Timing revisited

Ok after much hair pulling trying to remove all trace of knock from all logs, I had found I was going around in circles. No matter what timing was there would always be some logged knock.

After some discussions with fellow tuners the consensus appears to be that as mentioned previously, real knock you should worry about is "saw tooth" in shape, while incidental and false knock is just a small spike which will show now and again. Or in other words "false positives". Just like an anti-spam engine will block good emails on occasion, the knock sensors will log random nothings from time to time. However big spikes and saw tooth shapes suggest real knock so be wary and careful not to take this post as a recommendation to allow real knock to exist at all.

So in summary Im pretty much back at my timing table I ran for the dyno pull happy with the fact that the odd tick on the log now and again is acceptable. With this in mind Im warming up to an OTRCAI purchase to go with the cam and possibly some Dart 205 or 225 heads.

Sparky

As time progresses my right foot seems to fall heavier on the throttle putting me into load areas previously not dwelt on for too long before. Ive pulled some more timing out and am now sitting on around 20deg total at WOT, part throttle timing has also fallen. Interestingly enough power is much the same. This reinforces the often read and heard line that "best timing is miles away from knock". The idea being that you should run the minimum timing you can to attain peak torque. This point is known as MBT (Minimum best timing) afterall burning the charge before TDC means you are fighting the compression stroke. To set timing at minimum buys you some safetly for dodgy fuel and conditions.

As mentioned previously this is ideally setup on a load dyno. I tried to get some 0-60 times on myGTech the other night as a kind of "check" for my tuning changes, alas, it appears that it may have completed its life on earth as it was spewing out non intelligable figures not related to the mode I was in. Ill try it again and have another go, else its time for an upgrade to the GTech-R version which does torque graphs. Perhaps you are wondering if I may have hastened its demise? Ill leave that question unanswered.

Very shortly I shall have in my posession the following items;

• LS6 Intake
• 28lb injectors
• OTRCAI
• Short throw shifter

These plus my 220/224 cam = more tuning fun.
I have tentatively booked in late Feb for the cam and other parts install. Though Ill put the shifter in myself beforehand.

Idle thoughts..

Firstly a clarification of an earlier post on KR. Tordne brought to my attention the fact that I mentioned voltages fluctuations can indicate false knock etc. More correctly this is fluctuations in the recorded KR, which does relate to voltages obviously, but the item to log and observe is the KR in degrees, not a voltage reading. I dont want to edit previous posts except for grammar as I think it shows the learning process more clearly where there is slightly confusing statements, but thought this was worth mentioning anyway.

Ok so after more reading and yesterdays trials I think I now have a good understanding of Throttle Follower and Cracker settings and they actually have nothing to do with idle! They are for transitioning to and from idle.

A lot of the idle tables are inter-related and some effects that appear similar can be down to other tables, here are my current thoughts on 2 off the idle transition tables.

If you have an issue when coasting and going into neutral where rpm rises I think this will be a Cracker issue, you need to reduce the cells where the problem occurs.

The Follower is for leading into and out of throttle transitions so rpm's ramp in and out rather than hammering in and out. (Perhaps to prevent wear on the driveline!?)

The desired airflow (RAF in HPTuners) and IAC Parked Airflow tables are the ones to give you a smooth parked idle from cold to warm.

So if your vehicle bogs off the line, you should look at the Follower values, if it rasies or drops rpms coming to a stop its likely the Cracker tables (during shifts also consider the Follower as it decays airflow on throttle reductions).

If you put too much Follower in you might need to reduce the Cracker accordingly.

Also as per my previous post if you want more off idle throttle response take a look at the Follower tables (The the added airflow and multiplier ones)