by "Jake - Has Bad Luck So You Don't Have To" (murdersofa)
Published 03/13/2017 at 11:32
by "Jake - Has Bad Luck So You Don't Have To" (murdersofa)
Published 03/13/2017 at 11:32
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STARS: 4
Miata does not haz it. 6th gear, 4k rpm on the highway for the whole 190 mile drive to Kansas City. I got 20 mpg. Yikes. What idiot added a 6th speed and made it only 500rpm less than 5th gear?
"bob and john" (bobandjohn)
03/13/2017 at 11:36, STARS: 1
probably the same guy that did the gearing on my F800R. 4th, 5th, and 6th? MAYBE 900 RPM difference between the 3 of them @ 75mph.
"bhtooefr" (bhtooefr)
03/13/2017 at 11:37, STARS: 0
20 sounds like something’s wrong even for those speeds.
And, the 5-speed is really the better transmission in the NB - 5th in the 5-speed is actually (with the respective final drives used) a touch taller than 6th in the 6-speed, and it shifts better.
"E90M3" (e90m3)
03/13/2017 at 11:37, STARS: 1
Your Miata is doing a nice job at getting M3 fuel economy. I took that 85 mph road in Texas, on my way up to OK, and I got 18 mpg at an average of close to 100 mph.
"Daily Drives a Dragon - One Last Lap" (ddadragon)
03/13/2017 at 11:40, STARS: 0
My god. Even with the 4Runner’s low gearing it’s about 2500 at 80. That had to be buzzy as all hell.
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 11:43, STARS: 0
Yeah. The five speed is fantastic. The 6 speed is still a good transmission relative to most other cars and you get another gear to play with, which is more fun on the street. For track or autocross, though, the 5 speed is the only option.
"SidewaysOnDirt still misses Bowie" (sidewaysondirt)
03/13/2017 at 11:44, STARS: 1
I feel like most sports cars with a sixth grear should really have tighter 1-5 and a super long 6th. Most of them won’t pull in 6th when you’re going fast enough to shift at the top of fifth, so why not just make it a super overdrive? Also, your sixth gear appears to be the same ratio as my 5th gear judging by 4k at 80. Must be nice having a muffler at that speed.
"Seat Safety Switch" (seat-safety-switch)
03/13/2017 at 11:45, STARS: 0
Reminds me of the 4.10(?) gears in my straight-piped ‘91. I kept a tube of earplugs in the glovebox.
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 11:46, STARS: 0
Nah. It’s a mellow hum. You barely notice it, which is why I laugh at people who say “ugh I’d hate to listen to a strung out 4cyl revving for a whole road trip” and it’s like, dude, it doesn’t sound like anything.
"TheD0k_2many toys 2little time" (thed0ck)
03/13/2017 at 11:49, STARS: 1
uh might wanna check some stuff out. i get close to 30 in my 03 on the highway with it pegged at 4k
"Daily Drives a Dragon - One Last Lap" (ddadragon)
03/13/2017 at 11:50, STARS: 1
Really. Huh. Kinda shows I’ve never driven a Miata.
"ateamfan42" (ateamfan42)
03/13/2017 at 11:51, STARS: 1
What idiot added a 6th speed and made it only 500rpm less than 5th gear?
The majority of 6 speeds in production cars are close-ratio (or at least semi close-ratio) gearboxes. The point is to reduce the drop in engine revs between shifts for performance reasons. It is funny this is so widespread in application, considering how many drivers would rather have wider ratios and a taller highway gear for economy. But since when do auto manufacturers always give the public what they want?
Also, in general, auto makers are leary about putting too tall top gearing in manuals in the US, because there are so many bad/lazy drivers that won’t downshift when they should. This puts excessive wear and load on the engine, increasing the probability of early warranty repairs.
A lot of people mistakenly think converting a 5 speed Miata to a 6 speed yields and “extra” gear. A review of the ratios in both transmissions shows the 6 speed is much shorter across the board, necessitating a taller final drive to even roughly match the 5 speed on the highway. (5 speeds came with either 4.3 or 4.1 final drives; most 6 speeds have the 3.909.)
There is a 3.636 final drive available in the Mazda catalog (that was used in certain Australian and European models) that brings gears 1-5 in the 6 speed pretty close to those of the 5 speed (+ the 4.3). A lot of folks with turbo Miatas swear this is the way to go.
A few years ago there was also a group trying to put together a custom production run of 3.308 ring & pinion sets, but it fell apart when not enough people were interested at the target price to make it happen.
