Archives

MTBE was removed from the pumps after it was found out it contaminated water supplies.

Can anyone remember if it did anything to fuel economy?

IIRC, MTBE polluted ground water, was a known carcinogen and neurotoxin, but did not affect MPG.

Sidenote:

Other oxygenates including ETBE are available but not used due to cost AFAIK.

I found some studies a while back, can't find them now. What I remember is this:

E10 = 3.x% reduction in mpg.
MTBE = ~1.5% mpg loss. It's better than ethanol, but still not as good as real gas.

Why does fuel need to be oxygenated, anyway?

Why does fuel need to be oxygenated, anyway?

Oxygenated fuel burns much cleaner and produces less pollution (esp. smog-forming ozone). A consequence of the 70s environmental disasters.

We (in Hungary) have a type of fuel that's advertised as having (bio) ETBE as additive (MTBE is no longer used). I filled several times with it and did not experience any measurable difference to the usual E5. Well, whatever. The difference may be there, just too small to notice it.

http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

Gasoline: 114,000 btu/gal
10% mtbe: 112,000 btu/gal

So, about 1.7% drop in energy content. Tests have shown mpg variance to roughly match btu content.

IIRC, MTBE polluted ground water, was a known carcinogen and neurotoxin, but did not affect MPG.

At levels found in ground water MTBE has not been a health threat. It has ruined the taste and smell of water at minute levels unfortunately.

From wikipedia:

The IARC, a cancer research agency of the World Health Organization, maintains MTBE is not classifiable as a human carcinogen. MTBE can be tasted in water at concentrations of 5 – 15 µg/l.[15]

MTBE is not classified as a human carcinogen at low exposure levels by the International Agency for Research on Cancer (IARC).[16] However, exposure to large doses of MTBE carries significant non-cancer-related health risks.

As of 2007, researchers have limited data about the health effects of ingestion of MTBE. The United States Environmental Protection Agency (EPA) has concluded that available data are not adequate to quantify health risks of MTBE at low exposure levels in drinking water, but that the data support the conclusion that MTBE is a potential human carcinogen at high doses.[17]