[squish72]

Need some help and suggestions. I've already asked this on hptuners but I figured I'd give it a shot here too.

My town is around 6700 and my current tune has zero knock reguarless of what I'm doing and at what whatever temps 90s-40s (wot, dod/afm, normal driving).

Everytime I take my car south to lower altitudes (mid 2,000ft) I get knock retard. I did a few things like changing how much spark is pulled at higher intake air temps and such but it still seems to never get rid of 100% of it.

Here are two logs on my drive back home, I know they can't be compared with each other due to temps and altitude but I just wanted to show what I'm talking about.

[squish72]

[Trochoidal]

I’ll jump in with this unconfirmed revelation. It’s been stated that areas in high altitude sell fuel that has lower octane than advertised. This source came from an RV post and here’s the link. So do you think it’s possible you are being sold a lower octane fuel as mentioned here?

https://www.rvtravel.com/high-altitu...-engine-knock/

[squish72]

Originally Posted by Trochoidal

I’ll jump in with this unconfirmed revelation. It’s been stated that areas in high altitude sell fuel that has lower octane than advertised. This source came from an RV post and here’s the link. So do you think it’s possible you are being sold a lower octane fuel as mentioned here?

https://www.rvtravel.com/high-altitu...-engine-knock/

I don't doubt that is happening in my very rural town. These logs were done with fuel from the lower altitude.

[Trochoidal]

Originally Posted by squish72

I don't doubt that is happening in my very rural town. These logs were done with fuel from the lower altitude.

FWIW, I had no idea that high altitude vs low altitude fuel varied. So without a doubt I thought let’s see what this is all about.

While I was responding to you a thought came to mind and it was,”watch this response, he will tell me he has low altitude fuel”.

I saved your logs when you posted but never took a look at them. I’ll do it later. Maybe I’ll catch something and get back to you one way or the other.

Hopefully some other folks will take a look at your logs.

[Trochoidal]

So in the 5 events enclosed, there is one area that has common issues and I don’t have answers. I noticed your LTFT stops logging for some reason in the low altitude log. The high altitude doesn’t miss a beat and LTFT logs are there.

Maybe these screenshots will produce more interest in a solution.

[squish72]

Wow good catch on that! Thats weird. I didnt even notice that the torque stuff wasnt logging either. Ive never had that happen. I do have another log that I took down there. Ill have to look if I have it


Edit: Found it and remembered why I didnt upload it, WB didnt log for some reason. This one is with a tank of fuel from my home town and its pulling onto the freeway and the freeway goes up a fairly steep grade so I assume the more knock is because of the load

[6spdhyperblue]

Did you mess with cam phasing by altitude.

When ppl hear this stuff they suggest spending more time dialing in your vve table

[squish72]

Originally Posted by 6spdhyperblue

Did you mess with cam phasing by altitude.

When ppl hear this stuff they suggest spending more time dialing in your vve table

If you are talking about the Desired angle: low, med, high. It looks like the tuner did change those to fairly basic numbers vs the factory file