What happens when your outside of the 10%...? You'll have the issue, it'll just take longer to realize it


(for the record my ECU also adjusts itself with O2 feedback)

 

I think I'm switching to a bosch

 

I have never had a problem with my Walbro's. The first one I have had for 5 years that is now being used with the dual setup and not one problem that I can see. I do make sure I always have at least a half tank of gas though and never go below that. This way the pumps are always in the fuel and staying cool.

 

exactly, these pumps are extremely prone to failure if ran on low fuel for an extended amount of time.....

 

If 1/2 a tank is "low" fuel, come on -- that's retarded. Maybe they should realize not everyone wants to fill up every 90 miles?


Spoolin, do you have a fuel pressure gauge? Drive it enough and I guarentee your pressure is dropping.

I'm thinking about a bosch pump now...I drive myself nuts worrying about driving too far

 

surge tank fed by stock pump, bosch 044 inline.

i never noticed any problems, but i might just have to keep myself busy with projects once my S is back on the road...and this sounds like a fun project

 

I just make sure to always have at least a half tank in the car at all times to keep the pumps submerged and cool. I only drive it on the weekends and for cruising and roll racing purposes, about 50 miles a weekend night. I would notice a problem in the A/F's if the pumps werent holding pressure all the time and I have never seen this. I have a fuel pressure gauge on my FPR and even after a drive, I have stopped and checked my fuel pressure while the car is still idling and its always holding strong at 45-46 psi.

 

These pumps aren't great they fail lose pressure and make funny noises. We can't fit a bosch in the tank? Seems like someone would make a hanger for it by now or should

 

How much base fuel pressure are you running?

 

Thats true, I hadnt thought of that.

If your base pressure is too high and you boost on it and it ups your fuel pressure past about 80 psi (this is about what the Walbro's max at), you will be over driving the pump pressure and the relief valve will open but this may also wear on the pump over time. Although, you can push the relief valve in and get about 10 more psi out of the pump, but again may wear on the pump.

What I'm getting at is.....I run a base pressure of about 46 psi and when Im boosting 27 psi, my end fuel pressure is 73 psi. If you have your base pressure set at 60 psi and are boosting 23 psi, your end fuel pressure will be 83 psi, which is overdriving the pump and the relief valve will open and you will lose fuel pressure.