Should I get a tune?

[Laurence Dunn]

I have a standard 2007 GT 3V 4.6 with long tubes an X pipe and high flow cats. Nothing else except stainless exhaust and custom cylindrical 14" mufflers. The car runs ok but will a tune make it better?

 

[Dino Dino Bambino]

If you're still running the crappy stock tune, an aftermarket tune will definitely help. Contact the tuning department at Brenspeed. They can send you a custom email tune that you can upload into your ECU with a handheld tuner such as the SCT X4.
I've been running the same Brenspeed tune on my 06 GT for the past 12 years and the difference from stock was night and day.

 

[Miker]

A tune wakes up a completely stock 4.6 GT. Seems like the mods you have would really respond to one. I do have to run 91 instead of 87 octane but the increase I got in MPG with the tune almost negates the price difference.

 

[Laurence Dunn]

We have 95 in the UK, is that the same a US 91?

 

[Laurence Dunn]

If you're still running the crappy stock tune, an aftermarket tune will definitely help. Contact the tuning department at Brenspeed. They can send you a custom email tune that you can upload into your ECU with a handheld tuner such as the SCT X4.
I've been running the same Brenspeed tune on my 06 GT for the past 12 years and the difference from stock was night and day.

Will a SCT 3015 be ok to do this?

 

[StockishS197]

If you are running the stock tune with longtubes, you have a lot to gain with a tune.

Email Lito to get you sorted but you will probably gain a good 25-30rwhp with a tune, and it will drive a ton better.

 

[Forty61]

We have 95 in the UK, is that the same a US 91?

Google it but I'm pretty sure they're about the same. The US uses a different measuring method that gives the lower rating.

Will a SCT 3015 be ok to do this?

I think you'll want the X4 to do the custom tunes and stuff but if you have access to an affordable used (and unlocked!) 3015 I ran the canned SCT tune on my car for a little bit and it, while not perfect, was much better than factory.

 

[Kev555]

We have 95 in the UK, is that the same a US 91?

Yes Laurence, I looked this up a while back as I am in the process of getting a tune from Lito. I personally wouldn't run my Mustang on E10, its pure rubbish, although with the price of fuel ATM I can understand the E10 argument LOL

 

[Dino Dino Bambino]

Yes Laurence, I looked this up a while back as I am in the process of getting a tune from Lito. I personally wouldn't run my Mustang on E10, its pure rubbish, although with the price of fuel ATM I can understand the E10 argument LOL

In case you didn't know Kev, all petrol (gasoline) sold in Europe is currently E10 (stoich air:fuel ratio 14.1) and our Mustangs run fine on it. The ethanol content was fairly recently increased from 5% to reduce CO2 emissions.

We have 95 in the UK, is that the same a US 91?

Pretty much. European 95 RON octane is equivalent to 91 R&M/2 octane. However European petrol has a 10% ethanol content so it's E10. That entails a slightly lower 14.1 stoichiometric air:fuel ratio compared to 14.7 for pure gasoline, and means that the engine will run slightly leaner on E10 if it's tuned for pure gasoline but not enough to require a retune. If one was obsessive about getting a ECU retune though, a simple adjustment of a commanded 1.0 lambda from 14.7 to 14.1 is all that's required.
For what it's worth my 06 GT is tuned for 91 US octane pure gasoline, goes like a raped ape, and delivers pretty good fuel economy too (33-34 Imperial mpg at 70mph GPS motorway cruise).

 

[brasil]

@ Dino Dino Bambino. Did I miss something ? Yesterday I filled up my Pony - with Shell V Power E5 95 Octane.. all Gas Stations here in Germany sell E 5 95 Octane..as well as E 10 95 Octane. Then there is the "Super + which is a 98 Octane E 5 fuel.. Shell / Aral also sell V-Power Racing 100 Octane E 5 ( Shell ) ... and Aral Ultimate 102 Octane ( no ethanol... but ester.
Perhaps the EU is short of real fuel...so they start to " upgrade "with ethanol ??

 

[Kev555]

In case you didn't know Kev, all petrol (gasoline) sold in Europe is currently E10 (stoich air:fuel ratio 14.1) and our Mustangs run fine on it. The ethanol content was fairly recently increased from 5% to reduce CO2 emissions.



Pretty much. European 95 RON octane is equivalent to 91 R&M/2 octane. However European petrol has a 10% ethanol content so it's E10. That entails a slightly lower 14.1 stoichiometric air:fuel ratio compared to 14.7 for pure gasoline, and means that the engine will run slightly leaner on E10 if it's tuned for pure gasoline but not enough to require a retune. If one was obsessive about getting a ECU retune though, a simple adjustment of a commanded 1.0 lambda from 14.7 to 14.1 is all that's required.
For what it's worth my 06 GT is tuned for 91 US octane pure gasoline, goes like a raped ape, and delivers pretty good fuel economy too (33-34 Imperial mpg at 70mph GPS motorway cruise).

I will double check Dino but i am nearly sure the 97 Ron super unleaded is still E5 at my local pumps but because I haven't been out in the Mustang this year yet so I don't know if its recently changed?. I have used the 95 Ron but I use 97 on all my 2 stroke and gardening tools. I have found 2 strokes are smokie as hell on the E10 due to it being hygroscopic, especially in my climate. My Mustang just seems that bit livelier and runs sweeter with E5 97 that's why I brim the tank with it before locking her away for the winter. In the summer months I sometimes mix E5 and E10 50/50 in a tankful if I'm feeling begrudging to the billionaire oil companies

 

[Dino Dino Bambino]

Here's a more detailed answer Kev.

