Need some advice on low IAM
 

I got a OFT recently and flashed Stage 1 map on my stock BRZ. Started logging and I kept seeing 0.4 IAM. I did some research, adjusted base timing with Kodename47's spreadsheets and I got 0.5 IAM.

I also went back to stock map with initial IAM set to 1 and I saw 0.3 IAM.

This was all on Cali 91 octane from Arco. I pumped in some 91 from 76 and the IAM was about 0.4 - slight improvement but not enough.

Sooooooo... my question is what do I do to get it IAM up? Is my engine somehow more prone to knocking?

Right now I have all the parts to go Stage 2 but I'm not sure if I should even go there with stock map hovering @ 0.4 IAM.

Any advice is appreciated!

Mother of God. Do NOT use Arco.

There is a thread floating around for how to adjust for Cali gas since it sucks. But Arco in particular is awful stuff above and beyond the rest.

2x do not use arco.
I did testing on another car and consistently got less mpg. Did some math and arco ended up being more expensive per mile.

I'll be staying away from Arco but IAM improvement using 76 wasn't anything noticeable...

So you uploaded the 91 octane tune onto your tablet and flashed that right? The tune that comes on the tablet is for 93 octane.
Run that tank to nearly empty and put in a full tank of Shell or Chevron from a busy gas station. I've had the best luck with Shell. Once you have some better gas running through there flash the 91 octane tune (with ignition timing compensation if you want)

Yup, 91 octane stage 1 with 76 isn't much better. Still hovering ~0.5

Try a fresh tank of Shell or Chevron on the 91 tune.. I had knock on stg 1 tune in Cali too, but never that bad. I did eventually make some intake air temperature and Base Timing B compensation to make IAM solid at 1.

I've had the same problem recently. First full tank after going from an e85 tune was okay, probably as there was enough still in the tank to raise the octane slightly. 2nd tank was from 76 and my IAM dropped to ~.71-.79. A visit to A Shell station fixed it.


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I'm running Stage 1 OFT and finally found the right CA 91 gas the car likes. Shell has been consistenly at 1 IAM. Chevron, 76, Mobil, and Costco have all been ~0.50-0.70 IAM

I'm running a modified stg1 91 tune (with wayno's ignition timing tables) and I had the same issues with my IAM. I have a JDL catted UEL header, TRD catback, and a Perrin drop in filter.

The easiest solution for me....royal purple octane booster! lol At least my IAM is a lot more stable now when I'm thrashing the car around. I still get a bit of flkc but not as bad as before.

Cali gas is pretty shit. I found shell to be the most consistent. Chevron was super knock prone, haven't tried anything else.

IAM solid at 1 with stg 1 OFT base map. But then again I'm running like .5 gallons of 100 octane in there. Going to be sad once it's all gone.

Thanks for the suggestions. Unfortunately Shell is awful... IAM is no better than Arco but crickets are chirping LOUD. Search for better fuel continues but I might just convert over to E85 if I can't find anything reasonable.

Don't mod your car before you solve the AIM issue. Check also if you have the same behavior with stock tune.

Even on the stock tune your IAM will drop (stock starts @ .70) 91 octane sucks, this car was meant to run 93 for sure...

I adjusted my timing tables & IAT tables a bit but on occasion my IAM still drops below 1.

I only fill up with Chevron & this yields the best results.

I think when IAM drops below 1, people make a bigger deal out of it that it actually is. Ideally it should be at 1, if you get a custom tune. Running an OTS tune will generally not provide this, to my (basic) knowledge all the ECU is doing correcting the timing for the fueling conditions. I don't think your engine has a higher chance to blow up if its below 1, just means your ecu is doing more work.