Prob b/c the Walbro is not as high a quality as the stock stuff and also b/c its putting out a lot more flow so its doing more

I am really hoping that PE or some other JDM manufacturer will step up with a snap in stock fitament 255 lph or higher replacement pump

On my car - I have had no issues with the walbro - however - the quality is questionable

Frankly - the stock ones are so inconsistant in out put that you have no real choice but to upgrade if you want to be safe

 

Everything this gentleman has said is 100% correct

I prefer to post specific data at this point as there has been so much negative attacks and comments on this subject recently

For point of reference - when I installed cams on my Evo - over a year ago - the fuel pressure was falling down after 6,000 rpms with the stock pump so thats why I sought out an upgrade

As far as I know - I was the first to try the walbro 255 lph pump from the WRX in an Evo and report the results here

Comming from a WRX - you learn that fueling is the key to making big whp

Now - I have reached the limits of the Walbro 255 pump and I need something bigger in my car if I want to go into the high 500 whp range

BTW - IF you know the VE of your engine - you can calculate down to the last drop how much fuel is required to achive a certain power level - its a matter of pure physics and mathematics

 

So is running stock pump with these mild mods(3"TB, 3" HF Cat, K&N Drop in Filter, MBC, DynoFlash and Denso IW24) unsafe? Do I have a ticking time bomb?

 

You know - the funny thing is that NONE of my customers - or very FEW have the essential gauges - especially FUEL PRESSURE, EGT and a knock link

WHEN you have a fuel pressure regulator you can stick with the stock pump and just peridocally watch it on full boost in 3rd or 4th gear to verify its putting out enough fuel to maintain fuel pressure on boost

As stated many times - I have seen several evos with failing stok pumps

Furthermore - we gerally see smoother power bands with lower injector duty cycles - which may not apply in your case but does occur in the cars with cams

 

So how much would it cost me for another reflash? Am I still paying $199.99 for it??? I already had it dynoflashed before. I just need it reflashed again just for the walbro fuel pump.

 

Ahh crap! So how would I know that my pump is failing? Is there symptoms I should look for? I don't really want to get the Walbro now since I have read many complaints about it from this site. I wonder if another company makes a better quality one.

 

I'm sure PE does make a 255 lph fuel pump for Evo.... I know some tuner in Japan and HK is using it. Too bad they are not for sell here in the State.

so do we have any other choice beside Walbro 255 ???

 

Aeromotive technology sells a fuel pressure regulator for $144. You can buy it here:
http://www.lancershop.com/turbo_fuel_evo_8.htm

 

You could also get a Holley ... but, I'd take the Walbro complaints with a grain of salt. There are a LOT of satisfied Walbro customers out there (and not just Evo owners). However, it is noisier than the stock pump, part of which, as I understand it, is because it is metal, not plastic like the stocker...

l8r)

 

www.pruvenperformance.com - my dyno location produces a amazingly nice billet adapter piece which allows you to attach the aeromotive regulator - the small street rod one - right on the end of your fuel rail

The good thing about this set up is there is no modifications required - its a straight bolt on

and the aeromotive is a first rate regulator

I use it on my car

When i first installed the Magnus intake manifold - it conflicted with this set up and I had to go back to the stock regulator for about a week while I converted my set up

ALL I can tell you is I would not run the stock regulator on any evo - its a total peice of junk and not well suited to high boost applications at all

My suggestions are - by pass the solinoid on the end of the intake manifold and hook up the areomotive regulator

The bad news is that we HAVE NO THROUGH THE MAIL reflashes for anyone who wants to do this modification - you would have to get the full custom tune

The good news is that you get an even smoother power band and much better control over the fueling under raising and lowering boost

 

READ above - fuel pressure gauge

www.pruvenperfromance.com also makes a billet fuel pressure gauge sender adapater which bolts to the input side of the rail inbetween the rail and the fuel line which requires no cutting of lines - total bolt in - this unit allows you to easily add the sendor for any common fuel pressure gauge

My recomendation - which prob no one will follow - buy a fuel pressure gauge and use it !

 

Yep, fuel pressure gauge is already on my shopping list.

 

I'm no expert, but I'm pretty sure that all things being the same adding a new fuel pump will NOT make you run rich. The amount of fuel that enters your engine is determined by your injector size, pulse width, and fuel pressure in the rail. All a new pump will do is insure that you fuel system can flow enough VOLUME to keep a constant pressure rate in the rail. The fuel pressure regulator is responsible for making sure there is consistent pressure in the rail. If your pump creates excess volume, then the regulator relieves some of it back into the gas tank. Either way it is a good idea to get a new pump for safety. And I’ve never heard good or bad stories about the stock regulator, although it seems to be good up to about 350WHP since there are quite a few people close to that with the stock regulator.

But, hey I could be wrong. I have been in the past.

These guys seem to be one of the leading industry authorities on fuel injection from all that I’ve read. They would probably be a good resource for questions on the matter.

http://www.rceng.com

 

You seem fairly stuck on your ideas concerning fuel pressure and a/f on the stock pump and the bigger capacity walbro pump

Please remember that the fuel pressure in the rail will increase when you install the walbro pump after the ecu kicks into high pump speed mode - - this will result in more fuel being squirted per injector opening

 

Isn't the pressure regulator going to sustain a linear pressure in the rail by diverting some of the flow back to the tank when there is too much? That is what the regulator is for, right?