I was just wandering how much power i will gain by doing this. And will it cause it to run rich at idle. And yes i do have a warlbro.
12v mod
- Thread starter Supraboy89
- Start date
You will likely not gain any power. That walbro already has the little stock fpr working overtime, no reason to make it worse. It will run too rich at idle, and that's about it.
I think the walboro has the same properties as most electric pumps. Its output directly relates to the force making it do its work. So you can essentially use like 4 volts, but it won't much of pumping. There is the minimal amount of force (volts) necessary to make it accomplish it's task. There is also a maxium amount of force (volts) that will all it to do it's work without destroying itself. Most manufactures have the safe operating range which for the walboro is probably 12 volts, but you can usually go alittle above or below without much of a problem.
if i remember correctly, the operating voltage of a wallypump is somewhere in the viscinity of 9-14v. (don't quote me on that, but that's what's in my head) i wouldn't run it at less than 9v.
you won't gain any power by doing the 12v mod, but if you're tuning, it'll make the task easier because you won't have to try to tune around the voltage switch at various different throttle/loads.
-shaeff
you won't gain any power by doing the 12v mod, but if you're tuning, it'll make the task easier because you won't have to try to tune around the voltage switch at various different throttle/loads.
-shaeff
On a dc fuel pump like a Walbro or a stock pump, the voltage rating (9-14v) is the voltage range at which the pump will make it's rated output or come within a certain percentage of it's rated output. If you run the pump at a lower voltage, it will make less pressure and the flow will be decreased, but that is not going to damage the pump. Going higher then the rated maximum voltage could damage the pump.
The whole reason for the stock relay/resistor setup is because the pump should supply less fuel pressure at idle, when very little fuel is actually being consumed by the engine. There is no reason for the pump to be running full tilt at idle, it's actually worse for the pump because there is extra heat generated. Many late model engines now employ a fuel pump ecu which can continually adjust the voltage to the fuel pump as needed, rather then just hi or low voltage like the a70.
The only reason you would want to do the 12v mod is for tuning purposes like Shaeff said, but that is probably not the reason most people want to do this mod. Toyota had good reason to make it work like they did.
The whole reason for the stock relay/resistor setup is because the pump should supply less fuel pressure at idle, when very little fuel is actually being consumed by the engine. There is no reason for the pump to be running full tilt at idle, it's actually worse for the pump because there is extra heat generated. Many late model engines now employ a fuel pump ecu which can continually adjust the voltage to the fuel pump as needed, rather then just hi or low voltage like the a70.
The only reason you would want to do the 12v mod is for tuning purposes like Shaeff said, but that is probably not the reason most people want to do this mod. Toyota had good reason to make it work like they did.
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supra_supra said:
Exactly right.
I guess I said exactly the same thing, but I didn't see your post at first. :biglaugh:
I have the fuel pump wired to be just on or off now I have a standalone, but there is no choice without the stock ecu.
There is also a much wider range of tuning possiblities with a standalone then with a stock ecu and a piggyback.
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Big A is right on the money. The 12V is just for loads, even on the stock pump. It keeps it from wearing out sooner.
If you are stand alone, or making significant power over stock, then that is different.
If you are stand alone, or making significant power over stock, then that is different.
Now that I think about it, it would be very easy to make it work like stock with a standalone. You could just have one of the aux outputs switch the pump relay based on boost pressure. I guess with 550cc injectors and a Aeromotive afpr it's not that big of a deal. :dunno:
i remember always hearing people saying walbro pumps failing, is that due to the 2 stage voltage? or from running at full 12 volts at all times?
I'm not sure, but the dual voltage would not be the cause. You're probably right about the constant 12v being one possible cause of a shortened pump lifespan.
Well can you still use the stock resister pack with the 12 volt mod? I have low impedence 550 injectors .
Yes, the best way to do it is to upgrade the stock relay to a Bosch 30 amp, and run a heavier gauge wire from the relay back to the pump. Then you have a little higher voltage when you actually need it, when the engine is under boost.
The best characterization of fuel pumps (including supply voltage) I have found is here.
http://www.stealth316.com/2-fuelpumpguide.htm
http://www.stealth316.com/2-fuelpumpguide.htm