"AfromanGTO" (afromangto)
03/13/2017 at 11:52, STARS: 0
My mom’s Mazdaspeed Miata was bad too. My auto GTO got better highway mpg than she did. lol
"Highlander-Datsuns are Forever" (jamesbowland)
03/13/2017 at 11:58, STARS: 1
My old 4 speed datsun 240z was at 4,000 rpm at 80 mph, but it got about 25 mpg. That I6 at full hum was a glorious sound.
"red014" (red014)
03/13/2017 at 11:59, STARS: 0
Just took this pic the other day in my NC to illustrate the same point. This is an NC2 though which gives it a slightly taller 6th gear. 6th in the NC1 was even shorter than 5th gear in the 5 speeds.
"gawdzillla" (gawdzillla)
03/13/2017 at 12:01, STARS: 0
This is the correct 6 speed trans for the Miata (or any longitude rwd car)
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 12:03, STARS: 0
Flowmaster 60 Series Delta on otherwise stock exhaust. One of the best exhausts I’ve heard on one of these. About as loud as a stock NA but a *lot* more mellow. Stock NBs sound like vacuum cleaners, all intake noise and fans, no exhaust.
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 12:03, STARS: 0
RX7 trans?
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 12:04, STARS: 1
Well yeah, the GTO does like 1200 rpm on the highway.
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 12:05, STARS: 1
Hmm. I wonder if I could swap rear end gears in my Torsen? First gear is completely useless on these cars. It’s ridiculous.
"random001" (random001)
03/13/2017 at 12:05, STARS: 2
The Corvette (C5) did this. Top speed was in 5th, 6th was a .5/1 ratio. 33 mpg all day long at 75 mph.
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 12:05, STARS: 0
Seriously? huh. I don’t know what it would be. This car only has 120k on it and runs like a top. I get 26mpg around town.
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 12:06, STARS: 0
Ew. No. God no. I had a ‘91 with broken exhaust and it was horrid. Got a stock exhaust system ASAP
"gawdzillla" (gawdzillla)
03/13/2017 at 12:09, STARS: 0
when did they make a 6 speed rx-7 !!!?? ;)
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 12:10, STARS: 0
RX... 8?
idk. I know one of the rotary cars has a 6th speed that people sometimes swap into Miata transmissions because it’s taller.
"gawdzillla" (gawdzillla)
03/13/2017 at 12:11, STARS: 0
Or you can make changing out the rear gear (relatively) painless
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 12:16, STARS: 0
What’s that?
"bhtooefr" (bhtooefr)
03/13/2017 at 12:18, STARS: 0
The wind noise is the worse problem.
(Source: I did a 2000 mile round trip roadtrip in my Miata, sitting between 3000 and 4000 RPM the whole way.)
"gawdzillla" (gawdzillla)
03/13/2017 at 12:19, STARS: 0
t56
the very same trans that goes into camaro, cobra, viper, aston martin and everything else in between
"Jayhawk Jake" (jayhawkjake)
03/13/2017 at 12:19, STARS: 1
Jake exclusively drives terrible cars, so I would take his measure of comfort with a grain of salt
"gawdzillla" (gawdzillla)
03/13/2017 at 12:21, STARS: 1
http://oppositelock.kinja.com/name-the-subframe-v2-1792305474
"LongbowMkII" (longbowmkii)
03/13/2017 at 12:21, STARS: 0
had a 1.6 that got 33mpg at 80mph/4k
I’d expect a bit less from the heavier, bigger motor’d NB but not ~20mpg
"ateamfan42" (ateamfan42)
03/13/2017 at 12:23, STARS: 1
It is technically not the Torsen that gets swapped, but the ring & pinion set which drives the differential. There are a number of sets (OEM & aftermarket) that fit within the Miata differential case— most of the aftermarket sets are even shorter ratio than the 4.3. (They are targeted for race use.)
A new ring & pinion set is about $700, then you have to figure installation. Setting up a ring & pinion set for correct wear requires some precision tools. Most people elect to have a professional do the work.
Used 3.606 gear sets do show up for sale from time to time, as do used differential assemblies with the gears already installed. (I have one stashed in my shed awaiting the future day I add a turbo.)
"Daily Drives a Dragon - One Last Lap" (ddadragon)
03/13/2017 at 12:23, STARS: 0
Fair. There’s too many Jakes on this site and I can’t tell all yall apart.
"TheD0k_2many toys 2little time" (thed0ck)
03/13/2017 at 12:25, STARS: 0
yea that is very weird. you have done spark plugs and such. injectors are good?
Im still on stock air filter just replaced with better brand. Only mods are straight pipe exhaust.
"Jayhawk Jake" (jayhawkjake)
03/13/2017 at 12:29, STARS: 0
The one doing dumb things is the one with the Miata
"ateamfan42" (ateamfan42)
03/13/2017 at 12:34, STARS: 1
My mom’s Mazdaspeed Miata was bad too.