As of May 2026, the standard gasoline in the EU is E10, which contains up to 10% renewable ethanol, following the European Commission's Fuel Quality Directive to reduce GHG emissions. Most petrol cars are compatible with E10, while E5 (5% ethanol) remains available as a "protection grade" for older vehicles, and the EU is currently exploring E20 (up to 20%) to accelerate decarbonisation. [1, 2, 3, 4, 5]
Key Aspects of Ethanol in EU Gasoline

• Standard E10: E10 is now standard in most EU countries, offering a 79% reduction in GHG emissions compared to fossil petrol.
• Availability: While many nations have adopted E10, some—including Italy and Spain—have not yet widely adopted it, sometimes using E5 as the standard.
• Future - E20: The European Commission is examining E20, a 20% ethanol blend, as a potential future standard, with formalization possibly arriving in 2026, pending updates to the Fuel Quality Directive.
• Compatibility: While the vast majority of petrol cars are compatible with E10, it is advisable to check specific manufacturer guidelines, especially for older vehicles.
• Octane Ratings: The ethanol percentage does not replace Octane ratings (e.g., 95 RON). Both E5 and E10 are usually sold as 95 RON, while higher octane (97+ or 98) often remains E5.

Note that the fuel systems of our Mustangs are compatible with E10.

 

[Kev555]

Doesnt make sense asking a guy with a mustang to support decarbonisation So looks like they possibly intend do drive us S197 owners off the road eventually by introducing E15(America) and E20 fuel in Europe unless E10 will still be available? or will somebody come up with an additive for our fuel tanks as Ford are saying only 2014> mustangs are E15 compatible?

 

[Juice]

All cars are set up to run e10 after early 2000s. 14.078 afr is the oem setting. Except flex fuel obviously.

 

[GriffX]

Standard E10: E10 is now standard in most EU countries, offering a 79% reduction in GHG emissions compared to fossil petrol.

This is only valid for the ethanol part of it and it is debatable. Distilled EtOH cannot be used for fuel, too much water in it, therefore the residual water must be removed on the chemical way which is energy intensive. For E10 itself a good rule of thumb is a 5% stellar carbon reduction.

 

[Kev555]

This is only valid for the ethanol part of it and it is debatable. Distilled EtOH cannot be used for fuel, too much water in it, therefore the residual water must be removed on the chemical way which is energy intensive. For E10 itself a good rule of thumb is a 5% stellar carbon reduction.

Interesting comment Griff as I've heard other local mechanics and people who work with petrol engines in general comment that E10 is full of water. I don't read into this sort of stuff as my head is full enough. But I do see by checking Google that the UK uses bioethanol in which contains 3-4% water. That's very little so I don't see an valid argument for "its full of water". I do see however its hygroscopic which is a concern as transport, storage and other factors could raise the water content more in the right climate before you take ownership of it. Now I have gone down the Google rabbit hole on E10, the more I read the more concerning it is.

 

[Juice]

You guys are overthinking it.
Ethanol free fuel is nonexistent today. E10 is what we got, and debating the pros& cons of it is totally pointless. And E fuel can make more power, safer, over pure gas in some applications.

 

[StockishS197]

E10 isn’t going anywhere. Use E10 and be done with it, as Juice said that is the standard. People make 1000+ hp all day long on E10 pump gas.

 

[brasil]

in Brasil I use E 100... pure ethanol in our Ford Fiesta 1.6.. this little car goes like hell with E 100. With E 100 the Fiesta makes 140 hp !! not too bad for a car that weights around 1200 kg .

Never used "Gasoline " in that car. never.. But in Brasil more or less all "Gasoline" Cars are FLEX Fueler.. so E 5..10..37..or even E 100 is no problem for them

For the Mustang... (Also down there in Brasil) the regular Gas is E 27..hard to find purer gas.. and all the Mustang owners use this E. 27...... looks like it works too. Even the old Beetle ( Volkswagen ) drive with that BR - Petrobras "Super Gas "...

 

[GriffX]

Interesting comment Griff as I've heard other local mechanics and people who work with petrol engines in general comment that E10 is full of water. I don't read into this sort of stuff as my head is full enough. But I do see by checking Google that the UK uses bioethanol in which contains 3-4% water. That's very little so I don't see an valid argument for "its full of water". I do see however its hygroscopic which is a concern as transport, storage and other factors could raise the water content more in the right climate before you take ownership of it. Now I have gone down the Google rabbit hole on E10, the more I read the more concerning it is.

I marked the E10 in the diagram with the green dot. That means if you increase the water content only a few percent, the fuel will separate into two phases. Therefore you must use 100% water free ethanol for production. Destillation gives you only 96% of ethanol (azeotropic mixture). When E10 absorbs water from the air it separates into two phases when it reaches around 0.5% (I had a wrong number in my mind, sorry), that is the reason why it is only stable for 3-6 month. Then you have a Ethanol/Water phase which ignites bad and a low octane fuel phase.