Qestions answered #1 VIPEC ECU
- Thread starter brycter
- Start date
Closed vs. Open Loop
Can you go a little more in depth on the subject of open loop vs. closed loop elaborating what each does and why you feel the closed loop is not effective for snowmobiles? I don't have a kit nor a ecu but have been very interested in the standalone ecu and trying to learn as much as I can about them.
Kyle
Can you go a little more in depth on the subject of open loop vs. closed loop elaborating what each does and why you feel the closed loop is not effective for snowmobiles? I don't have a kit nor a ecu but have been very interested in the standalone ecu and trying to learn as much as I can about them.
Kyle
Kyle,
Closed loop means that the ecu uses the AFR value (or any sensor value of your choice) to constantly adjust your fuel map on the fly to get your actual AFR reading(or any sensor value of your choice) to a predetermined AFR Value (or any sensor value of your choice) based on a AFR value (or any sensor value of your choice) Map you create usually based on RPM and throttle position for a 2 stroke application.
Open Loop really means nothing. Basically it means that the Closed Loop control is off so the ECU does no changes to your fuel map on the fly
I think the reason its not really that great of an idea for a two stroke application is because of many reasons, but one being that the AFR guage is just not that reliable of a reading 100% of the time.
Also one thing is the way snowmobiles are used with constantly changing throttle positions and RPM and power valves opening and closing (sometimes at varying RPM's and throttle positions due to atmospheric conditions and mechanical conditions)
Because of these things, It would be making drastic changes to your fuel map at all times which would throw your tuning out of wack, which in turn would make it run poorly.
I'm sure thats some of the reasons they have not had success with constant closed loop tuning for 2-strokes.
Now for a car for instance, the AFR Reading is more reliable because of a few reasons, no burnt 2stroke Oil, more consistent RPM's, etc. Now lets say your driving down the highway on cruise, RPM's are pretty much constant, throttle positions is pretty much constant, now an ECU closed loop tuning operation has a chance to take over and get the most ideal fuel economy for those current conditions.
Closed loop means that the ecu uses the AFR value (or any sensor value of your choice) to constantly adjust your fuel map on the fly to get your actual AFR reading(or any sensor value of your choice) to a predetermined AFR Value (or any sensor value of your choice) based on a AFR value (or any sensor value of your choice) Map you create usually based on RPM and throttle position for a 2 stroke application.
Open Loop really means nothing. Basically it means that the Closed Loop control is off so the ECU does no changes to your fuel map on the fly
I think the reason its not really that great of an idea for a two stroke application is because of many reasons, but one being that the AFR guage is just not that reliable of a reading 100% of the time.
Also one thing is the way snowmobiles are used with constantly changing throttle positions and RPM and power valves opening and closing (sometimes at varying RPM's and throttle positions due to atmospheric conditions and mechanical conditions)
Because of these things, It would be making drastic changes to your fuel map at all times which would throw your tuning out of wack, which in turn would make it run poorly.
I'm sure thats some of the reasons they have not had success with constant closed loop tuning for 2-strokes.
Now for a car for instance, the AFR Reading is more reliable because of a few reasons, no burnt 2stroke Oil, more consistent RPM's, etc. Now lets say your driving down the highway on cruise, RPM's are pretty much constant, throttle positions is pretty much constant, now an ECU closed loop tuning operation has a chance to take over and get the most ideal fuel economy for those current conditions.
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rsp must have taken notes. we have not found it to work across the board yet. we can plug in a 5% or 7% adjustabily factor. some will call that closed loops others will not. if you want to go more in depth let me know. call me I can discuss everything with you.
Oh man are you kidding with me brycter. I was 99.99% sure that there werent going to come a choice for vipec on the axys.
But now we need to know more! Is it a brand new unit/ecu or a previously pro-ride unit that just is modified to run the axys?
If its the later then im very happy. Have a vipec unit at home thats collecting dust at the moment
Hope you get everything sorted out! You need to keep us in the loop and updated!!!
But now we need to know more! Is it a brand new unit/ecu or a previously pro-ride unit that just is modified to run the axys?
