Apexi Pen Turbo timer - A/F tune?

[Hawker180]

Hey just trying to get the Air/fuel ratio close on my car so i can drive it to the tuner (4 hours drive )

I understand the Apexi turbo timers is just an estimate but is there a way to get it close enough so i can drive my car to get it tuned, trailering it is out of the option too!

How do you set up the O2 voltage my car at idle reads 1020v (on the power FC) theres no 1020v setting on the APexi TT!!!!!

Can anyone help me out???

Thanks

Luke

[paulr33]

the 02 reads between 0.00mv and 0.10mv or 1.00mv. I think you are referring the airflow meter value? AF in the sensor display is airflow meter and it will be around 1.00volts at idle (its max value is 5.00volts). The pen timer needs to have its wire tapped into the cars ecu loom (02 wire which is oxygen sensor not airflow meter). once that is doen you can with handbrake pulled up move to a/f o/2 on the timer press right and then it will show theoritical value then press left, move up to a/f, press right and it will show a/f and then flash to oxygen sensor value and then back again. once its working when you move the timer to display a/f instead of it showing --- and light changing from green/red constantly it will show like 18.5 or higher at idle and "green" for lean and then when you drive it should hover around 13.0 ish and god mixed between orange and red for rich. if you still have --- no matter what make sure when you move the timer to display oxygen (the 2nd item of the four) it has a value and the value is changing all the time, thats the oxygen sensor value. if its 0 or --- then its not wired in correctly or the 02 sensor is dead. they die after about 50,000 k ish

[midnight]

exhaust temp gauge might be a better way to do a rough tune

[usuckpoo]

yes the af on the turbo timer is nowhere near an estimate...let alone accurate

[Hawker180]

I understand its unaccurate, but i thought i could at least get it close! That doesnt help me out though!!!

Anyone got any ideas on how to get a close read out??? as 4 hours is along way to drive when the cars either rich or lean! i dont wanna damage it on the way there!

[bmxwrx]

stock computer?

[Hawker180]

Nope its a Power FC

[RB30-POWER]

PowerFC has a basemap already did i miss something?

[bmxwrx]

I meant, why can;t you use the stock computer to get it there?

And yeah i thought the power FC came with a base map too.

[RB30-POWER]

Ok i understand now.

You have upgraded the injectors.

Therfore the standard ecu won't run it (it will overfuel by a mile)

However, in the powerFC, there is an option which will trim the entire base map to suit larger injectors, without changing every parameter. (Have to do a search, im not familiar with the powerfc, to find what setting you have to change)

If you don't change this, it will overfuel with the bigger injectors, the same as what will happen with the stock ecu.

Do you have the Turbo Timer wired up to the O2 sensor at all?

If it is wired up it will give the feedback from the standard "Narrow Band" O2 sensor.

However i wouldn't use this sensor to tune, its highly innacurate at anything but stoich ratio's.

[Hawker180]

Yep the stock computer runs very rich, very very rich as the injectors are upgraded!

yeah i have changed the whole map in the Power FC so that it is close, but all i did was change the injector flow down untill it stoped belching black smoke out the exhaust!

On the power FC i had to bump the injector flow down to 44% (base map is 100%) as it was overfueling!

The timer is wired up to the 02 sensor (exhaust sensor) im getting a readout but it says like 12.8 and then i read that you can alter the setting of the O2 read out, something-arother about depending on the voltage of the o2 senser!

If i have the car running rich (like as close as i can tell, by bumping the whole flow up and down) would it be fine to drive???? can any harm happen from running the car rich?

My cars been out of action for 5 months now, so as you can imagine im itching to get it tuned and back on the road...My R31 just doesnt cut it

[midnight]

correct me if im wrong, but shouldnt you be able to calculate how much to cut the injectors down based on the injector sizes... rather than hit and miss

[RB30-POWER]

If you have the maps trimmed down so they are close, what you will find is under light load driving (i.e off boost) it will be running in closed loop operation and maintaining a stoich ratio of 14.7:1 and your plugs won't foul.

(Closed loop is where the ecu uses the feedback from the 02 sensor to trim the injector pulse to keep a stoich ratio, minimising emissions and maximising economy)

So if you drive under that condition, it should be fine.

If it were a brand new motor just rebuilt, i would advise against running it rich as the rings won't bed properly and this needs to happen in the first few hundred km's of driving.

If the motor has just had bolt ons applied, i wouldn't worry to much.

Just drive it offboost so it can run in closed loop and your plugs wont foul.

If you boost it and the plugs foul, you may not get the car there without removing and cleaning them.

Not a job you really want to do on the side of the road.

[Elithrar]

Running it a little rich is safer than having it lean out; I suppose, at the worst, you'll just foul your 'plugs up a bit and lose a bit of power on the run there. The former is easily fixed, and the latter is basically redundant as you're getting it tuned anyway.

[Hawker180]

Ok cool as, Thanks heaps guys!!! should i take a new set of plugs in case? the ones in it are only just brand new...i guess they should be fine as long as its off boost!

Thanks again!

[RB30-POWER]

Take a new set of plugs for when it gets tuned.

You don't want to try and tune it if the plugs do happen to be dirty.