Volkwagen/Audi owners! 2.0L turbo..

[RaginRog]

Originally Posted by TechJunky

I've got a 2011 VW GTI. Absolutely love it! Really the only thing I'm not thrilled with is the low profile tires. I love the look of the wheels, but lo-pros suck when it comes to hitting pot holes. Two weeks after I bought the car, with only 500 miles on the clock, slammed into a huge pot hole right in front of work that was covered in snow. Blew holes in both tires. But that's not really an issue with the car/VW per se, just an issue with the type of vehicle and wheels it has. Beyond that, I've been nothing but in love with the car. Handles well, rides great, has all the features I want, tons of space (managed to get a big recliner in the back once, a chest freezer another time. I also got all of my music gear when moving which consisted of 3 amps, 3 basses, 2 electric guitars, 1 acoustic, a huge pedal board, a few stands, and two laptops!)

I hate low pros...had them on a lowered S10 a few years back...you feel every little road imperfection.

[atomicdog]

I had that engine in a 2001 VW Golf, no problems, at least until last year (vacuum hoses), and VW did stop putting that engine on gas-powered Golfs 2 years ago (it was available only on the diesels; the gas models had a 2.5 5 cylinder). But in general the Jettas and Golfs are pretty solid (I bought a second one last year.

[Jim Nazium]

Originally Posted by RaginRog

I hate low pros...had them on a lowered S10 a few years back...you feel every little road imperfection.

+1 to that, in fact I replaced the stock 17" wheels on my A3 with 16s. The roads where I live and work are really bad.

[dmusic148]

Mechanic here. You can run regular in cars that 'require' premium fuel.
The issue is that the engine will want to knock, due to its high performance nature. To avoid this, engines have a knock sensor. At the onset of knocking the sensor will instruct the computer to reduce the ignition advance. No big deal.
The downside is you'll have slightly less power on tap, which may negatively affect fuel economy. So it may be a wash.

[blastoff99]

^^^

True for most, but not all, engines. There are exceptions.

[Pilgrim]

Originally Posted by dmusic148

Mechanic here. You can run regular in cars that 'require' premium fuel.
The issue is that the engine will want to knock, due to its high performance nature. To avoid this, engines have a knock sensor. At the onset of knocking the sensor will instruct the computer to reduce the ignition advance. No big deal.
The downside is you'll have slightly less power on tap, which may negatively affect fuel economy. So it may be a wash.

That's a good engine - VW and Audi both use it. Don't jeopardize it by following the advice above.

Engines have a knock sensor. They can fail. If yours does, you may burn a hole in the top of a piston. Turbos are especially prone to this if the knock sensor fails.

As stated above, you will also lose power, which stinks by itself, but you probably will also lose gas mileage because it's lower on power.

There is NOTHING to gain except a few cents per gallon, and you would be specifically using the wrong fuel. Yes, the engine will "run" on it. But that doesn't mean you're operating it properly...and it doesn't mean that it's a good idea.

DO NOT USE regular fuel. The engine is not designed for it and you are taking a chance on major damage and repairs!!

A primer on turbo vehicles:

- ALWAYS use the fuel with the required octane. Turbos can be damaged quickly with the wrong fuel. (If some engine management parts don't do their job)
- ALWAYS run synthetic motor oil. It holds up better under the extreme heat load of a turbo, as it's part of the turbo cooling system.
- Always change oil and filter together. Filtration is more important in a turbo engine.
- Never pull off the road after running at high RPM and shut the engine down immediately. You should idle the engine for at least 30 seconds to give the turbo time to spin down. When you shut off the engine your oil pressure goes away, and if the turbo is still spinning (they spin at more than 10,000 RPM) it wears the bushing out faster.
- Avoid running the car low on oil. The motor oil is part of the cooling system and turbos need the correct heat sink capacity, which includes motor oil.

Following these rules can mean the difference between a turbo that lasts 100K miles and one that dies in 40K miles. I have been driving and researching turbos since 1987.

