[rauni]

Hi all! Recently bought a used 2007 year Mazda 3, 1.6L petrol, 5 gears, manual transmission.

For me, driving experience has been quite smooth, but I've noticed that at high speeds, the RPM is higher than I would expect. When I am driving at 100 km/h (62 mph) in 5th gear, the RPM is about 3000 while cruising. For me, this seems to be a suspiciously high number. What do you guys think?

Also, the petrol usage is quite high. I measured it to be 8.5 l / 100km, although I drive 60% of the time on highway and 40% in the city. According to the specs, the petrol usage should be 8.9 l/100 km in the city and 5.7 l/100 km on the highway.

One more thing - not sure if this is relevant or not - a signal light for the knock sensor showed up on the dashboard after I first bought the car. I suspect that this was due to the previous user using wrong petrol (95 instead of 98). Could this have damaged the engine somehow? From what they told, I gather that this knock sensor light could have been showing for quite a long time.

Cheers,
Rauni

 

[Mark L]

Yeah, I've got 2.3L 2004, same thing about 3k rpm at 100km/h. Seems to just be the way the gear ratio is setup.

 

[rauni]

Yeah, I've got 2.3L 2004, same thing about 3k rpm at 100km/h. Seems to just be the way the gear ratio is setup.

Ok, good to know!

 

[SizeableFowl]

Yeah, I've got 2.3L 2004, same thing about 3k rpm at 100km/h. Seems to just be the way the gear ratio is setup.

Likewise, at ~130 kph I'm nearly touching 4k rpm.

Hi all! Recently bought a used 2007 year Mazda 3, 1.6L petrol, 5 gears, manual transmission.

For me, driving experience has been quite smooth, but I've noticed that at high speeds, the RPM is higher than I would expect. When I am driving at 100 km/h (62 mph) in 5th gear, the RPM is about 3000 while cruising. For me, this seems to be a suspiciously high number. What do you guys think?

Also, the petrol usage is quite high. I measured it to be 8.5 l / 100km, although I drive 60% of the time on highway and 40% in the city. According to the specs, the petrol usage should be 8.9 l/100 km in the city and 5.7 l/100 km on the highway.

One more thing - not sure if this is relevant or not - a signal light for the knock sensor showed up on the dashboard after I first bought the car. I suspect that this was due to the previous user using wrong petrol (95 instead of 98). Could this have damaged the engine somehow? From what they told, I gather that this knock sensor light could have been showing for quite a long time.

Cheers,
Rauni

Not really that uncommon for small engine cars, my Fiesta ST operated at similar rpms cruising on the highway.

 

[rauni]

Got it. By the way, what's your average fuel consumption?

 

[SizeableFowl]

Got it. By the way, what's your average fuel consumption?

Depends on what speeds I want to maintain. My daily commute is approx 100 miles (just under 50 miles per direction) and if I set the cruise control to 65 I get about 28-30 mpg. If I set cruise at 75+, I'll see about 25 mpg. Easy for me to justify 6 minutes of extra time in the car everyday for about 20% better fuel economy.

It is worth noting that I have a 2.3 MZR with a 5 speed manual riding on larger, wider rims and tires.