He had an '07 2.3L HB w/the man-u-matic before the '08 5-sp, so he is not talking out his a$$ about the differences.

 

BTW, I am not putting it down, but I did figure out what the biggest difference is. With the 4 Speed auto, it was running about 500 RPM less than my 2.3 in 5th gear at the same speed.

 

If you want to go through the trouble, there is an over-over drive 5th gear available for the 5-sp? ... Or was.

 

Now that would be interesting. I find that I'm running about 3,100 RPMs at 70 mph, and that turns out to be the second highest engine speed at that pace of any car I've ever owned. FWIW, the only car with a higher RPM was my 1970 Challenger with an 8 3/4 limited slip rear end with a set of gears in it. IIRC, the tach in that car hovered at about the 3,800 RPM mark at 70 mph.

 

It took me a while to find it again (it's been so long,) but if you are willing, here ya' go!!
http://www.nsnmotorsports.com/produc...roducts_id=206

Oh, and here's a related thread from another forum: http://www.mazda3forums.com/index.php?topic=47528.0

 

Thanks Richard!

Looking at their web page they say:
This 5th gear swap from NSN provides you with a direct drop in gear set for 5th gear that will drop your rpm's by 5%. This results for most people in a gas savings of about 1-2 mpg and lowers your highway cruise rpm's to about 3,000 rpm's at 70mph.

Hmmm, I'm thinking that I'm missing something. When I posted before that I was running 3,100 @ 70, I rounded up. In reality, the tach is just a hair above the 3,000 mark, so call it 3,050. If the new gear set drops the RPMs by 5%, then I should see more like 2,900 @ 70 mph. Not much of a change.

Then I go over to the Mazda3Forums post and Steve from NSN says:
We have a kit for replacing the 5th gear in all Mazda 3's (2.0L and 2.3L) with MANUAL transmission... This gear will reduce your cruising rpm's by about 300-400 rpms' at 75 mph.. in other words those of you that use to cruise around 3400 at 75 mph will now cruise a hair over 3,000 rpm's...

Okay, that's a bit better. Assuming that my car is currently doing 3,050 @ 70 mph, then it will be doing 3,268 @ 75. If I then apply the 5% reduction, I would then be seeing 3,104, still a far cry from the "300-400 rpm" reduction he posted, but a bit better than I'm doing now.

When all's said and done, I'm thinking that unless the new gearset can yield at least a 10% reduction in RPMs, then it's unlikely that the one to two miles per gallon improvement in fuel economy is realistic.

For the moment I'm going to take a wait and see approach.

 

Yeah, on the auto i'm running pretty close to the 3,000 range doing about 70mph on a flat stretch highway, I'll know for sure tomorrow. Slow depressing the pedal to the "od" raises it to about 3600

 

Ummm, it's kind of the other way around. The archaic term "Over Drive" (or "OD" as some folks call it) means that the output shaft of the transmission is turning more RPMs than the crankshaft of the engine. What you are most likely experiencing when the RPMs pop up to 3,600 is the torque converter coming out of lock-up. That said, you're still in "Over Drive" until your transmission downshifts to at least 3rd gear.

For the 2009 model year, the gear ratios for the 4-Speed automatic are as follows:
1st - 2.816:1 (Under Drive)
2nd - 1.497:1 (Under Drive)
3rd - 1.000:1 (Drive)
4th - 0.725:1 (Over Drive)

For the 2009 model year, the gear ratios for the 5-Speed Automatic are as follows:
1st - 3.620:1 (Under Drive)
2nd - 1.925:1 (Under Drive)
3rd - 1.285:1 (Under Drive)
4th - 0.933:1 (Over Drive)
5th - 0.692:1 (Over Drive)

 

I am just going by the fact at 70MPH my HB is setting right about 3000 RPM while the Sedan was at 2500. I did have a lot of pep in the 3 lower gears though.

 

Yeah, I would agree, Going to school today, I noticed around 2450-2500 around 70MPH. 2900-3100 ~80MPH. Kicking in OD at 70mph gave me around 3200..

Problem with auto's in races is usually I smoke in 1st and most of 2nd...They start to catch up if they driving a manual, usually in my later 2nd into 3rd...this is how it is for me against honda's and scions