Throttle stop testing on a diesel

[mwebb]

Originally Posted by JulianEdgar

Sounds good! Got some test results that you can share with us?

yes
2 of the initial baseline screen caps
with VCDS you can dial in the values , upper and lower for each parameter id or PID selected up to 10 PIDS , better to use fewer when you can collect what you need from just a few
less noise on the graph

instead of graphing , VCDS would log the data as csv and you could store longer samples and fuss with them using whatever office type software you are using

this is with Generic OBD2 not with VW KWP using measuring value blocks , engine data would be in address word 01

since i was / are only looking for change in in load OR MAF flow at a constant speed 3 PIDS in generic data was enough

my way is right for me , julian 's way is right for him
and what ever way YOU choose
will be right for you as long as what you choose has one constant that is repeatable
the variable will show improvement or lack thereof

[JulianEdgar]

Originally Posted by mwebb

yes
2 of the initial baseline screen caps
with VCDS you can dial in the values , upper and lower for each parameter id or PID selected up to 10 PIDS , better to use fewer when you can collect what you need from just a few
less noise on the graph

this is with Generic OBD2 not with VW KWP using measuring value blocks , engine data would be in address word 01

since i was / are only looking for change in in load OR MAF flow at a constant speed 3 PIDS in generic data was enough

my way is right for me , julian 's way is right for him
and what ever way YOU choose
will be right for you as long as what you choose has one constant that is repeatable
the variable will show improvement or lack thereof

Attachment 29914Attachment 29915

Yes I had VCDS on my Skoda Roomster, so I am familiar with it. But I was hoping for some comparisons of your different results with aero mods?

[COcyclist]

Originally Posted by JulianEdgar

What does this show when you do it windows up / windows down?

Good point. I did the testing using cruise control over my flat test road of roughly 2 miles (3K?) in my wheel cover test, before I saw the windows up/windows down idea. I may be able to test my testing method in the next few days. I will report back.

[COcyclist]

I had a few minutes today and dry roads before the storm coming in tonight so I decided to test my testing method. At Julian’s suggestion I did a total of 4 runs on my reasonably flat, straight 2 mile test road. 30 degrees F and winds calm (3 mph from the west according to the weather radio from the airport next to the road). I did an east and west run with the windows up and repeated the procedure with all the windows down and the cruise control set to 65 mph (63 on the GPS) for all runs. There was no other traffic on the road during the testing.

I averaged the windows-up runs and got 51.05 mpg.
I averaged the windows-down runs and got 48.05 mpg.

That is almost a 6% difference so I feel pretty good about the ScanGuage current mpg test model.

[JulianEdgar]

Originally Posted by COcyclist

I had a few minutes today and dry roads before the storm coming in tonight so I decided to test my testing method. At Julian’s suggestion I did a total of 4 runs on my reasonably flat, straight 2 mile test road. 30 degrees F and winds calm (3 mph from the west according to the weather radio from the airport next to the road). I did an east and west run with the windows up and repeated the procedure with all the windows down and the cruise control set to 65 mph (63 on the GPS) for all runs. There was no other traffic on the road during the testing.

I averaged the windows-up runs and got 51.05 mpg.
I averaged the windows-down runs and got 48.05 mpg.

That is almost a 6% difference so I feel pretty good about the ScanGuage current mpg test model.

Yes, that's a great result.

[diesel_john]

The adjustable fuel rack screw on my diesel rabbit reduces the fuel when I back it out. Would that work for "throttle stop" testing?
Or would a mechanical stop on top of the injector pump work better?
I do not know if there is a internal governor that can introduce variation at full rack.
I do know fuel temperature must be controlled from past testing.

[aerohead]

I wasn't aware that this thread existed, and just stumbled across it while digging into the past here at the Aerodynamics Forum, page-10.
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1) It would be technically improper to associate 'throttle stop' testing with any diesel vehicle.
2) Diesel-powered vehicles have an 'accelerator' pedal, not a 'throttle' pedal.
3) As, diesel engines do not have 'throttles.'
4) Diesel engines have no restriction of any kind in their inlet tract.
5) The diesel's pedal is associated with the Robert Bosch fuel injection pump, whether by direct mechanical means, or drive-by-wire, which modulates the 'racking' function of the pump, as mentioned in the most recent post.
6) What might be referred to as 'wide-open-throttle' on a gasoline-powered ICE engine might be compared to 'full-rack' on a diesel.
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7) Any discussion of a 'TPS', or its signal, on a diesel would also constitute an oxymoron, for the same reason as above.
8) A ScanGauge cannot intercept a TPS signal, as one doesn't exist.
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9) Testing, and interpreting data for a supercharged, or turbo-intercooled diesel would be a massive challenge, even in the absence of a ' stopped-rack.'
10) Data collected under 'logic death,' thermal non-equilibrium conditions, and uncorrected to SAE Standard 60-F, 29.92-inches Mercury, would essentially be 'meaningless'.
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11) One current proponent of the' technique', according to the 'math', allowed a 4.39% rpm excursion ( 123-rpms ) as acceptable on his 1991 Toyota DLX 4WD pickup's 2.4-liter IL-4 engine.
* On a 2022 Genesis G80 3.5 AWD, this would allow a 57-rpm allowable test window.
* On a 2023 Lamborghini Huraca'n Technia, an excursion of 285-rpm would be the limit.
Thought I'd mention it.

[freebeard]

* On a 2023 Lamborghini Huraca'n Technia, an excursion of 285-rpm would be the limit.
Thought I'd mention it.

Didn't know they are diesel. Learn something every day.

[aerohead]

Originally Posted by freebeard

Didn't know they are diesel. Learn something every day.

I'm just pointing out rpm constraints inferred but never specified by Mr. Edgar, nor VMAN 455.
VMAN455 was 'comfortable' with a delta-4.3928% rpm 'window' on his 1991 Toyota.
If this were to hold for the Genesis, only a 57rpm engine change would be tolerated during testing.
Mr. Edgar never provided any rpm parameters for Gasoline ICE, nor additional parameters for diesel ICE.
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TDI issues are self-explanatory.

[freebeard]

I left off the [/jk]

I thought I'd found someone to characterize my Lexus electrric axle. On the condition that if they liked it they could buy it, but if they didn't they'd tell me why.

All I got was that it wouldn't deliver power above 35MPH. I asked for your attention at Hot-rodding the Toyota MGR #406. Does it seem reasonable that an SUV AWD axle would only provide power at parking lot speeds, if it has a external oil cooler for trailer towing option?

GrayRaceCat gave it a shot at #407. They admitted they didn't try to spin it.