LO206 CARB ?

Where are you located. Look for a shop with a dyno that builds and services the LO 206. GT Macchine in little river sc does a ton of 206 engines and dynos all of them.
 

sundog

Member
It's sooo easy to do it yourself. All they can do is give you a base line set up anyway unless they know the actual track and weather the day of. The info you need is right here at the top of the LO206 section and Brian sells some tools that make it even easier.
 
D

Deleted member 21174

Guest
What kind of air density change will trigger a change in carb setup for the LO206? If I set my carb up right for 90% dry air density but later this year spikes to 95% or 100% should the carb settings be changed?
 
What kind of air density change will trigger a change in carb setup for the LO206? If I set my carb up right for 90% dry air density but later this year spikes to 95% or 100% should the carb settings be changed?
Absolutely.
1% change in A/D requires a 1% change in fuel. Air quality goes up, fuel needs to go up proportionally.
In the real world, moving the clip down (richer) on the needle 1 notch is pretty much equivalent to going up 1 jet size.
Most times, that requires a 5% change on your A/D gauge before any action is needed. Also depends slightly on your altitude and humidity, but that'll get you close. That's assuming that your carb was tuned correctly on the dyno to begin with.
An A/F Ratio gauge, or O2 sensor, is even more accurate (in my opinion), but slightly more difficult to use considering you cannot use it during actual racing (ie only for practice.)
Bottom line, if it's faster on the stop watch (or Mychron) run it.
I've seen engines that were tuned terribly wrong still make it into the tech barn at the end of the day. :)
 
D

Deleted member 21174

Guest
I'm in the process of setting up the lambda sensor now. It is kind of a pain to set up and we would only use it on practice days (and then keep a notebook of air density, lambda for WOT and on turns, carb settings, lap times and general observations etc).
 
D

Deleted member 21174

Guest
Hi Jimbo - I got the MyChron one. It was pricey but promise of plug/play was worth it. I have not installed it - a local muffler shop did the bung for us (they were really nice) in a test pipe. The vendor said the heater in the sensor would run off the existing MyChron battery - I bought a 2nd battery in case this ends up draining the battery like crazy (worst case I can mount a Mini Swift battery on the kart if it comes to that). If I can get a SmartyCam that would really neat as the video would potentially provide data from all the sensors synced with video which would pretty cool. If I ever get it set up and working I will update. Thanks for all your help and advice!
 
D

Deleted member 21174

Guest
So I finally got this set up (was injured for a while and not able to do karting stuff). I had a bung drilled and welded into the muffler by a local shop (it's easier for me to swap out the muffler). The AIM lambda sensor requires an external power supply to heat the probe before the engine is started - so I had to get a 12v battery with F2 terminals and strap this to the kart (I was not crazy about this but when we did our testing there was no one else on the track).

The data were interesting. The display can be set up on the MyChron so the data is visible in real time to the driver, but to recall the data I had to download it to a laptop at home (did not want to lug a laptop to the track). The lambda data is spiky - so I overlayed 2 or 3 laps at the same time to smooth things out and throw out outlying data. We had a lambda in the .80-.89 range which I think is good? The air density at the track was about 100% which is high for our area. We ran blue slide, clip on 2nd notch from the top, and had the float around .900. To get it to idle I had to turn the air screw all the way in - even a little bit out and the engine would die but it ran well - no popping or backfiring and my kid reported good power. I might drop the float level a little if the air density stays like this for the race and that may allow the air screw to be backed out a little.
 
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