Question about FMUs
 

Hey guys i am going to be starting to gather parts for a custom turbo kit using a small DSM t25 , at the stock wastegated 8psi. I have a DOHC ZC motor and i was wondering if i could use a vortech FMU 10:1 or 8:1 for management and be safe? I do NOT plan to go past the 8psi until i have my block work done (i am going to buy another block and do the work, then switch that in later).

Please let me know, i am trying to keep this as cheap as possible so i can get it done this summer.

Bottom line: will a vortech FMU 10:1 or 8:1 be safe enough for daily driving t25 dsm turbo at 8psi (will be intercooled).

Re:Question about FMUs
 

well lets think about it like this. Are you gunna use that FMU when you put the built block in and turn the psi up? Of course not! What were you planning on running with the built block?

Hack?
stand alone?

Re:Question about FMUs
 

I dont know how to do my own chips but i wanted to use turboedit. if i proved too stupid to figure it out was going to get a zdyne silver secu.

Re:Question about FMUs
 

first of all, 8 psi with an fmu is not such a good idea. second of all, if you did use the fmu i would think you would have to definatly get the 12:1 to make sure you dont run lean!

Re:Question about FMUs
 

Haven't many people here complained about being pig reach with 12:1?

Re:Question about FMUs
 

yeah but for 8 psi? i think you need all the fuel possible to not run lean with that shitty fmu :-X

Re:Question about FMUs
 

If at all possible, a safe baseline tune in TurboEDIT would be your best bet.

Post TurboEDIT related questions, people will help you.

Re:Question about FMUs
 

*exactly*.. since at that pressure, FMU might want to increase way too much fuel pressure, and pump might start to fail... thus not giving enuff fuel.
And for those that had goo dpump were running way rich.
Dunno... all I can say - works for me with 10:1... and by that shitty A/F meter, seems to be way rich. Still waiting for dyno to see there real A/F ratio...

Re:Question about FMUs
 

yeah i get ya, i just usually see everyone using the 12:1. plus my friend had a 12:1 fmu on his greddy kit and at 7psi steady, it was like 2-3bars rich, which is decent to not be tuned yet.

Re:Question about FMUs
 

Voltage for a single wire O2 sensor is not linear. You can't say, "Two or 2 bars rich". If you tune from that, you're going to be screwing yourself, as it only measures stoichometric, which is 14.7:1 and would be lean for a boosted application. Don't tune from your stock O2.