Does anyone have a walbro255 they have used without a after market pressure regator and can tell me what the car acted like without the pressure regulator. thanks guys i have a 88 t2

 

When I got my first rx7 it had a walbro with the stock fpr. No issues that I remember.

 

^I've read it will overwhelm the stocker. Ultimately, the point at which you upgrade the fuel pump is the point at which you are upgrading the FPR because of the mods...

 

hell its prolly easier to just swap it anyways. the stock one is pushin 20-25 years old man. time to retire it. and come one its only like another 20-40 bucks for a new one. thts not too bad

 

Tons of people have used them. You can search through the section to read all about it.

Yes, it will drive fuel pressure up. In the brief time I tried one, I measured 46 psi at idle (stock is ~30 psi) and 48 psi with simulated atmospheric pressure (stock is ~40 psi). Under boost it was closer to normal at ~4 psi over stock specs. Idle will never be quite as smooth as with a OEM-style pump; even when you compensate with the variable resistor. My engine idled a full AFR point richer until I adjusted the resistor. In other words, it works, but it has side effects.

 

Cause that is the only other thing i can think of it being cause the injectors have been rebuilt and it bucks real hard at about the time the secondaries open up but its weird some times it will be like that there and then it will do it at other rpms

 

Search 3800 RPM hesitation.

 

I have and how do you test the voltage to the injectors to make sure they are getting the correct voltage

 

You can use a multimeter, but when they key is 'ON' you'll just see 12+ vdc on every injector. It won't tell you if they're pulsing correctly.

 

Couldn't you test the PWM with a scope? Its been a while but I seem to remember doing that before...

 

I have heard that using a fuel pump out of a cosmo better than the 255 walbro?

Any body done this and does it actually flow better / more fuel?

 

It depends on your power goals. FD and 13B Cosmo fuel pumps flow enough for somewhere around 300 whp, but also won't overrun the stock FPR. Other Denso pumps like what are found in the 20B Cosmo or Supra will flow even more, but still play nice (ish) with the FPR.

 

Is the FPR a problem on s5's for only 300hp? Because it's all one unit so I'd have to get aftermarket rails for my setup and I'm really not trying to do that

 

Been running a whinebro 255 on my S5 turbo for 3 years now. Never checked my fuel pressure but my car idles smooth at 700 rpm, I get 23mpg on the hwy, and didn't get any detonation when my car boost creeped up to 15psi.

 

Other than an ebay special where do you find an FPR for 20 to 40 bucks. Any decent brand I found is easily over $100. But if you know of one please share.

 

ya i dont have any issues with this done this in both my t2's and it never changed a thing, needed to adjust the R/L resistor at idle but thats simple crap.

 

Ok so aparently it's less of a problem on s5. What about if u were pushing 300 to the wheels would it become problematic then

 

if you have that much power you NEED a FPR

http://www.racingbeat.com/FRmazda2.htm

not a cheap ebay special for 40$ but i prefer name brand on my baby.

 

i have a 91 n/a and i just purchased the walbro 255 fuel pump because mine went out. will i have any issue with this and a stock motor? anything i can do to help it?

 

Re-read the thread.

With an aftermarket FPR, you'll run richer throughout the RPM range. This is pointless on an NA, and will only serve to make the car slower. Get a replacement NA fuel pump.

 

Well I have never heard of someone upgrading the fpr on their s5 for only 300 hp. I have heard a million times that one of the first steps to creating power is the fuel pump and the injectors because the OEM pump and injectors are esentially maxed out. Now people would probably upgrade the FPR to get rid of the sideeffects but the s5 fuel rail is a sealed unit, u can't remove the FPR or the PD... So u would have to get custom rails.. If I'm wrong someone please inform me but from what I understand the stock FPR on a s5 would work fine for 300 horse power