Discussion and questions related to the course Road Tuning
I do some infrequent tuning - and this weekend I’ve been playing around with the sprint car again following a turbo upgrade.
My equipment is a Smiths Racing “The Knock Box” and a Phormula KS3.
I’m seeking some advice on the settings for the KS3 and also some general advice.
The engine is a 3SGTE on an MR2, with a Garrett GT30 turbo; forged and all the other whatnots you’d expect for an uprated engine.
The question is: for anyone who has mapped a 3SGTE and used a KS3 (/4), what settings have they found useful?
I have The Knock Box sensor mounted in the standard factory position. The KS3 is mounted on the top surface of the cylinder head.
The pistons are standard sized - 86mm - so the Phormula web site suggest 6.7ish frequency.
I have a choice of 6.5 or 7.0 on the KS3, so I’ve chosen 6.5. I have gain of 6 and on regular pull get about 35 on the readout.
Now then... here’s the reason for my question...
I’ve worked UP TO the ignition values provided by Andre for a turbo charged engine. I’m working at about 1.2 bar (220 kpa) ... based on the suggested startup figures I should be on about 15 degrees advance at 200, a bit less at 220.
At these figures, the car drives fantastically on a pull. Some research on similar engines suggest these starting figures are actually a general sweet spot for these engines (my research may be on flawed data!)... in the headphones I can’t hear anything major - although paranoia make me think I can... but the KS3 sometimes registers a 50 readout and a warning.
Now I could be missing the sounds. While I do think I know what det sounds like, I found that advancing even a further 6! Degrees made no difference to what I heard, nor what I see on the KS3.
Sorry for the long intro - but I would appreciate any experience on these engines, which I’m pretty sure are knock limited, and also any experience in successfully configuring the hardware mentioned.
This is a hobby car, so the objective is not to push the boundaries and to be safe to the engine.
I haven't used the Phormula KS3/4 so can't comment on specific settings. Please understand that the base ignition table numbers that we give in the course are only approximate and won't be safe for every engine. You still need to use knock detection and may need to retard the timing below the suggested numbers in some instances.
I recommend starting out by purposely introducing some light knock 2500-3000 rpm and moderate load so you can audibly hear the difference between knock and background noise.