How much fuel used during a regen?

IXLR8 · Sep 27, 2019

I did a few searches, here and Google, and couldn't find this info.
I was wondering how much fuel is used during a regen?
I know it is going to vary some depending on various factors but I figured there would be a range of fuel used.

JELLOWSUBMARINE · Sep 28, 2019

Good question. I've seen others claim up to 5mpg gain with delete and tune. you also need to factor in the tune will swing toward efficiency over EPA smog. I've read many seeing 200 mile regens. I've also read it should be once a tankish. I've only put less than 5k and cant say mine yet.

Different driving probably is biggest factor?

Matt927 · Sep 28, 2019

I do not have the information you are asking for. But at idle I see approximately .20 GPH consumed. At idle during an active regen with EGTs stable at 1000 degrees F, I see fuel consumption at .70 GPH.

IXLR8 · Sep 29, 2019

Matt927 said:
I do not have the information you are asking for. But at idle I see approximately .20 GPH consumed. At idle during an active regen with EGTs stable at 1000 degrees F, I see fuel consumption at .70 GPH.

This is the best info I have seen so far, thank you.

03GolfTDI · Sep 30, 2019

JELLOWSUBMARINE said:
Good question. I've seen others claim up to 5mpg gain with delete and tune. you also need to factor in the tune will swing toward efficiency over EPA smog. I've read many seeing 200 mile regens. I've also read it should be once a tankish. I've only put less than 5k and cant say mine yet.

Different driving probably is biggest factor?

If it regenerates while doing some steady state driving (freeway or state roads) you really won't notice it go in an out of regen. It's really around town driving you will notice the increased idle speed and the fans running full tilt. It would surprise me if yours has not regened in 5k miles, there is a set mileage limit where a regen is performed whether the DPF needs it or not.

Mine is performing a regen every ~170-180 miles, mainly due to mostly short tripping the car.

JELLOWSUBMARINE · Sep 30, 2019

JELLOWSUBMARINE said:
Good question. I've seen others claim up to 5mpg gain with delete and tune. you also need to factor in the tune will swing toward efficiency over EPA smog. I've read many seeing 200 mile regens. I've also read it should be once a tankish. I've only put less than 5k and cant say mine yet.

Different driving probably is biggest factor?

03GolfTDI said:
If it regenerates while doing some steady state driving (freeway or state roads) you really won't notice it go in an out of regen. It's really around town driving you will notice the increased idle speed and the fans running full tilt. It would surprise me if yours has not regened in 5k miles, there is a set mileage limit where a regen is performed whether the DPF needs it or not.
Mine is performing a regen every ~170-180 miles, mainly due to mostly short tripping the car.

Right, I think it may be regening fairly often as its only occasionally been on a few longer steady high speed jaunts. Although I ve only witnessed 1 heated, both fans on, shut down. The wife runs it around town alot and hasnt always paid attention to this. The DPF is brand new also. I have convinced her to make a practice to idle it about 60 seconds before shut off. I have a new turbo timer I may have installed and I will be adding a polar fis for input sake. So...?

Geordi · Oct 4, 2019

The last cycles mine did, were 20 miles and 2 days apart. I let it finish both times, and it pi$$ed away over a gallon each time. When it started doing a THIRD regen about 3 days later, I had enough. I guess the goal of the reprogramming and "fix" is to make the engine make THE MOST emissions possible by putting 100% of the fuel right into the trap and not use any of it to turn the wheels. When a small diesel becomes as inefficient as a class 8 truck, that must make the EPA smile - their goals have always been to completely eliminate diesel from the marketplace. It is utter lunacy.

Pharcyde145 · Oct 4, 2019

Since the "Fix" regens happen much more frequently. I usually get a small/quick regeneration roughly every 150 or so miles not lasting more then 5-6 minutes. I experience longer regens every 3-400 miles.

My gut feeling is this is heavily dependent on how you drive your vehicle. If you do frequent short trips, almost always shifting at low revs you're going to build up more ash and carbon which the car will recognize and take steps to counter act. The "Fix" only made this process more sensitive, meaning it will happen more frequently because of the conditions you are subjecting the car to. If you drive longer trips and allow the vehicle to come fully up to temperature and stay closer to the middle of the power band (3-4K rpm) the ash/carbon accumulation will still happen, but with less frequency than the first scenario.

Obviously everyone's commute situation is different, but see if you can change things slightly and if you see a difference be sure to let us know. And if you're truly sick of it, just delete and tune if you live in a place that doesn't test for emissions. Good luck!

JELLOWSUBMARINE · Oct 4, 2019

Geordi said:
The last cycles mine did, were 20 miles and 2 days apart. I let it finish both times, and it pi$$ed away over a gallon each time. When it started doing a THIRD regen about 3 days later, I had enough. I guess the goal of the reprogramming and "fix" is to make the engine make THE MOST emissions possible by putting 100% of the fuel right into the trap and not use any of it to turn the wheels. When a small diesel becomes as inefficient as a class 8 truck, that must make the EPA smile - their goals have always been to completely eliminate diesel from the marketplace. It is utter lunacy.

