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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!

Cheers,
shiv
www.vishnutuning.com
 

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Shiv you rule! :D
 

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Possibly THE best post I've seen in a long time. Thank you, Shiv! :D
 

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Thanks for posting the tip Shiv. I've heard nothing but good things about your work. I hope to introduce you to my car when I return to the BAy Area. You two should have a wonderful relationship.

dan.
 

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Just curious, why do you have to press the brake pedal for a couple of seconds after removing the battery cable? Thanks.

Looking forward to getting my sub-zero reflash, soon.

Leo
 

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That closes the brake light switch and drains all the residual 'tricity out of the vehicle. :D
 

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Once 'learned', how long does the ECU stay in this state? Or what would throw it out of this state?

Thanks.
 

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can i do this to my stock wrx? and am i actually gonna feel a 10 hp increase or is this some kind of bull:confused:
 

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Doing this "trick" only speeds up the process that would occur anyway over time anyway.

Your car isn't going to have any more peak power because of this.

It'll just get to it's "happy" state of knock correction more quickly.

You're losing 10-20hp on the ECU reset - so the 10-20hp you gain back (either in 5 seconds with the "trick" or days/weeks of normal driving) nets you 0.

Please note that this is all assuming that you don't have any knocking going on that would make the ECU give a lower positive knock correction.
 

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but this does work on the stock ecu?

im assuming so since the modified ecu is just remapped right?
 

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I attempted this ECU learning trick yesterday after installing my EMI adapter, and it worked perfectly. I am running the stock ECU with a Dastek Unichip, EMI harness and EMI adapter.

Awesome trick. And very nice, since it will hopefully save me some gas money, since the ECU doesn't have to learn so slowly, like after every ECU reset.
 

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After doing the up/dp I didn't notice as big of a difference as I hoped... did the vishnu trick and woah it's much faster now :D
 

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Shiv said:
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

Cheers,
shiv
www.vishnutuning.com
Exactly how does one left-foot brake a manual transmission car?

-Jim
 

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Use the e-brake?
 

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Ummm.....use your left foot on the brake while gasing with your right. You only need to do it for 5 seconds, and you're not clutching during that period. Very simple. It's to maintain a constant RPM and boost.
 
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