How well does the GTP run on 10% ethanol

[K15004X4]

I live in the midwest and around here a 10% ethanol mix is available at gas stations cheaper than regular. Now I understand that the GTP does not run well on 87 octane but what about a 10% ethanol mix - which I believe is 89 or 91 octane?

[richtazz]

two things. Ethanol is corrosive to fuel system parts and doesn't yield the same thermal output as gasoline. Since higher octane fuels burn slower that low octane fuels (that is how they reduce knock and thus KR) and ethanol burns much slower than gasoline, that is how Ethanol "raises" the Octane. I don't own a GTP, so I can't say for sure, but in past experience, I didn't have good luck with Ethanol fuels, especially in Hi-perf applications.

[Madmunky]

My GTP ('95 w/ 3.4L DOHC) runs just fine on 87 Octane gas, I thought about going to a higher octane, but why bother if I don't have to...can anyone give me a reason too switch?
My mother used 10% Ethanol in her '01 Grand AM (3.1L) and she found that she was having problems with starting, she switch back to regular pump gas and no more problems.
Jamie

[GMMerlin]

High ethanol content in fuel WILL cause undesirable driveability concerns.
Also, alcohol absorbs water and this is why high alcohol content fuels will damage fuel systems.

[K15004X4]

I run 87 octane in all of my other vehicles with no problems at all. Now my question is specifically for the GTP's supercharged 3.8. GM's reccomendation as well as other GTP owners is to use premium fuel. Will 89 or 90 octane 10% ethanol blend work or is necessary to use high octane non-ethanol gas?

[richtazz]

To keep KR under control, use Premium gas. My mother-in-laws Park Ave Ultra runs like crap on 87 or 89 octane. We took a trip and she filled up before we left with 89 octane, we got 22-23 mpg on the highway (flat road, cruise set at 75mph) on the way there. We filled up for the return trip with 93 octane, and got 28-29 mpg over the same route. And no, we didn't drive uphill against the rotation of the earth into a head wind on the way there and draft a semi downhill on the way back. I would stick with premium, for the better mileage alone. Ethanol mixed fuels are not a good substitute for "real" premium fuel, especially in a supercharged engine that requires it.

[regalfriend]

Speaking of fuel additives...In New York, i believe it is law that all gas sold is oxygenated....im not sure what this is...i was told its used only during the cold months, and is used to help prevent the depletion of the Ozone....any comments?

[ericn1300]

Originally Posted by GMMerlin

High ethanol content in fuel WILL cause undesirable driveability concerns.
Also, alcohol absorbs water and this is why high alcohol content fuels will damage fuel systems.

yes, alcohol does asorb water. thats why "gas driers" such as STP are mostly alcohol. the water is carried by the alcohol thru the combustion process as is removed from the fuel system. as an occasional additive it can be useful, but i avoid using 10% fuel as a rule because alcohol is a solvent that strips the benificial oil products off engine parts such a cylinder walls and rings, shorting the life of engines not specificaly designed for it's use. most modern vehicles have fuel guidelines included in the owners manual, including instructions on us of ethanol gas.