Fuel System Upgrades

[got traction]

This is what frustrates me. A guy is trying to build his engine and wondering what parts to get and everyone gives him answers, but no rhyme or reason as to why.

Here are the facts:
Desired HP: 250
Desired PSI: 10
B.S.F.C.: .60
Safe Duty Cycle: 80%

Finding Injector Size:
(250HPx.60B.S.F.C.) over (4# Inj.x.80Duty Cycle) = 46.87lbs./hr per injector of fuel.

46.87lbs./hr = 492.13cc/min.
This means the you need at least 492.13. and at 10 psi, the new flow rate of those injectors will be 528.5cc/min.

Finding needed fuel pressure.
43.5stock FR+10 boost+5 assumed pressure loss= 58.5psi of fuel, but a straight 60 to be safe. But be warned that fuel pressure loss can be up to 10psi., so 65-70psi would be safer to run.
If your stock FRP can run it, then go ahead and use it, but that is highly doubted.

FRP: 65 to be safe
Required Fuel: 150lbs/hr

150lbs/hr = 23.66gal/hr

At 65psi FRP and 23.66 gal/hr, a 190ltr/hr Fuel Pump is needed.

because lots of people have made that horsepower, so its pretty common to say he needs s 255lph fuel pump (becaue its common) and injectors. He dosent need a fuel rail, and he dosent need a fuel pressure regulator.

Also, you can go above 80% duty cycle, hell...you can go 100% duty cycle. The chances of the injector failing are slim.

 

[2NRSTV]

So the stock FRP can run 70psi?

 

[got traction]

So the stock FRP can run 70psi?

you dont need 70psi of fuel to make 250whp

 

[sohclubkid]

you dont need 70psi of fuel to make 250whp

jeez... 70psi of fuel is rediculous...
that would mean making 600hp would need like 155psi of fuel pressure LOL

seriously, stock rail and fpr are good for like 400hp, and like traction said its been done 1000 times.

 

[2NRSTV]

At idle, your stock fuel pressure is 43.5psi.
For every psi of boost the turbo puts out, fuel pressure needs to go up 1psi also.
Plus you have to account for pumping loss which can range anywhere between 5-10psi of pumping loss.

So, Stock Fuel Pressure+Boost+Pumping Loss=Fuel Pressure Needed by FRP. So, depending on fuel filter, fuel lines, fuel rail, etc. quality and condition, the Fuel Pressure needed should be anywhere between 60-70psi.

jeez... 70psi of fuel is rediculous...
that would mean making 600hp would need like 155psi of fuel pressure LOL

seriously, stock rail and fpr are good for like 400hp, and like traction said its been done 1000 times.

You're doing the math wrong. To achieve 600HP at say 25psi of boost, you would need at most 78psi of fuel. Fuel pressure has nothing to do with actual HP, it has to do with engine vacuum/pressure. See above. Also, I wouldn't LOL since you couldn't find the appropriate FRP psi. And yes, it's been done a million times, but so has bike racks on cars whose owners are too fat to even own a bike, but that doesn't make it necessarily right. So has tuning with Crome, but according to you, that doesn't make tuning with Crome necessarily right. Lowering your car by cutting or torching the springs have been done millions of times.

 

[sohclubkid]

At idle, your stock fuel pressure is 43.5psi.
For every psi of boost the turbo puts out, fuel pressure needs to go up 1psi also.
Plus you have to account for pumping loss which can range anywhere between 5-10psi of pumping loss.

So, Stock Fuel Pressure+Boost+Pumping Loss=Fuel Pressure Needed by FRP. So, depending on fuel filter, fuel lines, fuel rail, etc. quality and condition, the Fuel Pressure needed should be anywhere between 60-70psi.


You're doing the math wrong. To achieve 600HP at say 25psi of boost, you would need at most 78psi of fuel.

okay, well that walboro 255 will push plenty of fuel to that OEM FPR, and will return whats left over anyways... and i did absolutly zero math lol i was just messin with ya man.

 

[got traction]

im telling you right now that i, with a stock rail and stock fpr, have 50psi at idle. I have a 255lph fuel pump and it is plenty of fuel pressure to make 300+...i've done it, i've seen it done, its possible /argument

 

[hybrdthry911]

At idle, your stock fuel pressure is 43.5psi.
For every psi of boost the turbo puts out, fuel pressure needs to go up 1psi also.
Plus you have to account for pumping loss which can range anywhere between 5-10psi of pumping loss.

So, Stock Fuel Pressure+Boost+Pumping Loss=Fuel Pressure Needed by FRP. So, depending on fuel filter, fuel lines, fuel rail, etc. quality and condition, the Fuel Pressure needed should be anywhere between 60-70psi.


You're doing the math wrong. To achieve 600HP at say 25psi of boost, you would need at most 78psi of fuel. Fuel pressure has nothing to do with actual HP, it has to do with engine vacuum/pressure. See above. Also, I wouldn't LOL since you couldn't find the appropriate FRP psi. And yes, it's been done a million times, but so has bike racks on cars whose owners are too fat to even own a bike, but that doesn't make it necessarily right. So has tuning with Crome, but according to you, that doesn't make tuning with Crome necessarily right. Lowering your car by cutting or torching the springs have been done millions of times.

a stock honda FPR is a 1:1 rising rate regulator. also you said the new flow rate of of 492cc injectors with a 10psi increase in fuel pressure would be 528cc is just wrong, the flow rate doesnt actually increase, it needs the added fuel pressure to push against the positive pressure of the air pushing against it and equalize it back to the base pressure. the injectors will still flow 492cc worth of fuel at 53.5psi.

dont get me wrong i agree with what you said its better to explain to someone why they want a certain part or why to do certain things especially because there are a lot of variable in a turbocharger car. as they say teach a man to fish.....

 

[oc_civic]

maybe it is different with turbo.. but when I ran nitrous and a 255 pump I could not get the fuel down to a manageable pressure at idle and low cruising without modifying the FPR.. I also ran an electronic fuel pressure gauge IN the car so I could watch it real time to be sure everything was good to go..

 

[BlueSiclone]

This thread has completely confused me. He would need close to 500cc injectors to make 250 hp...yet my b16 is at 240 now with only the 310cc injectors that came with my kit. ???????????

 

[got traction]

This thread has completely confused me. He would need close to 500cc injectors to make 250 hp...yet my b16 is at 240 now with only the 310cc injectors that came with my kit. ???????????

he does not need 500cc injectors to make 250whp. With a 255lph fuel pump, 440cc injectors will hold up to 300whp

 

[BlueSiclone]

I was wonderin...can someone answer a ?? for me??

Not to thread jack or anything, just fig'd keep all very similar info together. On my B16a2 with my Greddy 18g, I'm shootin for 325-350. Motor is getting rebuilt now, thinkin 12-14 lbs will do it...wut injector size do I need to shoot for?? I was guessin 750's but you all seem to have a better handle on this than I do. Can't find this good info anywhere...

Sorry and thanks!