Using regular 87 octane on a turbo engine

[oil_burner]

So we're considering an Audi Q5 with the 3rd generation EA888 and direct injection.

Owners manual calls for 87 min but 91 recommended. Before you start, yes I am a cheap bastard that abuses every vehicle I own to the very last inch of it's life, within the parameters of not causing permanent damage. It is a ~$25 extra cost per tank to use premium.

I am not an automotive engineer but I will challenge that here in Canada where we get frigid winters for 8 months of the year, where the temperature dips below freezing and in the months of November to February where it can get to -30C or -22F, the engine is probably receiving an equally ice cold jet of fuel while the parameters are perfect for a turbo engine to NOT knock or detonate. IE we are so far to the edge of the temperature/timing advance tables that it just won't matter. Sometimes it takes 20 minutes of driving before the thermostat even opens in the winter. What do you think?

 

[ctechbob]

I did the following with the Ranger (Turbo GDI I4) and do the same with the 3.5 in the F150.

In the winter, if I'm not planning on working the truck hard (towing) I'll just 87 or 89 depending on my mood. If I'm towing I go with 91/93.

In the summer I bump up to 89 minimum for not towing and the same 91/93 when towing.

Not necessarily for the extra power, although there is about a 20hp bump from 87 to 91/93, but just for the extra headroom that 91/93 provides with hot ambient, hot intake, and hotter coolant temps.

If I had a Turbo car I would probably follow the same train of thought. There would just be fewer times I needed to bump up to 91/93, unless I was tracking the car or doing some mountain runs.

 

[daves87rs]

Not using premium is going to kill the point of buying one of these-the driving experience. So to me, I would use 91 - regardless of cost.

 

[oldhp]

I have a 2024 GMC Canyon Elevation 2.7 L3B, 310hp / 430lbft turbo with D.I. that the manual recommends a minimum 87 octane. I just flipped 10K. I've tried every octane combination you can think of to get better MPH OR Power. Nothing matters. It runs just as good on Casey's 87 as Shell V-Power 93. I don't tow OR haul heavy. At first I "thought" 93 was making engine run stronger. Nope. I think the ECU was just learning my driving style. I am impressed with the little critter when you floor it being it's a 4 door, 4WD, 2.7 automatic, 3.42 gear truck with 31.5" tall tires and it will spin the rear tires pretty good when floored from a stop. My thoughts on turbos and D.I.

 

[dishdude]

I personally think all turbos should get premium. If buying an Audi is contingent on regular or premium fuel, you can't afford an Audi.

 

[GaryMX5]

Had a 21 Mazda CX5 turbo. Mazda said it was OK to use 87 octane but for optimum performance to use 93. Here in Colorado we have 85 octane for regular and 91 for premium (mid grade is 87....go figure that one). Apparently altitude reduces the need for higher octane requirements. Premium is anywhere from 50 cents (lucky if you can find this difference) to a dollar more per gallon. I did not want to run the car on 85 thinking that might have taxed the anti knock controls, etc. I got in the habit of alternating fill ups at a half a tank with 85 and 91. That resulted in about 88.5 octane in the tank. Ran it that way for 4 years without issue. There was no seat of the pants performance difference between this blend and 91. I have a Costco a mile or so from my home so it was convenient and a little cheaper to do. When gas prices occasional went down below 3 bucks for premium I would treat it to a full tank of 91.

 

[fantastic]

Sounds like by the time you're done it'll be an oil burner.
Yes, use 91 every time.

 

[billt460]

Not using premium is going to kill the point of buying one of these-the driving experience. So to me, I would use 91 - regardless of cost.

Exactly. If you want to use 87, then buy a car that only requires 87. I'm not seeing the economics in paying more for a turbocharged engine, then trying to save a few bucks by burning low octane fuel in it.

Unless the owners manual specifies that it's OK to burn 87, I would stick with 91. If something got damaged by low octane fuel, the dealer is going to know it, and most likely it won't be covered under warranty.

And if it's out of warranty, that's even worse. Because you'll be paying for it. And it's a sure bet it will end up costing a lot more than what you saved by burning the cheap gas that caused it.

 

[Danno]

There is nothing cheap about running an Audi. Time to move on ?

