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Mazdaspeed3 vs. Mazda3 Transimssion Gear Ratio Analysis

25K views 46 replies 16 participants last post by  Maizee3T 
#1 ·
Hey guys,

I was feeling nerdy today. So, I did some calculations and created some graphs to compare the stock Mazda 3 5-speed manual transmission versus the Mazdaspeed3 6-speed transmission when used in a regular Mazda 3. The data might be useful for those interested in swapping the MS3 transmission to their Mazda3's.

Variables:
- Overall tire diameter based on stock 2004-2009 Mazda 3 17" wheel/tire package (205/50/17)
- 5-speed transmission ratios taken from 2006 Mazda 3 specifications
- 6-speed transmission ratios taken from 2007 Mazdaspeed3 specifications
- Final drive ratio for 6-speed gears 1 through 4 (3.941:1) used for gears 1 through 6, with the equivalent ratios for gears 5 and 6 calculated (Remember, gears 5 and 6 have a final drive of 3.350:1)
- Maximum engine speed of 6800 RPM

Now for the resultant data (pretty self explanatory):








My conclusion: This upgrade is worth every penny and all the headaches!

As always, thoughts and comments are welcome.
 
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#4 ·
I guess I should read a little better next time. I noticed it on the first post after you replied.

Did you use the circumference of the tire or did you use the rev/mile rating for the stock RSA's?

It looks like a good upgrade for track days and autocrossing. But I am not sure what class that would put you in for autocrossing.

Big difference in rev drop between 1st and 2nd gear.
 
#5 ·
You read it correctly the first time. I just edited the main post a few min ago hehe.

The tire circumference is based on the tire size, not the RSA's specifically.

Yeah, the kicker for me is the 1-2nd shift. It keeps the RPM's up. The 1st to 2nd gear in the stock 5 speed in the Mazda 3 annoys me every time I have to make that shift. Also, gear for gear, the MS3 unit is much closer. As you said, big advantage for track days, and probably autocross too.
 
#7 ·
It depends on what year Mz3 you have.

04-05 hubs are different so the axle splines won't match. So you need to buy no hubs.
You have to replace shifter linkage, including shifter and base,both axles,joint(jack) axle,driver's side motor mount,and lower transmission mount,new clutch,and fly wheel. You might have to replace the shifter cable braket that attaches the shifter cables to transmission. (not 100% sure on that one)
I am not 100% positive the conectors are plug and play for the back up lights and the neutral switch. The master cyclinders are the same though.

If you don't have a lot of performance mods I don't know if the extra weight of a six speed would be worth it.
 
#10 ·
p.s. do we know what the weight difference is between the two boxes? Just because it is a 6 spd, does not necessarily mean it's heaver than the 5 spd. Many variables here... I think Aisin manufactures the 6spd from the MS3? I'll see if I can get a weight comparo.

As for performance, I think it will be great for an N/A vehicle, especially on a road course.
 
#11 ·
I am not sure about the weight difference. It could be marginal.
I believe your right on the Aisin manufacturing the 6sp. Funny thing is on the Tripoint car it was a second faster around the track then the Ms3 and I thought I remember them saying it had to do with less shifting with the 5spd. I wonder if the mz3 can take full advantage of the 6spd on the track since the computer limits are top speed to 115 mph?

Ha ha if you want too. I was just posting that to give people an idea on what changed.

How did you calculate rpm drop?
 
#12 ·
Yeah, I could see how certain gearing could be better for different tracks. However, all of the tracks in my area would definitely suit the 6spd ratios. Anyhow, it's still pretty interesting stuff. Was the Tripoint car turbo'd?

Haha, I was just joking. Yeah, i'll definitely calculate the 2010 ratios as well (based on the 2004-2009 Mazda 3 tire sizing). It's pretty easy since I have the template setup. Who knows... These gear boxes might be able to be retrofitted to our generation Mazda3's? It could be an option somewhere down the road, for sure.

As for the calculation of RPM drop, it is basically looking at the road speed at the RPM of the previous gear, then calculating what the RPM would be for the gear in question.
 
#15 ·
I do prefer the normal 3's 5 speed because I have to shift less. The car has enough torque that it's always at a good enough spot without needing shorter gearing to downshift more frequently and keep the revs up to stay in the powerband like with the 6 speed. In autocross, you get an extra 10mph or so in 2nd without needing to waste time shifting to 3rd, which can be super helpful on really fast courses. On the track at Mazfest this year (Cal Speedway) I was able to top out at around 115mph in 4th on the main straight without needing to shift to 5th, which was nice, and only had to downshift one gear where the speeds were downshifting two on some corners.
 
#22 ·
It might be 6800 on the Mazdaspeed 3, but the NA 3s you can rev out to 7,200rpms and probably should...so that drops the 1-2 shift to almost spot on 4,000rpms which is close to perfect.

That said it would be nice to have the gear set for (at 7200rpms)
1st 36mph
2nd 62mph
3rd 90mph
4th 120mph
5th 170mph

Supposing a 5 speed and the powerband of our engines. Everything in 1-4th just a little bit closer together. For a 6spd the current 2010 6spd is just about perfect, though I'd have 3-5 just a bit shorter.

If I had to put a number on it I'd say the 6spd probably isn't more then 10lbs heavier then the 5spd, probably less. the Case only needs to be a hair bigger, and it might be the same size between the 2010 5 and 6spds. If I do get a later model Mazda 3 it'll probably be a 2.0...but I am going to be considering getting a 6spd off a junker...pretty seriously. It would be nice if they offered it as an option, I'd certainly pay more for it. But I want the fuel economy of the 2.0. Though I'd also like DSI and some real engine tweaking. Mazda I know you can hear me, I can't believe you can't manage 80hp/l on the 2.0 and at least 72hp/l on the 2.5 (IE 160hp 2.0 and 180hp 2.5) without serious compromises. Give us those numbers and we shall be happy (till we start tearing in to the cars to get even more power).

