My 255 HP Walbro came in today and I installed it in my 2k2 Maxima because the stock fuel pump could not support the massive nitrous system I now have installed. The pump went into the cartridge but it did require a bit of tweaking. There are two plastic rings or standoffs on the top (feed) side of the pump that have to be cut off. All of the other stock parts need to be used which includes the bag filter and nipple fittings. Even the stock wire harness plugs right upto the thing which is great. Once you put the three main parts of the cartridge back together you will have to apply some extra force to squeeze the rubber bushing at the bottom. This is because the Walbro is still about 2mm (or more) longer than the stock pump on it's top platform. The overall distance from nipple to nipple is almost the same as stock.
Overall the pump went in fairly easy and does not make that much noise. It can be heard if the car is quiet at idle but other than that it's non existent (or at least my pump is).


Upon the first test I noticed that my fuel pressure drops a few psi at WOT and 6500 rpm which my stock pump did not seem to do. Perhaps the bearings in the pump need to break in a bit. But my first tests with a massive fuel shot on the kit were much better than before. But even this setup was dropping to about 40psi from the standard 52. There are a couple of explanations for this. One being that this Walbro isn't as good as it's advertised to be. The other explanation is that the size of the fuel line is the culprit. Because the regulator is in the fuel tank it could very well be running at or very near 52psi at the same time the system under the hood has dropped to 40. I have ways to find out which of these is the issue and I can resolve it if I choose to do so.
The saga continues.......

 

Please continue to keep donkey informed. He is too lazy to try anything for himself

 

Si.


Donkey was the first to hear about it.

 

mr matt
glad to head the pump is working fine and u went with the crazy one.
What was the model number you ordered?

I think its the in-tank regulator as you said limiting it to 52, by the time the engine and the solenoids are consuming the 52 psi comming in, the fuel pressure should drop, as you saw..
Dont want to be running lean now.

If you dont figure this out, you can always do what jim did. Have a seperate 1 gallon fuel system striclty for the nitrous at 113 octane
Jim as it behind his bumper...

 

I'm still suspicious about Jimes' setup, but since SR20DEN already has the aux pump, he could easily add a fuel cell like Jime.

I just don't think mixing two different octane fuels in the combustion chamber is effectively delaying the detonation, since you are still limited by the detonation point of the 91-93 pump gas portion of the uncombined mixture. I doubt they homogenously mix enough to result in an average octane ratio for the complete mixture. However, I'm still trying to find out more info on how that intermixing of the different octanes interacts.

Jimes' setup appears to be working, so I'm going to believe it's helping delay the detonation point some, however I wouldn't trust it as much as just running race gas in the main tank.

 

I mean, obviously the best thing would be to go for race fuel in the main tank and mix with the nitrous fuel cell.

What matt can also so, is do an alcohol conversion so the octane would be much higher and create a higher average mixture.

I dont know how mixture works either, Jim seems to be doing fine and he montitors his motor quite a bit. The wideband hes getting this week will tell us all how hes running.

Lower octane is my problem here. 91 is the highest and race fuel is 5 bucks a gallon...