OZ Duster

[OZ Duster]

Took the Duster in to get the Tune done and a couple of runs on the Dyno. First problem was the mystery rattle came back, After a bit of stuffing around we found that despite my best efforts of securing the flex plate to the torque convertor, the bolts were bottoming out in the blind holes resulting in the rattle at idle.

Once sorted and a few adjustments made three runs were made to set everything up. Then two power runs peaking at an earth shattering 167.5 Hp at 136 km/h in third. AFR dropped from 14.3 down to 13.2 at full throttle, little rich, but on the safe side. I suppose thats fine for a stockish 318 "Cruiser" for now....

Recomended to have the dissy graphed and sort out the blown exhaust gaskets, a few more things for the to-do list

[GregWeld]

Who told you that 13:2 A/F @WOT is "rich"?? Most times I see 12:8 or 12:5's at WOT...

Not arguing -- just wondering...

[OZ Duster]

Originally Posted by GregWeld

Who told you that 13:2 A/F @WOT is "rich"?? Most times I see 12:8 or 12:5's at WOT...

Not arguing -- just wondering...

From what I understood the stoichiometric air/fuel mixture is approximately 14.7. Any mixture less than 14.7 to 1 is considered to be a rich mixture. I told him given the relatively stock nature of the engine some efficiency would be good all things considered.

Would a figure of 12.8 see an increase in Hp or would it just use more fuel?

I am assuming that the 14.7 is the peak efficiency figure for petrol and lowering the ratio provides a safer level of tune rather than leaning out the mix and increasing heat. Still new to this technical side of things myself so any input is appreciated.

[GregWeld]

Air fuel ratio is a relative game.... idle is one thing -- cruise part throttle low load is another - and Wide Open Throttle is another...

You're right 14.7:1 is perfect -- but maximum effort WOT requires mixtures around 12.8 or 12.5.... which is why I asked you - because you seemed to want to see 14.7 there and that would NOT be good.

Idle just needs to be what the motor wants -- which is what an idle adjustment screw is for -- you want this adjusted for "max" RPMs (without touching the throttle/idle adjustment) and vacuum. Some motors need a A/F ratio fatter to achieve that than others... so it just "is what it is".

Cruising - light throttle - light load - can even be leaner than 14.7 -- new fuel injected cars might even hit mid 15's. You can go to 14.7 and be "comfortable" with that.

WOT needs to be where the motor wants it (thus a dyno - to find what that is) but is typically mid to high 12's even in a modern EFI motor.

If the car runs well - doesn't buck - doesn't ping - idles fine -- then you're good to go.

TIMING will actually make a far larger difference in HP/TQ than a perfect fuel ratio.

[OZ Duster]

New Head unit and front speakers (were in my old car however never hooked up)

Old Speakers and the cheap and nasty wood mount


Kick Panels completed with new Kicker 6" with proper mounting blocks


Kick Panel installed


Pioneer Head Unit and iPhone



Sound is fantastic compared to the sony stuff. Can hook up the iPhone to the head unit. The temporary home is the Ashtray however, a centre console will go in when the bucket seats are purchased. Just have to wait for my bonus from work.