Time for a tune and delete IF possible. How are you getting your regen fuel used figures?

03GolfTDI · Oct 4, 2019

Geordi said:
The last cycles mine did, were 20 miles and 2 days apart. I let it finish both times, and it pi$$ed away over a gallon each time. When it started doing a THIRD regen about 3 days later, I had enough.

That is crazy - my car has done something similar once. Last Thursday it started regen on my way to work, was early for work so sat in the parking garage until it completed (it was prob ~10 mins total), 2 days later on Saturday bringing it to the dealer for an oil change I did not notice the regen start and just shut it down once I got to dealer and sure enough cooling fans stayed on and the regen burning smell was evident.

That was the only time it has done that, figured it was a fluke but will monitor.

Geordi · Oct 5, 2019

JELLOWSUBMARINE said:
Time for a tune and delete IF possible. How are you getting your regen fuel used figures?

Scangauge telling me the GPH, multiplied by the time the fans were at full blast.

I don't remember the number now, but I checked with vag-com and the DPF trap wasn't full but it also wasn't empty like a "freshly fixed" VW should be. I don't need to worry about that anymore though, that was before Christmas last year when I'd only had the car for 2 months. Shortly after that, I hit a pothole and that problem was resolved.

Now I'm just thinking about swapping tunes, it seems that the Malone might be using too much fuel and there's more economy to be found.

jackbombay · Oct 6, 2019

Matt927 said:
at idle I see approximately .20 GPH consumed. At idle during an active regen with EGTs stable at 1000 degrees F, I see fuel consumption at .70 GPH.

Geordi said:
it pi$$ed away over a gallon each time.

Your regen lasted 2 hours?

If regen bumps up fuel consumption from .2 to .7 GPH that is an increase of .5 GPH, to use 1 gallon at a consumption rate of .5 GPH takes 2 hours.

Geordi · Oct 6, 2019

Congratulations, you can math.

Mine showed a consumption of 1.1 per hour, and it took about 45 minutes before it calmed down both times.

JELLOWSUBMARINE · Oct 6, 2019

Geordi said:
Scangauge telling me the GPH, multiplied by the time the fans were at full blast.

I don't remember the number now, but I checked with vag-com and the DPF trap wasn't full but it also wasn't empty like a "freshly fixed" VW should be. I don't need to worry about that anymore though, that was before Christmas last year when I'd only had the car for 2 months. Shortly after that, I hit a pothole and that problem was resolved.

Now I'm just thinking about swapping tunes, it seems that the Malone might be using too much fuel and there's more economy to be found.

Thanks all for the GPH input. My Polar FIS will be in soon, hoping it will be very useful info related to DPF. My DPF is 5k new with mixed driving so Im anxious to see its status also. Unfortunately I cant seem to find anypotholes here in California but hope to find some in another state soon. BTW Ive been looking into tunes. The Kerma seems like my direction but doesn't do delete (future)?... The great debate

Geordi said:
Congratulations, you can math.

Mine showed a consumption of 1.1 per hour, and it took about 45 minutes before it calmed down both times.

ha ha!
I wonder if external temps effect regen much? Again thanks all on your regen info.

jackbombay · Oct 6, 2019

Geordi said:
Congratulations, you can math.

Yes, I learned it in elementary school.

turbobrick240 · Oct 6, 2019

It will take well over 200k miles for the delete to pay for itself in fuel savings. The real benefit is increased reliability. The downside is violating federal law. Pick your poison.

notabiker · Oct 9, 2019

Matt927 said:
I do not have the information you are asking for. But at idle I see approximately .20 GPH consumed. At idle during an active regen with EGTs stable at 1000 degrees F, I see fuel consumption at .70 GPH.

Dang my scangauge shows .21-.22 at idle and only something like .36 during a regen, at least that's what I remember, and I would remember if it was up past .50 GPH.. At least I think I'd remember, it's hell getting older.

03GolfTDI said:
That is crazy - my car has done something similar once. Last Thursday it started regen on my way to work, was early for work so sat in the parking garage until it completed (it was prob ~10 mins total), 2 days later on Saturday bringing it to the dealer for an oil change I did not notice the regen start and just shut it down once I got to dealer and sure enough cooling fans stayed on and the regen burning smell was evident.

That was the only time it has done that, figured it was a fluke but will monitor.

Dang, I had a regen pop up just before shutting down and I didn't realize until I shut the engine off. What I do is restart and hold a high idle of 1k-1.2k to flush the heat out and then shut down once the E3 temp sensor drops to 450F (read that that is the temp nearest the exhaust side of the turbo somewhere on here).

Matt927 · Oct 10, 2019

notabiker said:
Dang my scangauge shows .21-.22 at idle and only something like .36 during a regen, at least that's what I remember, and I would remember if it was up past .50 GPH.. At least I think I'd remember, it's hell getting older.

This is during a full active regeneration, with EGTs hovering around 1000 degrees F at idle, higher while driving and the DPF maintaining close to the same. These regens, as noted by others are also lasting longer.

The smaller passive regens that occur throughout the drive cycle, now more frequently, I see a lower fuel flow rate. Similar to your observations.

How much fuel used during a regen?

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