Flex Fuel or straight up e85

[drumstick]

New here with my 18 GT-

How much power different would there be on a full bolt on (with tune obviously) set up?

Also, what extra parts are needed to run either?

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[Lonmon]

No extra parts are needed. Its all in the tune. On the 18's you do not need to worry about the injector size as the factory dual injection is more then enough to support it. A flex fuel tune theoretically should provide the same power on e85 as a dedicated tune but allow for the freedom to use 93 at will or any mix of the two. I will say theoretically because this is dependent on how well the tune is done and how well the a/f sensors are functioning. A dedicated e85 tune may more consistently make the most power but I believe it would be close enough to make the flex tune worth it. I personally had great experience with making good/safe power on my flex tune and loved the ability to simply add 93 if and when I needed to without changing the tune or making sure that it was completely switched to all 93 or all e85. Especially in the winter when the car runs the best on 93. Its also wise to switch back to 93 every several tank fulls to keep the system from gumming up.

 

[Saywhen]

^^^what he said. I can tell a noticeable difference when I run E85 over 93. The exhaust note is slightly different as well. Sounds “smoother” but both run well on my flex tune

 

[drumstick]

No extra parts are needed. Its all in the tune. On the 18's you do not need to worry about the injector size as the factory dual injection is more then enough to support it. A flex fuel tune theoretically should provide the same power on e85 as a dedicated tune but allow for the freedom to use 93 at will or any mix of the two. I will say theoretically because this is dependent on how well the tune is done and how well the a/f sensors are functioning. A dedicated e85 tune may more consistently make the most power but I believe it would be close enough to make the flex tune worth it. I personally had great experience with making good/safe power on my flex tune and loved the ability to simply add 93 if and when I needed to without changing the tune or making sure that it was completely switched to all 93 or all e85. Especially in the winter when the car runs the best on 93. Its also wise to switch back to 93 every several tank fulls to keep the system from gumming up.

Thanks for the detailed response! You mentioned its wise to switch to all 93 sometimes to prevent gunking- the tune recognizes/adjust for this automatically?

 

[VooDooDaddy]

On the 18's you do not need to worry about the injector size...

O.K., does that hold true (injector size) for the '15-'17s as well??

I am about to pull the trigger on Lund's flex fuel tune, but was thinking I would need to upgrade to 47lbs/hr injectors when going E85 or any mix of 93/E85??

 

[ahl395]

When speaking to them about it, Lund told me a dedicated E85 tune will make more power than a Flex tune.

O.K., does that hold true (injector size) for the '15-'17s as well??

I am about to pull the trigger on Lund's flex fuel tune, but was thinking I would need to upgrade to 47lbs/hr injectors when going E85 or any mix of 93/E85??

Pretty sure on the 15-17 you need to upgrade injectors. Only reason it may be fine as is on the stock 18 is because they have dual injection.

Thanks for the detailed response! You mentioned its wise to switch to all 93 sometimes to prevent gunking- the tune recognizes/adjust for this automatically?

Only if its a Flex tune, it will recognize and adjust automatically.

 

[nastang87xx]

It will adjust to a point automatically. Depending on your mixture, you'll need to take it easy for the first few miles so the knock sensors can report back the correct timing and call the correct map values so the AFR hits the right stoich. I think it's basically anything greater than 60% E85 and you can give'er hell. So if you filled up on 12 gallons of E85, let the car adjust, and then filled up on 12 gallons of E85 again, you can just let it rip. But always talk to your tuner about this when flex tuning so you're 100% sure.

 

[Lonmon]

O.K., does that hold true (injector size) for the '15-'17s as well??

I am about to pull the trigger on Lund's flex fuel tune, but was thinking I would need to upgrade to 47lbs/hr injectors when going E85 or any mix of 93/E85??

On the 15-17's it is recommended to upgrade to the 47's if you are running a better intake mani with the e85. It just makes sure there is plenty of headroom in the fuel system to not run the injectors too close to the limit at high rpm with the upgraded intake mani's. Most of us are shifting close to 8k+ rpm. With the stock IM the stock injectors will be ok.

 

[beefcake]

all you need is one of our lund custom tunes.

flex fuel will be available soon, for now you can get a pump and an e85 tune

let me know if you have any questions or we can help

www.teambeefcakeracing.com

 

[Angry50]

any updated reports on this e85 vs flex fuel? would it be better to just have a 93 tune and an e85 tune vs a flex fuel tune?

 

[Sean@LethalPerformance]

any updated reports on this e85 vs flex fuel? would it be better to just have a 93 tune and an e85 tune vs a flex fuel tune?

As a few others have mentioned, having dedicated e85 tune will likely be able to squeeze out a little more power over a flex fuel tune on full e85. However, its really nice how with the flex fuel tune, your not pressed on always having to chase after e85 stations.

So it a little trade off between a bit more power vs ease of use of not having to switch over tunes and draining the tank when switching fuel.

 

[ryant601]

I'd go with a flex fuel tune, it's nice to not have to worry about mix %.

Beyond happy with my tune from Rob S...now at PBD.

 

[wireeater]

As a few others have mentioned, having dedicated e85 tune will likely be able to squeeze out a little more power over a flex fuel tune on full e85. However, its really nice how with the flex fuel tune, your not pressed on always having to chase after e85 stations.

So it a little trade off between a bit more power vs ease of use of not having to switch over tunes and draining the tank when switching fuel.

And not having to test the fuel is nice too. I'm still not sure if I want to tune my 18 yet as I feel it's already ridiculously fast but always loved when I got to pump some E85 into my last GT. Just placing a yellow pump into your tank makes you feel special on a Mustang.

 

[Sean@LethalPerformance]

And not having to test the fuel is nice too. I'm still not sure if I want to tune my 18 yet as I feel it's already ridiculously fast but always loved when I got to pump some E85 into my last GT. Just placing a yellow pump into your tank makes you feel special on a Mustang.

I hear ya, its a hard temptation to fight.. Especially when these 18 coyotes love e85 that much more than gen 1 and gen 2 motors with the bump in compression.

 

[Lonmon]

I have all three from Lund. A 93 tune, flex tune, and e85 only race tune. Lol! I am running the race tune with my daily driven 18 right now, but I have an e85 station on my way home from work. If I find myself away from e85 I will just switch to my flex tune. Then for the winter I will stay will the flex with 93 in it or switch to the 93 tune. I really only have the 93 tune because when I started Lund had me start with that first since the 18's were so new at the time. I got my e85 race tune for free with my flex tune. You just have to send some logs in before they will give it to you.

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