This may not be the place for this… so maybe a mod should move it, but what are your reasons for going D-jetro. From what I can tell unless your goals are over 500hp its really not worth it. Not so much cost but just the fact that everytime you change something you need to retune again.
Great question Dustin,
That’s exactly why I chose to stay with a MAF based system. My z32 will never be a limiting factor in my build so why chage it.
Also, MAF based systems are considered, by many tuners, easier to tune.
Yeah, I’m gonna split this into a seperate thread in Car Chat.
I’m gonna be switching to MAP this spring as well, not with the Power FC though, but MAP is a more accurate system.
Not that I’m doubting the statement, but how is MAP more accurate then MAFS? Correct me if I’m wrong but, MAFS is a direct measure of air into the intake track. Where as MAP determines the air based on Manifold Presure and Intake Air Temp.
if you need to go above 500 whp then wire in dual z32 maf’s
MAP is harder to tune,
more of a pain in the ass to deal with
but it looks sick sicne you can run open turbo and have no maf, less wiring.
MAP is essentially used by all GOOD tuners (i can count them on my fingers) — for a reason.
MAP measures pressure like you guys said. when you tune a turbo car, you want to decreasing timing as boost increases. you want to add more fuel as pressure increase. these figures become relative. for example, at 1 bar of boost at 5000 rpm, you use x fuel. at 2 bar of boost at 5000 rpm you will use ~2x fuel. for ignition, you’ll note about ~0.5-1.5* timing drop per 1psi of boost depending on a lot of factors (such as the compression ratio of the motor, fuel used, etc.) do you have to retune a lot? no. if you setup your tune right from the beggining, ie use ambient air temp fuel maps, air temp ignition maps, etc etc, you car will be fine. if you change the intake, exhuast, etc, these wil effect the fuel maps minor.
here’s a fuel sample maps off my 3g eclipse (aem sorry!).
(using boost trim for fuel map if anyone is wonering why the main fuel pump isn’t increasing the load direction)
yep
thats called boost comp
its sick.
basically you do a pass with the wastegate fully open (0psi) tune it for whatever AFR you want, usually 14.5 or 14.7:1
then its basically just simple math to get perfect AFRs for eveyr other rpm and load point
say you want 11.8:1 at 1bar. Well 0psi = 1bar absolute so it is really 2bar absolute. Twice the pressure = twice the air. So to keep the AFR at 14.7 you would just double the fuel. Then multiply that figure by 14.7/11.8 to get your fuel to 11.8:1
so easy.
MAF is good too though because if you know exactly what amount of airflow corresponds to a certain voltage you can tune your fuel map just as easilly. You know x air is coming in so you put in y fuel. Same thing.