When will I over run my 255

[Hiitman]

I don't want to switch to a dual in tank setup if I don't have to. Here's the parts of my setup that I think will determine this

PTE 4431 25-28psi
255lph
Aeromotive fpr ~38psi
1600s
-6an feed/return to tank
E85
Dsmlink

Flowing about 49 lbs/min at 6000ft. Also, will the car run uncontrollably lean if I do start to run out of pump?

 

[dsm-onster]

49lb/min at 6000ft is the same as 49lb/min at -500ft .

Either way, you willnot run lean because of a walbro 255 fuel pump at such an airflow level.

 

[Hiitman]

49lb/min at 6000ft is the same as 49lb/min at -500ft

Good call.

I guess I'm just curious as to what airflow range should I start to expect to over run that pump.

 

[dsm-onster]

A walbro 255 hp fuel pump will flow enough to supply 850cc injectors at 100% IDC at 35psi. You can look in various places on the web to find out how much 4 850cc injectors support .

 

[Dsmx17]

E-85 uses 30% more fuel, a rewired 255 starts to run out around 450-500whp mark on gasoline, subtract 30% for E-85 and it gets iffy....

 

[Boosted98gsx]

A Walbro 255hp can only support 42 lbs/min of airflow on e-85....

 

[SpeedAddict62]

See here: E85 Fuel Pump Calculations

Theoretically, you can flow about 52 lb/min at your highest boost level and still be ok...but thats dangerously close to 49 lb/min. IMO, I'd go for dual pumps just to be safe. I'd rather have more than enough fuel rather than too little.