What is the safest lean condition to run?

[chriso]

I just installed my new handy dandy AEM wideband and was wondering what the leanest condition that is safe to run????

At idle it hovers between 14.7-14.8 and while boosting it dropped down to about 11.8 (I think) and under some circumstances will jump up to around the 15 range. Just wondering since I will probably be strapping the car down tomorrow and didn't want any problems. I don't have a AF controller installed yet if that makes any difference.

 

[cjsupra90]

it depends on what the condition is at the time i.e. crusing, WOT, ect......

 

[GotTurbos?]

idle = 14.5-15

cruising = 13-15, not too important

wot = 11-12, that is a "safe" tune... you never want to see anything in the 13's under WOT

Jon

 

[chriso]

idle = 14.5-15

cruising = 13-15, not too important

wot = 11-12, that is a "safe" tune... you never want to see anything in the 13's under WOT

Jon

Quick clarification: Under boosting conditions I am in the high 11 range. During deceleration and under normal stop/go traffic conditions it can go into the 15 range which I am not too worried about at this time. It's the lean condition I am concerned about since I am planning on dynoing tomorrow.

 

[GotTurbos?]

deceleration you dont have much to worry about, im assuming you have the aem uego wideband, which is the same as me, under deceleration, I will be off the charts lean. same at idle at times. High 11's are very good.

 

[lagged]

when under decelleration the fuel injectors cut off, no combustion is taking place. so no worries there.

 

[chriso]

Yup, AEM UEGO Wideband. Like I said it's no worry on the rich condition under decel. It's the WOT where I have concerns. I haven't seen under 11.8 under boosting and WOT so I guess I should be alright for the time being. Thanks guys.

 

[dbsupra90]

running 110 octane my car kept making power up to 12.2:1 after that it started to fall off. i just wanted to see what it was happy with and then put it back a little richer.
i always tune for 11.5-11.8:1 my opinion is that is the best a/f for safety vs power. there is a huge difference in power from 10.5 to 11.5, but not as much going from 11.5 to 12.5. id rather sacrifice 15-20rw for the extra safety margin and many years of a happy motor.
also to note, be advised a/f on the dyno will be a little richer than a/f on the street. not a huge difference, usually .2 or so. yet another reason i tune to the rich side.
good luck on the dyno!

 

[pimptrizkit]

if going from 10.5 to 11.5 makes a god difference, then what would going from 8.8-9.2 wot, 4.5-5k+ be like when leaning her out to 11.5?

 

[dbsupra90]

if going from 10.5 to 11.5 makes a god difference, then what would going from 8.8-9.2 wot, 4.5-5k+ be like when leaning her out to 11.5?

huge difference in power going from off the chart rich to 11.5.
why are you running that rich? you have 2000cc injectors? :icon_razz

 

[pimptrizkit]

no, i cant grasp the concept of tuning very well.. ive adjusted stuff, and forgotten..

 

[tookwik4u89]

if going from 10.5 to 11.5 makes a god difference, then what would going from 8.8-9.2 wot, 4.5-5k+ be like when leaning her out to 11.5?

Like a whole different car I imagine, thats pig rich blowing black smoke!

 

[tookwik4u89]

What electronics/ inj/ fuel pressures are you running?

 

[pimptrizkit]

well thats a bit werirfd, im running with no cat, well gutted, and i have never seen black smoke or have had any one say any thing, nore do i hear back fires.

i do have sute, that will dirty up my back bumper every few weeks, when driving every day,

i have satock injectors, a walbro, maft pro, lc-1, mbc(but not turned up, and the lowest boost i run is 10 pounds, i cant turn it down any further.. i run 92/93 pump, stock fuel pressure as far as i know, i haven't done the 12v mod or clipped any wires..

and due to a coolent issue i have gaven up on tunning because i run the car so hard while tunning, just not worth it to watch her get hot..


/sorry for highjacking thread.

 

[dbsupra90]

yeah def get the coolant issue sorted first.

did you remove/drill out the J-tube on the fuel return? running the walbro pump and having the restriction it may cause exessive fuel pressure which would cause the super rich condition.

 

[pimptrizkit]

no i haven't done thsat yet. looks like i missed that minor mod, there is only the one end capped with a pin hole right?

 

[shaeff]

^yes. you could drill it out or just bypass it altogether.

-shaeff

 

[born2drv]

would it be bad to run AFRs in the 16-17 range for idle and highway cruising?

 

[figgie]

would it be bad to run AFRs in the 16-17 range for idle and highway cruising?

nope as long as the car is not missfiring you will get better MPG if it is TUNED right (ie correct timing and proper octane).

 

[chriso]

Oooops, brain cramp. I was actually running extremely rich <10. (I thought that meant I was running too lean). What is a good range to run from lean side to rich side, or is it best to run fairly constant throughout the range.