How much fuel
How much fuel If I am pushing 100 lb/min(1400cfm) of air, How many lbs/min of fuel will I need?
I have a t-rex external booster pump and a stock pump in the tank. I am at 630RWHP now with about 75lbs/min. Just need to know how much fuel I need to get to 800RWHP mark with the T-trim. I think I will be seeing 100lbs/min(1400 cfm). Just need to figure out what type of fuel system. I was thinkin a walbro 341 in tank with the T-rex booster pump.
Any suggestions.
I have a t-rex external booster pump and a stock pump in the tank. I am at 630RWHP now with about 75lbs/min. Just need to know how much fuel I need to get to 800RWHP mark with the T-trim. I think I will be seeing 100lbs/min(1400 cfm). Just need to figure out what type of fuel system. I was thinkin a walbro 341 in tank with the T-rex booster pump.
Any suggestions.
Originally Posted by 30thta436
If I am pushing 100 lb/min(1400cfm) of air, How many lbs/min of fuel will I need?
I have a t-rex external booster pump and a stock pump in the tank. I am at 630RWHP now with about 75lbs/min. Just need to know how much fuel I need to get to 800RWHP mark with the T-trim. I think I will be seeing 100lbs/min(1400 cfm). Just need to figure out what type of fuel system. I was thinkin a walbro 341 in tank with the T-rex booster pump.
Any suggestions.
I have a t-rex external booster pump and a stock pump in the tank. I am at 630RWHP now with about 75lbs/min. Just need to know how much fuel I need to get to 800RWHP mark with the T-trim. I think I will be seeing 100lbs/min(1400 cfm). Just need to figure out what type of fuel system. I was thinkin a walbro 341 in tank with the T-rex booster pump.
Any suggestions.
Choose one
Another question?
Would I be correct if I assumed:
Since I need fuel for 110lbs/min of air. I could devide the air flow by air fuel ratio (110/11=10). If so I come up with needing a 10lbs/min of fuel flow. I know I would need some extra fuel for spikes and to feed both sides of the fuel rail evenly. So I can surmise one walbro 340 and the t-rex are not going to be near enough. One walbro flows a max of 255liters per hour or 404lbs per hour. If I devide that by 60 minutes I come up with 6.73lbs/per min.
So would twin walbro's in tank without and external pump be enough @ 13lbs/per min combined?
Would I be correct if I assumed:
Since I need fuel for 110lbs/min of air. I could devide the air flow by air fuel ratio (110/11=10). If so I come up with needing a 10lbs/min of fuel flow. I know I would need some extra fuel for spikes and to feed both sides of the fuel rail evenly. So I can surmise one walbro 340 and the t-rex are not going to be near enough. One walbro flows a max of 255liters per hour or 404lbs per hour. If I devide that by 60 minutes I come up with 6.73lbs/per min.
So would twin walbro's in tank without and external pump be enough @ 13lbs/per min combined?
TECH Enthusiast
Joined: Aug 2003
Posts: 596
Likes: 0
From: Downers Grove,IL
The answer is very simple. Simply divide your airflow by the fuel ratio you desire. for a 11.5-1 af ratio- 100/11.5 = 8.695
now convert that into the more common lbs/hr and you get 521.7 lbs/hr.
divide by 8 and you need to flow 65.2lbs per injector.
So figure maybe around an 80lb/hr injector and a fuel pump that flows at least 650lbs/hr IMO.
now convert that into the more common lbs/hr and you get 521.7 lbs/hr.
divide by 8 and you need to flow 65.2lbs per injector.
So figure maybe around an 80lb/hr injector and a fuel pump that flows at least 650lbs/hr IMO.
Originally Posted by y2khawk
pair of 340 intanks in parallel, pair of T-rex external in parallel w/ no intank, single weldon 2025 external, or a big aeromotive external.
Choose one
Choose one
Thanks
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Originally Posted by S_J_H
The answer is very simple. Simply divide your airflow by the fuel ratio you desire. for a 11.5-1 af ratio- 100/11.5 = 8.695
now convert that into the more common lbs/hr and you get 521.7 lbs/hr.
divide by 8 and you need to flow 65.2lbs per injector.
So figure maybe around an 80lb/hr injector and a fuel pump that flows at least 650lbs/hr IMO.
now convert that into the more common lbs/hr and you get 521.7 lbs/hr.
divide by 8 and you need to flow 65.2lbs per injector.
So figure maybe around an 80lb/hr injector and a fuel pump that flows at least 650lbs/hr IMO.
You say I need 65lbs per hour injectors. The 50lbs I have now are rated at 43.5 PSI fuel pressure. What does that equate to at our 60PSI fuel pressure.
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TECH Fanatic
Joined: Nov 2001
Posts: 1,190
Likes: 0
From: Las Cruces, NM
Originally Posted by 30thta436
If I am pushing 100 lb/min(1400cfm) of air, How many lbs/min of fuel will I need?
I have a t-rex external booster pump and a stock pump in the tank. I am at 630RWHP now with about 75lbs/min. Just need to know how much fuel I need to get to 800RWHP mark with the T-trim. I think I will be seeing 100lbs/min(1400 cfm). Just need to figure out what type of fuel system. I was thinkin a walbro 341 in tank with the T-rex booster pump.
