MattB

is my walboro 225 lph fuel pump going to be able to pump enough fuel to 680cc injectors so that i can increase my boost to 10psi safely?

skir2222

umm yea! or go buy another one and run 2 inline pumps

MattB

yeah thats what i figured because i read its possible to boost to 10 stock but i wanted to make sure it would be safe if i did it with the new pump and injectors

BoostedRex

I spent a little over a year with the Walbro 255 and 680cc injectors boosting to 12-13psi with absolutely no problems. I was running an SAFC also though. Just my experience with it.

Zach

RETed

The Walbro 255lph is good to about 400hp or so.
If you're talking about just 680 secondaries, this is more than enough...


-Ted

MattB

i have a walbro 225...it came with the car when i bought it. im not looking to make a lot of power...300 at most because this is my daily driver.

CyborgRyu

iTrader: (8)

how much is stock good for?

dmuirhead

iTrader: (1)

On an '87 TII, with stock original engine, fuel pump, TMIC, and turbo, and the following added in 1992,when the 5 yr/50K extended warranty ended,

HKS fuel cut defencer
HKS PFC-FCON fuel controller
HKS boost controller
HKS boost gauge
HKS 2.5" catback exhaust
HKS air cleaner

I have been making 11 psi (according to the HKS gauge) for over 40,000 miles now. The only time I had a problem was when the tid and vacuum lines started cracking in 1999. Replaced the lines with silicone and bought a new stock tid, and the car remains strong at 87,000 miles. According to long-ago HKS literature, it should be making around 250 hp, and my seat-of-the-pants dyno indicates that is reasonable.

It was a daily driver until '98, but summers only (Minnesota) after '92. Street driven only, I don't race, occasional jaunts up to 120 mph out in the country, fairly frequent trips to near redline in 2nd and 3rd when traffic allows and the mood is in me.

Your mileage may vary, but it seems like the stock fuel pump is up to the job.

BoostedRex

That's cool to see that it has held up for you so well. But as cheap as you can pick up the Walbro and some 680cc secondaries, I would say that it's a must just for safety's sake.

Zach

RETed

Stock FC turbo fuel pump can maybe max out at around 250hp.
This is assuming max voltage around 13.0VDC.


-Ted

Latch

A lot of folks seem to prefer upgrading the fuel pump (I found the Walbro for cheap on rx7store.net) and making sure to rewire it because with a bunch of accessories running (lights, stereo, etc) the voltage to it can drop -- and with it, the fuel pressure.

Also you'll need an FCD to prevent fuel cut when your boost rises, and an aftermarket boost gauge since the FCD will make the stock one lie to you. Racing Beat will be glad to sell you an FCD for $100 or so, which is a pretty awful price considering how simple a device it is, but I haven't been able to track down another one. Apparently someone on this forum was making them for a while but I can't find much info.

Tournapart

iTrader: (4)

what would a stock TII put out at 10psi

SidewaysFC

mine won't put out at all ...what a prude

91mazdarx7

iam running 10psi on stock fuel pump and stock injectors with the mods listed in my sig i won't go above 10psi because the injectors will start to max out at around 12 on up i heard also the turbo isnt making any more hp up at 13-15psi just creating hot air i am getting injectors and fuel pump when i fet the money

RETed

That is correct.
Mazda designed it so both the (safe) fuel injector capacity and stock turbo fuel pump max out around the same time - about 250bhp (NOT at the rear wheels).
This is about 220 - 230hp at the wheels on a DynoJet.


-Ted