suzboy wrote:I am putting 91 into mine.... like what I did with my previous two cars. I never owned any European cars in the past.
I wonder what 95/98 Ron will do to the car. Will it give better cruse range? Is the
''increase'' in performance justify the premium I pay at the pump?
I doubt it'll get an increased performance since J24B engine has 10.0:1 compression ratio, hence higher octane fuel would result in almost no difference in terms of increased performance. Higher compression engines (10.2 and above) would get marginal increases.
As for the range, it might give you a bit better fuel economy.
I'll use 98 octane next time I refuel just to see what difference it makes..
Any engine that has a knock sensor as part of the EFI system (I doubt there are any new vehicles that haven't) has the potential to reap rewards from a higher octane fuel.
I use it for the engine cleaning benefits and as a preventative measure against detonation. It get's very hot where I live and is hilly - two variables for increasing the risk of detonation. I've heard our 2004 Suzuki XL-7 detonating and it's only supposed to use 91RON fuel, so I've used 98 since that day.
I use only regular gas which is 87 octane in the US. It's what the car calls for in the owner's manual and I see very little reason why the engine would need higher octane gas. After all, Suzuki is a budget-minded brand and has always focused on the affordability and low-cost of ownership of their vehicles. It's not to say they are low quality, but to feed a Suzuki car premium gas kind of defeats the point of owning a Suzuki. They are more like a low-cost dependable car.
If I was going to constantly pay for premium gas, I would have simply got a higher performance car that would justify it like a Subaru WRX. Something that would actually have a performance return on the higher fuel investment.
I have no issues with running regular in my Kizashi and think that any MPG benefit that may come from burning premium is easily offset by the extra cost of premium.
Yes, some premium gas contains more detergents than regular, but any auto parts stores contain a multitude of gas additives to clean the fuel system. I personally run a can of Seafoam about every oil change or so into the gas. Been doing it in different cars for several years. All the engines have run very well for their age and mileage.
Lastly, if your Suzuki engine knocks from regular gas, I would look into the knock sensor of the car. These engines weren't designed with premium grade fuel in mind so knocking with regular gas may indicate an issue with the sensor, not the gas.
Do you run the cheapest 5W30 mineral oil because that's all Suzuki specs call for? Or, do you buy something a bit better for the extra protection it offers?
Look into how a knock sensor ties into an EFI system and you'll see that the ignition timing is retarded or advanced from maps based on the knock signal. It is (of course) limited in it's operation, but on a NA engine that is where you'll gain or lose your power. Run lower octane fuel and you run the risk of engine knock- especially in hot/ hilly conditions under load. The timing should be retarded enough to prevent it, but you'll also lose power and be at higher risk of long term engine damage if the knock isn't eliminated. If I get a bad batch of fuel, I have a safety margin. It also gets to 45 degrees C where I live and is hilly.
I'd rather take the safer option, but if other people don't want to I can understand.
I will use full synthetic oil at the next oil change (still on whatever oil the car had when I got it), but I don't see how gas and oil are very comparable in their purpose. Oil is for lubrication and its quality can effect heat, protection, cleaniless, and oil break down in the engine. Also, full synthetic oils hold up longer to allow extended oil change intervals.
One can actually save money by extending their OCI by using full synthetic oil while reaping the benefits of better lubrication.
Gas on the other hand, pretty much burns for rotating the crankshaft. As you stated, modern cars' electronics are tuned for the grade of gas. I have lived in very hot regions with mountains and still used regular gas on my previous cars. Over 200,000 miles later, the car was still running strong.
Studies by experts have repeatedly shown that using premium gas in engines not calling for it have little or no effect on the performance or longevity of the engine. In fact, the history of different grade gasoline comes from a time before electronics controlled detotation therefore, engines relied on octane ratings far more to prevent knock. I have read this is the reason why mid-grade gasoline (89 octane in the US) exists, but almost no car calls for it anymore. In Japan, it's either Regular or Hi-Octane. Mid-grade does not even exist.
Now, with modern electronics, most engines have little need to use a grade of fuel other than what is specified because the sensors can monitor the knock.
On the other hand, the benefits of synthetic oils in any engine (other than a rotary) are well documented.
While some may swear that higher octane gas is better, I just don't see it being actually worth the extra cost. In the US, the difference is typically 20 to 30 cents more per gallon. Perhaps scientically, higher octane gas is somehow better for all engines, but from a practical standpoint with a cost/benefit analysis, it appears that it's not worth it.
Okay, just to clarify some (important) points:
- The original poster is from Australia and by talking "premium fuels" would be talking 95 RON or 98 RON.
- "normal" unleaded is 91 RON
- RON = Research Octane Number and is the Australian fuel octane rating system
- MON = Motor Octane Number and is the octane rating most USA based people seem to quote (I assume that's the rating system you're quoting?)
- here is a link to the specs on the fuel I use (BP Ultimate) http://www.bp.com/liveassets/bp_interne ... _Power.pdf
In it you'll find the following:
91 RON (ie. the fuel specified for the Kizashi in Australia) = 82 MON
95 RON = 85 MON
99 RON = 88 MON
So........ by using 87 MON fuel you're using fuel of a higher octane than even our local "premium" 95 RON fuel. It's basically the same as the fuel I'm using (BP Ultimate) which is rated at 88 MON.
I tested.
I get better gas mileage running Mobil premium than any other brand/type/octane.
"Measured"......
Performance enhancement is less measured, because I don't run my car at drag races, but based on my personal ass-time experience (figure well over half-million miles so far just in Vermont; since January 1992) my Kizashi 'feels' stronger running on premium.
murcod wrote:Okay, just to clarify some (important) points:
- The original poster is from Australia and by talking "premium fuels" would be talking 95 RON or 98 RON.
- "normal" unleaded is 91 RON
- RON = Research Octane Number and is the Australian fuel octane rating system
- MON = Motor Octane Number and is the octane rating most USA based people seem to quote (I assume that's the rating system you're quoting?)
- here is a link to the specs on the fuel I use (BP Ultimate) http://www.bp.com/liveassets/bp_interne ... _Power.pdf
In it you'll find the following:
91 RON (ie. the fuel specified for the Kizashi in Australia) = 82 MON
95 RON = 85 MON
99 RON = 88 MON
So........ by using 87 MON fuel you're using fuel of a higher octane than even our local "premium" 95 RON fuel. It's basically the same as the fuel I'm using (BP Ultimate) which is rated at 88 MON.
Wow, you blokes Down Under (terms I remember from living in Australia for a year as a kid) get some low-oc. gas if those conversions are correct. It would explain the knocking you experience too.
Yes, if it's the MON rating system where you are?? I did find another rating system which was (RON+MON)/2 -> which would match up better to the figures in that pdf link?
Don't forget the cleaning benefit of some higher octane fuels though. It like why you run better oil - to keep the engine internals clean. Carbon build up is one of the contributors to detonation, so if you can help prevent it.....
It's worthwhile reading the factory handbook too. It would appear some Kizashis do require 95 RON fuel and it all depends on the market and labeling inside the fuel filler flap. (Just to add to the confusion!)