Any suggestions.
I have a t-rex external booster pump and a stock pump in the tank. I am at 630RWHP now with about 75lbs/min. Just need to know how much fuel I need to get to 800RWHP mark with the T-trim. I think I will be seeing 100lbs/min(1400 cfm). Just need to figure out what type of fuel system. I was thinkin a walbro 341 in tank with the T-rex booster pump.
Any suggestions.
So 100 lb/min / (AFR=12) = 8.33 lb/min fuel
8.33 lb /min * (Density =1 gallon/6 lb) = 1.38 gallons/min
1.38 gallons/min *60 min = 82.8 gallons/h
82.8 gallons/h = 313 liters/h
So the engine will ingest 313 liters/h, however, this is not the size pump you need.
This number assumes that all the gasoline pushed/pulled by the pump goes into the engine. Some has to go to the return line (from the fuel pressure regulator) otherwise you have no pressure control. Also since you are boosted if your fuel pressure goes up one psi for every psi of boost, the pump output drops.
So basically a walbro 340gs (255 lph) and inline is not a good idea. Walbro 340gs is good for maybe 500 rwhp the inline cant really add much more than that just helps with pressure drop.
Gary
Total airflow requirements:
1415.92 cfm
106.38 pounds of air.
7.22 pounds of fuel
Fuel Supply requirements:
1.2 gallons per minute for 14.7 A/F ratio.
92.5 gallons per hour for 11.5 A/F ratio.
350.11 liters per hour for 11.5 A/F ratio.
airflow calc
1415.92 cfm
106.38 pounds of air.
7.22 pounds of fuel
Fuel Supply requirements:
1.2 gallons per minute for 14.7 A/F ratio.
92.5 gallons per hour for 11.5 A/F ratio.
350.11 liters per hour for 11.5 A/F ratio.
airflow calc
excuse the ignorance and my mistakes right off the bet I thought 100 lb/min maf flow equals 1000 rwhp. Now I have some measurement wrong but I could always translate my autotap reported maf flow directly to rwhp. It would correlate on the dyno every time. What am i missing? I THINK Harlan was getting the same correlation when he JUST had 600 rwhp on his stock motor/maf and incon. Please teach a brothah!!!
I thought 100 lb/min maf flow equals 1000 rwhp. Now I have some measurement wrong but I could always translate my autotap reported maf flow directly to rwhp. It would correlate on the dyno every time. What am i missing? I THINK Harlan was getting the same correlation when he JUST had 600 rwhp on his stock motor/maf and incon. Please teach a brothah!!! 
Originally Posted by y2khawk
pair of 340 intanks in parallel, pair of T-rex external in parallel w/ no intank, single weldon 2025 external, or a big aeromotive external.
Choose one
Choose one
figure minimum -8 feed, -6 return. I prefer -10 feed and -8 or -10 return depending on the pump setup.
1 lb/min of air ~= 10hp, so 100 ~= 1000 FWHP, give or take a few
Originally Posted by y2khawk
a pair of 255l/hr pumps will flow 120+ g/hr of fuel, a single 340 is good to nearly 60g/hr with a good hot wire supply.
figure minimum -8 feed, -6 return. I prefer -10 feed and -8 or -10 return depending on the pump setup.
1 lb/min of air ~= 10hp, so 100 ~= 1000 FWHP, give or take a few
figure minimum -8 feed, -6 return. I prefer -10 feed and -8 or -10 return depending on the pump setup.
1 lb/min of air ~= 10hp, so 100 ~= 1000 FWHP, give or take a few
Will 57# @3 bar or 66# at 4 bar be enough to support 700 rwhp?
Originally Posted by NA$TY-TA
So what your saying Matt is that two Walbro 340's are good enough for over 800rwhp and -8 feed and -6return will support it???
Will 57# @3 bar or 66# at 4 bar be enough to support 700 rwhp?
Will 57# @3 bar or 66# at 4 bar be enough to support 700 rwhp?
The pumps will supply plenty of fuel, over 1000HP worth at 70 psi or so, but I'd personally go to the bigger feedline if I was pushing them that far. A bigger return is a good idea if you plan to run both pumps all the time. Otherwise you might get into pressure creap at idle when trying to bypass most of that fuel back to the tank. I run a -10 return a still see a jump in fuel pressure when i switch to high speed on the pump at idle, just not enough return flow through the regulator and line.
a 66 lb/hr injector, assuming you use a referenced regulator, should be able to supply enough fuel for about 770 FWHP at 80%, and about 960 at 100%. With an auto in the car, they will just be on the edge depending on how rich you want it. I was figuring .55 BSFC which is pretty normal for boost.
I am running:
Weldon 2025
Seimens 83 lb injectors
Weldon regulator, 43 psi at idle
FAST system
-10 feed, SS Racing fuel rails, -8 crossover and -6 return.
Aeroquip fittings
Weldon 2025
Seimens 83 lb injectors
Weldon regulator, 43 psi at idle
FAST system
-10 feed, SS Racing fuel rails, -8 crossover and -6 return.
Aeroquip fittings