I’ll be leasing a new car shortly.

[wyliec]

This isn’t a post about the positive and negatives of leasing/buying.

The particular car I’m interested in has something I haven’t seen before. It has two horsepower ratings based on octane rating; I hope I used the correct technical term. The car is a Mazda CX 30 with turbo. Are there other vehicles advertised that way? I’m not asking if you can get more hp with higher octane, just if there are others advertised with multiple hp’s? The hp goes from 227 to 250.

[BLUEKNIGHT911]

This isn’t a post about the positive and negatives of leasing/buying.

The particular car I’m interested in has something I haven’t seen before. It has two horsepower ratings based on octane rating; I hope I used the correct technical term. The car is a Mazda CX 30 with turbo. Are there other vehicles advertised that way? I’m not asking if you can get more hp with higher octane, just if there are others advertised with multiple hp’s? The hp goes from 227 to 250.

This is interesting .... I know if you / they add a Turbo the normal compression ratio has to be lower than what you'd expect. .... so after adding a Turbo, higher Octane will be needed for Max performance .... jmho .... Mike

[Little Blue]

Trying to understand your Question. A Turbo powered engine can get more HP from a smaller Engine. A Non-Turbo power engine maybe a larger size or weight to get same or more HP as the Turbo. More information is needed if this does not help. .......

[Steve W.]

Just so you understand some basics: "octane" does not make horsepower. "Advanced ignition timing" does not make horsepower. What makes horsepower is burning more air and fuel (in the correct ratio). There are several ways you can burn more fuel: 1. larger displacement. 2. spin the engine faster. 3. higher compression.

Higher compression is generally the easiest way to improve performance, but it increases the heat of the air/fuel mix. Sometimes this get to the point where the mixture is ignited before the spark lights it. Adding "octane" to fuel raises the ignition temperature to prevent this. However, the higher-octane fuel also burns slower, so you need to advance the timing so the combustion is all done at the proper time in relation to crank angle to get the most power.

With all the electronics in today's vehicles, you can set up several ignition maps so the 'knock sensors' are listening for that pre-ignition and will retard the timing a bit to prevent it. Since that will be minimized by using higher-octane fuels, they give the rating for higest output with the high-octane fuel, but are also kind enough to give you the rating for the lower-octane fuel, after all the ignition adjustments are made.

I have known for some time that adjustments were made and lower output would be the result. It's nice to see some actual numbers.

On a side note: it is possibly the same way with our Spyders. Can-Am 'recommends' 93-octane fuel, but I have seen in one manual that the minimum was 87. Is it possible that the 1330 engine will give its full 115 horsepower using 930-octane, but will make adjustments when using 87-octane and might only put out 105 or so?

.

[wyliec]

Here’s a link

https://www.motortrend.com/cars/mazd...-drive-review/

It’s near the beginning of the article where you pick up the two horsepower ratings for the turbo engine.

Also, right on the factory window sticker it gives the 2 horsepower ratings with the turbo engine, and the two different octane ratings. I specifically went down and looked at the car. The regular aspirated engine is rated 186 hp.

[wyliec]

Trying to understand your Question. A Turbo powered engine can get more HP from a smaller Engine. A Non-Turbo power engine maybe a larger size or weight to get same or more HP as the Turbo. More information is needed if this does not help. .......

Originally, my only question was if other auto manufacturers had dual hp ratings for the same engine?

[wyliec]

Just so you understand some basics: "octane" does not make horsepower. "Advanced ignition timing" does not make horsepower. What makes horsepower is burning more air and fuel (in the correct ratio). There are several ways you can burn more fuel: 1. larger displacement. 2. spin the engine faster. 3. higher compression.

Higher compression is generally the easiest way to improve performance, but it increases the heat of the air/fuel mix. Sometimes this get to the point where the mixture is ignited before the spark lights it. Adding "octane" to fuel raises the ignition temperature to prevent this. However, the higher-octane fuel also burns slower, so you need to advance the timing so the combustion is all done at the proper time in relation to crank angle to get the most power.

With all the electronics in today's vehicles, you can set up several ignition maps so the 'knock sensors' are listening for that pre-ignition and will retard the timing a bit to prevent it. Since that will be minimized by using higher-octane fuels, they give the rating for higest output with the high-octane fuel, but are also kind enough to give you the rating for the lower-octane fuel, after all the ignition adjustments are made.

I have known for some time that adjustments were made and lower output would be the result. It's nice to see some actual numbers.

On a side note: it is possibly the same way with our Spyders. Can-Am 'recommends' 93-octane fuel, but I have seen in one manual that the minimum was 87. Is it possible that the 1330 engine will give its full 115 horsepower using 930-octane, but will make adjustments when using 87-octane and might only put out 105 or so?

.

I found this; it's an excerpt from an article 2 years ago. The rest of the article doesn't matter. I believe this part goes along with what you are saying:

"Raising the octane rating (also known as the anti-knock index) doesn't change the energy content of a gallon of gasoline. A higher octane rating indicates greater resistance to knock, the early combustion of the fuel-air mixture that causes cylinder pressure to spike. When higher-octane fuel is flowing through its injectors, the engine controller can take advantage of the elevated knock threshold and dial in more aggressive timing and higher boost pressures to improve performance."

Hey Steve W.,

Did you write that article?