mapping idle

[damo_S13]

Any one know any links to were i can read about mapping/setting up the idle? or have any info you would like to share

got my s13 up and running im not using an sort of Idle Air Controller (IAC) its currently at 15-1600 rpm once warm. i would like to get it down to the 1-1200 range

thanks
damo

[cliffb75]

Any one know any links to were i can read about mapping/setting up the idle? or have any info you would like to share

got my s13 up and running im not using an sort of Idle Air Controller (IAC) its currently at 15-1600 rpm once warm. i would like to get it down to the 1-1200 range

thanks
damo

Have a look at what ignition advance you're running - I would try to be at about 10 BTDC. Play with the ignition timing map and see what response you get. If you get to 10BTDC and are still idling high you will need to reduce the air getting in - hopefully just by winding back the throttle stop until you get to the desired idle speed.

If you really can't get any less air in then you could retard the ignition even further, but by the time you get to -5, -10 it'll probably run rough and the exhaust will get pretty warm due to the late burn, so I wouldn't advise going later than TDC as a last resort.

[damo_S13]

ok thanks you for the info will have ago tomorrow

damo

[damo_S13]

well i have taken all the air out i can and the throtle is now shut. timing is now at 13 my afr is 14.5 and its idling at 1450 and when the rad fan comes on its down to 1300 so thats not to bad. Will have a play some more tomorrow and see if i can get it down a little more

damo 

[rob@vems.co.uk]

You were saying on MSN that theres a stutter between idle and 2300 as theres such a leap in advance.

It would be worth setting your RPM scale so that you have another row of cells in between idle and 2300

Its an idea to try and get the idle as low as it will go, then put a row 250 to 300rpm below idle speed and 250 to 300rpm above as this gives a smoother stable idle.  You'll find that you need to group the rows in smaller steps down at the lower RPM scale to get smoothness when the engines VE is quite low, once the engine becomes efficient you'll not need many cells to provide the control you need - VEMS has very high resolution interpolation (which is why we dont need huge tables)

Rob

[cliffb75]

well i have taken all the air out i can and the throtle is now shut.

damo 

How have you got your breather system connnected? If its standard then it will still be drawing make up air after the throttle, so you could try restricting this.

If you already have it breathing to atmosphere through a catch tank then thats obviously a no go.

Stupid question - but you have checked there are no air leaks haven't you? Simple bits like make sure there are no unused stubs that are not bloked, and that where you've removed the IAC valve there is no air getting past. Also spray some brake cleaner or similar around the inlet manifold and watch the lambda - if it goes rich you've got an air leak somewhere.

[damo_S13]

thanks for the info the cleaner helped. no leeks any were and block off every thing i could find

i think its down to my overside throttle body that was sticking a little but its down to 1200 now once warm and im happy with that

damo

[cliffb75]

Cool 

If you do make it to Donny and you're about Sunday give me a shout if you want me to look over the cal (or tell me to bugger off and mind my own business  )

[rob@vems.co.uk]

We'll all be at Donny, Laptops at the ready

[damo_S13]

Cool 

If you do make it to Donny and you're about Sunday give me a shout if you want me to look over the cal (or tell me to bugger off and mind my own business  )

yeah cool my mapping skill is not great at all im still learning so your more than welcome to have a look at what i have done so far, tell me how crapy it is   and then change a few things 

damo

[damo_S13]

We'll all be at Donny, Laptops at the ready

same for you too rob  will come home with a mapped car if i play me cards right lol

damo