is it bad to use 99 octane gas?

[dion51]

they sell 99 octane gas at a station here in town, its next to a track so people use it to race with. is it bad to use and switch right back to 91 after?

 

[jersey_emt]

as long as its unleaded, it is fine

 

[Evo Scooter]

You can use it if you want but it's reallly a waste to pay for what you don't really need. These cars are tuned for 91. If your car had an aggressive tune or you had raised the boost then you would need the 99. If your car is stock don't waste your money.

 

[desperado-c]

You can use it if you want but it's reallly a waste to pay for what you don't really need. These cars are tuned for 91. If your car had an aggressive tune or you had raised the boost then you would need the 99. If your car is stock don't waste your money.

I don't think it's so cut and dried. A guy who posted on the Mazda Three Forums as Mazda_Tech claiming to be an MNAO product dev engineer for the MS3 said that the jump from 91 to 93 is good for a couple degrees of timing advance and a couple of extra hp. So the question is at what octane will the MS3 ECU cease to advance timing when no knock is detected? The Euro Focus ST will produce 8% more power when running the UK equivalent of 96-97 octane in the US over what it puts out with the equivalent of 92-93 octane. Maybe the MS3 has the same capability.

 

[assman]

From what i heard it might fry your O2 Sensors but I may be wrong because maybe it only apply to older cars

 

[nvmsp]

well, i used race gas on my car a few times and now I have a bad o2. It also made the car not run right, but it sounded meaner. Felt slower.

 

[Mocoso]

I don't think it's so cut and dried. A guy who posted on the Mazda Three Forums as Mazda_Tech claiming to be an MNAO product dev engineer for the MS3 said that the jump from 91 to 93 is good for a couple degrees of timing advance and a couple of extra hp. So the question is at what octane will the MS3 ECU cease to advance timing when no knock is detected? The Euro Focus ST will produce 8% more power when running the UK equivalent of 96-97 octane in the US over what it puts out with the equivalent of 92-93 octane. Maybe the MS3 has the same capability.

Ill agree that IF THE ECU knew how to compensate and dynamically change the tune to make use of 99 octane that it would matter and you could see some performance gain.

Having said that I REALLY DOUBT they would program the ECU to handle 99 Octane and Im skeptical that the ECU in the MS3 is smart enough to dynamically adjust tune to get more performance of anything above 93 Octane.

And Ive never heard of higher octane gas causing damage or lowering performance on any car.. its just a waste of money for engines that cant make use of the higher octane (such as low compression engines)- I suspect if "racing fuel" clogged sensors etc. it was due to the lack of detergents and "low quality" storage rather than the octane rating...

 

[sephiroth]

And Ive never heard of higher octane gas causing damage or lowering performance on any car.. its just a waste of money for engines that cant make use of the higher octane (such as low compression engines)- I suspect if "racing fuel" clogged sensors etc. it was due to the lack of detergents and "low quality" storage rather than the octane rating...

using higher octane gas dosen't directly harm the engine, no.. but it does increase the rate of carbon build up which can bog performance. To answer the orginal question though, no it's not bad but it's not going to do anything and just cause more gunk build-up which isn't exactly desirable.

The Euro Focus ST will produce 8% more power when running the UK equivalent of 96-97 octane in the US over what it puts out with the equivalent of 92-93 octane.

the euro focus ST is also designed from the get-go to take advantage of higher octane fuels, even economy corolla's and civics over there are programed for the equivilent of US 91+ octane gas.

 

[Mocoso]

using higher octane gas dosen't directly harm the engine, no.. but it does increase the rate of carbon build up which can bog performance. To answer the orginal question though, no it's not bad but it's not going to do anything and just cause more gunk build-up which isn't exactly desirable.

Well this is one of those subjects which has passionate camps on both sides. We could argue this all day long so I will leave it at: I politely disagree with the carbon buildup... Octane is just a measure of the fuel's resistance to early detonation (knock) and a properly tuned engine shouldnt cause more carbon buildup due to the Octane rating of the fuel... using higher octane gas than what the engine is tuned for is a complete waste of money

So dion51 there you have it: some of us think its just a waste of money while others think it can actually do more and damage the engine... which ever ones are right either way it is bad for you (actual engine and/or your wallet)

 

[desperado-c]

. .... So dion51 there you have it: some of us think its just a waste of money while others think it can actually do more and damage the engine... which ever ones are right either way it is bad for you (actual engine and/or your wallet)

Once again, not so cut-and-dried. Since most ECU's now use anti-knock systems to change timing/fuel parameters, OEM tuning of cars for higher than recommended octane is an technique that increases output even on the recommended octane fuel. http://www.bp.com/sectiongenericarticle.do?categoryId=9009565&contentId=7018404. And if a car has an "adaptive engine management system" like the Euro Focus ST, it can apparently take advantage of substantially higher octane. http://www.bp.com/sectiongenericarticle.do?categoryId=9009114&contentId=7016932. There's a ton of info on this on the BP website, as part of their effort to sell their outrageously expensive BP 102 (about 96-97 octane US).