If its the later then im very happy. Have a vipec unit at home thats collecting dust at the moment
Hope you get everything sorted out! You need to keep us in the loop and updated!!!
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Regarding 800 Pro RMK with Vipec, 8-10 lbs of boost, Garrett GT2860RS, 1,000cc injectors, Indy Dan upper end, 6-10k elevation.
What clutch weight brands and weight are you guys running?
Bryce said he is having good luck with 10-70
We have Team Rooster weight kit with 65g base weight + 14.5g = 79.5 g total (3 red bolts + think and thin washer in tip) and still hitting 8400+ RPMs at 1,000 feet elevation.
Sled heading to Cooke City today and worried about bringing down RPMs
We can still add 8 more grams before the weights are maxed out.
Seems like a lot of weight for this kit setup.
Suggestions?
What clutch weight brands and weight are you guys running?
Bryce said he is having good luck with 10-70
We have Team Rooster weight kit with 65g base weight + 14.5g = 79.5 g total (3 red bolts + think and thin washer in tip) and still hitting 8400+ RPMs at 1,000 feet elevation.
Sled heading to Cooke City today and worried about bringing down RPMs
We can still add 8 more grams before the weights are maxed out.
Seems like a lot of weight for this kit setup.
Suggestions?
T
TurboMatt
Well-known member
I had my sled out in the Snowies last week, I was getting a bog at WOT. Is anyone Interested in looking at some logs and giving me their opinion on what's wrong? One other question: is it normal for the boost gauge to read 9psi, but the vipec to read only 130kpa(approx 4.5 psi), that's seems like a big difference.
Why don't you jut post you log and I am sure you will get comments.
Ended up adding an additional 2.5g so a total of 82g so RPMs are now at 8100
Your team roosters are the same profile as 10 series Polaris weights when loaded evenly.
Did you miss a 0 on your rpm question? Otherwise simply by going 8k-9k up higher in elevation your RPM (HP) is going to drop and you'll be pulling weight to get target RPM
I have been working with the Vi-Pec software doing some tuning but have a question about altitude compensation.
Can anybody direct me to the area within the software that adjusts for altitude?
I can get the sled tuned for 8500 ft elevation but as soon as it gets into higher altitudes it has runs inconsistently.
I think the "BAP" is the barometric pressure sensor that provides input to the Vi-Pec but not sure where in the software to adjust the settings.
Any guidance will be appreciated.
Can anybody direct me to the area within the software that adjusts for altitude?
I can get the sled tuned for 8500 ft elevation but as soon as it gets into higher altitudes it has runs inconsistently.
I think the "BAP" is the barometric pressure sensor that provides input to the Vi-Pec but not sure where in the software to adjust the settings.
Any guidance will be appreciated.
I probably was not clear in my question.
At 1,000 ft elevation it was over-revving with 79.5g of weight. - higher than 8400 rpms
Was hoping once got to Cooke City the RPM would drop but was still hitting 8400+ rpm.
Then added 2.5g to middle bolt (82g total) and got RPM to drop down around 8200.
Should be good to go!
Hi! Look at the 5Dfuel table
(ECUsettings--Fuel--Fuelcorrections--5Dfuel)
You should be at 75 Kpa BAP at 8500 feet I guess.
And 70 kpa BAP and lower, you should correct.
I opened up a log and looking at the 5D table now - thanks!
It is showing around 72-73 range - the sled is in Cooke City so that makes sense.
The program is pulling fuel starting around 4,000 rpm ( removing -14) to 9,000 rpm (removing -30)
I may need to scale these number up / down depending upon a bit of testing.
Thanks for the direction
T
TurboMatt
Well-known member
Ok this will probably sound like a dumb question: my analog boost gauge reads 9or10 psi but the vipec is reading 130ish kpa. I thought 130ish kpa is around 4-5psi. Why the difference? This is riding at 9,000 ft elevation. I'm assuming this has to do with elevation, is there an equation for this?
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130 kpa is just under 19 PSI. Assuming your at altitude your boost gauge is correct.
To convert KPA to PSI multiply the kpa value by .145
To convert KPA to PSI multiply the kpa value by .145
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