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© copyright 1999-2017 Auto Performance Engineering

Fuel Pump FAQs

Please read all of these before you e-mail me with questions/comments. You'd be surprised at how many folks e-mail me with one of these exact questions.

Q: How will I know when I need a new pump?

A:  If your fuel pressure at wide-open throttle (WOT) falls off, that is a good indication that your current fuel pump can not provide the required amount of fuel. Either the voltage to your pump is weak, or your pump isn't manly enough.

If you plan on driving your vehicle in its stock configuration for the rest of its days, a new pump should not be required unless your stock pump fails.  If your stock pump fails, why not put one of these in there?  It's probably cheaper than a replacement pump from the dealer.

Q: Which pump is right for me?

A: If you're just going to replace your pump with something that is near stock because your stock one croaked, or if you are not going to do any mods, the 190 ltr/hr pump may be all you need.

Notice that the only difference between the 'normal' 255 ltr/hr pump and the 'high pressure' 255 ltr/hr pump is the flow above 50 psi of fuel pressure.  Unless you are running a high base fuel pressure, or are running some serious boost levels, the normal 255 pump should be enough.

I'm not trying to sell you a giant pump just to get a couple more bucks out of you. But, in my experience, when folks start modifying their vehicles, they never seem to make it fast enough. I'd hate to sell you a pump this month, then have you contact me in six months, telling me that you need more fuel, because you got a bigger turbo or some other go-fast part that is going to need more fuel. The cost difference is small;  just consider it a cheap insurance policy.  If you get the high-pressure pump, you'll probably only have to get into the fuel tank only once, too.

Your best source for accurate info is probably your vehicle-specific mailing list.

Q: How much horsepower will your pumps support?

A:  Let's use the formula that says

horsepower (HP) = lb/hr (fuel) / BSFC

If we assume BSFC of .5, then HP = 2 * lb/hr.  Then, if we round the weight of a pound of fuel to 6 pounds HP = 12 * gal/hr.  So, if we assume .5 BSFC, then you can actually multiply the numbers in the flow charts by 12 to compute supported horsepower.


For example, If you look up the flow rate of the 190 ltr/hr pump in the Technical section, you will see that it will push 36 gal/hr at 50 psi with a 12 VDC power source.   If your engine is pumping out 500 hp when the fuel pressure is 50 psi [@ 12VDC], you probably won't want to use the 190 ltr/hr pump [36 * 12 = 432].

Remember, that forced-induction engines typically raise the fuel pressure under boost. Be sure to take into account that you will have a higher-than-base fuel pressure under boost.

Q: Do I need an adjustable fuel pressure regulator, too?

A:  Need... no, but you may *want* one.  If you are modifying your vehicle for extra performance, chances are you will need more fuel for those heads/boost/etc.  An adjustable fuel pressure regulator is a way to fine-tune the fuel system for maximum performance after you've added that new pump.

Q:  Will a high performance pump do anything *bad* to my vehicle?

A:  If you are talking about fuel economy, no.  The fuel pressure regulator will just return all that extra fuel to the tank... keeping those lines cool.

If you're talking about the fuel lines/filter/etc., I don't think so.  The only time you see higher-than-normal fuel pressures is if you get an adjustable fuel pressure regulator and really crank it up.

If you're talking noise.. maybe.  I've heard from some folks that claim the Walbro pump is just as quiet and others that say the pump does make more noise.  I don't know why some are louder than others... maybe installation techniques.

Q:  What type of warranty comes with this pump?

A:  The pump is covered by a one year warranty after the date of manufacture (stamped on the pump itself).  This covers failures due to materials or manufacturing.   It does not cover failures due to fuel contamination (dirt/rocks), which is the most common cause of pump failure (per Walbro). My supplier understands that pumps can sit on the shelf for months, so they usually cover my pumps for one year from the date I sell them.   Visit the policies page for details.

Q:  How long will it take to get this pump?

A:  If I have the pump in stock, I'll ship it right out if you send a money order, or after your check clears.  If I don't have it, I'll have to order it.   That can take about a week.   I primarily ship via US Postal Service Priority Mail.  Priority Mail typically takes two to three days for delivery..   In the past, US Postal Service Priority Mail has taken as little as one day and as many as seven days.

Q:  Can you tell me if one of those kits will fit on my <car/truck not listed in application chart>?

A: If you have questions that pertain to a specific vehicle that isn't listed in the application chart, send me an e-mail.   Maybe we can figure something out.

Q:  What can I do if I need more fuel than the high pressure 255 pump?

A:  If you need more fuel than that, you are pushing some serious horsepower. I know some folks that are actually putting two Walbro pumps in the fuel tank. I don't have any kits to do that, but customers say that it isn't too difficult.

You may want to try a device that will increase the voltage to the fuel pump.   These pumps really push some fuel if you send 'em 16 volts.

Q:  Someone told me that the Holley in-tank pumps are made by Walbro. Is that true?

A:  Yes, Walbro makes those pumps, but they have different part numbers on 'em. Use this page to convert your Holley part numbers to their Walbro brothers.

Q:  Will you take PayPal?

A: No.   We got our merchant account before PayPal started. We don't want to keep track of two merchant accounts. Plus, it seems that PayPal's rates are higher, and they changes their policies quite often. We just can't keep up with that.

Q:  Can you send COD?

A: No.  It's just a big hassle and a lot of extra paper work.

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© copyright 1999-2017 Auto Performance Engineering