So, does this mean you will get the maximum benefit possible from using straight 99 octane? Highly unlikely. Would you get at least a marginal benefit from mixing in some unleaded 99 octane from a well-known, widely respected, widely distributed company? You definitely will if the resulting mix is 93 octane, to the tune of a couple of hp. And is it possible that you would get a substantial benefit from bringing the mix up to 95-96 octane? It depends on whether the MS3 has an "adaptive engine management system" like it's corporate brother, the Euro Focus ST. If it does, the benefit could be as much as a 7-8% increase in hp.

 

[mcb]

MS3 are tuned to work on these high octane... In Australia they use 98 and its the same tune that we have in north america. An other exemple, in japan premium gas is 100 octane. So imo yes you can will have more power with that gas. If you have $$ to try make 3 dyno pulls on 91-93 and 3 pulls on that 99 you will see if the power change.


i'll check on mazda (official) forum to see what moderators will tell.

 

[Perro del Sol]

I can say that the 94 Octane that I use is far superior than any 91 or 92 Octane that most stations sell. The leaded race full will make your O2 sensors go bad, mos def.

 

[SwampAss]

FWIW, the 2007 Mazda line up brochure lists the MS6 as *min octane 91 and the MS3 *min octane 93.

 

[desperado-c]

MS3 are tuned to work on these high octane... In Australia they use 98 and its the same tune that we have in north america. An other exemple, in japan premium gas is 100 octane. So imo yes you can will have more power with that gas. If you have $$ to try make 3 dyno pulls on 91-93 and 3 pulls on that 99 you will see if the power change.


i'll check on mazda (official) forum to see what moderators will tell.

Those octane figures are RON. We use a different measure, so the Ozzie 98 is the equivalent of 93-94 and the Japanese 100 octane is equal to about 95-96.

 

[mcb]

/quote FWIW, the 2007 Mazda line up brochure lists the MS6 as *min octane 91 and the MS3 *min octane 93.
/quote

then 99 Unleaded should be good isnt it? Be sure its unleaded because o2 sensors dont like that.

I run on 91 here caus i cant get 94 locally (its a 200km run to get) I made the trip once to get the gaz and i saw a big difference.

 

[Mocoso]

Once again, not so cut-and-dried. Since most ECU's now use anti-knock systems to change timing/fuel parameters, OEM tuning of cars for higher than recommended octane is an technique that increases output even on the recommended octane fuel. http://www.bp.com/sectiongenericarticle.do?categoryId=9009565&contentId=7018404. And if a car has an "adaptive engine management system" like the Euro Focus ST, it can apparently take advantage of substantially higher octane. http://www.bp.com/sectiongenericarticle.do?categoryId=9009114&contentId=7016932. There's a ton of info on this on the BP website, as part of their effort to sell their outrageously expensive BP 102 (about 96-97 octane US).

So, does this mean you will get the maximum benefit possible from using straight 99 octane? Highly unlikely. Would you get at least a marginal benefit from mixing in some unleaded 99 octane from a well-known, widely respected, widely distributed company? You definitely will if the resulting mix is 93 octane, to the tune of a couple of hp. And is it possible that you would get a substantial benefit from bringing the mix up to 95-96 octane? It depends on whether the MS3 has an "adaptive engine management system" like it's corporate brother, the Euro Focus ST. If it does, the benefit could be as much as a 7-8% increase in hp.

You missed my first post.. scroll up to see... I agree with your post only think its a waste of money because IMHO the MS3 ECU doesnt tune and adapt to anything above 93 octane

 

[Mocoso]

MS3 are tuned to work on these high octane... In Australia they use 98 and its the same tune that we have in north america. An other exemple, in japan premium gas is 100 octane. So imo yes you can will have more power with that gas. If you have $$ to try make 3 dyno pulls on 91-93 and 3 pulls on that 99 you will see if the power change.


i'll check on mazda (official) forum to see what moderators will tell.

Ok Ill believe the ECU will adjust the timing to make use of higher Octane gas if someone confirms that Australia and Japan use the same method for rating Octane as North America... I suspect that both Australia and Japan dont use the same avg method north america does and hence your 100/98 octane is really 91/93 octane if using the average method.... (yes there are 2 methods to report Octane)

At the end of the day its yer money and yer car... if you "think" or "perceive" its going faster then maybe the money is worth it

 

[mcb]

Dyno pull would be the only valid proof IMO.

 

[hellcat]

Better octane = less knock if you crank the boost.

 

[mcb]

we are arguing over a stock car, there is no way to crank the boost manually.