6 speed vs 5 speed

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6 speed vs 5 speed

Postby NC MX-5 » Mon Apr 01, 2013 6:06 pm

New to forum and will be buying a 2009+ in a few months. What are the advantages of 5 vs 6 speed? will be moding suspension on either touring or gt. May be autocrossed, but car will be used mostly for canyon driving. Opinions on reliabity/durability, shift feel, gearing, after market clutch options and 60/quarter times requested. :D
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Re: 6 speed vs 5 speed

Postby rpmchris » Wed Apr 03, 2013 6:26 pm

I've had the 6-speed for 78k+ miles, and loved every minute of it. It's a great tranny and served me well. That said, I just replaced it with a 5-speed. The 6-speed with my race tires (24.9" diameter) and a raised rev-limiter (to 7500) gave me right at 60 mph in 2nd gear...not enough for many SCCA National-level autocross courses. The 5-speed still feels great, and will get me to 66-67 mph in 2nd...perfect for the aforementioned longer courses. Add to that, the 5-speed is 30-35 lbs lighter than the 6-speed. Along with a more powerful engine and A/C removal, this season is looking great!
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Re: 6 speed vs 5 speed

Postby Brian » Wed Apr 03, 2013 7:52 pm

I have long been on record as saying I prefer the 5 speed.....particularly for autocross.

That said, I have recently converted our NCLIGHT track car from 5Speed to 6Speed because I have busted two five speed transmissions this year, both of them failed in third gear. The 6speed is the stronger box so at least for those of us pushing about 300 hp it is the better choice.
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Re: 6 speed vs 5 speed

Postby skeeler » Thu Apr 04, 2013 10:34 am

NC MX-5 wrote:New to forum and will be buying a 2009+ in a few months. What are the advantages of 5 vs 6 speed? will be moding suspension on either touring or gt. May be autocrossed, but car will be used mostly for canyon driving. Opinions on reliabity/durability, shift feel, gearing, after market clutch options and 60/quarter times requested. :D


Note that both the Touring/Club and GT come with a 6MT. Only the Sport now comes with 5MT.

I have a 6MT in my '09, and I like it very much. It gives more torque to the wheels in gears 1-5 than the 5MT. The '09+ cars have a 500-RPM redline, which improves top speed in second, partially addressing RPMChris' concern.
2009, STR & DD. 1995, HPDE. 2004 MSM, sold. 2010 Mazda3, hers.
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Re: 6 speed vs 5 speed

Postby jboemler » Thu Apr 04, 2013 4:18 pm

skeeler wrote:
NC MX-5 wrote:I have a 6MT in my '09, and I like it very much. It gives more torque to the wheels in gears 1-5 than the 5MT.


While it's true that "3000 RPM in third" on a 6-speed will have more torque than "3000 RPM in third" on a 5, it's also true that you'll be going slower. In fact, the difference in torque is precisely proportional to the difference in speed. I would contend that comparing the cars at equal speeds is more interesting, and here it's a mixed bag. Because the shift points are different (in terms of speed), you may have more or less torque compared to the 5-speed at any given speed, because you may be in a different gear.
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Re: 6 speed vs 5 speed

Postby rpmchris » Thu Apr 04, 2013 7:26 pm

Well, we'll see the difference on my next dyno run. I did a "baseline" run with my original engine and 6-speed just a week ago. I recently replaced the engine, removed the A/C, and swapped in the 5-speed. I'm doing a comparison dyno before I do a retune just to see what mechanical advantages the new engine brings to the table, but I know it'll be a bit different with the new tranny. Stay tuned... 8)
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Re: 6 speed vs 5 speed

Postby skeeler » Fri Apr 05, 2013 5:57 am

Boemler is correct in what he says, however, the subjective experience I had when test-driving was that the 6MT felt like it could accelerate better in general. Maybe I just like shifting more.
2009, STR & DD. 1995, HPDE. 2004 MSM, sold. 2010 Mazda3, hers.
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Re: 6 speed vs 5 speed

Postby jboemler » Fri Apr 05, 2013 12:01 pm

skeeler wrote:Boemler is correct in what he says, however, the subjective experience I had when test-driving was that the 6MT felt like it could accelerate better in general. Maybe I just like shifting more.


I agree. I drove a 6-speed for a while and it felt like it was quicker. Truth is, it was quicker getting to a slower speed. ;)
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Re: 6 speed vs 5 speed

Postby colt45 » Thu Apr 18, 2013 10:12 am

I have the 6-speed MT in mine. There is nothing mechanically wrong with it. The ratios are oddly chosen. Someone described it as 1, 2, 3, 4, 4.5, 5 and I agree that's a good description. The gap between 1st and 2nd is about 40%; that's too large. The gap between 4th and 5th is 15%, too small.
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Re: 6 speed vs 5 speed

Postby JonU » Thu Apr 18, 2013 12:38 pm

Have you had the ECU reflashed yet? After my Moto-East tune (which also got rid the "nanny" shift management) I think the 6 speed is awesome - particularly 2nd gear.
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