Interesting thing about stock inj and turbo

[hgallegos915]

Ok I know this goes againswhat ANYONE says at probetalk or even here...



I decided to try stock injectors... so of coure with no fmu.. it leans out.



Now.. stock injectors with fmu 12:1.


It runs 10 afs under boost.. WTF???



with millenias and no fmu it also runs 10 afs under boost.


Also I lot 1 psi of boost.. boost leak maybe? Im sure fuel has nothing to do with boost psi right?

[mx3boyze]

Fuel shouldnt have anything to do with how much boost. Any exhaust leaks? Check all of your piping and retighten/move some clamps if neccesary.

[hgallegos915]

No leaks... but I hjad to ue a boost controller to raise it to 5psi.



I tripped checked, intercooler, pipping, exhaust.. nada... strange eh? :/



oh well..


Now im running rich with STOCK injectors and fuel pressure at like 10 psi.. walbro 255 pump and cortec fmu.


Cruise I get some nice afs and under w0t.

I think its something else, maybe stock o2 sensors.

[kenken]

wow..how can this happen?

[hgallegos915]

I thought that maybe my wideband sensor was bad.. so I bought a new one. Connectd it and the same..


At idle it will be around hmm 13 afs to 12. at cruise its perfect.. behave like its normal n.a self. When I gun it the AFS go to 10...


and I know theres tons of pressure since the HOSE in the fuel pump.. popped like a balloon..


so there ya go.. stock injectors is enough for 5 psi.


I actually lowered my psi nto 3 since my "new" clutch is slipping at 5 psi.

[kenken]

does this mean that k8 can be boosted with a simple piggyback(something like Apex'i SAFC), high flow fuel pumps and STOCK injectors?
wow...thats very very interesting...
what's the highest boost you've tried?

[Ryan]

My first reaction:

If you're fuel pump runs at say, 12 psi, and you're boosting 20 psi, you'll actually get air backed up into your fuel. Its a hydro/pneumatic system. I would also think if you're boosting anything, really, it will counter the fuel flow. I think thats why Mazdas DISI motors run fuel at 200 psi....

[nos92mx3]

Ryan, he is using a 12-1 FMU
Basically for every pound of boost it raises fuel pressure 12 psi.
so say at the 5 psi hes running its bumping fuel pressure up 60 psi.
So no worries on the reversion of air into the injector.

[Ryan]

Oh, thanks
I just became one tiny fraction less turbotarded.

[hgallegos915]

I actually lowered it to 3 psi

the so called act extreme clutch only lasted about 2 to 3 weeks boosted.



stage 3 clutchmasters here I come.

[nos92mx3]

hey hec,
have you ever thought of getting a different disc for your FMU?
Like a 10-1 or and 8-1 to see if that helps with your wicked rich issues?

[hgallegos915]

will the 10-1 make it richer or leaner?

[nos92mx3]

leaner

[Shades]

10 A/F is really rich on WOT... what does your wideband range from for A/F's? Mine does 10 to 20 A/F... if it goes under 10 it still reads 10... so you may be running really rich and don't even know it.

Mazda's DISI motors need to run at 200psi cause it's directly injected into the cylinder, instead of the port, and has to overcome the pressure in the cylinder.

[Flinch]

hey i found this out kinda the hard way im using the stock fuel pump and injectors and no fuel management and have been driving around for monthes. I eaven raced my budds MX-3 with like 280whp and beat him on stock crap i put in an air to fuel ratio reader and took her for a spin and it said i was hitting 9 AF so tell me thats not wierd. this is a KLZE turbo at 7psi, i reacently did a comression test and its reading a85 across the bord plus or minus 1 so she is still running strong.