Why can't I run 87 in my car??

[Kennyredline]

Does anyone know what the fuck they're talking about?? All I want is better fuel mileage....I've changed my spark plugs, fuel filter, air filter had the vacuum system checked, changed my tire pressure....and then FINALLY....someone suggests lower octane fuel, and it works!!! A huge improvement in mileage!!!
BUT THEN I'm told I shouldn't be running regular gas in my car, that it's going to clog up my CAT-verter. They suggest removing it. I call around to arrange that, THEN I'm told that my O2 sensor will start throwing codes if I take out the Cat-verter.
Why can't I run 87 in my car?? The tag inside the fuel door says I can....why are Volkswagen service people telling me I can't run 87 octane in my car when the Volkswagen people who BUILT THE FUCKING CAR say I can?!?!?

[JRSC00LUDE]

Ummmm....go by the factory sticker/recommendation as opposed to the opinion of some asshat at the service desk.

.02


EDIT - Yes, removing cat will throw codes. It's unnecessary in your situation, I wouldn't consider it.

[G-ZUS]

-_-

[Kloubek]

Personally, I would never run a turbo car with a low grade gasoline.

With that said though, if it is working better for you then I don't *think* you're doing any harm. If the car notices a problem then it should retard your timing. This would (as far as I know) potentially result in lower power but no damage.

Anyone want to confirm that?

[JZS_147]

i'm going to go ahead and guess that this is an owning lol

[chkolny541]

go lower

[94boosted]

Originally posted by Kloubek
Personally, I would never run a turbo car with a low grade gasoline.

With that said though, if it is working better for you then I don't *think* you're doing any harm. If the car notices a problem then it should retard your timing. This would (as far as I know) potentially result in lower power but no damage.

Anyone want to confirm that?

Confirmed.

It should just pull timing (KR) and if you still missfire that should throw a CEL. I still wouldn't do it in my own car. Cutting back on power and potentially exposing your engine to more stress than nescessary all to save a few $'s.

[JRSC00LUDE]

Originally posted by 94boosted


Confirmed.

It should just pull timing (KR) and if you still missfire that should throw a CEL. I still wouldn't do it in my own car. Cutting back on power and potentially exposing your engine to more stress than nescessary all to save a few $'s.

If factory octane rating for a turbo engine is 89, presumably it's tuned to run perfectly fine/safe on 89. No?

[OriginalGoods]

the only way it would affect the o2 sensor and throw any codes is if its after the cat, and i doubt it is.

[CapnCrunch]

The owners manual should tell you what grade to run. If you're manual says 87, and you run 91, you'll lose power and get worse mileage. Same goes the other way.

[J-hop]

as mentioned kenny you really need to hit up CVD's (or eurodrivers, or dasdubbers) forums and get someone to VAG com your car, something isn't right with your car. A simple OBD scan won't tell you shit unless your car is throwing a code a VAG com scan and data log is really the only way to go with these cars.

with the vag you can actually test the quality of your cat with a simple diagnostic process it runs which compares outputs from pre and post cat O2 sensors while revving the car to a certain rpm, it will also tell you if one of the O2 sensors is faulty (ie: laggy response, erroneous readings etc).

VAG cars are very touchy, so it could be any number of issues. I wouldn't run anything less than 91 on a 1.8T but that is just me. And as I said I am getting similar mileage to you in my 24v VR6 which I always run premium on, so something is definitely wrong.

[Twin_Cam_Turbo]

Doesn't the 1.8T have a recommended 91 octane and minimum 87 octane rating?

[D'z Nutz]

Originally posted by Kennyredline

http://forums.beyond.ca/st/268206/ho...-your-thread-/

[Tik-Tok]

Originally posted by Kennyredline

Why can't I run 87 in my car?? The tag inside the fuel door says I can....why are Volkswagen service people telling me I can't run 87 octane in my car when the Volkswagen people who BUILT THE FUCKING CAR say I can?!?!?

What does the owners manual say? My Audi 2.7 twin turbo manual says run 91 octane, but also says I CAN run 87 octane, it just isn't recommended. If you run 87 for awhile (ie years), expect the cost savings to be nullified by maintenance.

What brand of gas do you use? Certain ones are shit for mileage (ie Husky,Mohawk, Tsuu T'ina Gas Stop), some are better (Shell).

Also look into chipping it (tuning). My APR tune gives me both more performance AND better fuel economy (at the cost of emissions, long live no Alberta exhaust regulations!)

[Sugarphreak]

...

[msommers]

Personally on any forced induction engine, I'd be running 91+. On high compression NA motors, they recommend 91 but plenty of guys on the G35 forums say they only use regular. Personally I wouldn't but apparently the ECU will retard the timing if it senses any knocking.

What's quite interesting though is the new F150 Ecoboost engine. A 3.5L V6 turbo'd engine that is recommended from the factory to run on 87! It's no slouch either, I imagine the tuning capabilities of that engine are going to be staggering.

[94boosted]

Originally posted by JRSC00LUDE


If factory octane rating for a turbo engine is 89, presumably it's tuned to run perfectly fine/safe on 89. No?

Yup your right. I've just never seen a Forced Induction car that didn't recommend or need 91+.

[HiTempguy1]

Originally posted by msommers
It's no slouch either, I imagine the tuning capabilities of that engine are going to be staggering.

Direct injection y0, its a wonderful thing. Makes detonation extremely hard to happen as there is literally no fuel to detonate earlier then you want it to.

[03ozwhip]

Its a mechanicss thing I think... If you have 91 and detonate it, you expect the same volume of detonated gas regardless of the original source of the gas. It also tends to burn cleaner. So when you detonate 87, there is less volume of gas produced. The other part of it is that trhe car is sold to a world wide market.

gas mined in canada may be different from stuff sold in poland. So you have to really try to set a standard. 91 guarantees a min level of filtration, and a universal adoption. 87 can be some fucked up mixture pulled from tanzania and you would have no clue. Could be alcohol derived. 91 just sorta establishes a solid base line. More or less lol

[JRSC00LUDE]

Originally posted by 94boosted


Yup your right. I've just never seen a Forced Induction car that didn't recommend or need 91+.

Good point (well, minus this Ford apparently...), never really thought about it beyond what he said in first post about car label saying it's ok.