The MSM was worse, because Mazda put in 4.1 gears with the 6 speed, instead of the 3.909. This is definitely odd, considering the wider torque curve of the turbo motor, which would better support wider gear ratios.
"DipodomysDeserti" (dipodomysdeserti)
03/13/2017 at 12:34, STARS: 0
I get 18-19 highway on my Wrangler...
"Smallbear wants a modern Syclone, local Maple Leafs spammer" (smallbear94)
03/13/2017 at 13:20, STARS: 0
"Chuckles" (chucklesw37)
03/13/2017 at 13:24, STARS: 0
I’ve got a 94 with a 5 speed, and I’m lucky to hit 24mpg on the highway, but that’s if I keep it around 60mph on a 55mph highway.
People always see it and say “wow, I bet it gets great gas mileage!”
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 13:33, STARS: 0
I honestly haven’t done a tune up on this since I got it. Should probably do plugs, wires, and fuel filter. I can’t imagine the injectors are messed up with just 120k
"gmctavish needs more space" (gmctavish)
03/13/2017 at 16:01, STARS: 1
My friends e30 318is has 4.10s and my god is it not a freeway car. 120km/h at 4500rpm or something like that
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 16:12, STARS: 1
Holy hell
"The Stig's former college room mate" (das-stig)
03/13/2017 at 17:04, STARS: 0
it’s gotta have low gears for the lack of torque. At 60 mph in 6th gear my camaro is barely over idle. 80 mph is something like 1600 rpm.
"TheD0k_2many toys 2little time" (thed0ck)
03/13/2017 at 17:12, STARS: 0
probably not. tune up will probably help a bit
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 17:15, STARS: 0
I don’t see why you need torque in a Miata at 80mph. 6th should just be a “maintain your speed” gear for fuel economy
"Shour, Aloof and Obnoxious" (shour)
03/13/2017 at 18:15, STARS: 0
All of the manual Mazdas I’ve been able to drive had this neat trick, and I’ve often wondered if it was intentional or not. It didn’t matter if gearbox was a five speed or a six speed, but in top gear, you could multiply your revs by two and very accurately get your speed. Even if your speedo was off. (In the MX-6 and the Miata I owned, both speedos would read a few mph fast.) So 4000 rpm would equal 80 mph, 3500 rpm would be 70 mph. And like I said, this did not change with the top gear being fifth or sixth.
So, I had pretty much exactly the same car you have, and this is what I found over six or so years of ownership:
Around town, I could pull about 28mpg by clutchless-shifting in the sweet spot around 2600k, and then settling into the highest possible gear for cruising around (which was often sixth). With anything less than 91 octane, I’d lose 4-5mpg. Since it was mostly driving at 45 mph and lower, rag top had no significant change.
On the highway, fuel economy became quite a bit trickier. She would still drop 5mpg (or more) using anything less than 91 octane, but both the rag top and engine speed meant everything.
Top up, 79 mph (or less): 32 mpg
Top down, 79 mph (or less): 26 mpg
Top up, 80-85 mph: 26 mpg
Top down, 80-85 mph: 21 mpg
So, as you can see, those are some pretty drastic shifts in economy numbers. Much of my highway driving is in the desert plains of southern New Mexico and west Texas, where the wind can be something nasty; in a light car with a relatively underpowered engine, keeping her at higher highway speeds required more shove, and moreso with the top down.
I’m sure you’ve found that the car finds its LET’S-GO point kind of in the 4k-6k range (sure, you can rev her up to 7k, but mine never pulled much harder up there), so it’s likely that it’s just a rev range that the ECU asks for more fuel since the valve timing has the engine at its peakiest in that area.
At least, that was my experience with the ‘02.
"daender" (daender)
03/13/2017 at 19:21, STARS: 0
That’s not right for a Miata’s highway mileage. Do another highway run sometime but keep the rpm’s at least 200 rpm below indicated 4k (preferably using cruise to maintain a constant speed). Mine doing 72.5-75 mph with the 5-speed gets around 28 and 29 mpg (sometimes 30-31 if I get lucky with drafting). If you’re still getting poor gas economy then maybe check if either (or both) of the 02 sensors in the exhaust are going out.
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 19:43, STARS: 0
Hmm. I did have to replace the after-cat emissions-nanny o2 sensor a little while ago. Maybe the pre-cat one needs replacing as well. I should probably do plugs and wires for the hell of it, as well, though $30 for a wire set = wtf
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/13/2017 at 19:45, STARS: 0
I always drive usually relatively light shifting before 5k and often skipping from 4th to 6th anywhere above 40mph. Hardtop permanently attached, haven’t hardly ever run the A/C since I got the car.
