The thing is, even if you were to find an economically feasable way of lowering the final drive ratio, you're really not going to improve your fuel economy much, if at all. From your current 26, I'd lay huge odds you wouldn't gain more than one or two mpgs at any speed.

Do I like tooling round with my engine turning over 3,000 rpms most of the time? No. Is there realistically anything I can do about it (short of buying a different car)? No.

They're probably out of business because there was no way they'd ever be able to deliver on their 1-2 mpg fuel economy improvement with only a 300 rpm drop. I'm thinking coaxing 1-2 mpg more out my engine would be tough even with an 800-1000 rpm drop (forgetting for the moment that such a drop in RPMs would render the car all but undrivable in 5th gear on anything other than a level road).

 

I agree. Plus, since the Mazda 5-speed automatic employs "Adaptive Shift Logic," I wonder if a different top ratio would screw up the shift points up and down between 4th and 5th.

 

This kit was only for the manual trans cars, and actually before the Mz5 was out which IIRC, was the 2006 model year, a few months after the OP.

But I would assume the same trans for the same chassis. We already know the 1st gen and now the second have the same engine and basic chassis as the 3 series cars.

 

I have an 08 with an auto trans and at 70 mph the tach reads 2600 rpm... but it is an automatic. Am averaging 25.5-26 mpg per tank of gas between me and my wife (yes she has a lead foot lol).

 

Well, I e-mailed the guy and got a reply.
NSNMS is going out of business @ the end of the year, "to focus on some new things", but if you are still interested, you can contact Steve Nackers via e-mail @ turfburn@hotmail.com
While he didn't specifically state it, I was left w/the impression he could still provide the gears set if you are interested?

 

This may have been covered in past threads, but I just read elsewhere that the 5-speed automatic in the 2012 Mazda5 carries the same gear ratios as the previous generation; however, the final drive ratio was numerically lowered from 4.388 to 3.458 to take advantage of the torquier 2.5L engine.

As such, the 70mph cruising RPM has dropped from about 3000 to about 2350.

 

DANG!! From 4:40 to 3:54!!! That's quite a drop.

I'd be willing to bet that it was a combination of things that brought Mazda to that decision, not the least of which was fleet mpg stds.

 

You got that straight, especially considering the overall ratio is only 2.39 and you've got a 4 cylinder lugging around a 3500-pound car.

 

Well I also know that a lot of customers complain about the higher rpms at speed as well. There have been many threads/discussions/questions (like this one) about it on the various forums I visit, so that too was a consideration, I'm sure.

 

Would the 6 spd manual from a 2.3 liter speed3 bolt in directly and if so is there any advantage?