UFO mods for diesel EGR Delete

[UFO]

I have finished data gathering with my EGR delete device, and now am back to running the factory EGR. I averaged 42.7 mpg over two tanks using pump diesel; I added very little biodiesel, as it's too cold and I failed to stockpile any blends for the winter. That's a little better than I usually can do with straight ULSD, but I had the grille partially blocked.

It's obvious again how much heat is put into the coolant with the EGR cooler. At 30F, my coolant rose to 205F on my morning drive. With the EGR deleted at this ambient temperature, I usually did not see the coolant rise over the thermostat setting of 190F.

[oil pan 4]

EGR can warm an engine up faster, you could have the best of both worlds and do an on demand delete. EGR on for warm up and off the rest of the time, if thats even possible with your vehicle.

[COcyclist]

Originally Posted by UFO

It's obvious again how much heat is put into the coolant with the EGR cooler. At 30F, my coolant rose to 205F on my morning drive. With the EGR deleted at this ambient temperature, I usually did not see the coolant rise over the thermostat setting of 190F.

This is precisely why I have kept mine operational. There is a Malone tune that retains the EGR until the engine is up to temp. I will follow your results with interest.

I was surprised to read that you feel you get better mpg on Bio-D than on regular ULSD. I just assumed I would lose mpg like you do using E-85 in a gasser.

[UFO]

Originally Posted by COcyclist

This is precisely why I have kept mine operational. There is a Malone tune that retains the EGR until the engine is up to temp. I will follow your results with interest.

I was surprised to read that you feel you get better mpg on Bio-D than on regular ULSD. I just assumed I would lose mpg like you do using E-85 in a gasser.

It surprises me too. I have not done an A-B-A, but it would be very easy to do once the weather warms. At the moment all my fuel logs show it, but you cannot separate the seasonal effects from the logs. But it looks consistent, my higher blends typically show 2-5 mpg better on high biodiesel percentages. I attribute the higher cetane numbers of the bio as partly responsible, as ULSD I think is running at the low end of 40, and it has less energy in it than the old LSD. I would bet the energy content of biodiesel is now nearly equivalent to ULSD.

[UFO]

I'm in the final phase of testing my EGR delete. My first full tank of fuel with EGR re-engaged compares to the last two tanks with EGR diabled (w/no CEL).

w/ EGR 40.5, 42.2
no EGR 42.4, 43.1
w/ EGR 42.6

Weather and driving conditions have been varied, so I am testing over multiple tanks to hopefully average out the variation.

At this point it looks like EGR on the ALH TDI doesn't seem to impact fuel mileage much at all. Perhaps because the intake is not throttled like other turbo diesel EGR systems like my Jeep Liberty CRD, which did respond well to EGR delete.

[NachtRitter]

Interesting results... Thank you very much for going through the effort and sharing!!

[COcyclist]

Originally Posted by UFO

At this point it looks like EGR on the ALH TDI doesn't seem to impact fuel mileage much at all. Perhaps because the intake is not throttled like other turbo diesel EGR systems like my Jeep Liberty CRD, which did respond well to EGR delete.

Interesting results. We do have an "anti-shudder" valve in our TDIs. I was under the impression that it did choke off the intake to introduce more EGR when called for. Regardless, your mod does not seem to be making a large impact on mpg. Do you suppose any increase is being cancelled by longer warmup times? It would be interesting to see if a big highway trip would show mpg gains.

[UFO]

Yes, all of this data is from my daily 20 mile commute down I-25. It would be good to test on longer trips; I will keep this type of testing in mind if the opportunity comes up. I also intend to re-do this test with my commute this summer, of course the fuel will be B100.

I think I have compensated for the warmup time with the grille block, as I could not run it with the EGR enabled without my temperature rising over 200 before I got to work.

[UFO]

Mileage on my second tank with EGR re-installed spiked way up, not sure if it's the warming weather or what, I've changed nothing.

w/ EGR 40.5, 42.2
no EGR 42.4, 43.1
w/ EGR 42.6, 44.9

But with the warmer weather, I filled with B50 and deleted the EGR again. I may alternate tanks enabled and disabled, just to see if a pattern will emerge. At this point there is no indication EGR delete improves efficiency in my TDI.

[rmay635703]

If you manage to delete EGR safely let me know, my folks need to clean the intake and turbo nearly every year because of EGR, I found a guy with a Vag com but our car was inop at that time so we couldn't change anything.

Ah well, see if I can find him again.