of it is "educated guess" material as well.
el_bandido
17-02-2021, 09:02 AM #8yeah I was reading his thread. Thanks for the info. I think (from above) that the factory fuel pump should absolutely max at 0.8 bar of boost with the 310cc injectors under ideal conditions before the fuel pump requires replacement.
In the real world this probably equates to a bit less than 0.8 bar, I imagine it also depends on pressure drop through the intercooler and intake temperatures etc for a horsepower figure so take what I've worked out with a pinch of salt. Some of it is "educated guess" material as well.
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