Is car safe to drive with low Advance Multiplier?

[djdnz]

I have the edelbrock kit with carb tune as well, no other engine mods, cali 91oct from chevron. From time to time (not as often as the OP) the car surges below 3k rpm. One night it was doing it so I went home and grabbed my ecutek and laptop to start logging, but it wasn't acting up anymore when I got back into the car. I recorded some logs anyway, and since I was going through this thread I decided to check the advance multiplier - in every log I don't have anything above 0.7, it's usually between 0.3 to 0.7.

http://datazap.me/u/djdnz/edelbrock-...og=1&data=6-35

[D_Thissen]

What at your IATs? I wonder if it's heat soaking.

Sent from my Nexus 6P using Tapatalk

[86fun]

Originally Posted by djdnz

I have the edelbrock kit with carb tune as well, no other engine mods, cali 91oct from chevron. From time to time (not as often as the OP) the car surges below 3k rpm. One night it was doing it so I went home and grabbed my ecutek and laptop to start logging, but it wasn't acting up anymore when I got back into the car. I recorded some logs anyway, and since I was going through this thread I decided to check the advance multiplier - in every log I don't have anything above 0.7, it's usually between 0.3 to 0.7.

http://datazap.me/u/djdnz/edelbrock-...og=1&data=6-35

Thanks for posting. I don't know how exactly these values relate to performance and what you feel exactly, or even what is good or bad, but your numbers look even more extreme than mine. How does it drive? Is the power consistent and stable? Or do you feel slight lags in the power band as you go through the RPMs? Looks like you were cruising on the highway at a good clip and giving it some throttle modulations. Have you had it dyno'd?

[NotSoJDM]

Originally Posted by wparsons

What other mods? I would pull logs to see if you're running lean causing more knock.

His AFRs looked good when he is seeing knock events (~13AFRs at the last log I saw of it). I don't think it is legitimate knock being picked up by the knock sensor for a couple of reasons:

1) Its a pretty low load/rpm situation (30% throttle & 2500-3000rpm), and he is seeing knock correction of -4 and sometimes even -5 in some areas.

2) Ignition timing values at the time of these knock instances are -5.5 (yes negative) from all of the knock correction going on, so its not like he is seeing really advanced ignition timing in this area. I've actually never seen a log with timing values in the negative before, so that is new territory to me. I have no idea how the ECU responds to negative timing. Maybe someone with more knowledge there can shed some light.


I like Shiv's idea of adding some octane booster to see if it effects anything. Hopefully, someone can be of more help than me to resolve his issue.

[wparsons]

^^ The low rpm/load situation is hugely knock prone. Getting stuck in stop and go traffic is a surefire way for my IAM to drop running 91 octane fuel and an OTS 91 map. On 94 octane and either a 91 or 93 OTS map I don't get any knock at all. I also don't get high RPM/high load knock on an OTS 91 map on 91 octane. I'm definitely not alone in this either, a few people have posted about experiencing the same.

[Lonewolf]

Originally Posted by 86fun

Heh, I'm not always intelligent, it's ok!
I always intend to get 91 octane, as long as my brain talks to my body correctly that's what I get LOL. I filled up from three different high volume stations with a full tank of 91 after using almost all of the previous tank, the problem never changed. At some point I might make the trek to the race track and get a little 100 unleaded to see if it changes much.

No need to drive out to the race track to get the good gas blend you want. Try some Torco Accelerator octane booster and mix to get somewhere near a 93 blend. I think you can order it online without issue.