should be "around" stoich...

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Wolf_Tm
TM 250 enduro 2 stroke
GT-four ST205 Snowy White with selfmade 3SGTE v4.1 - [2.34kg/bhp DynoDynamics]
http://www.youtube.com/WolfTm250
http://www.facebook.com/wolf.tm

yeah the afr is a little lean ther is it not? i know mine comes in on idle at around 13-14:1 i think

[quote="dale"]yeah the afr is a little lean ther is it not? i know mine comes in on idle at around 13-14:1 i


Exactly....idle should be around stoich, but usually it's on the rich side...

was it mapped by a professional tuner ?!?

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Wolf_Tm
TM 250 enduro 2 stroke
GT-four ST205 Snowy White with selfmade 3SGTE v4.1 - [2.34kg/bhp DynoDynamics]
http://www.youtube.com/WolfTm250
http://www.facebook.com/wolf.tm

That's surprisingly retarded, and is the reason for the high EGT.

I've mapped mine with an idle ignition range of 10-30° based on Delta RPM and a 780rpm idle, I've still got the IACV but it's response speed is damped right down, the variable ignition timing controls the idle speed in a much more stable manner than the valve can.

Interesting strategy. I'll see if I can do something similar on the link as idle is pretty horrific at the moment.

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If at first you don't suck seed, try drier grain.

It works a treat, as I find the ECU can vary ignition timing far quicker than the IAC can change the amount of air available in the cylinders.

Here are my settings if they are of use - I'm actually using 5-30°, however it usually sits well within the ±50rpm range, so is sweeping between 15-25°:

I know that's the reason but i have hard time to control IACV when i tried so decided to go another way.

It's a track car, not a daily drive, EGT @ 600° is not a real issue.

With ~16° my idle sat 1700rpm, and with less than 3% throttle my car stall here and there, so i use the idle timing vs throttle vs rpm tab my ECU offer

After severall hours tuning and trying, setup looks like this :
base timing 26°
throttle from 0 to 5% :
800rpm : -13°
1000rpm : -21°
1450rpm : -22°
1750rpm : -25°
3000rpm : -29°
throttle 6% and more : 0° correction

I agree it's not the best for a road car, daily drive or not, but as you say playing with timing to control idle is nice

Of course I also use the water temp vs timing table to idle up below 70°


If i use solenoid on the 205 WRC fresh air port and retard timing -60° (with my 1700rpm natural idle) it makes a "nice but not to much" ALS

What ECU are you using bozo-merlin?

I disagree about the high EGT not being an issue for a track car, when I use my car on track I load in a special map that has a cool-down feature with the sole intention of dragging down EGT and coolant temps as quickly as possible. It holds the IACV at 100% open and cyclically cuts the fuel to one cylinder at a time when it's idling to maintain idle speed (I raise idle speed to 1400 rpm in this mode). That pumps cold air through the engine and brings down coolant temps much faster than just allowing it to idle on 4 cylinders.

Perhaps your ECU has something similar, that will allow you to run without the IACV and yet have a stable idle. On my Autronic it's called "Antilag Cool Down", but most ECU manufacturers and mappers know it as "rotational idle". Here is a video of my car while I was playing around with the settings:
http://www.youtube.com/watch?v=joIeJyzlEMQ
It might be worth having a good look through all of the features on your ECU and see if they've got something similar tucked away?

It's a non-commercial ECU designed by a garret engeneer.

I have no ACD or rotational idle feature but could ask him to add, but to be fair an electrical throttle should solve everything.

I don't have cooling issue anymore and my EGT cool down quick to 600 and i can't see a lot of bubble from the swirlpot while idle after 25' of abuse on track

Thats way too lean... richen up the mixture, or better still have the mixture controlled by a lambda sensor.

You are aiming for 14.7:1 at idle

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
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Turbocharging - the replacement for displacement

thanks for the help:)

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BRD Page

http://www.brooks-brd.co.uk/

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If you have any exhaust leaks prior to the wideband sensor you're using, you will get an incorrect reading - usually it will read leaner than the actual mixture as air gets sucked in between the pressure pulses.

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If at first you don't suck seed, try drier grain.

exhaust is all good no leaks think the map need a bit of a tweak

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