gzon

I have problems getting enough fuel for my engine, I got my car runnin ok this weekend on 4 850cc injecotrs. I know they are to small so I will replace the secondaries. But maybe that isnt the only problem. I suspect the fuelpump/lines to.

One thing that makes me suspect it is that At 10-15 degree Celcius outside I get just about the fuel I need on 100% duty cycle, When there is 20-25 degree celcius I cant get enough fuel. Could this be the fuelpump/lines or is this a common problem when having to big D/C?

How much HP can you put out on oem fuellines? and Supra mk4 Pump?

diyman25

dont replace pumpe yet. upgarde your fuel pumpe wiring first

gzon

Whats the best way of doing that?

Mr rx-7 tt

iTrader: (5)

The lines are fine. I have seen 600 plus RWHP on them. Go with a Supra tt fuel pump.

gzon

Now fuel pressure is tested. Have to make some changes here. Will go for 2 pumps and run bouth lines to the rails and make new lines for return. Hopefully Ill have some fuel then.

rzograbian

so one supra tt fuel pump is not enough or something??? i want to know because i am also in the process of going single and wanted to know!

maxcooper

When the fuel pump or lines are reaching their limit, your fuel pressure will drop. For instance if you are running 13 psi and your fuel pressure regulator is set to 38 psi base fuel pressure, you should have 13 + 38 = 51 psi of fuel pressure under boost. The regulator should hold your fuel pressure to 51 psi at 13 psi of boost. If the fuel pump or lines are not adequate, the pressure will be lower than what the regulator wants under those conditions (i.e. 51 psi).

Note also that if your pump and lines are adequate (you can maintain 51 psi under the conditions described above), increasing the capacity of the lines and/or pump will have absolutely no effect on the amount of fuel delivered to the engine.

-Max

gzon

fuel pressure drops @ high rpm:s. I got 14psi @ 4000rpm and when raising up over 6000rpm the fuel pressure starts to "wobble" and decreses. " pumps, lines and regulators might be overkill but is the easiest way to do the work.

Howard Coleman

iTrader: (6)

hi Martin,

while prepping for my setup i did lots of research on fuel...

first: Ari Yellen makes close to 700 hp using stock OEM fuel lines. i doubt fuel lines are your problem.

i run the same cosmo/supra pump as you and it is not quite up to the job when making over 400 rwhp.

you can buy a bigger pump of course.

i chose to retain my pump and added a Kenne Bell Boost A Pump. the BAP has been developed and sold by Kenne Bell for more than 20 years and is beautifully engineered. you hook a vacuum line from your UIM to a solenoid in the engine compartment. as soon as it reads positive boost an electronic message is sent to the BAP control unit. mine is mounted w my battery in the rear passenger compartment. the BAP comes w a dial which i mounted in the same compartment and can reach from my driver's seat. the dial allows you to up the voltage to the pump from zero to 50%.

Kenne Bell has an excellent website w lots of engineering data. the unit sells for $200. MSD has recently developed a similar unit.

install the BAP and forget about fuel delivery problems.

howard coleman

gzon

I have decided to try out the kenny bell unit, I will replace the standard model fuel filter and get 1300cc top fed secondaries to and hopefully this will give the results.