 

[The_Jeff]

Had a 21 Mazda CX5 turbo. Mazda said it was OK to use 87 octane but for optimum performance to use 93. Here in Colorado we have 85 octane for regular and 91 for premium (mid grade is 87....go figure that one). Apparently altitude reduces the need for higher octane requirements.

Turbos overcome the disadvantages of altitude so one should still run a fuel choice like they're at sea-level.

 

[Skippy722]

My ram and Challenger both recommend 89 but state 87 is okay.... They both get premium (93) since neither see high mileage. When I was daily driving the truck it got 89. I paid for all the horsepower, I want all the horsepower.

 

[rstsco]

So we're considering an Audi Q5 with the 3rd generation EA888 and direct injection.

...yes I am a cheap bastard that abuses every vehicle I own to the very last inch of it's life, within the parameters of not causing permanent damage. It is a ~$25 extra cost per tank to use premium.

I had a 2022 Q5 and ran the recommended premium gas from day 1. Yes, you can get by running 87 octane, but the engine detunes, thus loses horsepower, in order to prevent knocking.

Based on your description of yourself above, I'd suggest you get a brand/model known for their engine's longevity, regardless of how well-kept (or abused) they are. As others have said, Audis are expensive to maintain. If you're not willing to spend the money to use the recommended fuel, it's probably not the car for you.

 

[charbaby]

[Quote: oil_burner] "Owners manual calls for 87 min but 91 recommended."

Your owner's manual state that 91 is recommended, not "REQUIRED".
Which means that you're safe to use any octane from 87 on up.
Using lower octane doesn't mean the engine will run poorly,
it just means that the engine won't have the kick in the pants(at WOT) or the response(with throttle tip-in) that higher octane(s) may or will have.

 

[PontiacHO]

So we're considering an Audi Q5 with the 3rd generation EA888 and direct injection.

Owners manual calls for 87 min but 91 recommended. Before you start, yes I am a cheap bastard that abuses every vehicle I own to the very last inch of it's life, within the parameters of not causing permanent damage. It is a ~$25 extra cost per tank to use premium.

I am not an automotive engineer but I will challenge that here in Canada where we get frigid winters for 8 months of the year, where the temperature dips below freezing and in the months of November to February where it can get to -30C or -22F, the engine is probably receiving an equally ice cold jet of fuel while the parameters are perfect for a turbo engine to NOT knock or detonate. IE we are so far to the edge of the temperature/timing advance tables that it just won't matter. Sometimes it takes 20 minutes of driving before the thermostat even opens in the winter. What do you think?

Why ask? Your mind is made up.

 

[Propflux01]

So we're considering an Audi Q5 with the 3rd generation EA888 and direct injection.

Owners manual calls for 87 min but 91 recommended. Before you start, yes I am a cheap bastard that abuses every vehicle I own to the very last inch of it's life, within the parameters of not causing permanent damage. It is a ~$25 extra cost per tank to use premium.

I am not an automotive engineer but I will challenge that here in Canada where we get frigid winters for 8 months of the year, where the temperature dips below freezing and in the months of November to February where it can get to -30C or -22F, the engine is probably receiving an equally ice cold jet of fuel while the parameters are perfect for a turbo engine to NOT knock or detonate. IE we are so far to the edge of the temperature/timing advance tables that it just won't matter. Sometimes it takes 20 minutes of driving before the thermostat even opens in the winter. What do you think?

Then stick with 89+, or another vehicle.

 

[shortyb]

The real question is, if you're a cheap bastard, why are you considering an Audi?

 

[GW.]

I wish you luck. My granddaughter had nothing but problems.

 

[4wd]

The real question is, if you're a cheap bastard, why are you considering an Audi?

after owning one - BiL had to go cheap on everything else

 

[Patman]

I would at least recommend using 91 octane whenever it’s going to be over 20 degrees Celsius. When it’s between 0C and 20C use 89. In the cold winter temperatures you will be fine with 87, especially since you won’t really be pushing the car hard in the snow anyway.

The money you save trying to run 87 all year long might get lost after you damage the engine.

 

[shortyb]

I wish you luck. My granddaughter had nothing but problems.

View attachment 304009

Ah, thats nothing a little Valvoline Restore and Protect and 93 won't fix .