blackisF08

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my numbers has always been low even after resetting the ecu, i blame my headers as well but we will see. they are getting replace by warranty at the moment. i will keep you guys updated

liquidtek

I've noticed intake temps above 90 will kill your KCLV numbers if you go hard on the throttle. I try to get the intake temps below 90 before I try doing any crazy acceleration after a dead stop. Not really reasonable when you daily drive your car in traffic though so your numbers will take a hit. Been getting cooler here in Colorado and the intake temps were in the 60s last night. Numbers were quite easy to get up into the high teens rather quickly.

Tom2769

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I wonder if Rafi could provide a tune optimized for 91 octane rather than 93 for those of us in max-91 octane states. If so, would that keep the Knock Learn numbers from dropping so much for those who can only get 91?

liquidtek

A few of us high altitude people have started mixing e85 with 91 (20-30% blend) and seeing an improvement. Might we worth looking into. Cheaper than running octane booster.

Defratos

I don't believe that driving with intake temps above 90 will kill your KCLV.

Currently the weather here has been getting cooler, ambient temp today driving home at night is 93f and that's considered average temps here.

For the past few months we've had temps between 104 - 122f but I still managed to get my KCLV into the low 20's.

Now what I've noticed since data logging is that fuel plays a big role, or at least for me it did.

Every few months I fill up with an octane booster bottle and within a day I see my KCLV go up above 20 and usually stays there for a few refuels so around maybe 600-1000km of driving.

After which the KCLV would drop down to around ~18.

I fill up from the same petrol station several times and data log my KCLV without octane booster (as I'm trying to find the cleanest gas station here).

Recently I switched to a new gas station and my KCLV have been at 21.5 - 21.8 which is the highest I've seen on my car so far. Now I did add octane booster two tanks back (if that makes sense) so I've emptied out my gas tank twice and filled it up 3 times (without octane booster) and still my KCLV is at 21.

It seems like the new gas station has better fuel, maybe it's just this time around but I'm going to be filling up from the same station a few more times (without octane booster) to see how the numbers change.


Also are you guys who are experiencing low KCLV numbers tried loading the car? as RR and others have suggested?

I did this a while back so maybe this has helped in someway. Plus I drive my car very aggressively on a daily basis at high speeds so maybe that also helps keep the KCLV above 20.

On average our temps here are 90f and anything below that is a blessing.

I don't think I've ever driven my car in temps below 80f.... can't even imagine how the car will feel at even colder temps

liquidtek

I'm not at sea level so maybe intake temps don't affect you guys as much but I've noticed anything above 90 IAT would drastically decrease my KCLV numbers by 1-2 points when being aggressive with the throttle from a stop. If the car is sitting and heat soaking (idle) the intake temps would rise & I need to drive around 40mph to get the temps down before any hard pulls or whatever. High altitude tune probably is slightly different in the timing behavior than the normal tune you guys are using. I reset my ECU yesterday and when I went out cruising in the cooler temps at night I was able to get my KCLV up to 19/17.3 which is probably the highest I've seen on my own vehicle with the tune. Mind you I haven't had a revised tune for very long but the results are promising so far with the revision and blending e85. Also I think my headers are cracked which also maybe affecting false knock. Just a theory but possible. RR Power Package will be ordered over the winter.

Defratos

Ok well I'm at sea level, literally so it's probably easier for me to get my numbers up.

As well I try not to data log my car if it's been heat soaking because as you've pointed out it screws up the numbers, or at least needs a bit of time to even things out.

I sometimes see a huge difference between my initial intake air temp reading and the act temp that flows in. Sometimes by a good 10-15c (50-60f) and that's usually right after the car has been sitting idling for a while.

DaOne54

Yeah I truly believe that elevation and fuel has a huge role on the way the knock learn values.
I'm right at 4,500' ASL. Highest octane found at gas pumps is 91. (besides VP racing)

Gsxr6k6

Just got my car back from lexus. KLV was 14%. A few months ago they replaced the cracked manifold thinking that was producing the knocking sound but it continued after that. They said it was poor fuel or could be time for a valve adjustment since I'm at 75k on my 08 ISF. I'm going to decarbonize the engine and see if that will help but I do notice it's only under heat soak that I hear the dreaded knock.

blackisF08

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Gsxr6k6

I have stock OEM headers. Only mod is full borla exhaust but the low KLV was there before I installed the exhaust.

blackisF08

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Gsxr6k6

They are brand new. I mentioned Lexus replaced them last month with brand new manifold. That's not the problem, at least with mine.

blackisF08

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