Originally Posted by bc928

Originally Posted by bc928

Originally Posted by BradT

I was fooled by all of the "easy peasy" posts about flex fuel for the LT1. First off, unless you have very small hands and really good eyes, it is a PITA to get to the ECU plug. The instructions have you loosen all of the connection points for the right front quarter panel. Once I did that the the ECU was just supposed to drop down and I could pull the plug to pin the ECU. My 2017 GS has a cable tie back out of reach that keeps the harness from dropping down. I had to remove the side air vent (black part with the GS logo) to get to the plug. So not much fun at all.

I ordered an HP Pro tuner and had a friend who knows how to tune help me tune on 93 octane. It is very involved. "Just turning on flex fuel" is far from accurate. There are many parameters that need to change when you go to flex fuel. So a flex fuel tune that will void your warranty will cost you at least $300 for the fuel sensor, $650 for the tuner or to have someone tune it and will get you some HP with the ethanol. Even though E85 is cheaper at the pump, your car needs more of it to make the same power as 93 octane so don't think you will save money. Also, if you want to take the sensor off, depending on which one you get, you might have to buy some plastic quick disconnect pieces, trim it down to just the right size and wiggle it in the small gap to get your stock line off of the sensor.

My conclusion is that I would not do this if I had it to do over again. I track my car about 4 times a year so now I have a little faster GS, with no engine warranty and I am out about $1000. I would have been wiser to use that money for another track day or a set of track tires. Just my two cents on the flex fuel conversation.

Originally Posted by Higgs Boson

That's correct and to add, most tuners who have done this a few times don't need to retune the vehicle for ethanol if the car is already tuned for 93. The chemical properties of ethanol are the same from car to car and the tables adjusting for most of it will not change. It's a quick tune update in most cases. Going from NA to FI the spark tables will be a little different. I am just saying you don't need a complete retune just to enable flex fuel, it's pretty standard stuff.

Originally Posted by Mr. Smith

Originally Posted by Nitro-C5

looking for some advice/help with a few questions.

I have been running modified cars for years now, however never actually switched over to the running E85. I recently bought a new 2017 Grand Sport which I have already done the normal first round of mods including intake, headers, x pipe, cats and tune. The car runs great, but looking to get ~500whp mark and on my research I should be there (or close with E85 change).

I have done quite abit of research on this fuel however I find quite a lot of conflicting information. What I am looking for is anyone who has actually done the switch (preferably on an LT1 motor) and can answer some very basic questions and/or give some advice/comments/suggestions etc..

Overall:

It seems like running E85 has very little downside. The biggest being availability and some slightly lower gas mileage. The upside is more power, running cooler and cleaner. Are there any other major drawbacks I'm not considering?

Hardware:

It looks like only need the DSX Flex Fuel Sensor kit, am I right? Right now I am just NA so would I need bigger/different injectors?

Install and Tune:

The install looks pretty straight forward. If I am understanding it properly the tune is set up to run full e85 and then also regular 93octane, is that correct? (note I am having if custom tuned again by someone who knows what they are doing)

This sounds like a simple question, but if I have not had the sensor installed yet...do I drive it to my installer shop on 95 octane...then drain the entire tank and fill up with only e85 and have it tuned?

Running a Flex Fuel:

It seems to be as simple as installing the flex fuel sensor then whatever I am running straight 93 octane, e85 or half and half the sensor will automatically adjust everything to accommodate? That is what I read, but in reality is it really that simple? Am I missing something here..I mean can I have it tuned to run e85 but then say run 93 octane for the next 2 years then fill up with e85 and bam it will literally pick up that tune seamlessly?

Storing the car with e85 in the tank:

This I know is a concern for many as Ethanol attracts moisture. I live in NC so I pretty much can drive the car year round, however there may be times when I don't drive it for several weeks....or I may have a tank of gas that may take me 2 months to get through. So my question is if it is sitting for how long, with how much in the tank would be considered a problem. Obviously I know that in the winter I can put in 93 octane when I don't drive it as much but I will probably never totally drain the tank so chances are I am always going to have some Ethanol in there (higher than normal gas).


Thanks for the replies, Rick