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Tuned vehicles and OAR (Octane Adjust Ratio) adjustment

Volksjager

Well-Known Member
Joined
August 11, 2019
Messages
320
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48
City, State
Indiana
Year, Model & Trim Level
2017 PIU EB
I have tunes from 5* which are oct specific and auto octane tune from Gear head. The auto octane will limit the amount of boost depend on the OAR. My PIU had a OAR of -.16 when i first loaded the tune. Count get more than 12 lbs. another individual suched i reset the KAM and try to force the OAR to read it live. The OAR number is based on the knock numbers. Pulled up those two figures on the BDX and trying doing slow pulls in a high gear to get the knock to -3 and -4. Took a bit but i got the OAR to -.84. Problem is it didnt last. I’m back down to -.6. Im going to try a different gas station but are there any mechanical issues that can affect knock? Or is this just going to be a fuel issue? Im running 93 from Sams club
 



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I have tunes from 5* which are oct specific and auto octane tune from Gear head. The auto octane will limit the amount of boost depend on the OAR. My PIU had a OAR of -.16 when i first loaded the tune. Count get more than 12 lbs. another individual suched i reset the KAM and try to force the OAR to read it live. The OAR number is based on the knock numbers. Pulled up those two figures on the BDX and trying doing slow pulls in a high gear to get the knock to -3 and -4. Took a bit but i got the OAR to -.84. Problem is it didnt last. I’m back down to -.6. Im going to try a different gas station but are there any mechanical issues that can affect knock? Or is this just going to be a fuel issue? Im running 93 from Sams club
True knock or false knock? False knock can be caused by noisy vehicle components, i.e. trans shifting, exhaust heat shield rattle, or frayed knock sensor wires where they rub on the block just below the connector (above the thermostat housing). True knock could be caused by deposits, poor fuel quality, or a number of other things. You can play around with fuel by running some E20 or E30 and see if the OAR goes back toward -1. Or buy so Torco Octane Booster and see if it makes a difference. It may take up to several days of driving to see changes for the OAR. You can also watch the part throttle for knock as the factory is pretty aggressive in timing there. You may be getting some knock in part throttle driving which drives the OAR back up.
 






You may be getting some knock in part throttle driving which drives the OAR back up.

i do see this. when i let off the throttle and and give it partial throttle again it goes back into the negative. auto octane tune is kind of a pain in the arse. i switched back to 92 oct tune from 5*. it's just easier to not have to focus on the OAR.
 






.... and unless you want to spend big money to your tuner to really dial in those tables it can be a chore. It takes time to get those tables really good.
 






.... and unless you want to spend big money to your tuner to really dial in those tables it can be a chore. It takes time to get those tables really good.
who is your tune through?
 






who is your tune through?
I am currently working with Torrie of Unleased Tuning. He is awesome to work with. Highly recommend! Pretty simple setup. 14 PIU. All stock except t-stat, 3-bar map, and meth (50/50 spray 8 psi initial, ramp to 12 psi). Using HP Tuners to datalog and modify.
 






You're better off getting separate tunes for lower octanes. I have 87, 89, and 93 octane separate tunes loaded onto my tuner and can switch on the fly. Of course it resets the adaptive learning each time you reload.
 






Have you upgraded your MAP sensor?
 












As long as you are not hitting more than 14.7 psi of boost then you don't need to upgrade to the 3 bar Map. It's only when you max out the 2 bar map (14.7 psi) that you would need to upgrade to the 3 bar Map so you can properly read your pressure. For reference I am on stock turbos and maxed out at 16.9 psi.
 






As long as you are not hitting more than 14.7 psi of boost then you don't need to upgrade to the 3 bar Map. It's only when you max out the 2 bar map (14.7 psi) that you would need to upgrade to the 3 bar Map so you can properly read your pressure. For reference I am on stock turbos and maxed out at 16.9 psi.
My issue is im getting misfire codes while using these tunes
P0300

P0316
 






On the stock tune do the codes come up? Are spark plugs and gap good? Read this and share with tuner.
 






Also too when I was on stock spark plug gap I was getting misfires and blowing out the spark on WOT. I went down to 0.028 gap and it eliminated it.
 






Also too when I was on stock spark plug gap I was getting misfires and blowing out the spark on WOT. I went down to 0.028 gap and it eliminated it.
They’re a step colder and came at .3 do you think thats too much?
 






0.30 should be fine. You will know if you are getting misfires and its a dog on high rpm WOT.
 






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