I get that as engines get bigger they get less efficient, but the 2.0 is 74hp-l, not terribly shabby, but certainly not overly impressive for the year 2009 (the civic is managing about 79hp-l, the RSX 80hp-l), the 2.3 with 156hp was ~68hp-l, quite a bit of drop off from the 2.0's efficiency and the 2.5 is ~67hp-l a further drop. I am thinking that the biggest difference in efficiency between the 2.0 and 2.3/2.5 is the balance shaft and probably secondarily the drop in compression ratio. I can see the need of 'smoothness' to be 'class leading', but why drop the compression ratio? Was it because it really couldn't run on regular gas otherwise?

It'd be nice to see a real 3s or even a Mazda 3r. I know there is the Mazdaspeed 3, but why not do some 'basics' to the Mazda 3 that would be cheap to improve performance from the factory. No balance shaft, maybe tweaked cams and engine maps, maybe a revised exhaust. Even if you didn't do revised exhaust the difference in manufacturing for no balance shaft (basically a BSD from the factory), one or two different cams and the engine maps couldn't possibly cost more then $300-500 for Mazda. Charge $1,000-2,500 for it and I bet people why buy. Maybe better exhaust (still quite) might add $100-300 per vehicle from the factory (well cost to Mazda) and still maybe call it only $1,500-2,500 MSRP increase.

Mazda 3r 2.5l, 175hp or maybe 180hp for the tweaked exhaust at only call it a $2,000 premium. Hey, other perk it would probably also get 1-2mpg better. Give me those power levels (oh and hey an extra 1-2mpg) and I would deffinitely get a 3r over a 3i. Until then, a 6spd and 19hp for a vehicle weighing 100lbs more isn't all that significant a performance boost. Hell compared to my 2005 3i a 6spd and 19hp isn't a lot for weighing 300lbs more in fact my 2005 with 148hp and 2696lbs comes out to about 18.2lb-hp, the 2010 2.5 with 167hp and 2968lbs is 17.7lbs-hp, even with all that extra torque ends up being only a little faster (the 2010 3i weighs in at around 2870lbs, so the 3s in that case is a fair amount faster since it is only a 100lb weight difference).

Still ranting here, sorry, but that is my either gripe...the curb weights, especially with no increase in output efficiency. The 3i is now quite a bit slower then the old one, 200lbs of extra fat on the car means it is probably something like half a second slower 0-60 then the old 3i was. By a consquence, ignoring the 6spd in the 2010 3s, all the extra weight means the 2.5l is/would be only a hair faster, maybe 1-2 tenths, despite the extra 2 tenths of a liter and 11hp. With the shorter gearing from the 6spd it is probably more like .2-.3s faster 0-60, but still a pretty small bump up. If it weighed the same we'd be talking a car that would hit 0-60 probably close to a full second faster, especially with the 6spd having shorter gears.

I really hope DSI and lighter curb weights are in the cards for the next generation for Mazda 3 (around when I'll be buying one, in 4-6 years). Mazda at least is claiming both.
-Matt
 
#23 ·
[quote author=azazel1024 link=topic=159743.msg3395641#msg3395641 date=1256996220]
It might be 6800 on the Mazdaspeed 3, but the NA 3s you can rev out to 7,200rpms and probably should...so that drops the 1-2 shift to almost spot on 4,000rpms which is close to perfect.

That said it would be nice to have the gear set for (at 7200rpms)
1st 36mph
2nd 62mph
3rd 90mph
4th 120mph
5th 170mph

Supposing a 5 speed and the powerband of our engines. Everything in 1-4th just a little bit closer together. For a 6spd the current 2010 6spd is just about perfect, though I'd have 3-5 just a bit shorter.

If I had to put a number on it I'd say the 6spd probably isn't more then 10lbs heavier then the 5spd, probably less. the Case only needs to be a hair bigger, and it might be the same size between the 2010 5 and 6spds. If I do get a later model Mazda 3 it'll probably be a 2.0...but I am going to be considering getting a 6spd off a junker...pretty seriously. It would be nice if they offered it as an option, I'd certainly pay more for it. But I want the fuel economy of the 2.0. Though I'd also like DSI and some real engine tweaking. Mazda I know you can hear me, I can't believe you can't manage 80hp/l on the 2.0 and at least 72hp/l on the 2.5 (IE 160hp 2.0 and 180hp 2.5) without serious compromises. Give us those numbers and we shall be happy (till we start tearing in to the cars to get even more power).
-Matt
[/quote]
1st Gear ought to be taller so there isn't such a sharp drop in revs from 1st to 2nd. I don't know about you all, but when I'm in traffic, waiting for the revs to drop between 1st and 2nd, I almost get rear ended by impatient automatic drivers.
 
#26 ·
[quote author=candal82 link=topic=159743.msg3394528#msg3394528 date=1256918306]
p.s. do we know what the weight difference is between the two boxes? Just because it is a 6 spd, does not necessarily mean it's heaver than the 5 spd. Many variables here... I think Aisin manufactures the 6spd from the MS3? I'll see if I can get a weight comparo.

As for performance, I think it will be great for an N/A vehicle, especially on a road course.
[/quote]

i cant find it now, but i remember reading that the 6-speed box is substantially heavier than the 5-speed.

you can read through to see if you can find it, lots of good info in there too:
http://www.specialstage.com/forums/showthread.php?t=30459
 
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