Somebody check my work & theory
06-11-2004, 01:54 AM
#1
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Somebody check my work & theory Alright, my car has basic bolt ons and I have been doing some logging here lately getting ready to tune my ltfts. During this I have noticed that every time I am in 6th gear and drive up a hill I get some KR. I have a good 60 rows worth of KR from one of these logs, and so I decided to do something about it.
In order to get rid of the KR I will have to reduce timing, so in order to do that I need the rpm at which KR occurs and the airflow. When I checked out those 60 rows, I pretty much came up with three average sets of data.
5.5 lb/min @ 1450 rpms @ 62 mph in 6th gear
5.0 lb/min @ 1470 rpms @ 63 mph in 6th gear
4.5 lb/min @ 1470 rpms @ 63 mph in 6th gear
In order to get grams/cylinder (What the pcm uses), I multiplied 5.5, 5.0, and 4.5 by 7.55987283 (Google gave me this conversion). This gave me grams/second, which I can combine with RPM's to get grams/cylinder (via HP Tuners unit converter). I then converted all these into grams/cylinder:
.43 grams/cyl @ 1450 rpms
.39 grams/cyl @ 1470 rpms
.35 grams/cyl @ 1470 rpms
The KR lessens as you go down these three values, with the top being around 4 degrees and the bottom around 1 degree. In order to rid myself of the KR Im getting should I simply take a few degrees of timing out of the 1400 x .32, 1400 x .36, 1400 x .40, and 1400 x .44 cells?
Thanks in advance
In order to get rid of the KR I will have to reduce timing, so in order to do that I need the rpm at which KR occurs and the airflow. When I checked out those 60 rows, I pretty much came up with three average sets of data.
5.5 lb/min @ 1450 rpms @ 62 mph in 6th gear
5.0 lb/min @ 1470 rpms @ 63 mph in 6th gear
4.5 lb/min @ 1470 rpms @ 63 mph in 6th gear
In order to get grams/cylinder (What the pcm uses), I multiplied 5.5, 5.0, and 4.5 by 7.55987283 (Google gave me this conversion). This gave me grams/second, which I can combine with RPM's to get grams/cylinder (via HP Tuners unit converter). I then converted all these into grams/cylinder:
.43 grams/cyl @ 1450 rpms
.39 grams/cyl @ 1470 rpms
.35 grams/cyl @ 1470 rpms
The KR lessens as you go down these three values, with the top being around 4 degrees and the bottom around 1 degree. In order to rid myself of the KR Im getting should I simply take a few degrees of timing out of the 1400 x .32, 1400 x .36, 1400 x .40, and 1400 x .44 cells?
Thanks in advance
06-11-2004, 03:35 PM
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Will do. Im heading to Miami late tonight and wont be back for a week, but I will post how it turns out as soon as I get back and get a chance to try it out.
06-11-2004, 10:52 PM
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If you aren't getting any KR at any time besides when you're lugging it, I would change your driving habits. With a cable actuated throttle, the driver can open the throttle no matter what the engine load. If you're opening the throttle in sixth, lugging the engine, it's no suprise that KR is intervening to prevent pre-detonation because of the lean condition created by too much A and not enough F.
