Question about Advance Multiplier
 

So on my car Advance Multiplier is finally displaying properly on my OFT. So far every time I start the car it reads .70, and then works its way up to 1.00. Is this normal? Is it always like this, or will the car start at 1.00 once it learns whatever an ECU learns for the first few miles?

I'm new to all this tuning stuff and just want to learn. I've read quite a bit about the OFT and tuning on here but haven't seen this mentioned.

It's normal for a stock tune.

Most tuned ROMs will have the initial multiplier changed from 0.7 to 1.0.

It's an OFT stage 2+ tune.

I just flashed this tune today. It seems each time I drive it, that it makes its way up to 1 faster and faster. I drove it 15 minutes and only made it up to .98. Then drove back home and within 3 minutes it made its way up to 1 and stayed there.

Just for some added the info, the advance multiplier will normally gravitate towards 1.0. This indicates that the ecu is not detecting knock. If while driving it moves towards 0, the ECU has determined there is enough knock to warrant an across-the-board reduction in timing. It may then increase timing gradually until it gets back to 1 or detects knock again.

As Tor said, stock tune starts at .7 for extra safety factor for bad gas, etc. If you load one of the oft files it should normally start at 1.

If you are looking to learn a bunch about how Subaru ecus deal with knock correction, this pretty much explains the logic. It's written for older ecus, but just know our advance multiplier ranges from 0 to 1 and that's written to assume 0 to 16.
http://www.romraider.com/forum/topic1840.html

Edit, wrote this before the post above. Oops.

Second edit, realized I linked to a link to the intended page. Corrected link

As long as it gets up to 1.00 quickly I guess I'm fine with it. Is it an easy thing to change in RomRaider if I wanted to change it?

Stage 2+ sounds like a MY17 tune.

IAM = 1 applies to all the old tunes. Apparantly Shiv didn't incorporate this into the MY17 tunes from what you describe - perhaps because the table has not been found in the new tune yet (my guess, didn't check). Still, it's normal behavior from the ECU so nothing to worry about.

I have a different theory about why 0.7 stock, I don't think it's for safety. I simply think that Subaru considers IAM 0.7 normal for 98 octane (or 93 for the US folks) and gives the ECU leeway to adjust timing in both positive and negative direction. In a way, I think we are leaving performance on the table to a certain extent by somewhat rigidly always targeting 1.0.

Check your 'initial advance multiplier' value (or something like that). Unless we are wrong about what is going on here, setting that to 1 should work.

On a related note, I've noticed that sometimes my multiplier is lower than 1 when I start my car as well. Usually assume that's because it was lower than 1 when I turned it off last, but now it's not making much sense...

Both good points.

It's a 2017 V4 tune. Not officially released yet. I guess he sent it to a few people, and one of those people sent it to me. Might seem crazy to some to run a tune that hasn't been widely used yet, but the way I see it is that if it isn't knocking, and the AFR looks good then it cant hurt anything.

I'm not sure I follow the rest of what you're saying. If .7 was normal for 93, then you'd think it wouldn't climb much higher. This tune is very new to me, it's only been on the car for a few hours and only about 75 miles. On my last drive, it rose from .70 to 1.00 in about 3 minutes.

I assumed it would pick up where it left off, but that apparently is not the case.

But it's a "tuned tune" "designed" to run IAM 1.

What I'm talking about is the stock tune. I think the Subaru engineers were perfectly happy with 0.7 and with the IAM moving a bit about during normal driving, whereas we as a community focus a lot on "IAM being 1" and "you have to remove timing if your IAM drops below 1".

Think of it this way... if you initial IAM was set to 1, but would sometime increase to 1.3 and sometimes drop back to 1 depending on your driving would that be more appealing than fluctuations between 0.7 and 1? :)

It's just a number I guess. I get what you're saying. So far I like this better than the last tune I was on, so I guess it's good.

Just to note that the Advance Multiplier will only advance in certain circumstances. If it stays at 0.7 that's not necessarily a bad sign, it just means that you've not met the criteria for it to re-evaluate. I believe that there is a minimum load/RPM threshold.

What changed that allowed you to see this info on your 2017?