If you don't know what a turbo is and how it works, I recommend this link: (you spent the money for the car, so make sure you know how it works...)

http://auto.howstuffworks.com/turbo.htm

And another cool article...EXCELLENT animations showing how a turbo works!!

http://www.squidoo.com/what-is-a-turbo

[Pacman]

Especially turbos.


edit: Pilgrim's faster than me.

[Bob Lee (QSC)]

Originally Posted by hover

Of course he did. He wants to to have to replace sensors, injectors and other goodies down the road.

What do those have to do with regular gas?

The recommendation of premium fuel for the 2.0T is because of the higher compression ratio that turbo boost provides, and the higher AKI indicates the fuel will be less prone to detonation under those conditions.

If the car runs on regular fuel, the driver will probably not notice any differences in driving with light acceleration--i.e., that doesn't involve boost. But if the ECU detects detonation it will instantly reduce boost and ****** timing, and thus it will reduce acceleration torque. This takes away much of a turbo's contribution to engine performance, but it does not harm the injectors, sensors, etc.

[Jim Nazium]

^ I'm laughing at the starred-out word above. It starts with an 'r'.

[Bob Lee (QSC)]

Originally Posted by Pilgrim

- ALWAYS use the fuel with the required octane. Turbos can be damaged quickly with the wrong fuel.

Turbos can be underused with the "wrong" fuel, but I can't see how they could be damaged.

[hover]

Originally Posted by Bob Lee (QSC)

This takes away much of a turbo's contribution to engine performance, but it does not harm the injectors, sensors, etc.

So noted, that's contrary to what I've heard re: knock sensors and turbos and whatnot, but I admit I'm not as knowledgeable as yourself or Pilgrim above, so I concede to your knowledge... but the point is moot anyway because his engine requires premium. It's not recommended use, it's required use on that engine. Why take the chance on something that could thoroughly pooch his warranty?

[Pilgrim]

Originally Posted by Bob Lee (QSC)

Turbos can be underused with the "wrong" fuel, but I can't see how they could be damaged.

You're mostly right, Bob. Normally, turbos will simply underperform with the wrong fuel in them. Combustion takes place, creating a knock because of the inadequate octane rating. The knock sensor kicks in, retards the timing to protect the engine, and the car loses performance but is not damaged.

That's the normal outcome. And that's putting a lot of faith in a knock sensor. As we all know, sensors fail...and this is an important one on a turbo.

If the knock sensor fails, then the timing is not retarded, the engine runs hotter, and the not-infrequent result is that the combustion process burns a hole through the top of one or more pistons.

The result of that event is pulling the engine and an engine rebuild, probably in the $3000 to $5000 range today.

That's a pretty expensive repair when it could have been avoided by running gas that costs a few cents more per gallon.

Hover says it nicely:

Originally Posted by hover

...but the point is moot anyway because his engine requires premium. It's not recommended use, it's required use on that engine. Why take the chance on something that could thoroughly pooch his warranty?

It's required for a reason, and this sums up the answer. Do it the right way.

Incidentally, two out of three of our cars require premium fuel: my 280ZX Turbo and my wife's BMW 328iX. We never ever run anything but premium in them. Our third car, a 2007 Nissan Murano, can run on regular, plus or premium. Performance varies according to the fuel we run, and so does MPG; both increase as octane increases. The higher the octane rating, the more power the vehicle develops and the better the gas mileage. Difference between regular and premium fuels is 2-4 MPG. I run Plus in it most of the time, and I run Premium on road trips because the MPG advantage is maximized at road speed with cruise control on.

[Kawai-chang]

2008 Jetta 2.5L I-5, manual tranny. Had about a year, and besides some squeaky rotors in the morning, has not been any problem. It does enjoy drinking the gas, but that's mostly my fault for driving too fast.

