AF Under boost?

[hgallegos915]

WOW am I the only one who posts alot here? LOL


anywho... I think my "new" fmu took a dump..


Its been a few months, i have been running under 10 afs under boost...

yes 10 afs.... I dont know why.. I know thats way to rich right? and at idle i will sometimes go to 12.. yes idle


so i think my fmu is taking a dump

I will replace it.. but

What is the target af unnder boost? I sometimes hear 12 is just about right, sometimes that 12 is to lean and should go for 11.5? Im at 5 psi..

any tips?

[WhiteFinish]

Wikipedia often helps a lot

Normal no forced induction is 12.8 @ WOT

I would aim for 11 isch 11.5 but certainly no 10 You'd be missing a lot of power

[nos92mx3]

rich best toruqe 11.8
lean best 12.3
aim for inbetween
whats your base fuel pressure at hec?

[hgallegos915]

rich best toruqe 11.8
lean best 12.3
aim for inbetween
whats your base fuel pressure at hec?

well theres something wrong with my fmu or my fuel pressure regulator, the gauge reads like 10 at idle but yet the car is runnign rich, around 12 afs when cold, when warm its at 13. as I rev the car the pressure goes up to around 30ish and maybe when the fmu turns on it goes up higher. Under boost im at 10 afs but I feel that Im missing ALOT of power compared to when I used to run 11 afs under boost or 12.

Ill be going megasquirt over the winter and just wanted to do some research, and maybe temporarily fix my current situation.

15 mpg can be fun but i rather the car running right.

[nos92mx3]

10-1 is very rich and you are missing some power.
I would be careful ideling a motor at a 10-1 AFR , not only will you foul plugs quicker than s---. You can wash cylinder rings.
Basically the extra amount of gas will remove the oil from the cylinder walls.
No good.

[hgallegos915]

my friend ivan fixed my fmu. He opened it up, replaced the aluminium disk, the thin one.. used an ALUMINIUM CAN to make another disk... and it worked... at idle im at 15 afs, 16. under boost tho im still at 10(its the spring thats bad possibly)

but wow... my gas mileage is up the roof now..

[nos92mx3]

well there are different ratio's for a fmu.
12-1, 10-1, 8-1 etc etc.
What are you running right now? 12-1? Find a 10-1 disc that should help with the overly rich under boost.

[hgallegos915]

well there are different ratio's for a fmu.
12-1, 10-1, 8-1 etc etc.
What are you running right now? 12-1? Find a 10-1 disc that should help with the overly rich under boost.

12:1

yeah so now understand 12:1 is to rich , my friend got a 10:1 and his runs perfect 12 under boost.