mulot30th
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- Jul 7, 2007
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- Snowmobile
- 2023 thundercat
apex mountain crracing 174
apex blower 136 for asphalt racing
osp drag race sled (apex engine based)
mbarryracing said:
mine does runs to perfection if I tune is at the same elevation as I ride.[/img]
JIM
Extreme
well I was shocked when I read about your problem about something over correcting the fuel curve on the apex. I was in oregon Sat and was about 4-5k above my normal riding elevation and both apexes with rb3's had some serious troubles. Both leaned out so bad at 8500-9000 ft that they were un rideable. Now we richened them up and it helped, they ran, but it was a whole day of tuning. At the end of the day as we dropped back to 5000 ft they start to become too rich. So I am at a loss. Is the stock apex barometric sensor over adjusting, or is it the rb3? What does the map sensor do for the rb3? Does it have any affect on altitude?? Does it sense attitude? I thought all it sensed was air pressure. Well if your boosted them it really isnt affected my altitude. Now the stock barometric sensor on the factory apex injection isnt tie to boost. Should it be? I am at a loss as to what to do. I made a few calls to dave and he is at a loss too.
JIM
Extreme
I have a buddy who has a boondocker nitro with the boondocker box and he had the same troubles. had to add alot of fuel. I think the sled is making less boost and putting the sled in a lower percent column than it should be which would cause it to definetely be lean. What can fix this?? besides several maps? I was under the impression this system was capable of running well all all elevations. I guess next year i am going to buy a tuning bike and leave it on the sled.
how about bypassing som map sensors? three maybe one to much.
just an ïdea...
just an ïdea...
JIM
Extreme
I think after several conversations with several smart fellas, I think we have this solved. I think that the boost made at high altitudes is less and lets the rb3 fall into a different/lower column which has less fuel and runs lean. Now I think this cam be fixed 2 ways, one is having a switch map for this elevation or just lowering your max voltage enough to get you back into the colum you need. There is load conversion on here that shows the load voltage relative to boost. Now it you are only going to run 14 lbs of boost then there is no need to run your max voltage at 4.25 you could be in the 3.8 range and be safe. Now i am still swollowing the fact that the boost guage doesnt show absolute pressure and so your guage may say 12 lbs at 9k ft but you are actually in the 8-9 lb range and in a lower collum than you thought. So a volt guage would be more of a help than a boost guage. I cant find one that works in the 0-5 volts range is powered by 12 volts and is waterproof.
You need all of them in the system!!!!! MAP stands for Manifold Absolute
Pressure. This measures boost pressure in the intake, must have!! Install
between intercooler and intake. IAT Intake Air Tempature measures temp
of air going into engine also a must. Calculates air volume by knowing the
temp of it. Should be placed between intercooler and engine intake.
Pressure. This measures boost pressure in the intake, must have!! Install
between intercooler and intake. IAT Intake Air Tempature measures temp
of air going into engine also a must. Calculates air volume by knowing the
temp of it. Should be placed between intercooler and engine intake.
JIM
Extreme
why does the older mcx kits run a boost line from the intercooler to the front barometric sensor? I was told it was to clean up the bottun end. Would this help with the rb3? what does this do at boost?
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