Walbro Fuel Pump Questions

[mnetwork]

I am looking into buying a 255 pump and an AFPR soon and I had two questions...

One, what is the difference betwen a 255 and a high pressure 255?

Two, the owner of a local import shop tried telling me that they don't usually have problems with 255's overrunning the stock regulator, but they do with the supra pumps or something. Anyone ever heard of someone actually running fine with a 255 and no AFPR?

 

[Stone'S GSX96]

I ran a w225 with a stock FPR for a little bit. Didn't have any problems!

 

[pj91gsx]

dont cheap it out, its not worth it ruining your motor.

 

[1992awdlaser]

Pretty sure The 255 flows more than a supra pump. That guy doesn't know what he is talking about. the 255hp can provide more pressure. Once the regular 255 reaches a certain pressure a valve in it releases some of the pressure. The 255hp does this same thing just at a higher pressure. A regular 255 can be "converted" into a 255 hp easily though.

To convert the regular 255 you have to find the steel cap with a spring under it next to the pump outlet nipple. Tap it down with a nail until it bottoms out the spring. That is it you just removed the crack pressure.

If you are awd you will want to drill out your siphon too. If you don't you could get higher fuel pressure even with an adjustable fpr.

Here are some pics so you know what it is.

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Use an 1/8" drill bit. The 2g awd's have a saddle tank and the siphon is what helps gas get from one side to the other to keep it level in both sides. Don't drill it out any larger though or you will lose the proper ratio of fuel coming in to create a good enough vacuum to suck any fuel out of the driver side saddle.


Edit: Oh yeah, you need an adjustable fuel pressure regulator.

 

[pj91gsx]

People will say that they have no problems with a stronger fuel pump. The fuel pump overpowers the regulator, whether or not they notice it or not. The way to tell would be a wideband o2. Just get a fpr with a stronger fuel pump. I had a motor ruin after installing a 255 hp.

 

[No_Skillz]

The 255 flows more than a supra pump.

I thought a Supra pump was a 300lph Bosch unit? Can anyone verify?

And I second, use an AFPR. If you want to know why, do a search. Keep in mind that "no symptoms" is far from "no problems."

 

[mnetwork]

I already plan on getting an AFPR... I was just curious if some people didn't have issues with it... Does anyone know how much pressure a 255 can build max and how much a 255 hp can build max?

 

[DGajre777]

I already plan on getting an AFPR... I was just curious if some people didn't have issues with it... Does anyone know how much pressure a 255 can build max and how much a 255 hp can build max?

Notice how flow just drops after 90 psi of pressure on the regular 255.

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I thought a Supra pump was a 300lph Bosch unit? Can anyone verify?

260, not 300.

RRE Instructions

 

[mnetwork]

Hmm, so it does flow more than a 255...

 

[daren_p]

This one really should have been searched abit, there are a tonn of posts already on all these questions. 255HP flows slightly more then the reg. 255 most of the pressure range & once you get to the higher pressures, you can see how the reg 255 then drops off alot. The supra pump also flows more then the 255HP. Yes you do need a FPR to run a 255 pump, some say I run one without a FPR & its fine. Anyone that did & then tested with an actual gauge usually finds out there are seeing an overrun condition. Get an FPR with any of these pumps. The 255 & 255HP are suually the same price, go for the HP. The Supra pump costs more but it is OEM quiet.

 

[DGajre777]

Hmm, so it does flow more than a 255...

According to RRE...