2006 XC70 and E15

[FarmallM51]

I just completed a 2500 mile trip and the friend riding along was fueling the car with 88 octane E15. My mileage increased from it's usual 23.5mpg to 24.7mpg average. After I dropped him off, and started using the usual 91-93 octane with 0-10% ethanol, I was back to my usual fuel consumption. Does this make sense? Even though Volvo does not recommend >10% ethanol, will using E15 cause any permanent damage. My 2004 V70AWD has 303K on it and I haven't used anything >10% ethanol, so I'm reluctant to change for 1 mpg, but interested in knowing if there's any correlation between E15 & increased mileage. Thanks.

[MoVolvos]

I just completed a 2500 mile trip and the friend riding along was fueling the car with 88 octane E15. My mileage increased from it's usual 23.5mpg to 24.7mpg average. After I dropped him off, and started using the usual 91-93 octane with 0-10% ethanol, I was back to my usual fuel consumption. Does this make sense? Even though Volvo does not recommend >10% ethanol, will using E15 cause any permanent damage. My 2004 V70AWD has 303K on it and I haven't used anything >10% ethanol, so I'm reluctant to change for 1 mpg, but interested in knowing if there's any correlation between E15 & increased mileage. Thanks.

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Interesting, will have to try it next time if I came across it. I have been using Supreme or Premium since it came out and have never gone back except for testing purposes. The cars run better overall with the Premium.
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A quick search didn't find any info on why it's for 2001 and later models.

Will Unleaded 88 Damage My Car? Is It Safe?
https://mechanicbase.com/cars/will-unle ... ge-my-car/
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[vtl]

ECM detected subpar octane number and retarded the ignition and cut boost in half to save the engine. Your car was not able to burn as much fuel as it usually does with 91-93 octane gas. It was accelerating slower and used less gas.

[MoVolvos]

ECM detected subpar octane number and retarded the ignition and cut boost in half to save the engine. Your car was not able to burn as much fuel as it usually does with 91-93 octane gas. It was accelerating slower and used less gas.

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Can you provide a link or two or testing to that analysis or conclusion?
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[vtl]

ECM detected subpar octane number and retarded the ignition and cut boost in half to save the engine. Your car was not able to burn as much fuel as it usually does with 91-93 octane gas. It was accelerating slower and used less gas.

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Can you provide a link or two or testing to that analysis or conclusion?
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I drive with this thing: https://github.com/vtl/volvo-ddd and use the highest grade gas available. With the stage 1 tune my XC70 has I see boost pressures of 11-12 PSI easily.

When traveling up up up north in wild parts of Quebec, where they only have regular gas, I once tried to pass a semi on James Bay Road, only to find XC70 is gutless and barely able to pass the semi. I looked at the boost number, it was no more than 5 PSI. BTDC was also retarded.

Filled with 93 when it was available, yet it took the engine half the tank to recover from 87.

[jonesg]

ECM detected subpar octane number and retarded the ignition and cut boost in half to save the engine. Your car was not able to burn as much fuel as it usually does with 91-93 octane gas. It was accelerating slower and used less gas.

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Can you provide a link or two or testing to that analysis or conclusion?
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I drive with this thing: https://github.com/vtl/volvo-ddd and use the highest grade gas available. With the stage 1 tune my XC70 has I see boost pressures of 11-12 PSI easily.

When traveling up up up north in wild parts of Quebec, where they only have regular gas, I once tried to pass a semi on James Bay Road, only to find XC70 is gutless and barely able to pass the semi. I looked at the boost number, it was no more than 5 PSI. BTDC was also retarded.

Filled with 93 when it was available, yet it took the engine half the tank to recover from 87.

usually anywhere you find snowmobiles they will have ethanol free gas.

[vtl]

usually anywhere you find snowmobiles they will have ethanol free gas.

http://jamesbayroad.com/ttr/

If you drive on a weekend, you may see no other cars for hundreds of miles. Volvo needs 2x 5 gal extra jugs to make it to the end of the road and back to the nearest public gas station (Mirage Outfitter).

[Krons]

88 octane E15. Even though Volvo does not recommend >10% ethanol, will using E15 cause any permanent damage.

My rule of thumb is just to not let 88E15 sit in the tank and fuel system more than a day or two as I’m unsure the P2 fuel system seals can handle it well.

88E15 is plentiful here in Iowa and sometimes significantly less $ than 87E10. I will sometimes fill up with E15 to start a long road trip, then run below a 1/4 tank at end to get back to E10 for shorter trips. Never seen a fuel consumption change on my 08 S60 2.5T FWD with it.

[scot850]

One of the main reasons for not running >10% is that the fuel lines and seals when the cars were built, were not rated for ethanol greater than this. I have read of many older vehicles running ethanol where it has literally degraded the fuel line to mush. You can replace the lines to higher rated lines and possibly o-rings that are compatible, but the engines may not be tuned to deal with it. However, some components may not be able to run with ethanol due to it's properties.

Your cars, your risk and choices of course.

Neil.

[vtl]

Ethanol belongs to human bodies, not cars.