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Tranny swap?

2119 Views 10 Replies 6 Participants Last post by  TrueRedSpeed
Some of you are probably aware of the fact that I don't like the close ratios in our gearbox. I think that even stock it's limiting the car's performance, and as power increases, this will become even more of a limiting factor. First and even second gear are practically useless. Unless you keep the gas floored, every time you shift your boost drops off, and we have to shift twice before we can even get past 60mph...which comes pretty quick in our cars. I've been shot down in a couple of threads on a couple of forums about the idea of getting different final drive gears for the car. Apparently not enough people would be interested to make it worth the manufacturer's time.

I would like to limit this thread to a discussion of the following idea's posibility, not its practicality.

So the easy first question that could shut the whole thread down, and I'm having a hard time answering this one myself since I have limited google-fu skills. I know that the differences between the MS3 and 2.3 MZ3 motors are countless, but is it the same BASIC motor? Basically, would a tranny swap between the two be possible?

Second question, assuming the MZ3 tranny would mount up without difficulty, could it handle the significant difference in power between the two motors?

Third, assuming the tranny could handle the power...any chance our halfshafts would mate up? I'd imagine that the axles in the speed are beefier than those in the 3, but then again I would have thought the motor mounts would be as well.

Fourth, what is the availability of LSDs for the standard 3 that would be likely to withstand the increased power?

I know this would be very expensive even if it were possible, I'm just trying to get some ideas going. I know I'm not the only one who thinks our gears are too short, I've heard plenty of you complaining about it around here :lol:

Again, if all you have to contribute is "You should have bought a WRX if you wanted a 5-speed", please keep in mind that I LOVE my MS3. I bought it because I think it kicks a WRX's ass, even if I personally believe the ratios were poorly chosen.
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Another option could be the auto tranny out of cx-7. Should handle the some power increase and designed for the same motor. Might give you the gearing you are looking 4 but it an auto. Might need a ecu also. Just a thought, u might not want an auto but could be viable swap.
Well, not sure of course but I don't think the stock 3 trans. could handle the power, nor do I think the half shafts would line up. You would also have to get around the nannies in the ecu. Sounds like a ton of work.
I the half shafts on the MS3 are equal length and since most of the mags made a big deal of this I'm assuming that the ones on the MZ3 are not. Therefore you have already run into a big fit problem. Not to mention that you want the equal length half shafts to help with torque and power control. Not saying I know this info, but you need to look into before going any further.
[quote author=TrueRedSpeed link=topic=67967.msg1171093#msg1171093 date=1169861040]
I the half shafts on the MS3 are equal length and since most of the mags made a big deal of this I'm assuming that the ones on the MZ3 are not. Therefore you have already run into a big fit problem. Not to mention that you want the equal length half shafts to help with torque and power control. Not saying I know this info, but you need to look into before going any further.
[/quote]

The regular Mazda3 does have equal lenght drive shafts! The magazines made a big deal of it becuase it is one of the main factors to reduce torque steer.
I have yet to see anything that is different other then the tranny itself on the MS3.

I would do alot of research on it and if possible look into part numbers to see if any cross reference. And I would want to compare both.

Our axels are pretty good as they are alot thicker than the auto axels.

It should bolt up the the engine no problem.

As far as the tranny holding up, there are a few putting out more power then the MS3 on here.
You also have to spend quite a bit to get the LSD installed into the 5speed.
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[quote author=AzMz3 link=topic=67967.msg1171324#msg1171324 date=1169874672]
[quote author=TrueRedSpeed link=topic=67967.msg1171093#msg1171093 date=1169861040]
I the half shafts on the MS3 are equal length and since most of the mags made a big deal of this I'm assuming that the ones on the MZ3 are not. Therefore you have already run into a big fit problem. Not to mention that you want the equal length half shafts to help with torque and power control. Not saying I know this info, but you need to look into before going any further.
[/quote]

The regular Mazda3 does have equal lenght drive shafts! The magazines made a big deal of it becuase it is one of the main factors to reduce torque steer.
I have yet to see anything that is different other then the tranny itself on the MS3.

I would do alot of research on it and if possible look into part numbers to see if any cross reference. And I would want to compare both.

Our axels are pretty good as they are alot thicker than the auto axels.

It should bolt up the the engine no problem.

As far as the tranny holding up, there are a few putting out more power then the MS3 on here.
You also have to spend quite a bit to get the LSD installed into the 5speed.
[/quote]

So if someone with an auto is trying to convert to a manual, he would have to replace the axles too?
[quote author=boardumb link=topic=67967.msg1171326#msg1171326 date=1169874841]
[quote author=AzMz3 link=topic=67967.msg1171324#msg1171324 date=1169874672]
[quote author=TrueRedSpeed link=topic=67967.msg1171093#msg1171093 date=1169861040]
I the half shafts on the MS3 are equal length and since most of the mags made a big deal of this I'm assuming that the ones on the MZ3 are not. Therefore you have already run into a big fit problem. Not to mention that you want the equal length half shafts to help with torque and power control. Not saying I know this info, but you need to look into before going any further.
[/quote]

The regular Mazda3 does have equal lenght drive shafts! The magazines made a big deal of it becuase it is one of the main factors to reduce torque steer.
I have yet to see anything that is different other then the tranny itself on the MS3.

I would do alot of research on it and if possible look into part numbers to see if any cross reference. And I would want to compare both.

Our axels are pretty good as they are alot thicker than the auto axels.

It should bolt up the the engine no problem.

As far as the tranny holding up, there are a few putting out more power then the MS3 on here.
You also have to spend quite a bit to get the LSD installed into the 5speed.
[/quote]

So if someone with an auto is trying to convert to a manual, he would have to replace the axles too?
[/quote]

Yes, along with a bunch of other stuff....ECU, gauge cluster, a few engine mount brackets, auto gear shifter..ect!
Then after you get it all done you need to tow it to the dealer before it wil start.
auto gear shifter? Man this is going to be a long and painful projects *kicks myself for buying a AT*
[quote author=boardumb link=topic=67967.msg1171346#msg1171346 date=1169876238]
[/quote]

:lmao:

Thanks for the constructive posts guys, so far you've given me a lot to think about. The ECU is a factor that honestly hadn't occured to me, but swapping it with a tuned MZ3 ecu would present some benefits as well, although I cringe to think of the problems it might cause in the process. Final drive gears would be by far the quickest solution, if only somebody made them. It's good to hear that there are some MZ3 powerhouses out there, that gives me a bit of hope. Redms3gt, the CX-7 auto tranny swap is a great suggestion, but I'm not ready to give up my manual tranny yet :D

Desperado Callado sent me to a link with a post about a Japaneese tranny for the MS6, which apparently has taller gearing. Sounded great in theory since we use the same motor, but there's the factor of FWD vs AWD to consider, and doing a full blown AWD swap is way too rich for my blood, haha. It does beg the question though...could we just snag the final drive gears from the tranny? Here's a link to a breakdown of the tranny in case any of you are interested and haven't seen it (courtesy of Boother) http://forum.mazda6tech.com/viewtopic.php?t=4206
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I am thinking that this car has enough power to just start in second gear stock. Just slip the clutch a touch more. With upgrades this should be no problem. Then you only gotta shift once to 60. You also would start out with less boost limiting in 2nd than first. Who wants to volenteer there clutch to some timed 0-60 sprints with 2nd and 3rd only to see if its faster?
I would say the car is still very new and some waiting my be in order, maybe there will come along a final drive swap option. You could always get taller tires in the mean time 8)
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