Inline Fuel Pump.

OrangeMustangGt

Founding Member
Mar 7, 2002
1,976
0
36
Cape Cod, MA
I got ny car dyno'd today, and was told, again that i NEED an additional inline fuel pump before i can turn up my boost past 5lbs. I just did 3 runs today, and found that im running lean at 5psi(due to my new MAF), so i'll have to wait till march when i can get my chip re-burnt, and THEN, i will want to turn up the boost to say 10psi.
 
GreenMustangGt said:
I got ny car dyno'd today, and was told, again that i NEED an additional inline fuel pump before i can turn up my boost past 5lbs. I just did 3 runs today, and found that im running lean at 5psi(due to my new MAF), so i'll have to wait till march when i can get my chip re-burnt, and THEN, i will want to turn up the boost to say 10psi.
i had a regular 255 intank pump couldnt keep up with boost so changed to a 255 high pressure like mentioned above and fixed problem depending on hp but if your making close to 500 rwhp id recommend a inline bbk pump as well good luck
 
well, does it have to do with the amount of boost as well as the horse, or is it more just the horsepower? I have a 255, and i plan on running no more than 12 psi, well, until i decide to fry the motor, but if the psi will kill the pump, i'll do other things such as heads and intake etc. first.
 
94Blue302GT said:
well, does it have to do with the amount of boost as well as the horse, or is it more just the horsepower? I have a 255, and i plan on running no more than 12 psi, well, until i decide to fry the motor, but if the psi will kill the pump, i'll do other things such as heads and intake etc. first.
change to a high pressure .i needed a high pressure at 10psi making 450rwhp and also added bbk inline for extra insurance
 
a Whinebro 255 will be more than enough, generally speaking it's the diameter of the fuel lines used that cause a flow restriction, ideally you want to go up to whatever size matches the internal diameter of your fuel rail, and upsize any filters and fittings on the way.

Personally, on all my previous cars we've run -8AN feeds and a -6AN return, we normally use a Mallory 4305m or similar regulator, feeding both ends of the rail which has -8AN fittings tig welded onto it:

321156_20_full.jpg


Our 94 GT will be receiving the same treatment when it arrives(19 days!)
 
miran587 said:
i had a regular 255 intank pump couldnt keep up with boost so changed to a 255 high pressure like mentioned above and fixed problem depending on hp but if your making close to 500 rwhp id recommend a inline bbk pump as well good luck


At what point did your regular 255 go lean? I have a regular 255 and when I got my tune I was going lean at my power levels...
 
thanks guys, i have a walbro 255 High Pressure, and everyone keeps telling me i need an inline pump as whell if i want to turn up boost(although my car has never been out of fuel yet).....So, if i DO need one, what pump complements my intank?...do i want one of equil volume, or greater? thanks
 
Running two pumps in series can be a hazardous setup, unless there is a surge tank between them with a return to the tank, otherwise if the second pump is bigger than the first, it will often create so much suction that it will bind up the first pump - this is especially true if they are diaphragm pumps, centrifugal pumps don't usually suffer from this.

Having said that, a 255lph pump should be more than enough fuel, our old car had a 140lph bosch 909 pump and we were turning 300hp at the wheels with no sign of pressure drop in the rail.
 
94gts said:
a single 255 high pressure intank (gss340) should be more than enough. A guy i know made 623 to the tires on pump gas and 18 psi on stock lines and rails in a 90 gt. with that pump of course. and the fox rails suck compared to ours

im quoting myself here because i guess no one read it.