[Bob Lee (QSC)]

Originally Posted by Pilgrim

You're mostly right, Bob. Normally, turbos will simply underperform with the wrong fuel in them. Combustion takes place, creating a knock because of the inadequate octane rating. The knock sensor kicks in, retards the timing to protect the engine, and the car loses performance but is not damaged.

That's the normal outcome. And that's putting a lot of faith in a knock sensor. As we all know, sensors fail...and this is an important one on a turbo.

If the knock sensor fails, then the timing is not retarded, the engine runs hotter, and the not-infrequent result is that the combustion process burns a hole through the top of one or more pistons.

Here's what you should have written after "If the knock sensor fails,":

the ECU will store a 16709 (sensor 1 malfunction), 16710 (sensor 1 range/performance), 16711 (sensor 1 signal too low), 16712 (sensor 1 signal too high), 16713 (sensor 1 intermittent), 16714 (sensor 2 malfunction), 16715 (sensor 2 range/performance), 16716 (sensor 2 signal too low), and/or 16717 (sensor 2 signal too high), 16718 (sensor 2 intermittent) fault code and the MIL will light.

The VW ECU has a "limp mode" that, among other things, prevents boost in the event of a system failure such as a knock sensor, EPC (drive-by-wire accelerator pedal) failure, etc.

The result of that event is pulling the engine and an engine rebuild, probably in the $3000 to 5000 range today.

That's a pretty expensive repair when it could have been avoided by running gas that costs a few cents more per gallon.

For that to happen would actually require more than simply a knock sensor to fail. There's nothing wrong with putting a lot of faith in knock sensors. That's what they're for.

I'm not saying anyone should run regular fuel in a 2.0T (I run 91 AKI in my 1.8T, the 2.0T's forerunner); IMHO, that's a waste of a fine engine's performance potential. But neither should one fear that injectors and sensors will be ruined and other terrible things will befall their engine if, in a pinch, they have to use regular fuel.

[MakiSupaStar]

I've had a few cars with that engine. It's better than the 1.8T engine, but I prefer the 2.5l engine. Although, I currently have a TDI and I LOVE the mileage I get on this engine. As far as reliability goes, I haven't had one for more than a year, but within that time, I never had any problems with them.

[dmusic148]

Originally Posted by Bob Lee (QSC)

The VW ECU has a "limp mode" that, among other things, prevents boost in the event of a system failure such as a knock sensor, EPC (drive-by-wire accelerator pedal) failure, etc.

+1. Limp mode, puke mode, whatever you want to call it. Prevents boost, retards timing. No engine damage is possible.

Now, if we're talking older high-performance cars without electronics, that's a whole different story.

[dmusic148]

Originally Posted by MakiSupaStar

Although, I currently have a TDI and I LOVE the mileage I get on this engine. As far as reliability goes, I haven't had one for more than a year, but within that time, I never had any problems with them.

I've had mine for 10 years and 190K. Wett chip, PP 520 nozzles, VR-6 clutch/lightweight flywheel, Magnaflow cat-back, EGR delete. Car is a blast. Aside from a temp sensor and a couple of glow plugs it's been bulletproof.

[Jim Nazium]

Originally Posted by dmusic148

I've had mine for 10 years and 190K. Wett chip, PP 520 nozzles, VR-6 clutch/lightweight flywheel, Magnaflow cat-back, EGR delete. Car is a blast. Aside from a temp sensor and a couple of glow plugs it's been bulletproof.

I'll bet that's a blast to drive. I drove a diesel A3 for a day while mine was getting serviced, and the low-speed torque was really impressive. So is the mileage; even allowing for the higher per-gallon cost, I figured it would be 20% or so cheaper to run than the gas version.

[dmusic148]

Originally Posted by Jim Nazium

^ I'm laughing at the starred-out word above. It starts with an 'r'.

That was weird.

[Pilgrim]

Bob, nice explanation - that's deeper than I've ever been into that system.

Let's face it - there are a lot of things you can do with equipment and get away with MOST of the time. But sooner or later you may find "bad things happen....bad things, man."