Although I'm not at home for a few days so can't lay my hands on it, Peter Dron's book M3W back to the future! discusses final drive ratio's, listing OE and hypothetical higher ratios which would allow 60mph in second.
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
Slight tweak. I forgot to add in the tire diameter. This is with that in place. Which seems to line up a lot better with that 115mph-ish top speed.
But like I said before more time in the sweet spot, driving through Twisties is a lot more important than how fast you can get to the next stop light. At least for how I drive.
I agree Richard, six speeds would be great. There are times in traffic when even 1st gear isn't low enough.
I have felt 1st is too high, if trickling along you need to keep declutching. I take mine down to 2400 rpm in 3rd & 4th on a level road steady speed then drop a gear for accelerating or hill climbing.
Yeah the six speed definitely would be a better option there for first considering you're looking at 3.76 vs 3.1 using that calculator that would mean theoretically that your first gear would only take you to 28mph
Given stop and go traffic I think it would definitely be nicer having that 6 speed. Either way sounds like something worth looking in to further.
Someone who actually has a three wheeler here should check clearance through the trans tunnel. Just how tight are things there in referenced to the pics I posted of the trans. If it could be done I'd imagine this would be a hell of a mod, with most of it just being your own labor as a 6 speed Miata transmission is pretty easy to come by still.
I own a Miata which has a 6spd in it and Ill tell you the gearing is far tighter and often ill find myself simply skipping over gears as they arent exactly needed. The 6th gear isnt a taller gear as you get with many 5 to 6 gear upgrades. The 6speed is slightly more robust, but unless you are planning on pushing 250+ hp through it, you wont see any gains there.
Many people who autoX and otherwise actually swap their 6 speed for a 5 speed.
I own a Miata which has a 6spd in it and Ill tell you the gearing is far tighter and often ill find myself simply skipping over gears as they arent exactly needed. The 6th gear isnt a taller gear as you get with many 5 to 6 gear upgrades. The 6speed is slightly more robust, but unless you are planning on pushing 250+ hp through it, you wont see any gains there.
Many people who autoX and otherwise actually swap their 6 speed for a 5 speed.
I maintain a 6 speed box on the M3W would be a great advantage given the narrow power band. I find 1st gear fine and certainly wouldn't one lower, but in town traffic with 30 and 40mph speed limits, spend too much time with the engine at 2400 (too low) or 3500 rpm (too high) when in traffic on a light throttle.
An extra gear that allowed me 3000 rpm when trickling along at such speeds would be great. Better chance of finding just the right gear for a swift overtake manoeuvre as well
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
The 6th gear isnt a taller gear as you get with many 5 to 6 gear upgrades. Many people who autoX and otherwise actually swap their 6 speed for a 5 speed.
I've found the opposite to be true, rarely have I see a 6 speed transmission where you have an "overdrive" 5th as well as an overdrive 6th. Unless it's something with an absurdly high top speed and a hell of a lot of horsepower. i.e. Lambos and the like.
Nearly all the BMW M series have 5th as the 1:1 with everything before it being closer together, rather than just adding potential higher top speed. Same with the higher powered subarus. Their 5th is close enough to 1:1 as makes no difference.
For a vehicle that tops out at around 115-120 or so, having a closer ratio transmission, while there's the possibility for a little more rowing, it gives you a lot more time in the sweet spot in your torque band and you don't have an absurd drop from 1st to 2nd.
Regarding autocross the less time you have to shift, the better off you are. I don't think that many of the M3W crew are doing autocross though.
I think for the Miata itself though skipping gears can also be attributed to what rear end you're running. What's the ratio yours is running?
I'm definitely with richard on this though. I love a close ratio 6 speed for overall driving, than a 5 speed with a lot wider spacing.
The 6th gear isnt a taller gear as you get with many 5 to 6 gear upgrades. Many people who autoX and otherwise actually swap their 6 speed for a 5 speed.
I've found the opposite to be true, rarely have I see a 6 speed transmission where you have an "overdrive" 5th as well as an overdrive 6th. Unless it's something with an absurdly high top speed and a hell of a lot of horsepower. i.e. Lambos and the like.
Nearly all the BMW M series have 5th as the 1:1 with everything before it being closer together, rather than just adding potential higher top speed. Same with the higher powered subarus. Their 5th is close enough to 1:1 as makes no difference.
For a vehicle that tops out at around 115-120 or so, having a closer ratio transmission, while there's the possibility for a little more rowing, it gives you a lot more time in the sweet spot in your torque band and you don't have an absurd drop from 1st to 2nd.
Regarding autocross the less time you have to shift, the better off you are. I don't think that many of the M3W crew are doing autocross though.
I think for the Miata itself though skipping gears can also be attributed to what rear end you're running. What's the ratio yours is running?
I'm definitely with richard on this though. I love a close ratio 6 speed for overall driving, than a 5 speed with a lot wider spacing.
Both the 5spd and 6spd NC miatas run 4.10 rear end/final in the US. I do not know if a different read end/final is offered in other parts of the world.
If you notice, the ratios are extremely close both in the low end and on the higher end which leads many to skip gears. While shifting in AutoX is due to the fact of not wanting to shift often, with such close gears it leads to almost no advantage to shifting and doesnt help much in keeping you in the ideal torque curve, but rather eeps you peddling through gears or skipping them on leisure drives. While this can be fun, I dont think it results in much of an advantage over the 5 speed.
Granted that's just flat out, and from 3rd gear so not especially relevant to the initial topic question, but it looks like the 6 speed doesn't have much difficulty walking away from a 5 speed. So I definitely think it depends on what type of driving you're doing with it.
I've personally never driven a 6 speed and thought "I have too many gears."
If they are both in 3rd gears, its a 1.64 vs a 1.33. Of course these is going to be a difference between the two.
In practical application, the closeness between 3rd and 4th in the 6speed means that I often find myself skipping 3rd all-together as I dont need it for much. If I were racing, it might be beneficial to eek out each gear to keep it in the torque curve. However for everyday use its honestly just as well to have the 5speed.
My guess is that it would be cheaper and easier to simply swap out ratios and keep the 5 speed vs grafting in the 6 speed.
