Type Of Gas For Milly???

[enginph]

I was for prem at first but since Ren talks about precats and since i experience nothing than more power with midgrade I mix them.

[Renboy]

Even if the 6% more expensive gas gave a 2% power increase (which it doesn't in this case) then you're still getting ripped off. And if you saved that 6%, after 6 months you would have saved enough for a CAI which will give you a 2% increase. Save a little longer and get headers, which in this case could net 6%. After a year and a half, you've got more power and less money.

 

I have a business degree too.

[Graham]

BUT if you had your timing as advanced as mine.... you too might be able to run mid-grade and generate less carbon...

 

Hmm, this one goes against my understanding of engine operation, or at least makes me think you are talking of two separate things.

 

From my experience and reading, you advance the timing of an engine to get more power.

Advance it too far though and the burning fuel charge will try to push the piston down before it has completed the compression stroke, robbing power and potentially damaging the engine.

 

Higher octane fuel is required in high compression engines to prevent pre-ignition or knocking.

 

Advancing timing would not change the need for high octane fuel in a hi comp engine though.

 

One thing to note - the higher octane fuel is actually more stable than lower octane which is why it's required in high compression engines. So low octane fuels burn more readily, so maybe that's why you generate less carbon?

 

So, to the crux of my initial sentence: Knock sensors retard timing to avoid knock, so if your engine can knock with low octane fuel, it's timing can be more advanced with high octane fuel.

 

So is your one liner an invitation to dummies to break their engines or something else that I've overlooked ???

 

G.

 

edit: p.s. In my experience high octane fuel makes no difference in a low compression engine, it just makes your wallet lighter, but in a high compression engine with the right ECU / tune, it should allow for more power and/or better economy.

[Renboy]

Actually MTS was right, with timing advanced you burn earlier in the combustion cycle, thus burning more of the gas. The higher percentage of gas you burn, the lower will be the HYDROcarbon emissions. HC's are not good for the precats (in unusually high quantities) and thus it ends up saving down the road.

 

That last point is a note to remember as I've never heard of any car that goes through (pre)cats like the milly does. If it didn't have those precats I don't think the car would have a chance in hell of passing emissions tests (especially with premium).

 

But Graham you're right, advance too far, and you release too much NOx, and potentially destroy the engine.

[street3890]

So is midgrade the best?

[Renboy]

Yup.

 

A lot of people don't realize (BHR included) that when stats for import cars (and their requirements) are released, they're done so in their country of origin. Take the rx8 for example, when it reached North America it didn't (doesn't) produce the hp numbers that it claims. The Japanese one does, but not the North American one. You can add the miata and tiburon on that list (these are just off the top of my head). The JDM cars are different than those meant for export. A JDM milly for example does not have an egr system in place. The whole purpose of the egr is to lower combustion temperatures, prevent knock, and reduce NOx emissions. Funny that the egr has the same effects as higher octane gas isn't it? Since the import milly has an egr, it does not require premium gas, putting that in is just wasting money now, and down the road when you have to replace precats.

[colbylamb2006]

Sorry I'm just now getting back to the thread. I have the 2.5 litre engine. I run 87 most of the time, every once in a while i will burn 93...that's if i have the extra cash, but it hurts me everytime when i open my gas lid and it says Premium Recommended...haha....what grade of gas is better for high mileage vehicles? 87, 89, or 93? I have 114,XXX miles

[Graham]

I've just filled up my 2.5L and decided to go with standard unleaded (91RON) for a tank.

I figure the KL ZE engine at 149kW should need high octane, but the detuned KL03/KLDE probably doesn't need it.

I've only done < 8miles so far, but can't notice a difference yet.

Will post back a little later.

 

Cheers, G.

[Matt64341]

the 2.5 doesn't require premium, it recommends that you use it, but says in the book that low grade can be run at "slightly reduced performance"

[Renboy]

The 2.5 in North America is slightly different than the 2.5 in Japan (and prbably Australia). Here the 2.5 has 9.2:1 cr, while theirs has 10:1, and ours has an egr valve, theirs doesn't. I have the klze engine in my mx6, with an egr valve, and I run midgrade. I ran regular for a long time, but pulled one of my plugs one day and it was white and blistered. It's been midgrade since.

[Graham]

Well, I've done almost 200kms (over 100miles) with standard unleaded (91 RON) and it still drives and revs very well. No noticeable sign of pinging/knocking, and possibly it's actually got a bit more poke from the engine.

