denElias

Hi everyone.

Asked a million times I know, but still debating if I should purchase a 6 speed.

Currently have a 5 speed and 4.1 torsen rear end.
I'm adding a turbo right now and I'm aiming for 220rwhp on my 1990 1.6.

I'm scared that i'm having to shift too much with my current 4.1 read end on track.
The ideal scenario is getting a 6 speed + a 3.6 rear end, but that will end up costing me like $1200

Should I just stick with my 5spd and hope it doesn't break, or swap in a 6spd.
Car is mainly used for weekend fun and trackdays

der_vierte

Keep tq "low", stick with your 5 speed, put good oil in it and wait for it to pop. It simply shifts better. Maybe a MR shifter helps the 6 speed to shift nicely, but thats >300$ on top.

I can imagine at 200tq it can survive for a good time with a bit of luck.

Dr.Sep

I was at 200whp with a 5 speed for a couple years, no issues! That being said,

I am now running a 6 speed and 4.1 torsen and really dont think it is too bad on the street -- can always skip shift 1-3-5-6 and space it the shifts, car seems to like that

Midtenn

iTrader: (15)

For your power level, you'll probably be good with either a 6spd/4.1 or a 6spd/3.9 depending on your track. The best thing to so is look at min/max speeds on the track your plan on going to and see where they fall on a gear/speed plot.

Gearing with speed plot (not just top speeds per gear): Gearing Calculator - Graf Garage

poormxdad

I blew up a five speed late last season. On inspection, I found the clover-shaped damper on the front of the rear end had separated and was free to do whatever. I don't believe the failure of the five-speed was a coincidence. I had a six speed languishing in the garage, so I installed it to get myself back on track quickly. I hated it. I hated it enough to purchase a rebuilt five-speed from JO Motorsports. I will say this, a 220hp Miata with a 4.10 and a six-speed is a hoot on the street...

rascal

I went to a 6 speed a few years ago on my nb1 for the track gearing advantages. I also wasn’t initially that thrilled by the shift but changing to a miataroadster shifter made all the difference. Now I also have the supermiata style hybrid poly engine mount setup, it is better again.

I’ve now got 240hp with a 4.10 and a six speed and totally agree.

Though I do hit the rev limiter in 6th on front straight at Phillip island so will need to look into that before the next time I am there on full power.. ( I restrict mine usually due to class regs)

denElias

To finish up this thread, I found an amazing deal on a 3.6 diff.
Now I have the 6spd - 3.6 diff combo
It is the same as a 5 speed + 4.1 + you have an extra overdrive gear.

If hou have the $$$, definitely go for it

der_vierte

I also went from 5speed/4.1 to 6speed/3.6 and it feels pretty much the same, but with a longer "overrun", I like it!

Dr.Sep

And I am jealous of both of you hahah! Its on the list... went on a short highway drive and some of my friends drive like hooligans, cruising at 80-85mph which puts me right in the 4100-4600 rpm range steady, no fun. Keeping my eyes out for a decent deal on a 3.6, I got quoted $1k shipped to my door from a well known miata parts pickers in SC (more than I want to spend, but...... )

HarryB

I might have a decent condition 3.6 ring and pinion only for sale in the coming weeks, PM me if interested.

Aaroneous

Is it everything you hoped? I also found that 6spd + 4.1 was just too short on a boosted Miata. Imagine the 3.6 would be just about right -- is it?

allofit

I have a 6 speed with the 3.6 diff. Standard on EUDM NB2’s.

I’d say it’s just about right.

Longer 6th gear would be nice. Maybe I’ll try the MFactory 3.3 gears some day.

fjs0001

I'm collecting parts to swap in a 6-speed and Getrag 3.42 rear end. It'd be easier to go with the 3.63 Torsen, but the guys selling them want $1000. For not much more I can swap in a stronger Getrag, with better gearing, and have new axle shafts. There is a guy on ebay selling swap kits that include axles for under $1000.