flex fuel ready cons?

[Johnyed]

I'm looking at buying a new sierra 2500.

It's like 150 extra to get it e85 ready.

I think I want to get it that way. I can't think of a reason not to.

I've tried googleing it but all I get is pros and cons of e85 when what I want to know is there any cons to having the truck e85 ready if I plan on running gas in it.

Is there any major differances in the motor or computer, or is this a really minor difference?

Is there a difference in clearances?

Is it more likely to knock or ping running on gas compared to a truck thats not e85 ready?

 

I would greatly appreciate any info on this.

Thanks

John

Edited October 7, 2021 by Johnyed
fixed typos

[shakenfake]

No cons really. Every now and then your alcohol percentage could get thrown off and it messes with your truck but that is pretty rare.

In terms of engine and computer differences, the fuel lines and injectors are different. I believe the pump is as well. There is also an added sensor or two. For the PCM it is just in the tune and you would never notice/find it normally.

No change in knock likeliness.

 

Don't know what you mean by clearances though.

[Black02Silverado]

Unless something has changed in the past few years. The only difference is the sensor is added and the E85 tables in the ECM are turned on. 

 

Like on our 2016 Suburban.  It wasn't a flex fuel vehicle, but I added a sensor and plugged it into the harness that the connection was already there.  Then I had Black Bear Performance tune it and turn on the E85 table and tune that as well for optimum use of the E85.  So now I have a FF vehicle and run E85 in it all the time.  Runs so much better to me and as far as the lower fuel economy.  That is a wash since FF is less cost than premium that I was running.

 

So if you can get it from the factory as a FF, then go for it.

Edited October 7, 2021 by Black02Silverado

[Kjduvall]

For the price it's a no brainier, I clicked that option and am pretty sure it had to have some other option paired with it, I believe it was the brake controller at an extra 275. That is only 375 total. Totally worth it in my opinion, I plan on going with a tvs 2300/2650 blower in the future so it will do well for my needs.

[Johnyed]

Thanks shakenfake.

Not really concerned about clearances. I said that wrong.

A few extra sensors isn't too concerning.

I was wondering if there was anything different with the internals like for example diesels have a lot more compression then gas engines. With e85 having a low octane rating, I was wondering if there was any big differences like that to make them burn the e85, or are they basically the same engines with a few external changes like the injectors and sensors like you mentioned. I'm fine with the minor differences. If they're the same engine undernieth it all and they usually work fine I'm probably going to go with the e85 ready option.

 

Thanks

John

 

[Johnyed]

57 minutes ago, Black02Silverado said:

Did making the change affect the milage when you run the gas you used to run, or is it only lower when you run e85?

I know e85 has a lower mpg due to the low octane. My concern is how it does on regular gas. There isn't a station within 10 miles of me that has e85 but if it doesn't affect my milage using regular gas then it makes sense to have it in case I wnt to use it later.

 

[CamGTP]

With the way things are going, they may never have tuning available for the new 6.6 gas truck engines.

[shakenfake]

4 hours ago, Black02Silverado said:

Unless something has changed in the past few years. The only difference is the sensor is added and the E85 tables in the ECM are turned on. 

 

Like on our 2016 Suburban.  It wasn't a flex fuel vehicle, but I added a sensor and plugged it into the harness that the connection was already there.  Then I had Black Bear Performance tune it and turn on the E85 table and tune that as well for optimum use of the E85.  So now I have a FF vehicle and run E85 in it all the time.  Runs so much better to me and as far as the lower fuel economy.  That is a wash since FF is less cost than premium that I was running.

 

So if you can get it from the factory as a FF, then go for it.

I thought that the fuel lines had changed because of the corn? I might be wrong about that but I thought that was what I read once before when looking at it. Something about the corrosiveness. Could be different on the newer trucks and I might be thinking about something else.

I am almost 100% certain the injectors are larger though. Unless they are now putting the same size on all trucks, are they?

[Kjduvall]

9 hours ago, CamGTP said:

With the way things are going, they may never have tuning available for the new 6.6 gas truck engines.

Unfortunately your prolly right. But I'm hoping someone will figure it out. I thought the same about the C8. It would be nice if edelbrock / procharger, or any other supercharger vendor could make a bolt on kit with tuning included. They would sell very well in my opinion. 

[Black02Silverado]

13 hours ago, shakenfake said:

I thought that the fuel lines had changed because of the corn? I might be wrong about that but I thought that was what I read once before when looking at it. Something about the corrosiveness. Could be different on the newer trucks and I might be thinking about something else.

I am almost 100% certain the injectors are larger though. Unless they are now putting the same size on all trucks, are they?

The only difference has been that they didn't add the sensor and turn on the E85 table in th ECM.  Everything else is the same.  I checked part numbers of injectors on a FF vehicle and one that wasn't and they were the same part number.  Now on these newer ones, I'm not 100% sure but I would think that they are the same.  GM isn't going to have a disruption on the assembly line just for a few items different.  Now a sensor can be added easily but injectors and such why waste the time.  Make them all the same is how I look at it.  My 2002 Silverado wasn't FF and I ran up to 50/50 mix for over 40k miles with no issues.

[shakenfake]

ah okay I looked it up and it was just the NNBS trucks that seem to have a different pump part number for flex fuel and without flex fuel. Different filler neck part number too which was weird. IDK maybe I'm ******

 

Just was looking at an 08 Silverado on GMPD

[C/K Man]

A lot of the newer E85 trucks use the EVAP system to determine the percentage of E85 in the tank.  There is a pressure sensor on the fuel pump module (that's why the pump part # is different) and the ECM reads the vapor pressure.  The older E85 trucks did have higher flow injectors, but I think they are all the same now.  I have run E85 in my Yukon for years, only downside is the fuel mileage is worse.  Sure keeps the combustion chambers clean.  I pulled the fuel pump at 110,000 miles just to look at it and it was also very clean and had almost no wear.