“I’m sure you’ve found that the car finds its LET’S-GO point kind of in the 4k-6k range (sure, you can rev her up to 7k, but mine never pulled much harder up there), so it’s likely that it’s just a rev range that the ECU asks for more fuel since the valve timing has the engine at its peakiest in that area.”
dat VVT tho :3 but yeah, I always feel like I should shift at about 5500rpm because anything above that seems like extra noise and not much forward momentum
"daender" (daender)
03/13/2017 at 20:01, STARS: 1
Dunno, I’m still on the stock wires. :B At least try keeping a constant highway speed below 4k first. I told you in the past that around 4k the ecu is programmed to go “fuck it, let’s reduce any chances of knock” and proceeds to dump fuel in an open-loop fuel map.
"AfromanGTO" (afromangto)
03/14/2017 at 01:09, STARS: 0
Yes, they had 4.1 gears and if I remember correctly it topped out at 128. lol It was a fun little car, but it was very cramped.
"AfromanGTO" (afromangto)
03/14/2017 at 01:10, STARS: 0
In 6th yes. lol
Hooray for fuel efficient V8s idling down the road!
"ateamfan42" (ateamfan42)
03/14/2017 at 07:57, STARS: 0
Yes, they had 4.1 gears and if I remember correctly it topped out at 128.
The MSM is one of the very few somewhat modern cars that has a gear-limited top speed. Most cars are drag limited (unless the electronic limits are lower).
Between the final drive ratio and the lower engine redline, the MSM actually has a lower top speed than the “slower” regular NB Miata.
"AfromanGTO" (afromangto)
03/14/2017 at 11:58, STARS: 0
Driving it on the interstate made you want to have at least one more gear. One of my buddies picked one up last year, and told me there was a kit for even lower gears. It was something like 5, and was used mainly for autocross. It would top out at 83 with those gears.
"ITA97, now with more Jag @ opposite-lock.com" (ita97)
03/14/2017 at 14:13, STARS: 0
This is how I saved gas through buying a corvette. My NB1 (14" tires with a shorter overall diameter) spun at 4200rpms with the cruise set at 82-83mph for my 50 mile round trip drive to work for 22-24mpg (usually with the top up and A/C blasting).
"AfromanGTO" (afromangto)
03/14/2017 at 15:12, STARS: 1
So I just tested it out to see what my manual 6 speed GTO would do at 1200 rpm on the highway. I averaged 31.3 mpg in 6th at 1200 rpm. ;)
"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
03/14/2017 at 16:38, STARS: 1
;_;
"AfromanGTO" (afromangto)
03/14/2017 at 17:14, STARS: 0
Don’t be sad. V8s can be fuel efficient too! :)
"ateamfan42" (ateamfan42)
03/15/2017 at 11:12, STARS: 0
One of my buddies picked one up last year, and told me there was a kit
for even lower gears. It was something like 5, and was used mainly for
autocross. It would top out at 83 with those gears.
Yes, there are several aftermarket ring & pinion sets, some of which have ratios above 5:1. I can’t imagine using them on anything but a trailered race car.
"AfromanGTO" (afromangto)
03/15/2017 at 11:38, STARS: 0
I would trailer it if it had 5.1 gears. I wouldn’t want it screaming going down the interstate inhaling gas like a sailor does liquor.
“have ratios
below
5:1"
Remember the higher the number the lower the gear. So technically if the number is larger it is lower, and if the number is smaller it is higher. That was drilled into my head so many times by the old timers who worked on vehicles, and after being yelled at so many times it stuck.
"ateamfan42" (ateamfan42)
03/15/2017 at 12:25, STARS: 1
I would trailer it if it had 5.1 gears. I wouldn’t want it screaming
going down the interstate inhaling gas like a sailor does liquor.
Paco Motorsport makes a 5.375:1 set. I don’t think 5000 rpm at 75 mph sounds too fun to me!
Remember
the higher the number the lower the gear. So technically if the number
is larger it is lower, and if the number is smaller it is higher.
The
ratio
of the final driver is higher, because 5:1 is greater than 4:1. But of course that means “lower gearing” because the vehicle speed is lower at the same engine speed.
English semantics sometimes aren’t the best at conveying automotive concepts. I think the terms “taller” and “shorter” for gearing are less confusing, because almost everyone agrees on what those mean.
"AfromanGTO" (afromangto)
03/15/2017 at 12:34, STARS: 0
5.375:1 sounds like a trailer is a must unless your speed limit is 45 at the highest. lol
I know the ratio for the final drive is higher, but after being screamed at numerous times I just accepted it. English isn’t great for conveying most concepts. That’s why scientist use Latin. My friends from foreign countries hate talking about stuff like this. Then one of the old timers would scream at them until they gave in and accepted the American lingo. lol