walbro on an N/A?

evolutionmovement · Post by **evolutionmovement** » Fri May 21, 2004 6:27 am

I've had a couple times of hard starting now where it feels like when the fuel system has been relieved and then you go to restart the car after and it takes a few seconds before a sputtering start. I suspect the original fuel pump is getting weak. Since I'll need a Walbro for my turbo conversion, would there be an issue with getting one and running it in my N/A until whever the hell I get a job that pays money again? or would this cause issues with the injectors?

Steve

vrg3 · Post by **vrg3** » Fri May 21, 2004 8:02 am

A Walbro pump ought to be fine. It wouldn't cause trouble with the injectors.

The only potential problem would be if the fuel pressure regulator was unable to flow enough fuel back to the return line; it would keep fuel pressures from reaching the lowest they should be under conditions like idle. Current generation Impreza 2.5RSes have this problem, for example. I don't think it's a problem with BC/BFs, though, because I've seen both the turbo and non-turbo FPRs up close and they look pretty much identical, and we know Legacy Turbos can maintain good idles with Walbro pumps.

greg donovan · Post by **greg donovan** » Fri May 21, 2004 4:35 pm

is there anything to gain by using this pump? i would assume it wouldnt hurt on my frankensubie motor project would it?

vrg3 · Post by **vrg3** » Fri May 21, 2004 4:37 pm

Only if you think you'll exceed the stock pump's capabilities. What's the rest of your frankensubie motor's fuel/fuel injection system gonna be?

greg donovan · Post by **greg donovan** » Fri May 21, 2004 7:24 pm

as of now stock. i think that this is now a good place to move the topic to here as i have figured out the physical part of the engine. the guy i have bees talking to on rs2.5 club put a motor like this into a gc OBS and he used 2.5 injectors w/his stock delivery system. he thought the spray of the 2.5 injectors was better.

vrg3 · Post by **vrg3** » Fri May 21, 2004 7:46 pm

Hmm, I suppose even stock you could risk hitting the fuel pump's limits.

The stock injectors are 280 cc/min at ~43 psi, right? So that means 1120 cc/min total flowing through four injectors, or 67.2 liters per hour. The stock non-turbo pump is rated at 80 lph at 36.3 psi. Given that injector flow will be higher and pump flow will be lower at WOT, and that your pump is probably old and tired, it probably makes sense to get a Walbro or something similar.

Aren't the EJ25 injectors bigger than EJ22 injectors?

greg donovan · Post by **greg donovan** » Sat May 22, 2004 5:18 am

do you mean physical size or flow rate bigger, wrt 2.5 injectors?

isnt the walbro pump cheaper than the oem pump. which one would i need?

vrg3 · Post by **vrg3** » Sat May 22, 2004 5:41 am

I meant flow rate, not physical size... sorry about not being clear.

Yeah, the Walbro pumps are about the same price as any other pumps you might buy. I think Walbros come in 190lph versions and 255lph high-pressure and low-pressure versions. Any of them ought to outperform the rest of the stock fuel system, I think.

You can get lightly used Walbro pumps very cheaply on NASIOC.

greg donovan · Post by **greg donovan** » Sat May 22, 2004 6:06 am

cool i'll keep looking on nasioc. im sure my pump has seen better days its at least 14 years old w/130k on it assuming it has never been replaced.

evolutionmovement · Post by **evolutionmovement** » Sat May 22, 2004 6:26 am

Mine's original, too.

Steve

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walbro on an N/A?

walbro on an N/A?