 

I'm not sure if my engine is a KLZE, I obviously want it to be, so I'll post up some pics in another thread to see if any of you can help to ID it.

 

Cheers, G.

[///BHRpowered]

compression is not the issue, its the ecu, and sensors throughout the car, it requires prem, PERIOD, and I will be laughing when all of you have severe engine problems.

 

Also, except for who, ren? miller, who has gone through pre-cats, the people who go against billions of dollars of research and use regular. I can't think of anyone with pre-cat problems.

 

And the fact that wouldn't pass emissions is b.s, whenever I get my emissions test its well below the limits, infact out of 3 cars, the millenia has the lowest emissions.

 

Also saving up for performance parts would be fine, except alot of people don't want them, and thegeneral public isn't going to go for it, or pay for install and waiting blah blah blah, plus on cars like say the millenia, those parts don't exist. certainly no headers, chi and jdubs are theonly ones with intakes.

 

I agree automakers are trying to scam you by making you believe the bigger engines are producing more power and saving fuel, that isn't true, BUT, for the size of the engine it is X% more efficent, and its not at all because of the gas prices or because there in cahots, its simply because the american public doesn't care despite what they say, we'll pay the prices, so why should automakers waste millions and millions of dollars in something when they can just spend 50k on an advertisement for a feature of engines they were going to produce anyway?

 

Oversea's engines are getting smaller and/or taxes areincreasing forcing people into smaller engine cars

[Renboy]

It's a good thing (for you) that YOU'RE not a lawyer, because you sir are a complete moron and can't argue/debate worth a shit. Never in any debate have you given any proof to support any of your claims. You always default to some idiodic retort like 'the manual says so'.

 

You're the moron the gas companies love, higher octane does NOT mean better, it just means higher octane. And because of morons like yourself they can charge more for higher octane. Stupid ass mentality, bigger=better, and more expensive=better...you sure you're not a Texan?

[///BHRpowered]

wow, you couldn't be further from the truth, all you talk about are old myths and crazys who believe everything the media says.

 

Your forgetting a ket point, requiring prem gas HURTS sales, and the last thing any automaker wants to do, is pinch there bottom line, if there was a way to safely use regular, they would, they don't care because there not at all involved with oil companies, tire companies, battery companies, plastic companies, hell yes, but no oil.

 

Your always bitching about some problem like precats or the s/c and how your always working on things, if you jsut did what your suppose to you wouldn't have any problems, its people like YOU that keep lawyers in business.

[mts]

That is OK your 60,000 is upcoming... we shall see.... there is much bitching and whining in your future too...

[///BHRpowered]

it will be another 6-8 years at the very least before 60k, however, I will most likely do it around 58 or 59k. And you will hear no bitching, spark plugs are done every 45k, transmission in flushed every 25, coolant is done every other year, I do the brakes myself once a year. CAI has taken care of the air filter, I'm looking at other fluids, belts, and general inspection and preventative maintance. And no MTS, even if it cost me the full 6-1000, I wouldn't care.

[mts]

That is peanuts.... I am referring to the S/C in that engine you baby....

[///BHRpowered]

perfect, AND, should it ever go for whatever reason, tomorrow or in 35 years. I will simply replace it, its not something I would even give any thought to

[Renboy]

wow, you couldn't be further from the truth, all you talk about are old myths and crazys who believe everything the media says.

 

Your forgetting a ket point, requiring prem gas HURTS sales, and the last thing any automaker wants to do, is pinch there bottom line, if there was a way to safely use regular, they would, they don't care because there not at all involved with oil companies, tire companies, battery companies, plastic companies, hell yes, but no oil.

 

Your always bitching about some problem like precats or the s/c and how your always working on things, if you jsut did what your suppose to you wouldn't have any problems, its people like YOU that keep lawyers in business.

I believe everything the media says...you moron...all you ever do is quote the owners manual. You, in your entire life haven't experienced anything that remotely qualifies as a thought or idea. If you were a little hairier you'd be in a pasture eating grass and getting shaved down once a year for wool.

 

In your infinite wisdom I'd like you to explain to me how octane and s/c failure are related? Not to mention the fact that the milly s/c is a complete piece of shit, there have been many here that have had it fail and they did use premium. Furthermore, I'm not fixing my car...I know how to fix cars, everyone of my friends and family know this, and as such I'm fixing their cars. Recently yes, I was working on my car, but after 340000 km's my lower control arms needed replacing. And coincidentally my engine supposedly requires premium gas too and I only run midgrade. Maybe you can explain how ball joint failure and octane are related while you're enlightening everyone here about the s/c-octane relationship.

