Silly Question about Turbos

[Warpious]

So this is the first vehicle I've had with a turbo engine. We'll be going up to pretty high elevation this weekend so I'm excited to have the turbo. I know Ford "recommends" premium for best performance, I normally use regular 86 and haven't had any issues. Going to 10k feet though would premium be of benefit or no? My (uneducated) logic is you'll actually get less performance out of premium since there's less air to ignite the higher octane, or am I totally backwards on this?

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[BronzeSmokeBadlands]

So this is the first vehicle I've had with a turbo engine. We'll be going up to pretty high elevation this weekend so I'm excited to have the turbo. I know Ford "recommends" premium for best performance, I normally use regular 86 and haven't had any issues. Going to 10k feet though would premium be of benefit or no? My (uneducated) logic is you'll actually get less performance out of premium since there's less air to ignite the higher octane, or am I totally backwards on this?

I am no mechanic, with that said I've heard/watched on YouTube that engines with turbos are LESS affected in higher elevations than naturally aspirated engines. Makes sense to me since the air is forced through.

As for octane, the 250 HP of the 2.0L is measured with premium fuel, regular is safe to use, you will just have less HP to use....If your able, I would try the high elevation driving on regular and then try premium and see if you notice a difference.... might be worth the upgrade.

 

[Mark S.]

First off, you're playing with fire by using any fuel with an octane rating below 87. This is clearly specified in the manual, which contains a very clear warning that damage cause by doing so may not be covered under warranty.

The primary benefit of higher octane fuel is that it requires more heat to ignite. That means the PCM (powertrain control module) can advance timing and increase boost to get more power out of the engine without fear the increased heat will result in detonation. You will get the same benefit no matter what altitude you are driving.

My advice is if you think you need the additional power afforded by the use of premium fuel than that's what you should use. Otherwise, regular gas of at least 87 octane is perfectly fine.

 

[Warpious]

First off, you're playing with fire by using any fuel with an octane rating below 87. This is clearly specified in the manual, which contains a very clear warning that damage cause by doing so may not be covered under warranty.

The primary benefit of higher octane fuel is that it requires more heat to ignite. That means the PCM (powertrain control module) can advance timing and increase boost to get more power out of the engine without fear the increased heat will result in detonation. You will get the same benefit no matter what altitude you are driving.

My advice is if you think you need the additional power afforded by the use of premium fuel than that's what you should use. Otherwise, regular gas of at least 87 octane is perfectly fine.

I misspoke, You're correct, I usually do the 87, in my haste got my normal octane wrong. In TX we usually run 87, 89, 93. But I'll make sure to keep an eye on it when I cross state lines and just different regions in general as I know they vary by area.

 

[Mark S.]

I misspoke, You're correct, I usually do the 87, in my haste got my normal octane wrong. In TX we usually run 87, 89, 93. But I'll make sure to keep an eye on it when I cross state lines and just different regions in general as I know they vary by area.

Roger that. So, to your original question: If you find while tooling around the mountains you need more power then by all means use premium. You'll see higher gains in hotter weather, but all other things being equal, you'll see essentially the same power gain over regular at all altitudes.

 

[69cuda340s]

If you switch from 87 octane to higher octane you have to run a couple tanks before it takes effect. Its not like you fill up and all the sudden the ECU senses the better gas and adjusts. It needs to see the higher octane over time.

87 octane ECU adapts adjusts so if thats your preference its fine.

Like someone else said above turbo engines arent effected much by high altitudes. The ECU will up the boost to compensate for the thinner air.

 

[Mark S.]

If you switch from 87 octane to higher octane you have to run a couple tanks before it takes effect. Its not like you fill up and all the sudden the ECU senses the better gas and adjusts. It needs to see the higher octane over time.

There is a way to get the PCM to update faster; you can perform a complete OBDII Drive Cycle:

A Typical OBD-II Drive Cycle consists of...

1. Cold start (Coolant below 122 Degrees F).
2. Five to eight-minute warm-up and idle.
3. First acceleration to 55mph at half throttle with the air conditioning turned off.
4. First steady cruise at 55mph for three minutes.
5. First deceleration to 20mph.
6. Second acceleration at 3/4 throttle.
7. Second steady cruise at 60mph for five minutes.
8. Second deceleration without applying the clutch or brake pedal.

Many tune vendors recommended moderate acceleration (1/2 - 3/4 throttle) from 2000 - 5000 RPM over four to five cycles to retrain the PCM following installation of their software. The PCM will respond to the power demand by bumping boost and advancing timing until the first indication of detonation. This updates the fuel/ignition mapping table, and the new values are used the next time you step on it.

This suggests that it's a good idea to take it very easy when switching fuel from premium to regular to give the PCM time to retrain to the lower values.

 

[CrashBend]

So this is the first vehicle I've had with a turbo engine. We'll be going up to pretty high elevation this weekend so I'm excited to have the turbo. I know Ford "recommends" premium for best performance, I normally use regular 86 and haven't had any issues. Going to 10k feet though would premium be of benefit or no? My (uneducated) logic is you'll actually get less performance out of premium since there's less air to ignite the higher octane, or am I totally backwards on this?

I don't think you really need to spend the extra money for the higher octane. Your Bronco should run the same at altitude without any significant change in performance. Just my humble opinion.

 

[DMEARC]

So this is the first vehicle I've had with a turbo engine. We'll be going up to pretty high elevation this weekend so I'm excited to have the turbo. I know Ford "recommends" premium for best performance, I normally use regular 86 and haven't had any issues. Going to 10k feet though would premium be of benefit or no? My (uneducated) logic is you'll actually get less performance out of premium since there's less air to ignite the higher octane, or am I totally backwards on this?

The problem with higher altitudes is not a lack of oxygen, (which is what I think you meant) it’s that the atmospheric pressure is much lower. As a result the concentration of oxygen is lower. A turbo can overcome this by cramming more air into the engine, thus “concentrating” it again for you.

Typically engines run better on higher octane when performing under demanding conditions, such as climbing a mountain. I’d use a higher octane for such an activity.

 

[DMEARC]

If you switch from 87 octane to higher octane you have to run a couple tanks before it takes effect. Its not like you fill up and all the sudden the ECU senses the better gas and adjusts. It needs to see the higher octane over time.

I’m not sure this is true with most modern cars. In an effort to squeeze out as much performance as possible, I’m pretty sure that the engine ECU is constantly adjusting timing with the help of the knock sensor. If that’s true, then the ECU can figure out what octane it’s dealing with shortly after you pull away from the pump.

 

[Osco]

As for octane, the 250 HP of the 2.0L is measured with premium fuel, regular is safe to use, you will just have less HP to use....If your able, I would try the high elevation driving on regular and then try premium and see if you notice a difference.... might be worth the upgrade.

This Is the way :’P
Betcha can’t tell the difference.

 

[Codysooz]

At a higher altitude, you will be achieving a Richer Air-Fuel Ratio; therefore, an octane such as 87 will act as if it is higher because of altitude. Octane is dependent on your combustion chamber's compression ratio and some other dependencies.

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