6 replies to this topic

[Medmonic]

ok lads , its coming my new ignition to add to #3vd900project , with a special map for the 3vd engine with tps .

they were very kind to send me a map  to my specifications .

now i need some help here do decode how the software works and how to tune the ignition to my 900 engine .

who have experiente  with this kind of tune ?

regards 

 

[fixitsan]

The 3VD map might not be any good, you will have to try it first though

The 3VD has a 360 degree crank, but the 900 has a 270 degree crank

If the unit takes a trigger pulse from the flywheel directly it could be possible that it wokrs

I would start with verifying if it works or not, and if it does see how it runs under load.

As long as you don't hear pinking/pre-ignition you can probably safely advance the timing

In the UK we usually get ignition systems set up for a minimum fuel quality of 92RON, but I think the lowest grade we can buy is 95, so you can safely run slightly more timing advanced than standard, maybe by as much as 4 degrees, hence why you can buy a '4 degree advancer' for most bikes.

But if you think you'll go somewhere with 92 grade fuel then tune the ignition for that grade,  and then live with the compromise, unless you have 'switchable maps '  ?

[Medmonic]

The 3VD map might not be any good, you will have to try it first though

The 3VD has a 360 degree crank, but the 900 has a 270 degree crank

If the unit takes a trigger pulse from the flywheel directly it could be possible that it wokrs

I would start with verifying if it works or not, and if it does see how it runs under load.

As long as you don't hear pinking/pre-ignition you can probably safely advance the timing

In the UK we usually get ignition systems set up for a minimum fuel quality of 92RON, but I think the lowest grade we can buy is 95, so you can safely run slightly more timing advanced than standard, maybe by as much as 4 degrees, hence why you can buy a '4 degree advancer' for most bikes.

But if you think you'll go somewhere with 92 grade fuel then tune the ignition for that grade,  and then live with the compromise, unless you have 'switchable maps '  ?

Hi There , thanks for the replay .

basically what i heve is a 900 engine running at 360 degrees , the engine was all modified for that .

the map i requested from them was for a 3vd running at 360 degrees with tps active .

my ideai now is to adjust the timing to run smoother in the 900 engine 

i will post here the map i have for the 3vd engine running at 360 degrees 

[Medmonic]

here are the the maps 

first one is for tdm running the  engine at 270 degree 

second one is  for tdm runinng the engine at 360 degrees 

 IMG_20210331_204551.jpg   104.45KB   1 downloads

 IMG_20210331_205539.jpg   103.57KB   1 downloads

[fixitsan]

Interesting that the 360 degree map has a lot of advance in the 5 & 10% bands at higher RPM's, lean burn mode ?

 

The 270 map levels out at 7000rpm to 35 degrees, but the 360 map goes on to unreasonably high rpms !

 

The 270 map emulates a centrifugal ignition advance curve, where the amount of advance is always proportional to the rpm. It's probably always going to work.

 

Where did the 360 map come from ? Is it from a working bike or is it only  meant as a starting point ?

Edited by fixitsan, 31 March 2021 - 09:00 pm.

[Medmonic]

Interesting that the 360 degree map has a lot of advance in the 5 & 10% bands at higher RPM's, lean burn mode ?

 

The 270 map levels out at 7000rpm to 35 degrees, but the 360 map goes on to unreasonably high rpms !

 

The 270 map emulates a centrifugal ignition advance curve, where the amount of advance is always proportional to the rpm. It's probably always going to work.

 

Where did the 360 map come from ? Is it from a working bike or is it only  meant as a starting point ?

the map came preloaded on the new cdi , already tested and runs fine , problaly needs a litle tune .

[fixitsan]

the map came preloaded on the new cdi , already tested and runs fine , problaly needs a litle tune .

 

Interesting

 

I have seen a couple of 900 ignition maps, they tend to have a lot of advance at the lower rpm range , upto 1800 rpm  at low throttle openings, which i believe is to help with starting conditions, which might explain the 5%-10% advance figures of the second map

 

At the end of the day If it works, it works !