Lets talk tuning (KiDo Tunes)

[mynameisdaniel]

I'm still on 98RON.

Yeah, I was just referring to seeing Matt in SA next time he's here

[jay.ritchie]

Timing Chain rattle appears to have gone

Thats really interesting
I've had the passenger side tensioner replaced before, and even after that theres still a bit of noise about.
Matt might be able to help me out with that one when i get a re-tune!

[Robbks]

I don;t have the full def's to see what changes has been made to the AVCS tables,
but it may also be a factor of the different DBW which has a much smoother/ linear ramp-up than the stock ones>
so when I squeeze the throttle at the 2000-2500rpm area I would expect to see the AVCS angles not changing by so much over such a small load range, I never logged that on the stock map.
So as such the slower change in requested torqueis allowing the AVCS angles to change at a slower rate, maintaining oil pressure to the tensioner and reducing the rattle.

Bit more feedback re fuel consumption

Pre-tune, if I filled the car and only drove to work and back (20km round trip) ave fuel consumption would be up around 12.4L/100km
A whole tank (50L fill up) would last 400km

Post-Tune, I filled up on Thursday morning before work. So have now done 3 trips to and from work under the same conditions as any other day.
Fuel consumption is down to 9.0 L/100km
On current consumption. That will stretch the same 50L to 550km

Now what can be done about my Pig of a 2.5NA Gen3 that uses 13.5L/100km for the same cycle

[alexeiwoody]

I don;t have the full def's to see what changes has been made to the AVCS tables,
but it may also be a factor of the different DBW which has a much smoother/ linear ramp-up than the stock ones>
so when I squeeze the throttle at the 2000-2500rpm area I would expect to see the AVCS angles not changing by so much over such a small load range, I never logged that on the stock map.
So as such the slower change in requested torqueis allowing the AVCS angles to change at a slower rate, maintaining oil pressure to the tensioner and reducing the rattle.

Bit more feedback re fuel consumption

Pre-tune, if I filled the car and only drove to work and back (20km round trip) ave fuel consumption would be up around 12.4L/100km
A whole tank (50L fill up) would last 400km

Post-Tune, I filled up on Thursday morning before work. So have now done 3 trips to and from work under the same conditions as any other day.
Fuel consumption is down to 9.0 L/100km
On current consumption. That will stretch the same 50L to 550km

Now what can be done about my Pig of a 2.5NA Gen3 that uses 13.5L/100km for the same cycle

That's a fairly dramatic change in fuel economy. Was this tune done with a wideband sensor?

[KiDo_Tuning]

I don;t have the full def's to see what changes has been made to the AVCS tables,
but it may also be a factor of the different DBW which has a much smoother/ linear ramp-up than the stock ones>
so when I squeeze the throttle at the 2000-2500rpm area I would expect to see the AVCS angles not changing by so much over such a small load range, I never logged that on the stock map.
So as such the slower change in requested torqueis allowing the AVCS angles to change at a slower rate, maintaining oil pressure to the tensioner and reducing the rattle.

Bit more feedback re fuel consumption

Pre-tune, if I filled the car and only drove to work and back (20km round trip) ave fuel consumption would be up around 12.4L/100km
A whole tank (50L fill up) would last 400km

Post-Tune, I filled up on Thursday morning before work. So have now done 3 trips to and from work under the same conditions as any other day.
Fuel consumption is down to 9.0 L/100km
On current consumption. That will stretch the same 50L to 550km

Now what can be done about my Pig of a 2.5NA Gen3 that uses 13.5L/100km for the same cycle

That's a fairly dramatic change in fuel economy. Was this tune done with a wideband sensor?

You are aware that the front O2 sensor when AFR's in the Open Loop fuel table are leaner than the Minimum Active Primary Open Loop Enrichment, that the ECU ensures full Stoich fuel trims(ie 14.7:1) are applied via AF Learning and AF Corrections. The stock tunes DBW is so 'erratic' that it has constantly throttle tip in enrichment which makes the ECU see a rich spike, then a lean spike as AF correction is applied and sends it into a reduction sine wave of corrections until it stabilises etc

Also, since the H6 is NA, the factory wideband O2 sensors actually function correctly since the turbo models suffer from exhaust back pressure pre-turbo which throws out the stock WB readings. The H6 wideband values are actually EXTREMELY close to actual exhaust port AFR wideband values. Stick a WB up the tail pipe of a H6 like in a dyno situtation and the catalytic converters ruin the tailpipe AFR's

[Robbks]

That's a fairly dramatic change in fuel economy. Was this tune done with a wideband sensor?

nope,

But I've had a wideband up it before the tune and confirmed that the OBDII data is consistent and correct.