 

As for car sales and premium gas, the cost of installing an egr system is about $1000 to the consumer, using pistons that don't have valve reliefs costs nothing, but increases the reliability rating of the vehicle, and finally consumers want power, they'll pay for power, and if they have to use premium to get that power, they'll pay. Financially speaking, the car company can be more profitable by using premium than regular (given the right car). Not to mention there are a lot of idiots (yourself included) that would only put premium in their tank anyway (no matter what the owners manual says) because they don't know better (like yourself). Good to see that business degree of yours is hard at work.

[///BHRpowered]

Your thinking about 1970's byths and media propaganda, first of all, the owners manual has nothing about "if your s/c fails or how to avoid it" The lower octane isn't truely bad for the s/c, I never said it was, I said its horrible for the engine and knock sensors, sure it will move forward with less power, but then you wear out hte knock sensors.

 

your also forgetting that no automakers cares how much replacement parts are, because A, its not there problem, and B if it is under warrenty, what you are "charged" isn't the real cost. Now by your account, no car in the world would use prem, your saying an egr system is about 1k, ok fine, well lets look at it this way, lets say it needs to be replaced under warrenty, why would any automaker want to gamble like that? the idea is to have as few parts on the power train fail, rest of the car, eh maybe, but not power train.

 

Your thinking like an angry consumer, when infact, the automakers care very little about that and will do what is best ofr business, and requiring prem is never good for business

[Renboy]

Knock sensors don't wear out because of the gas you put in, they're like a microphone that's always on, and always sending a signal. The only time the knock sensor isn't working, is when the engine isn't running. So....no....premium gas will not save the sensors (whether it's required or not).

[///BHRpowered]

knock sensors adjust or retard the timing of the engine for the gas, and more wrong the type of gas you put in, the faster they wear out, its more or less abuse

[enginph]

Bah you are worrying about knock sensors if it is knocking?

 

There is a point that car works optimum. That includes temp, humid, octane, bla bla bla... Given temp, humid, bla bla fixed, there is a optimum octane. And it is not constant for every temp, humid., bla bla combination. Maybe on a 110F (43C) humid day premium is required in order not to knock.. And your manual says 91octane if you are using premium it is 93 oct. , and you are ruining your engine with higher than rated octane gasoline... Thats why i mixed 93 and 89 at times..

 

[Graham]

knock sensors adjust or retard the timing of the engine for the gas, and more wrong the type of gas you put in, the faster they wear out, its more or less abuse

 

Sorry, but DUDE!

 

Knock sensors are just a sensor. Just like a thermometer. (not like an O2 sensor, they aren't in the exhaust stream or anything that can "wear out" a knock sensor)

So just like a temperature sensor, they send a signal to the computer. The computer then advances or retards the timing to take advantage of the conditions.

 

Now that doesn't apply to all cars - some cars computer will use a specific timing and only retard it if/when the knock sensor detects knock. Some cars, under certain circumstances will advance the timing until knock is detected and then back off the timing to a safe point, thus providing the most power available in the conditions. Some cars will do this only when their computer is reset or somehow given a specific signal to "learn a new tune" so to speak.

 

If your engine doesn't knock with low octane fuel, then high octane will not make it any better.

Low octane will probably run fine at low RPM and low throttle %ages, so if you drive like a granny, high octane isn't worth much for you car, unless the mechanic thrashes it around the block for test drives, in which case it might be bad.

 

Premium fuel over here is up to 98 RON and normal unleaded is 91 RON, so if your Octane figures were "RON" octane ratings, then premium isn't a bad idea.

 

In the MCE engine, I'd think that Premium would be a must have.

 

I'm currently on a tank of 91RON normal unleaded in my 2.5 and it seems to go at least as well as premium. Just tonight on the way home I was held up by a Holden Commodore SV8 (235kW/315hp 5.7-litre Gen III V8). OK, I was pushing Milly hard, but definitely kept within 1 car length of him while he was accelerating to his max.

 

FYI, if your mechanic ever says that your knock sensor is worn (not melted or cut wires) then it's actually time to get a new mechanic.

 

G.

 

 

[Frankzao]

don't forget to ask him about your piston return springs!!!