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6 speed NON-Mazdaspeed transmission swap?

36K views 20 replies 8 participants last post by  verto 
#1 ·
Has anyone tried to swap the non-Mazdaspeed 6 speed transmissions onto the 2.0 or 2.3L engines? Most everything I'm finding while searching around the forum seems to be about putting the MS3 trans into an 04-09 car, not the new 10+ 6-speed that you can get in the MZ3 and MZ5. Are the bellhousing (or whatever you call the interface between engine and transmission) the same?
 
#5 ·
I've never seen anyone do it, I don't know why anyone would need to do it.

A lot of people make a big deal about how high RPMs you sit on the highway, well that's how the car is made, that's where it's supposed to be (welcome to low HP cars).
By adding in another gear.. it doesn't change that, you'll be at a very similar RPM, you'll jut be in another useless gear.

Don't count on it working, mount points changed.
An additional gear makes no difference, it just means more can go wrong with it.
 
#6 ·
A little negative lol but I agree ... Mount points will be a pain and the gearing may actually have a negative impact + ur adding some weight .... Idk about the mz6 6speed but the ms3 6er is waaaayyyyy bigger and much heavier ( I can pick up a stock transmission and carry it no problems but a ms3 one takes 2 guys and it's heavy for both )


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#7 ·
If the mount points changes then its definitely out of the question. I still would like to get lower revs on the highway. My other cars have similar weight to power ratio but turn ~2K @ 70mph the Mazda3 spins ~3K. In my opinion Mazda engineers missed the mark on gearing and if I can fix I will, just might be stuck with taller tires instead of a better spread of transmission ratios.
 
#8 ·
There's nothing wrong with being at higher revs, if you're any lower it's probably going to end up damaging the internals over the length of the vehicle more than a higher rev range.

70mph in a first generation manual in 5th is indeed 3,104 RPM
70mph with a second generation manual in 6th is 2,200 RPM

While yes it is lower, the 2.3L does not create sufficient torque to get the great MPG it already gets.

by swapping transmission sure you can get a lower RPM, but at the cost of a harder working, less MPG engine.

In basic terms.. you're bogging the engine down for no reason.
If noise is the issue, there are plenty noise cancelling products on the market that can and will certainly alleviate noise.
 
#9 ·
As an example, my first gen Miata used to turn 4,000 rpm at 70. Got the fuel economy it was supposed to, and engine wear was what it should be for the miles.

Same issue exists in both cases; the engine made such paltry torque at such high RPMs, it cruises at higher rpm. I don't see an issue with it either way.


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#10 ·
6th gear is nice when you live in an area where normal traffic flow is 80mph...

to each his own.

it should fit fine. just like the ms3 swap, you need to check the axles, flywheel, clutch, shifter cables...

the mount is the same. they just changed the way the tripod and frame side mount are connected, still a single bolt but also added a stud to help stop twisting.
 
#12 ·
The position of the engine in the bay moved though; would just the mount fix that..?

The speed3 trans though is even worse at highway speeds; because it swaps axle ratios in 6th you'd be sitting UNDER 2,000 RPM at 75MPH, meaning you're seriously loading the engine for absolutely no reason.


I mean maybe I'm the only one that feels like my engine feels like complete junk up until 3,000 RPM in any gear. I certainly don't want to be spewing fuel into the engine on a highway trip just so it sits at a lower RPM at the cost of MPG and more wear.
 
#13 ·
I mean maybe I'm the only one that feels like my engine feels like complete junk up until 3,000 RPM in any gear. I certainly don't want to be spewing fuel into the engine on a highway trip just so it sits at a lower RPM at the cost of MPG and more wear.
It may be pointing out that I don't believe you have VVT on your ealier 2.3 (correct me if I'm wrong.) My 07 pulls smoothly from 2,000 up, but it really doesn't take off till 3500 or so. It's most noticeable when passing on the highway in 5th gear (2800-3500) as the engine doesn't require a downshift unless you're in a hurry or there's a grade.

Still, I agree I think the engine's 5th gear is appropriate. My issue is the 1-2 spacing in that 1st is so damned short it's practically useless.
 
#14 ·
My 09 2.3 is perfectly happy shifting into 5th at 45 mph. By 70mph the engine sounds good and I have the zip to pass if needed but when its time to cruise I find myself reaching for another gear. I wouldn't spend a ton of money to remedy this but when I have to pull the tranny to do the clutch soon, a swap would be pretty easy and not to expensive.
 
#16 ·
We all have VVT

1 may seem useless, but when you find yourself in the mountains or on steep roads you'll be thankful it's there.
You're not supposed to go down to 1 when you're moving at all (it's also like that for that very reason).
I thought the early 2.3's didn't have VVT:huh: but all 2.0's had it.
 
#17 ·
they mounts are the only difference. position is still the same. it may look different because of how they redesigned the mount. it's similar to how the 5 speed and ms3 transmissions look like they are different, but the mounts line up the same.

on the ms3 trans it is 5th and 6th which have different final drive ratios. on mine 6th gear puts me at around 2600-2750 at 75mph. power is not lacking at all. I can pass people without downshifting... and I am N/A


1-2 spacing is a bit wide, they fixed it in a later version of the 5 speed transmissions. i don't remember which.

the only bad thing about the ms6 trans is second gear. the pads on the shift fork always go and then you cant use 2nd at all... i'm not sure if the normal 6 speed has the same problem. i doubt it does as it's a revised version of the 5 speed, they just added another external gear...
 
#18 ·
notice the massive weight gain with that trans though?

Seriously that's what has kept me away from it, even the brakes for a bit until I realized I needed just a bit more.

The Speed3 trans is huge as CRAP compared to the G35; like almost twice the size, I know it weighs like three or more times as well. I just don't see any advantage of it.
 
#21 ·
the ms3 trans is a triple shaft, while the g35 is only a double. that's why it's so much bigger and heavier. for me the weight doesn't matter, the LSD makes getting off the line much better, and at speed the weight has no impact.

the non-speed version of the 6 speed are small like the g35. they are essentially the same trans. on the g35, 5th gear is external and held under the stamped steel cover. on the 6 speed they just added another gear in the same area.
 
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