Will this fuel setup be OK for 20 psi?
03-09-2002, 08:17 AM
#1
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Will this fuel setup be OK for 20 psi?
B&M Command Flo Fuel Regulator
RC 440's
Walbro 255 lph FI fuel pump
Hondata Stage 3b
I want to raise the pressure from 40 to 60 psi to provide enough fuel for 300-325 whp. The RC 440's were doing about 96% duty cycle at 10 psi, tuning for a 12.2:1 A/F ratio.
Will increasing the fuel pressure do the job?
Thanks in advance for any info...
RC 440's
Walbro 255 lph FI fuel pump
Hondata Stage 3b
I want to raise the pressure from 40 to 60 psi to provide enough fuel for 300-325 whp. The RC 440's were doing about 96% duty cycle at 10 psi, tuning for a 12.2:1 A/F ratio.
Will increasing the fuel pressure do the job?
Thanks in advance for any info...
03-09-2002, 04:09 PM
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Re: Will this fuel setup be OK for 20 psi? (xThexHeadx)
Yeah that should be alright for a lil bit. You might want to start thinking of a bigger fuel pump such as a paxton, aeromotive, or welden. Welden pumps are the best thing but very expensive ,very expensive, you you wont need that till 540+whp. With the bigger pump you might alos want to think of running bigger fuel lines(steal briaded). Do you look up, i think Dustin has pics of his fuel lines.
03-10-2002, 05:12 AM
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Re: Will this fuel setup be OK for 20 psi? (ekb18c)
Thanks for the reply. My goal is 350 whp and 290 ft lbs o torque, which I think I can acheive with 20 psi. Then I'm going to stop on the motor and work on handling upgrades
03-10-2002, 07:14 AM
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Re: Will this fuel setup be OK for 20 psi? (xThexHeadx)
Well, I'm going to try it and see what happens.
Why do you think it won't work?
Why do you think it won't work?
yeah i know a couple that have had that mentality
KABOOM
you will need 750-1000cc ish for "reliable" 20psi
i wouldnt push more than 10psi on 440s
the reason you dont want to rely on increased fuel pressure to deliver more fuel is b/c you are multiplying the consequences of a momentary/partial pressure drop
[Modified by TurboR616, 8:17 AM 3/10/2002]
03-10-2002, 07:36 AM
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Re: Will this fuel setup be OK for 20 psi? (TurboR616)
l wouldnt push more than 10psi on 440s
the reason you dont want to rely on increased fuel pressure to deliver more fuel is b/c you are multiplying the consequences of a momentary/partial pressure drop
the reason you dont want to rely on increased fuel pressure to deliver more fuel is b/c you are multiplying the consequences of a momentary/partial pressure drop
But I dont see how the boost pressure has anything to do with what size injectors you are running. 10 psi produces different WHP levels depending on the size of the turbo you're using, right?
I come here to learn
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03-10-2002, 08:25 AM
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Re: Will this fuel setup be OK for 20 psi? (xThexHeadx)
basically you need air and fuel to make power
the more air you add (turbo boost)
the more fuel you need to accompany it
the more air you add (turbo boost)
the more fuel you need to accompany it
03-10-2002, 09:35 AM
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Re: Will this fuel setup be OK for 20 psi? (TurboR616)
Please correct me if I'm wrong but psi (boost pressure) and airflow (CFM) arent the same thing. A really small turbo produces alot less airflow at, say, 12 psi than a really big turbo.
03-10-2002, 09:41 AM
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Re: Will this fuel setup be OK for 20 psi? (xThexHeadx)
yes, but you are running a drag kit, which means you have a t3/04 b or e. Plenty of CFM from that. If you're maxing your injectors at 10-12psi, they are going to be static at 20psi and well before that. You can increase fuel pressure to compensate, but remember that fuel flow does not increase linearly with fuel pressure increases. So you'd have to be running a LOT of fuel pressure to make it work. I'd skip the drama and step up to some MSD 72lb (750cc), they are cheap and effective.
03-10-2002, 11:52 AM
#11
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Re: Will this fuel setup be OK for 20 psi? (VaporTrail)
Thanks. I understand that flow doesnt increase linearly with fuel pressure, I was just using 60 psi as an example. Sounds like I would need an extremely high fuel pressure to make the 440's work, but then, I dont know how the motor would idle with an extremely high fuel pressure...
You guys convinced me... Anyone want to buy some slightly used RC 440's?
You guys convinced me... Anyone want to buy some slightly used RC 440's?
03-10-2002, 02:56 PM
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Re: Will this fuel setup be OK for 20 psi? (xThexHeadx)
from blueshadow
JUST A WORD OF WARNING, the HP numbers I listed is IF the injector was running at 100% duty cycle. So subtract about 20-30HP from my numbers listed just to be safe. No one has been able to confirm these numbers though so I'll let everyone decide.
I quote BlueShadow (hey thats me)
270cc = 187 HP
310cc = 214 HP
320cc = 220 HP
370cc = 256 HP
400cc = 277 HP
440cc = 304 HP
450cc = 311 HP
500cc = 346 HP
550cc = 380 HP
600cc = 415 HP
650cc = 450 HP
800cc = 554 HP
880cc = 609 HP
If your selecting injectors and say for example your goal is 300 HP don't get the 440cc go with the next size injector like 550cc so that you have room for future upgrades and so you have a safety margin. (you don't wan't to max out the injectors capabilities.
here is the calculations:
CC = [(expected BHP x 0.55) / number of injectors] * 10.5
so to figure out the HP limit of a 550cc injector,
550 = [(HP x 0.55) / 4] * 10.5
550 / 10.5 = 52.38
52.38 * 4 = 209.52
209.52 / 0.55 = 380.95 HP
so a 4 550cc injectors will be good for about 380 HP AT 100% DUTY CYCLE
so I'd say about 350-360 HP is a safe number for the 550cc, the extra 20-30 HP gives you room for adjustability. http://www.preludeonline.com/showthr...threadid=37508
I quote BlueShadow (hey thats me)
270cc = 187 HP
310cc = 214 HP
320cc = 220 HP
370cc = 256 HP
400cc = 277 HP
440cc = 304 HP
450cc = 311 HP
500cc = 346 HP
550cc = 380 HP
600cc = 415 HP
650cc = 450 HP
800cc = 554 HP
880cc = 609 HP
If your selecting injectors and say for example your goal is 300 HP don't get the 440cc go with the next size injector like 550cc so that you have room for future upgrades and so you have a safety margin. (you don't wan't to max out the injectors capabilities.
here is the calculations:
CC = [(expected BHP x 0.55) / number of injectors] * 10.5
so to figure out the HP limit of a 550cc injector,
550 = [(HP x 0.55) / 4] * 10.5
550 / 10.5 = 52.38
52.38 * 4 = 209.52
209.52 / 0.55 = 380.95 HP
so a 4 550cc injectors will be good for about 380 HP AT 100% DUTY CYCLE
so I'd say about 350-360 HP is a safe number for the 550cc, the extra 20-30 HP gives you room for adjustability. http://www.preludeonline.com/showthr...threadid=37508
03-11-2002, 12:02 PM
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Re: Will this fuel setup be OK for 20 psi? (xThexHeadx)
You said you're already convinced, but let me just throw in my 2c:
I'm running 440s, with 58psi of static pressure, and they're basically maxed out at 85% duty cycle with 10psi of boost and a greddy turbo (~240whp on a b16)
-Xerxes
I'm running 440s, with 58psi of static pressure, and they're basically maxed out at 85% duty cycle with 10psi of boost and a greddy turbo (~240whp on a b16)
-Xerxes
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