----70 psi is not too far out of reality if your baseline is 45 ish and you run 25 lbs of boost-------are we running more boost overall these days than we used to????------i have a friend that runs 25 all the time with pump gas now that he has alcohol injection----------i doubt these relatively small pumps were ever intended to run at close to 15 amps for very long------combination of high turbo boost and volt boosters could be a recipe for problems????.....................RC
This is almost exactly what my theory has been since the advent of alky injection came out. Not knocking alky injection, but boost is addictive and alky allows insane levels of boost.
My theory is this, these pumps in OEM stock form were designed to operate under 12-13 volt range on OEM fuel pump wiring, 30-40psi fuel pressure at idle, and 45-55psi under WOT. (Stock car running 12-15psi on a 233 non adjustable fuel pressure regulator. Boost level depending on ambient temps) No swet for the Walbro 340 pumps to handle.
Now, you factor in these variables:
Adjustable fuel pressure regulator which allows the end user to up the pressure to 50psi if needed on small injectors, hot wire kits and volt boosters which spike the pump with 14-14.9 volts everytime you go WOT, insane boost levels of 25-30psi brought on by alky injection and or race gas. Now you add a semi clogged OEM fuel filter to the mix and you have a recipe for a failed pump.
Especially on a car that is constantly rode hard and put up wet.
Think about the voltage and boost pressure swings when you have these conditions. You can see the swing in flow vs voltage thanks to Mr. Clark's charts.
It doesn't surprise me that Walbros are failing. What does surprise me, are cars that put the pump on and have it fail within a week of normal driving.
That tells me that something might have changed with materials and production standards. The Japanease have been dealing with these issues for years on their Forced Inducted cars. You will notice that most serious Japanease turbo cars (1000-1400hp applications) will run 2 sometimes 3 external Bosch pumps on those setups. It always amazed me why they don't simply switch over to a Weldon style pump, but I digress.
One this is for sure, this has been an excellent post, and I'd like to thank Mike Licht and Mr. Clark for all their efforts with this issue.
I think it's time we get in touch with the DSM/Evo crowd and find out which pump they are using today? Those guys run serious fuel pressure/boost ratios. I know there is a superior pump to the 340/F20000169 pump, but I can't remember the part number. What would be nice if someone developed a bolt on retrofit kit using this super pump to our cars.
I'll do some digging on my end.
Sorry this is so long winded.
Patrick