Rock,

even with the system mikko and I have - we can only choose the jet BEFORE the race.....if the weather changes, then it means nothing but then it also affect most on grid.

This is the small disadvantage of running a fixed jet carby, nothing to do with the software or tuning aids.

yep. i guess that where the software solution have the advantage. pre check the jetting before going to the starting grid.

i found a pdf jetting chart from a japan kart shop
http://www.eikoms.com/item/EngineParts/ ... _Sheet.pdf

maybe Mikko or Jules can make sense of it and give us tips to use it.

That looks like the rows on top and bottom are temperature, and the vertical columns are atmospheric pressure in mb. These have by far the greatest effect on jetting, humidity doesn't change much and it's not taken into account in the graph it seems.

- So according to the graph at typical day in sepang of about 1008mb and 33 degrees celcius you'd through in a 160 but maybe a 162 which is quite right. If the temperature dropped to 25 you'd throw in a 165.

Rok,

Mikko is rite and the chart is good and it tallies with what my MAXJET will suggest....

Mikko - how different are the ROKs to what the Max in terms of jet sizes as recommended by your software?

Thats good to know. Thanks guys. I guess i try this cheapman system 1st. All i need now is a weather station. going to Toys"R"Us now..

ps. hope Mikko make a chart for Rok for us soon.

Rock,

Please buy a good weather instrument cos shite input means lousy & inaccurate output!

That's too true - depending on which system and what you're able to find look at spending at least RM500 for an ok weather station.

Oregon Scientific is a possible good brand....

that costs 129 UK Pounds
guess the author wants to follow bill gates footstep.

Mikko how are the Kestrel brand weather station?
looking at the specs, is Kestrel 2500 enuff to do the job needed?
http://www.nkhome.com/ww/kestrelchart.html

Yeah they should be good - they have weather stations from cheap to expensive. I got the kestrel mainly because it is so small! - and is known to be very accurate.



Lol... I'll invite the software author John Savage to come over to the forum . He's really passionate about his software and always answers questions quickly.


All that is missing is the humidity - although humidity isn't a very important factor. You could get something like the 2500 and a cheap analog humidity sensor from a DIY store or similar if you can find it.

upps, i better start editing..

hope he give forum members discount..

I think he has a sense of humor too so not to worry.

Found another Jetting chart

The problem with these jetting charts is that they don't specify what airbox/floats/float height was used. Best to make your own chart which is what I did a few years ago before I had jet-tech.

I finally got to properly using the software today. I got to "calibrating" my engine+carb to the software and ended up at the same jet+needle recommended by the program, so no need to change the jetting. The main advantage to a jetting program(or chart) is that it saves time - I won't have to do 2-3 sessions just to figure out jetting, I can jump straight into chassis setup.