You can run engines very lean if you can keep the timing and EGT's under control.
And you need to be a LONG way lean on an NA before you're running into issues. SO much so that performance will have well and truly gone out the window.

looking at logs before I had it tuned you would see a massive rich spike on any movement of the throttle which just kills economy,
all i see now is the tiniest bump if anything at all, which shows the tip-in is spot on for maintaining the desired AFR without putting in any more fuel than necessary.
Some cars like a little more fuel on tip-in than others for snappier response,
But my old GT forester was happier with running lean on tip-in in normal driving. Just something about the combination of free-flowing exhaust and intake, but with a small TD04 and lots of timing.

[alexeiwoody]

Thanks matt, no I didn't know that back pressure affects AFR reading

Great to hear about the new and improved tune, looks like your hard work is paying off

[Robbks]

Thanks matt, no I didn't know that back pressure affects AFR reading

Pressure, Temperature, Flow Rate, etc all are all very closely related items in thermodynamics

[alexeiwoody]

Thanks matt, no I didn't know that back pressure affects AFR reading

Pressure, Temperature, Flow Rate, etc all are all very closely related items in thermodynamics

LOL (at the picture)! I'm happy you know your thermodynamics, but could you explain what any of those have to do with the oxygen sensor? As far as I know the sensor doesn't measure flow rate, temp or pressure, but the difference in oxygen concentration between exhaust and the atmosphere.

Matt, am I right in assuming that the back pressure effect you're speaking of is relatively small - within say 0.5 from the 14.7 stoich? Since exhaust back pressure only sits around 1psi

This is turning out to make me think a wideband isn't so necessary unless to be doubly sure your std ones are doing their job

[dr20t]

Depending on the system and also the amount of boost/ ve of the engine, exhaust restriction can be up to 7psi from what I've seen (yes this is a huge amount and an anomaly)

0.5 afr differential is substantial.

[alexeiwoody]

Depending on the system and also the amount of boost/ ve of the engine, exhaust restriction can be up to 7psi from what I've seen (yes this is a huge amount and an anomaly)

0.5 afr differential is substantial.

I mean on average in a stock or just a simple TBE system running fairly normal boost between 14-19psi, it should be around 1 psi right?

And my wideband reads 0.4 leaner than the std O2 sensor. Probably won't make a difference of 550 to 400km though?

[Robbks]

could you explain what any of those have to do with the oxygen sensor? As far as I know the sensor doesn't measure flow rate, temp or pressure, but the difference in oxygen concentration between exhaust and the atmosphere.
This is turning out to make me think a wideband isn't so necessary unless to be doubly sure your std ones are doing their job

while the oxygen concentration will be the same per unit volume of exhaust gas when pressurised,
the oxygen sensor itself is basically designed to count individual oxygen atoms (ions), but it is designed in such a way that it assumes near atmospheric pressure.
When you pressurise that gas, you're physically pushing more oxygen atoms into the pumping cell of the sensor, so you're skewing the readings of the sensor.

When you move onto back-pressure and temperature relationship,
The o2 sensor needs to operate around 700-900'F but if you restrict the flow and create back-pressure you're either going to put the EGT's through the roof if the flow rate remains constant (same principle as a turbo will apply more heat for the same flow-rate at higher boost pressure)
Or you're going to lower the flow rate.
Either way, you're affecting the o2 atom count and throwing off the accuracy.

And my wideband reads 0.4 leaner than the std O2 sensor. Probably won't make a difference of 550 to 400km though?

That's not the issue with economy. Open Loop AFR's can be whatever you want.
it's the amount of EXTRA fuel that's injected every time you move the throttle, called "Tip-in Enrichment" that causes the problems.
factory tunes always pump in too much fuel, and with bad DBW logic (lots of throttle opening changes for small accelerator movements) the effect is amplified.

[dr20t]

Very good description

[Robbks]

Very good description

It's been 10 years since I studied that sh!t and though't I'd forgotten everything.
I'm amazed it's all in there somewhere

[bigBADbenny]

Very good description

+1 AWESOME