fuel pump question-vortech

[JesseW.]

car-vortech with water intercooler and lt headers. I bought it this way 3 years ago.

i was performing the fuel pump TSB for the 05-06 cars because i was having the car bog badly at autocross and when less than 1/4 tank and noted the fuel pump was built in 05. It ran great otherwise

To my surprise when i pulled the pump it DID NOT have the walbro 255 hanging off the side of it as is in the vortech directions and there is no BAP. took the pump out of the hanger and it is the stock 155 lph pump. the filter on the pump had a lot of stuff on it and the metal screen was half blocked by what looked like chunks of rubber.

anyway, the 1/4 tank and bog at autocross has went away since changing it, but i feel that i may be at or over the limit of the stock pump. what is the max power the stock pump will support?

I've outran several I/E/tuned 5.0's and C5 Z06's and have dyno sheets from the previous owner of 440whp. doesn't seem to be starving for fuel... should i upgrade the pump and if i do, will i need to go get it tuned? i am very happy with the way it runs now.

 

[JeremyH]

If you push the stock pump its good to around 400rwhp depending on boost level. I would fix it now! Only takes one time with some passengers in the car etc and in the upper rpms to go lean and hurt the engine.

I throw all the 05/06 pumps I remove from the stock hats right in the trash bc of the tsb.

If your interested in a pump upgrade or fuel sytem wire upgrade hit me up.

And yes if your installing a bigger pump, or dual pumps or bap etc you will need the tune adjusted.

 

[TheKurgan]

Why don't you just datalog it and find out ? When I was running nitrous at ~430rwhp/450rwtq, my fpdc was not even hitting 50% on the stock pump.

 

[JeremyH]

Why don't you just datalog it and find out ? When I was running nitrous at ~430rwhp/450rwtq, my fpdc was not even hitting 50% on the stock pump.

Nitrous and boost are not the same thing as far as fuel pump demand goes, especialy if your running a wet shot.

 

[TheKurgan]

Nitrous and boost are not the same thing as far as fuel pump demand goes, especialy if your running a wet shot.

Why is that ? It still has to push the same amount of fuel to get the right AFR. Yes, it is a wet kit - Zex.

 

[JeremyH]

The fuel injector has to over come boost pressure in the cylinder with a forced induction setup which raises rail delta pressure and reduces flow from the pump, so higher demand and duty cyle on the pump to maintain fuel supply. Where as the nitrous and fuel is sprayed at the same time, so no additional pressure to overcome in the cylinder. On a wet shot the solenoid opens and feeds fuel into the cylinder with the nitrous as well, bypassing the injector which increases this effect. Less injector delta is needed so less load and duty cylce on the fuel pump due to this direct path so alot less demand on the pump.

With 9-10psi of boost you will hit 95-100% duty cycle on the stock pump at around 400rwhp depending on injector size trying to maintain delta pressure.

 

[TheKurgan]

The nitrous will increase the cylinder pressure as well.(You're still increasing the amount of oxygen with the nitrous, and increased heat) Maybe not as much as a SC, but I wouldn't think the difference would be that much. 50% is ALOT more.

 

[JeremyH]

The nitrous will increase the cylinder pressure as well.(You're still increasing the amount of oxygen with the nitrous, and increased heat) Maybe not as much as a SC, but I wouldn't think the difference would be that much. 50% is ALOT more.

Not until combustion and after the fuel is injected with the nitrous. Yes it is a big difference.

 

[BruceH]

car-vortech with water intercooler and lt headers. I bought it this way 3 years ago.

i was performing the fuel pump TSB for the 05-06 cars because i was having the car bog badly at autocross and when less than 1/4 tank and noted the fuel pump was built in 05. It ran great otherwise

To my surprise when i pulled the pump it DID NOT have the walbro 255 hanging off the side of it as is in the vortech directions and there is no BAP. took the pump out of the hanger and it is the stock 155 lph pump. the filter on the pump had a lot of stuff on it and the metal screen was half blocked by what looked like chunks of rubber.

anyway, the 1/4 tank and bog at autocross has went away since changing it, but i feel that i may be at or over the limit of the stock pump. what is the max power the stock pump will support?

I've outran several I/E/tuned 5.0's and C5 Z06's and have dyno sheets from the previous owner of 440whp. doesn't seem to be starving for fuel... should i upgrade the pump and if i do, will i need to go get it tuned? i am very happy with the way it runs now.

Fwiw I maxed the stock fuel pump at 408rwhp. This was with a non intercooled Whipple and the 32lb injectors that come with it. Your Vortech probably came with corba 39lb injectors which give you more headroom. I'd put a bap on and call it a day unless you plan to go with more power sometime in the future.

Ford shows the stock pump at 255lph.

 

[JesseW.]

thanks guys, i'd data log it, but i don't have a handheld tuner, so i am going to have to go to tuner....

i'm gonna gather up some parts (better pump and maf) and get it retuned soon. the previous owner told me the tuner is very conservative. its the basic vortech h.o. kit but i knew something was up when there was no MAFia, and then i pulled the pump. may have been a tuner kit instead. at least its lived 5 lives and 30,000 miles like it is.