Ultra Low Sulfur Diesel - Regs & Discussion

[More Power]

Good catch! I guess I had 2007 on the brain....

I'll have a new article on the web site before long that shows the LMM components and describes how the new emissions system operates. I recently got an opportunity to shoot some photos.

I was a little surprised that the new diesel particulate filter isn't serviceable, and that more of the exhaust system is welded together. This might be due to a wish by GM to prevent tampering - though the interconnectivity of the exhaust system and the electronics will prevent much alteration anyway. It'll be interesting to see how the aftermarket responds, and how long it'll take them to produce products for the LMM (or any new diesel).

Jim

[convert2diesel]

Just a question about the chemistry. Having just returned from our annual 3,000 mile trek to the deep south (Ottawa - Florida return) I have been reviewing my mileage figures and discovered that somewhere I seem to have lost about 2 MPG on average. The two previous trips with this combination (6.2 na in a Buick Roadmaster with a 3,000lb camper out back) I got a consistant 28 MPG (IMP gal) throughout the trip. This time it worked out to 25-26 MPG.

This is the first time I have done the trip exclusively on ULSD. When they strip out the sulphur more then likely all of the other aromatics come with it. Is it possible these components added BTUs to the fuel? Up here in Canada we have yet to see ULSD on a consistant basis (or at least they are not advertising it) and this is the first time I could be sure I was using it. The car ran like a champ and I did use Power Service additive except for a couple of tanks of B5 but I can't seem to account for the drop in mileage.

Has anyone else noticed a similar difference?

Bill

[More Power]

I've read where the new ULSD contains about 1% less density, which could translate to a similar percent lower fuel economy. The local driving I'm doing here in Montana with ULSD hasn't produced much of a change in fuel economy. The last tank in our 2001 GMC produced about 17.5-mpg, which is normal for local driving (based on the prior 6 years of driving the same truck).

I suspect some fuel station owners are hesitant in labeling their pumps with ULSD stickers because of the fine that could be imposed if a sample is taken and they fail the 15-ppm sulfur limit. All of the stations I know about around here have been getting ULSD since about June of last year. It could take some time for the older fuel to be completely flushed out of the system, unless the station sells a lot of diesel fuel. Waiting a while before installing the new stickers may be an insurance policy against non-compliance.

Jim

[Dakster]

Good catch! I guess I had 2007 on the brain....

I'll have a new article on the web site before long that shows the LMM components and describes how the new emissions system operates. I recently got an opportunity to shoot some photos.

I was a little surprised that the new diesel particulate filter isn't serviceable, and that more of the exhaust system is welded together. This might be due to a wish by GM to prevent tampering - though the interconnectivity of the exhaust system and the electronics will prevent much alteration anyway. It'll be interesting to see how the aftermarket responds, and how long it'll take them to produce products for the LMM (or any new diesel).

Jim

I looked underneath my new truck today and noticed that the entire exhaust system is welded together. No "Off-Road" only pipe is going to replace the DPF easily...

Like you said electronics will most likely prevent it, but with programs that re-write ECM/PCM code, that can always be changed too...

Since the DPF should have a life expectancy of 200k miles give or take, cutting it off, cleaning and rewelding wouldn't be that big of a deal. By then, if this motor is truly like the LBZ I can see replacing the exhaust system, repgramming the computer, etc... By law, you can't tamper/modify a working, under warranty exhaust system and I doubt the DPF has a 200k warranty...

BTW, the selling dealer made me sign a "I won't tamper/remove emmission components from the Truck paperwork..."