[DWR]

Originally Posted by Bob@BPC

The throttle is there for safety, The only time it will close when driving is when the DDE goes into limp home mode.

Throttle is primarily there for the EGR. Without it, EGR as an emissions control, won't work properly. The throttle creates a pressure differential between the exhaust pressure and intake manifold pressure. EGR delete negates the primary purpose of the throttle.

Regarding the safety comment, I would completely agree, if we were dealing with a mechanical injection system. Even in a common rail injection system, the throttle could be used to stop an uncontrolled over fueling situation. I see no evidence that is how the DDE behaves. Moreover, that situation is a very, very, low probability event with electronic injection. There is greater risk running methanol injection - luckily nobody here is doing that

Running without a throttle does result in more WOT airflow and negates the need for a BOV. On the other side, an improperly setup BOV can result in turbo overspeeding. Still, it does make a cool sound.

Just another point of view, not telling anyone what to do. Make your own decision

[robnitro]

A throttle does help with oil runaway. My tdi started to runaway and since i kept the asv throttle, I was able to stop the engine with key off. One of my pistons was cracked and the blow-by built up oil until it ran away. I originally thought it was a bad ring, btw.

Ignition off closes it for a bit, to prevent shut down shudder.
The strength of the engine pulling in air in a runaway condition keeps the throttle closed until it slows down.

[335dsleeper]

I deleted my throttle about 8k miles ago. I have no issues with shut down. I hit stop and it stops, just like it did before I removed the throttle.

Agreed 100% it’s help to prevent a run away engine and truth be told, it crosses my mind regularly. My plan in case of run away is to collapse the 90* silicone hose that connects my charge pipe to my throttle delete. Or... use the fire extinguisher I have in my car. Hopefully I never have a run away engine.

[TDIwyse]

Originally Posted by DWR

...
Running without a throttle does result in more WOT airflow and negates the need for a BOV. ...

DWR, do you have any manometer measurements across the throttle vs airflow? Just curious, as I played with that a couple years ago and didn't see what I considered to be an issue with drop across the throttle when it's wide open. As opposed to the EGR valve which caused a very significant issue. I like the throttle for the runaway concern and the smoother shut downs.

As an aside, I'm still running with the throttle and swirl flaps and am able to flow a pretty good amount of air, and do not see logged parameters that show evidence of turbo behaviors that would benefit from a BOV. But perhaps that's due to peculiarities with the tuning and system configurations specific to my vehicle?

[DWR]

Originally Posted by TDIwyse

DWR, do you have any manometer measurements across the throttle vs airflow? Just curious, as I played with that a couple years ago and didn't see what I considered to be an issue with drop across the throttle when it's wide open. As opposed to the EGR valve which caused a very significant issue. I like the throttle for the runaway concern and the smoother shut downs.

I honestly don't find a significant difference in shut down. Perhaps, I am insensitive.

Yes, the EGR was the biggest culprit, by far. However, as you know too well, a half a PSI here, half a PSI there, starts to add up. I never measured it with a manometer, as it showed up (just barely) on the gauges I use. If I did document the difference it would be in a Torque Track Recorder video - that I deleted long ago.

There is something else that happens. The manifold is always under some pressure. Lots more air flow at what would have been "part throttle" conditions. The turbo seems to be spin down slower and hence is more responsive in dynamic on/off throttle driving. Granted the effect is small, but not unwelcomed. It is very similar to the effect of a BOV, just no tuning needed.
335dsleeper have you noticed the same behaviour?

[DWR]

Originally Posted by TDIwyse

As an aside, I'm still running with the throttle and swirl flaps and am able to flow a pretty good amount of air, and do not see logged parameters that show evidence of turbo behaviors that would benefit from a BOV. But perhaps that's due to peculiarities with the tuning and system configurations specific to my vehicle?

I think everyone with hybrid turbos has experienced a change in transient response. Some are worse than others. The tuners spent a good deal of effort mitigating that. I know your setup is probably better than most, but it is not unaffected. At least in theory, a BOV could contribute positively. Bottom line, if you are happy and I am happy, it is all good.

[TDIwyse]

Originally Posted by DWR

...
Yes, the EGR was the biggest culprit, by far. However, as you know too well, a half a PSI here, half a PSI there, starts to add up. I never measured it with a manometer, as it showed up (just barely) on the gauges I use. If I did document the difference it would be in a Torque Track Recorder video - that I deleted long ago.
...

I've been looking for my old measurements of the throttle impact and can't find any documentation. Think I was lazy and just "watched" the manometer impact without documenting. Lots of data from boost/rpm/acceleration versus various TCU tunes, but not the throttle manometer stuff. Irritating... But thanks for replying.

[e90Noobie]

I know this is an old thread but it seems like this would be discussed and known a lot more then in one little thread if this was an actual issue for these cars.