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Road tuneing ignition timing

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Hey guys and gals, im doing some road tuning on my turbo starlet using a stethoscope thats attached to the block via tubing on the intake side between cylinders 2 and 3 about 20mm down from deck height. I can hear pinging quite well with this setup.

I have a dip in my timing at about 3.5-4.5k where it makes peak torque but have had to run the timing pretty low here under full boost (14psi) to be rid of the pinging like around 8 btdc degrees. This to me seems too low in the timing department but it pings at anything higher.

Engine is 1.3L, 9.5:1 comp, 14 psi using 98octane fuel. Max timing at 6K is aprox 11-12degrees under full boost. Am I losing the plot ??

Timing retard is aprox 3 numbers more than boost pressure

Check if you have a timing drift. The toyota 24+1 trigger tend to advance timing with RPM

Provided your knock detection stethoscope is able to pick up knock accurately then you need to trust this. the timing numbers you're seeing are probably in the ballpark with my experience. 9.5:1 is quite high compression for pump gas and 14 psi so it wouldn't surprise me.

Thanks for the replies, I have checked with a timing light vs what the handset is telling me all the way to 32 degrees and its consistent.

So what ive done is dialed the boost back to 10psi (for safety) and crept up on the timing, with a maximum 16 degrees at 6000 rpm able to be used without detonation.

I guess ill just keep tuning it bit by bit till I can get back up to 14 psi again

You will find as you reach peak torque the knock limitations will become apparent, there are a few ways to get around this but the easiest is to switch to a higher octane fuel or start adding additives to boost the octane. After you pass maximum torque you can begin to add more timing in, the best way to find out if your reaching MTBT is to hire a dyno out for an hour or so to make sure your not advancing the timing past this point needlessly

Very normal timing numbers IMO.

~5* at peak boost for that kind of boost pressure and CR is pretty common for what I would expect also. I would say depending on how stable your fuel is and weather is, you may be pushing your luck running that much advance year round even.

I'm also going to add my experience - This normal.

All engines are different and make different power at different timing numbers.

Here are some examples:

(98ron fuel, decent intercoolers etc)

RB25, 9:1, GT3076, 20psi - Could only get about 14 degrees advance in without detonation.

RB26, 8.7:1, twin GT2860, 20psi - Could get around 22 degrees in before detonation. (26 degrees+ with E85 and heaps more power)

The size of your turbo (If it's pushing out of it's efficiency rage and heating the air) could be an issue. Static Compression ratio plays a part too.

Seen some other engines only take about 8 degrees, but make 500hp+. It's all about the design of the engine. Shouldn't be looking at the actual numbers on the table, but more so the output vs the bolt-ons.

Do you have access to E85 or a water methanol injection kit?

I've tuned a lot of 4eftes and at that cr it sounds about normal 9.5 is pretty high man

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