...fuel issue on 98 cobra

[super98snake]

need help deciding what pump to use in my 98 cobra
i have a walbro 255 in tank pump that i want to use
but i was told to use a svt focus pump intank instead
i did research and the svt focus pump is a 255 also?

im going to use a kb boost a pump instead of a inline pump
and i have 60lb injectors stock lines and stock rails
this is feeding a 4.6 stroked to 5.0 9.2:1 compression with a vortech v-1 t-trim centri blower air to water aftercooled running a 3.1 pulley and 10%overdrive crank pulley

what one will best suite my needs and what changes need to be made if i use the walbro in my sending unit?

 

[98 Saleen Cobra]

Hey I believe that I've helped you are before, but with just a 255 intake a BAP you will absolutley run out of fuel. I wouldn't even mess with trying to modify the hat for the walbro and I'd just get a focus pump they are cheap and you can recoup the money by selling the walbro.. In turn I would I also run a 255 inline pump and ditch the BAP. With the 2 inlines, stock rails, 60lb injectors, and fuel rails I was able to squeeze out close to 600 rwhp before I was running out of pump. Mind you had the exact same setup as you.. SO if that's what you are looking to do I would go the 2 pumps route and hopefully it'll be enough. I eventually ended up going with a full fuel system..

 

[JP_Stang]

^^^This! Yeah we have had this discussion before. You will NOT make it to redline on that one pump man. You really need to run atleast another 255 inline with the focus pump. Your boost levels will be way to high for that one pump and a BAP to keep your A/F ratio safe. You will waste all that tuning money if you try this. I have almost the exact same setup as you and I am running the 255 intank and 255 inline, and I am still really worried about the fuel pumps keeping up. I have thought about just putting it off a few more months until I can afford a complete fuel system.

 

[harvboi05]

a walbro 255 will not fit in your fuel tank unless you hack the bucket apart. youll need either an aviator/GT/focus pump to fit in the stock bucket but just like everyone else says, it wont keep up with your setup. youll need either an inline pump or go ball out with a division x style hat or sumped system if youre shooting for much higher than 550whp.

 

[Brutal Metal]

He has a 98 which is return, Focus pumps aren't designed for that type fuel system

 

[super98snake]

so is a focus pump at 255? will it fit in my sending unit or do i need to buy a focus sending unit with a pump in it? im going to run 2 pumps which is a good inline pump? im not a fan of areomotive either

 

[JP_Stang]

I know that the 98's were kinda of a bastard child for the fuel system. Didn't they have a return system but used returnless style pumps or something??....

I am not sure exactly what lph the focus pump is rated for, but Brute might be right about not being able to use it. If I were you man I would do what I had to to fit the Walbro 255 in the tank and get an inline Walbro 255. Or you could also go with something like a Stealth 340lph intank which I believe is a drop in and go with a Bosch 044 pump inline? I have heard of people doing this, but my tuner told me to keep the same size pump when running in series so that one pump doesn't over feed or suck dry the other??

I hate that I have to run this setup for now. I just want to know that I have an adequate fuel system that I don't have to worry about not having the fuel I need. My goal is to purchase a Kurgan fuel hat, triple Walbros, -10 Feed, -8 return, FPR and rails by the end of spring. Then I will know that my fuel supply is good for whatever I decide to do in the future. I am also making sure everything is E85 friendly just in case....;-)

 

[Cobra52898]

What ever in tank pump you decide to use be sure it is able to run at two speeds. The 98 Cobra's use a two speed pump. Ford used a dropping resistor to lower the voltage being delivered to the in tank pump during periods of low load. When high speed is called for by the PCM a relay closes across the resistor delivering full voltage to the pump. I was told they used an Aviator pump on the 98 Cobra's because it would work well in two speed mode. For what it's worth I've beening running an inline T-Rex with seperate power feeds from the stock pump for more than 10 years and haven't had any problems due to the in tank pump running in low speed. I also read in the Forums that Walbro just released a new pump for the 98 Cobra. I'm not sure if any of this will help with your situation but wanted you to be aware of the factory two speed pump.

 

[98 Saleen Cobra]

I thought the 98's stock intake pump was a 190lph not a 255??

 

[super98snake]

well im about to go drop my tank today and check out the situation and try to make my walbro 255 work in the tank and run a 255 in line but what will change from not running a speed pump? if its a 255 intank stock then i should just leave it alone and use an inline pump?

 

[98 Saleen Cobra]

Yes if its 255 stock ( but I don't think that it is) then leave it, and throw a 255 inline in there and you'll be good.

 

[JP_Stang]

I am pretty sure they didn't come with 255's stock??.... Like you said 98, 190lph tops I would think....

 

[harvboi05]

well im about to go drop my tank today and check out the situation and try to make my walbro 255 work in the tank and run a 255 in line but what will change from not running a speed pump? if its a 255 intank stock then i should just leave it alone and use an inline pump?

youll have to cut up the pump bucket to get a 255 wally to fit. a focus/GT/aviator pump is a direct fit, and still retain the bucket function, theyre ~255l/hr.

 

[Cobra52898]

I thought the 98's stock intake pump was a 190lph not a 255??

Well my bad, I've been searching for where I read that the 98 Cobra came with a 255 Lph pump and can no longer find it, but did find some info that points to a 180 to 190 Lph pump instead. My apologies for any confusion. But it is definitely a 2 speed pump, I have the Ford electrical service book and it is clearly indicated in the electrical schematics and is also discussed in the strategy guide.

 

[Cobra52898]

youll have to cut up the pump bucket to get a 255 wally to fit. a focus/GT/aviator pump is a direct fit, and still retain the bucket function, theyre ~255l/hr.

I recalling reading a thread here at SVT performance recently that Ford used an Aviator FP in the 98 Cobra. Here's the thread:
http://www.svtperformance.com/forums/sn95-cobras-24/812928-98-cobra-fuel-pump.html

 

[harvboi05]

yeah i posted in that thread too.

98 = GT/focus/aviator pumps
96/97 = 255 wally.

the 98 pump bucket/tank design is identical to 99+. I bought a 03/04 cobra fore hat with GT pumps to put into my 98 tank. bolted right up. i removed the pump holder that was tack welded to the inside of the tank and it fit right in. after removing the stock bucket, i pulled the stock 98 pump out and it was identical in design/fit as the GT pump (which is also the same as focus/aviator pumps). the only reason i went though the hassle was because 03/04 cobra tank i ordered was on national backorder.

the right way to do it is a multiple pump 03/04 cobra tank setup or an external pump sumped system. everything else requires DIY engineering. considering a well designed, properly functioning fuel system can make or break a several thousand dollar investment in a FI engine setup, id say its worth the peice of mind to not have a hacked up friggin gas can ziptied to a peice of scrap metal inside my gas tank. do it right, or keep you power level under 500whp.