6 Speed Conversion???
 

What all do i need to convert my 1.6L into a 6 speed??? Just the 6 speed transmission??? Do i need anything else?

this conversion has been discussed many times at miata.net. check there--and note that those who have done it don't just report negative gains in acceleration, but also rev more on the highway. I don't see any upside.

there are plenty of upsides.

1) 6speeds are sexy.
2) if you pair a 6 speed to a 4.3 rear end, then your gearing will be a lot shorter, making for a quicker accelerating car. Good for touge and city driving but high revs for freeways.

Other than the tranny, you'll need the shift lever, and a 6spd knob. Also you'll need the plate that goes between the block and tranny. don't forget tranny fluid. While you're at it, might as well swap out your rear main seal on the engine, the front and rear seals on the tranny and put in a new clutch. :)

the 6 speed can also handle more power before getting torn into shreds. The 600hp miata that was posted here with a link was discussed on another forum. It previously ran something like 500hp on the 6 speed with multiple launches. It didnt break until they reached 600hp.

Cool thanks for the replies.

yes, they do seem to be stronger; I have not heard of the 6 failing under high power, but bear in mind that there are hundreds of 5 speeds for every 6, so not much of a sample exists.

I am yet to see a 0-60 or 1/4 mile time improve after the conversion. I have seen them go down. there is nothing sexy about spending lots of time and money to lose performance, shift more and buzz on the highway.

if you have any contradicting data to share, please do so.

Well, if you were smart, you'd part the 6-speed with a 3.3, 3.6 or 3.9 rear-end. Which is exactly what many of the folks who've done the swap do. Kags1969 is running a 3.6 rear with his and loves it, from what I recall.

In fact, with the 3.6 and 6-speed, all the gear ratios will provid roughly the same speed potential as the 5-speed paired with the 4.3, except that 6th gear is now a bona fide cruising gear: 80mph is only 3600 vs. 4150 rpm for the 5-speed.

So, maintains great gear ratios, has true "gas-sipper" gear, is far stronger...what's not to like? Well, the price I suppose...

Where can i get this 3.6 Rear end???

You should ask Kags. I know there's a least one U.S. vendor that sells them. They came on the '79-'82 626 and the '01+ 6-speed Miata in Australia.

www.solomiata.com

And search M.net, as I don't believe he's the only one running a 3.6.

Edit: Okay, that was pretty quick; I just used the search button on M.net: http://forum.miata.net/vb/showthread...6+differential You can get them from Mazda Motorsports.

I do have a 6 speed complete conversion in like new condition for any NA or NB miata with driveshaft, block plate ,and a torsen with 3.90s all this coming form a car with a mere 18k miles.

msg me is interested

Just out of curiosity, what for? With the stock NA gearing, 1st is too short as it is in a boosted engine. The 6-spd's first two gears are even lower than the 5-spd's I think... and I even think the 6th gear is shorter than 5th in a 5-spd.
Sure it's stronger, but what kind of power are you running. It only really makes sense if you're going with a lower overall final drive and can get the revs down to make better use of the new power... basically what Bripab said.

It's cooler granted... but again, but unless you're talking about 400hp and want a road burner vice a street car, it just doesn't make sense to me. Somebody may say something to convince me otherwise, but for the price...

I've had the 5spd and 6spd cars

I prefer the 6spd personally, just feels better

That's why people that run the 6-speed and a lot of power also go with a 3.6 rear-end.

Doesn't the 6 speed shifter feel more sloppy?

No. At not least not that I could tell.

same here

I believe the 6-speed couple with a 3.6 rear-end will give almost the same mph-per-gear in the first 5 gears as the 5-speed with a 4.3 but with a taller 6th gear for cruising.

Courtesy of Savington:

Assuming a 7000rpm redline and 22.7" tire diameter, here are some of the speeds you're looking at.

Your current ratios (5-speed, 4.3 final drive)
33.1 in 1st
58.2 in 2nd
82.7 in 3rd
109.9 in 4th
135 in 5th (3371rpm @ 65mph, 3889rpm @ 75mph)

6-speed with 3.636 final
34.6 in 1st
57.3 in 2nd
79 in 3rd
103.4 in 4th
129.9 in 5th
154.1 in 6th (2952rpm @ 65mph, 3406rpm @ 75mph)

6-speed with 3.9 final drive
32.2 in 1st
53.4 in 2nd
73.7 in 3rd
96.4 in 4th
121.2 in 5th
143.7 in 6th (3166rpm @ 65mph, 3653rpm @ 75mph)

6-speed with 4.1
30.7 in 1st
50.8 in 2nd
70.1 in 3rd
91.7 in 4th
115.2 in 5th
136.7 in 6th (3328rpm @ 65mph, 3840rpm @ 75mph)

Oh yeah, plus the 6-speed holds together with 500+ horsepower on a Miata-sized vehicle...so, yeah, I don't see any downside at all, assuming you have a 3.6 or 3.3 rear-end.

How much you asking, PM me or email

luis.j.navarrete@us.army.mil

Your numbers assume a smaller tire, I run a 24" tire on the street. Makes a BIG, BIG difference along with the 8000 RPM redline. I'll see over 127 in 4th gear!

Mark

Yeah, I was assuming a stock-sized tire.

127mph in 4th, eh? That should be sufficient ;)