Start tuning SR20DET

[kamilp1908]

Solution for me (-8% LTFT) is to reduce K const by about this 8% and check AFT in cruise conditions?

[PL]

Yeah but 8% of K won't necessarily translate to 8% on your fuel trims though.

I usually get my cruise mixtures about right using K/TIM, then see if I can get full boost fuelling correct using just fuel map values, then go back and check cruise mixtures and trim them out using injector latency if needed. Give that a go.

In reality it's often an iterative process where you go back and forth a few times trimming K/TIM, fuel map values and latency.

PL

[kamilp1908]

I have reduce K const about 8% (35600).
I now I have LTFT around 0% driving on 4th/5th gear with rpm around 2.5-3k.
I am happy

[kamilp1908]

Little update.
Last weekend I have made about 500km in cruising mode. Fuel consumption was 9.3L/100km. I think not bad for old turbocharged engine.

[PL]

Yeah that's not bad. They seem to be capable of being tuned for decent fuel economy on cruise. They do quite well for an old low compression engine. You'll never get great figures around town with lots of start/stop and acceleration - but at cruise and open road work they're OK.

PL

[kamilp1908]

I have made some on-road tunning and have attached 2 logs, both are made on 3rd gear.
Boost is about 1.0B from 3k to 7k. I had to stop tunning due to cluch started to slip

[kamilp1908]

Extra question to my timing map:
Is 15' from 4.7k to cutoff (7.6k) is correct for my setup? When I had 16' I have started to hear knock.

[Matt]

Proper tuning techniques suggest you adjust your timing until you reach peak torque. After this you cannot make any more power, and will start to reach the point of detonation. So if you are detonating at 16 BDTC then it is obviously too much

[bachig24u]

ensure to sync the spark advance with nistune before its used as reference.

often ULP fuel is knock limited under high load before highest torque can be reached so best watch the knock counts or that sweet rattle that SR's make before they crack plugs.

[PL]

SR turbo engines are knock limited in all but the mildest of tunes (or when running E85). So tuning often comes down adding timing til they start to knock and then backing it off a bit. So monitoring knock is critical. If you try to tune them by watching torque on the dyno and tuning for peak torque you will break them because they are quite happy to make maximum torque while suffering severe detonation.

They typically make peak torque in the midrange and that's where you have to pull timing out to avoid detonation. After that you have to sneak the timing back in so that you can make some power at higher RPM.

See image attached of what I typically use as a starting map. I've drawn a red line where you'd expect to see it trace when doing a full boost pull.

PL

SR ign timing map.JPG

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[kamilp1908]

This is how it looks for me when 1B hits about 3k rev and stay to cutoff.

timing.png

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Max TP on 3rd gear was 94 aroung 5.5k. But my clach started to slip from now.

log.png

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[PL]

Looks pretty good to me. You might wanna take a couple of degrees out of that last column so if boost increases it'll pull timing out.

PL

[kamilp1908]

Due to current situation (slipping clutch), I have made some logging in cruise mode ( 4/5th gear, around 2,5-3k revs, wideband O2 sensor, disabled std O2, trims reset to 0%).
This is how look AFR avarage trace for 2 log sessions (about 4-5 min of constant ride to my work):

trace_avg_afr_1.png

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trace_avg_afr_2.png

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Do You think it looks ok?

[kamilp1908]

In addition fuel map trails:

trail_fuel_1.png

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trail_fuel_2.png

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[kamilp1908]

Current ecu bin file with logs.