so has anybody here ever tried the vishnu learning trick?
so has anybody here ever tried the vishnu learning trick?
Originally Posted by vishnu
Just a little trick that has been shown to accelerate the factory ECU's ignition timing learning process.
Background: There is something called "Ignition Advance Multiplier". It represents, by some complicated algorithm, the average learned positive knock correction applied to the ignition maps. It's represented in 1/8th degrees increments. 1 being the lowest and 16 being the highest (1/8 to 2 degrees in absolute terms).
The "happier" (knock free) the car is, the higher the number will be. Conversely, the lower it is, the more knock prone it is. This number, after ECU reset ore ECU swap defaults to 8 and usually creeps up to 16 (if well mapped) through normal driving. Depending on driving characteristics, this can happen within a few hours or a few weeks. Well, here's a way to make it happen in about 5 seconds ....
First: With the car fully warmed up, reset the ECU. This can be done by killing power the ECU or by simply pulling off the neg. battery terminal and pressing the brake pedal for a couple of seconds.
Second: Drive to a nice open road without traffic. Don't go on boost until you get there. Put the car into gear (3rd gear works the best) bring the revs up to 2600rpm. Push the go pedal down slightly so boost stays right around 2-4psi. You will need to MAINTAIN 2500rpm and 2-5psi for approx 5 seconds. You can do this by left-foot braking gently as to prevent acceleration. During these few seconds, the advance multiplier (which you can't see so you'll have to trust me) will go from 8, to 12 and then to 16. Works like a charm. And on our reflashed ECU, is worth an immediate 10-20 horsepower
In an attempt to save a lot of dyno time between reflashes (when the advance multiplier resets itself), I do this little trick after every reflash. In a typical dyno session, it's not unusual to reflash the same car up to 5 times. On the dyno, all I need to do is tell the dyno to hold revs to 2600rpm. Then I just lay on the throttle until I see a few psi of boost... Bingo!
Warning: This little trick artificially speeds up the learning process. This is only a good thing if the re-mapped ECU is mapped properly. If there are trouble-spots where knock is present, this trick will make it even more present. So be careful!
Background: There is something called "Ignition Advance Multiplier". It represents, by some complicated algorithm, the average learned positive knock correction applied to the ignition maps. It's represented in 1/8th degrees increments. 1 being the lowest and 16 being the highest (1/8 to 2 degrees in absolute terms).
The "happier" (knock free) the car is, the higher the number will be. Conversely, the lower it is, the more knock prone it is. This number, after ECU reset ore ECU swap defaults to 8 and usually creeps up to 16 (if well mapped) through normal driving. Depending on driving characteristics, this can happen within a few hours or a few weeks. Well, here's a way to make it happen in about 5 seconds ....
First: With the car fully warmed up, reset the ECU. This can be done by killing power the ECU or by simply pulling off the neg. battery terminal and pressing the brake pedal for a couple of seconds.
Second: Drive to a nice open road without traffic. Don't go on boost until you get there. Put the car into gear (3rd gear works the best) bring the revs up to 2600rpm. Push the go pedal down slightly so boost stays right around 2-4psi. You will need to MAINTAIN 2500rpm and 2-5psi for approx 5 seconds. You can do this by left-foot braking gently as to prevent acceleration. During these few seconds, the advance multiplier (which you can't see so you'll have to trust me) will go from 8, to 12 and then to 16. Works like a charm. And on our reflashed ECU, is worth an immediate 10-20 horsepower
In an attempt to save a lot of dyno time between reflashes (when the advance multiplier resets itself), I do this little trick after every reflash. In a typical dyno session, it's not unusual to reflash the same car up to 5 times. On the dyno, all I need to do is tell the dyno to hold revs to 2600rpm. Then I just lay on the throttle until I see a few psi of boost... Bingo!
Warning: This little trick artificially speeds up the learning process. This is only a good thing if the re-mapped ECU is mapped properly. If there are trouble-spots where knock is present, this trick will make it even more present. So be careful!
Originally Posted by simon lines
Look the "Vishnu Method" is just a hard EMS re-set followed by utilisation of the optimal load speed / load sites to get the advance multiplier up to 16. Once it's on 16 (assuming it stays there) you get best usage of the ign correction 3d map and therefore "best" ign advance.
However, as in most cases this is not a hard and fast rule, more a general assumption. It could be that your vehicle is running well it's multiplier has been on 16 for ages and it has positive learning in it's fine ign correction, this mean's your getting more than it you did the re-set and got it onto 16 again because the learning (good learning in this case has been wiped)
Without the ability to check your just stabbing in the dark...
However, as in most cases this is not a hard and fast rule, more a general assumption. It could be that your vehicle is running well it's multiplier has been on 16 for ages and it has positive learning in it's fine ign correction, this mean's your getting more than it you did the re-set and got it onto 16 again because the learning (good learning in this case has been wiped)
Without the ability to check your just stabbing in the dark...
Thread
Thread Starter
Forum
Replies
Last Post
Vishnu
Engine Management
36
Jan 4, 2009 07:35 PM