Piston Slap: Focusing on Turbo 93 Octane Tunes?

by Sajeev Mehta

Published: October 1st, 2015

Mark writes:

Sajeev,

Thanks for the recent advice on winter tires & wheels for my new Focus ST. I took delivery of the car two weeks ago and I’m having a blast. The first thing I did when I got it home was take Bark M’s advice and sign up for the Octane Academy.

So here’s another question: What’s your take on fuel octane and the ST?

I’ve been running 87 octane per the owner’s manual and will probably continue for another tank or two, recording fuel consumption each time. Then I’ll switch over to 93 for a few tanks to see how mileage and performance stacks up. Everything I’ve seen says 93 will only give a 5 hp bump, so I rather doubt premium will be worth the extra cost in the short term.

But what about the long run? Do you think this turbo engine will be happier/cleaner/longer lived by running the expensive stuff?

By the way, I may order a set of tunes from Torrie, just like I did for my Mustang a couple years ago. I don’t know if that will make a difference in the questions above, but I wanted to make sure I mentioned it.

Thanks again!

Sajeev answers:

I’m kinda shocked that going from 87 to 93 octane only nets 9 hp with no change to peak torque according to Car and Driver. Anything is possible with modern computers and their numerous fuel and spark tables. So I recommend the 87 octane and oddball 17-inch Ford winter wheels for maximum hipster ironic-ness. The forum junkies will hate you for it!

Will this hurt you in the long run? I doubt it. Today’s computers are smart enough to keep that from happening. The dyno video above shows how the computer kills timing on the 87 octane tune — a fantastic reason to save money. It also shows how the FoMoCo factory tune is Dick Cheney conservative; easy on the environment, durability and fuel economy.

So why would you run 93 octane — ever?

One reason: The aftermarket tune.

When you get Torrie’s electro-goodness sprinkled on the ST’s computer tables, you’ll want to run 93 and never look back. I bet the aftermarket makes a great 87 octane tune that’s still safe but spicier than stock. However, if such a tune on my 2011 Ranger can net gobs more torque below 3,000 rpm (four-banger, mind you), it’s likely to happen on an ST. It all depends on the quality of the tune and the tuner behind the computer.

What say you, Best and Brightest?

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

Sajeev Mehta

More by Sajeev Mehta

Comments

Join the conversation

2 of 23 comments

ERiic on Oct 01, 2015

The 2.0L ecoboost in the Focus ST is rated for 252 hp on 93 octane. You'll have less power with 87 octane. The 1.6L ecoboost in the Fiesta ST 197 hp rating is also based on 93 octane. The reduction in power for the Focus ST and Fiesta ST using regular vs. premium isn't listed however if you look at the ratings for the Fusion with the 2.0L ecoboost it says: 240hp using premium and 231hp on regular.

Like Reply
Dougjp on Oct 04, 2015

93 octane isn't available close to where I live. So I'm only interested in reading about 91 octane tunes, and this is nearly impossible to find (with specific details/charts etc). I can understand why not, as most people even considering a tune want to go all out.

Like Reply

Recent Comments

Ltcmgm78 It depends on whether or not the union is a help or a hindrance to the manufacturer and workers. A union isn't needed if the manufacturer takes care of its workers.
Honda1 Unions were needed back in the early days, not needed know. There are plenty of rules and regulations and government agencies that keep companies in line. It's just a money grad and nothing more. Fain is a punk!
1995 SC If the necessary number of employees vote to unionize then yes, they should be unionized. That's how it works.
Sobhuza Trooper That Dave Thomas fella sounds like the kind of twit who is oh-so-quick to tell us how easy and fun the bus is for any and all of your personal transportation needs. The time to get to and from the bus stop is never a concern. The time waiting for the bus is never a concern. The time waiting for a connection (if there is one) is never a concern. The weather is never a concern. Whatever you might be carrying or intend to purchase is never a concern. Nope, Boo Cars! Yeah Buses! Buses rule!Needless to say, these twits don't actual take the damn bus.
MaintenanceCosts Nobody here seems to acknowledge that there are multiple use cases for cars.Some people spend all their time driving all over the country and need every mile and minute of time savings. ICE cars are better for them right now.Some people only drive locally and fly when they travel. For them, there's probably a range number that works, and they don't really need more. For the uses for which we use our EV, that would be around 150 miles. The other thing about a low range requirement is it can make 120V charging viable. If you don't drive more than an average of about 40 miles/day, you can probably get enough electrons through a wall outlet. We spent over two years charging our Bolt only through 120V, while our house was getting rebuilt, and never had an issue.Those are extremes. There are all sorts of use cases in between, which probably represent the majority of drivers. For some users, what's needed is more range. But I think for most users, what's needed is better charging. Retrofit apartment garages like Tim's with 240V outlets at every spot. Install more L3 chargers in supermarket parking lots and alongside gas stations. Make chargers that work like Tesla Superchargers as ubiquitous as gas stations, and EV charging will not be an issue for most users.