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Unreliable fuel quality. (octane)

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Old Oct 7, 2016 | 02:18 PM
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Default Unreliable fuel quality. (octane)

I've been tuning on my Cadi CTS Coupe with HP Tuners software. I have a BP station by my house and have been buying 93 octane there. I always look at the pumps to find one that the last customer bought 93 so I don't get a hose and pump of regular before the premium starts flowing.

The data acquisition I have been doing has showed zero knock retard at cruise, part throttle and wide open runs meaning I have no detonation. I filled again a few days ago from almost empty. I immediately started showing massive amounts of knock retard almost in all areas of driving with this new tank of fuel. Power is down too because of the timing retarding. There were zero changes made other than the fuel, so the premium tank in the ground at the BP must be full of regular.

This really is a problem for me. The CTS protects itself with the knock retard, so it won't cause any damage. My 406 is a different story. If I get a tank of 87 octane for it to feed on, it will detonate violently with it's 11.8 to 1 compression. For this reason and others I think I am going to go to E85. There are E85 stations everywhere up here in Minnesota and the surrounding states. My fuel tank and all my lines are new and compatible , so why not?

Mike
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Old Oct 7, 2016 | 02:36 PM
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I got bad detonation about a mile from filling up at the premium pump. So I called the state certification office and they tested his fuels and fined him for having regular in all of his tanks
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Old Oct 7, 2016 | 02:45 PM
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Hi George!
A few years back the state went out and checked stations across Minnesota and found over 50% of stations checked had regular in all their tanks. The state did nothing about it. They said on the local news no laws were broken, which is BS. It's fraud.

Mike
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Old Oct 7, 2016 | 03:01 PM
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I Think E85 is a great idea, I watched the Corvettes (running E85) at Laguna several years ago and on the straights the were catching up to the LMP-1 and 2 cars and outright beat a Ferrari. I know FAST EFI is capable of using a Flex Fuel sensor and I believe the Holley HP can as well. If you're Carbed it's Jetting and Bleed changes at a minimum.
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Old Oct 7, 2016 | 03:06 PM
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Originally Posted by v2racing
Hi George!
A few years back the state went out and checked stations across Minnesota and found over 50% of stations checked had regular in all their tanks. The state did nothing about it. They said on the local news no laws were broken, which is BS. It's fraud.

Mike
Well here's a link to ETHANOL FREE gas stations in MN..as well as the USA/CANADA..
http://www.pure-gas.org/index.jsp?stateprov=MN

get your EO GAS from a station that serves an airport.I believe they are more attentive to fuel due to FAA regs....look at the list..a lot of 91-92 octane sources as well as 100 octane..
IF you have a local station that sells EO premium..Talk to them and verify how often they refill the tank..and when..and whose fuel they use..Jim

Last edited by jim in oregon; Oct 7, 2016 at 03:06 PM.
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Old Oct 7, 2016 | 03:58 PM
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FWIW, E85 ranges from E70 to E85 out of the pump. As long as you have a fuel composition sensor that will compensate for the variety, it's good to go.

I just put one on my ATS and it works great. The ATS's ECM is pinned and programmed for a sensor though, you need to wire it in and turn it on.
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Old Oct 7, 2016 | 04:10 PM
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Originally Posted by jim in oregon
Well here's a link to ETHANOL FREE gas stations in MN..as well as the USA/CANADA..
http://www.pure-gas.org/index.jsp?stateprov=MN

get your EO GAS from a station that serves an airport.I believe they are more attentive to fuel due to FAA regs....look at the list..a lot of 91-92 octane sources as well as 100 octane..
IF you have a local station that sells EO premium..Talk to them and verify how often they refill the tank..and when..and whose fuel they use..Jim
The ethanol free gas is all 91 octane. Tried it before. Doesn't do the job. Has to be good 93 or better with my compression.

I've talked to several people running E85 on the street and racing and they are not having any of the problems internet gurus say you have with E85. Obviously the carb needs to be converted and a few precautions done to prevent problems. I have a new fuel tank, new 140 GPH electric fuel pump, new -10 AN line feeding pump, -8 AN to the regulator and separate -6AN lines from the regulator to the carb. Should be more than enough supply.

Mike
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Old Oct 7, 2016 | 04:14 PM
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Originally Posted by Shark Racer
FWIW, E85 ranges from E70 to E85 out of the pump. As long as you have a fuel composition sensor that will compensate for the variety, it's good to go.

I just put one on my ATS and it works great. The ATS's ECM is pinned and programmed for a sensor though, you need to wire it in and turn it on.
I'm carbed, but what I've been told by E85 guys is to tune with true E85 and if it falls under that it will just be a little rich. Ethanol is way more forgiving on air/fuel ratio than gas. Even 70% is still way higher octane than pump premium too.

Mike
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Old Oct 7, 2016 | 04:45 PM
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You have the hard part done,I say go for it. Big power can be made with e85.
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Old Oct 8, 2016 | 10:56 AM
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Originally Posted by 76strokervette
You have the hard part done,I say go for it. Big power can be made with e85.
That is for sure. A lot of the boosted guys are running E85 and making massive power.

Mike
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