DIY: raised fulcrum short shifter - Miata Turbo Forum - Boost cars, acquire cats.

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Old 07-12-2013, 11:49 AM   #1
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Default DIY: raised fulcrum short shifter

Shown is the modification of a MSM 6sp shifter. The same method applies to just about any shifter.

Cost: ~$1.90 (for three longer bolts that mount the shifter)
Tools: something to cut metal, something to stick metal together
Parts: shifter, donor shifter turret(or the ability to fab a spacer in which case you wouldn't be reading this thread) and random metal bits.


Stock shifter with the top ripped off. Burnt most of the rubber isolator off with a small propane torch.



Donor '99 5sp that has some teeth sheared off of 3rd gear. Made a mark approx. 0.900" down from the top of the turret. This is going to be the spacer that raises the pivot point of the shifter.



My metal cutting tool of choice for this was a sawzall. Use whatever works for you, a precision cut isn't critical.



File the bottom flat. This will mate with the existing trans turret so attempt to make it flat.



Drill out the three bolt holes. Can't really remember but I may have used a 1/4" bit.


Measure the thickness of the spacer. Mine happened to be 0.850".

Chop up your perfectly good shifter and assorted bits of steel. I decided to use a PPF bolt for the upper extension - just because. Since the spacer is 0.850" thick, the length below the shifter needs to be extended by that amount.

Take measurements of the shifter before you chop it up!



Stick the metal bits together. I didn't bother doing anything tricky. I decided to just make it straight and drive it a day like that to figure out what I really wanted. Reuse existing bushings and wave springs.



Too tall, not close enough to the steering wheel and generally not ergonomic. Might be ok if I had a sequential.



Shortened and moved forward and to the left. Bad picture.



The shifter feels great, so much tighter than the stock unit. The throw is great. No vibration issues. The 2-3shift is precise now, no longer a Hail Mary.

You can make yours whatever throw and length you desire.
Attached Thumbnails
DIY:  raised fulcrum short shifter-small-1-20130705_144633.jpg   DIY:  raised fulcrum short shifter-small-2-20130705_151311.jpg   DIY:  raised fulcrum short shifter-small-3-20130705_151611.jpg   DIY:  raised fulcrum short shifter-small-4-20130705_153336.jpg   DIY:  raised fulcrum short shifter-small-5-20130705_153757.jpg  

DIY:  raised fulcrum short shifter-small-6-20130708_161745.jpg   DIY:  raised fulcrum short shifter-small-7-20130708_172132.jpg   DIY:  raised fulcrum short shifter-small-8-20130710_152203.jpg   DIY:  raised fulcrum short shifter-small-9-20130710_182947.jpg   DIY:  raised fulcrum short shifter-small-10-20130710_182921.jpg  

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Old 07-12-2013, 01:55 PM   #2
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Nice post. Its is basically a DIY version of the $250 miata roadster shifter without some of the extra delrin parts and attention to detail.
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Old 07-12-2013, 02:33 PM   #3
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Why do you guys waste your time with this ****? I suppose that from my days with the MK3 VR6, the stock shifter is short enough.
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Old 07-12-2013, 02:38 PM   #4
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Hussy, this is a shifter with ~stock throw but much closer to the wheel. You have to move your hand less to shift, and at least the miata roadster one has the benefit of making a 6 speed not feel like shifting turds, and make a 5 speed feel even more glorious.
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Old 07-12-2013, 04:12 PM   #5
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^^is that really a problem when you're racing in a hobby league?

I like the idea, not the execution. seems to me like something that will leave you stranded when it breaks off.
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Old 07-12-2013, 06:00 PM   #6
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Quote:
Originally Posted by Leafy View Post
Nice post. Its is basically a DIY version of the $250 miata roadster shifter without some of the extra delrin parts and attention to detail.
$325
MiataRoadster short shifter kits - MiataRoadster - High-performance customer service...and parts for Roadsters

I have the $15 delrin bushing.
MiataRoadster Delrin shifter tip bushings - MiataRoadster - High-performance customer service...and parts for Roadsters

Quote:
Originally Posted by hustler View Post
Why do you guys waste your time with this ****? I suppose that from my days with the MK3 VR6, the stock shifter is short enough.
To each their own. If you don't like it, that's fine. If something is outside of your personal preference, I'm not sure how that makes it **** or a waste of time.

Of the handful of short shifters I've made not one person wished that the throw was longer, more sloppy or less ergonomic.

Quote:
Originally Posted by shlammed View Post
I like the idea, not the execution. seems to me like something that will leave you stranded when it breaks off.
I know you do high level fabrication for a living, kudos to you. That's not the point of a DIY project for the masses. Not everyone has mills, lathes or GTAW setups. This was to show non Kool-Aid drinkers that you can make things successfully with little time and even less money.

Regarding breakage - I'm going to restrain myself from going off. Do you assume that non professionals can't weld? You'd be surprised how many people can build things that are reliable even if they aren't show quality.
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Old 07-14-2013, 07:08 PM   #7
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I appreciate the compliment and I wasn't trying to rag on your work. its a good idea, but I have seen too many shifters break (mainly Honda's) and so many people stranded that I don't really trust much DIY work in that area anymore even if it looks ok.

I don't do it for a living and I make use of my pretty limited tools in my home garage.... what I did do was take a few classes and get educated on how to do what I like doing. No mill, no lathe...just a few well selected tools.

The Garage Journal Board - View Single Post - HellaFab's 14'x24' Auto Fab shop
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Old 07-30-2013, 10:20 AM   #8
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Quote:
Originally Posted by shlammed View Post
...I don't really trust much DIY work...I don't do it for a living...
What's the difference between DIY work and not doing it for a living. It still appears as though you're referencing how the finished project looks and suggesting his welds will fail. What specifically do you think the short-comings are in this project.

DVCN- how many of your welds have failed? or is this the first time you've ever welded?
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Old 07-30-2013, 10:56 AM   #9
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shortcomings here are the materials used first and foremost. that bolt used for an extension is quite a bit smaller in diameter than the stock part that was cut.

Like i said, it looks like a good idea; just not executed well enough that I would be willing to use it. If you are someone who wants faster shifting be it from shifter mechanics or placement you will be someone that will try smashing gears and a small diameter bolt wont have the same resistance to breakage...especially after the welding of each part removing any kind of heat treating they may have had.


The OP mentioned the weld- I did not. The OP mentioned that I do high end fab work for a living - I do not (do it for a living, though i accept the compliment with a smile)
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Old 07-30-2013, 10:59 AM   #10
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Ahh actually that bolt is probably stronger than the stock shifter. Remember the diameter of the stock shifter is TINY (like 6mm), and it sticks into a hollow thinish walled tube filled with rubber. That 12mmish bolt is more than sufficient.
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Old 07-30-2013, 12:01 PM   #11
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Quote:
Originally Posted by m2cupcar View Post
What's the difference between DIY work and not doing it for a living. It still appears as though you're referencing how the finished project looks and suggesting his welds will fail. What specifically do you think the short-comings are in this project.

DVCN- how many of your welds have failed? or is this the first time you've ever welded?
Quote:
Originally Posted by Leafy View Post
Ahh actually that bolt is probably stronger than the stock shifter. Remember the diameter of the stock shifter is TINY (like 6mm), and it sticks into a hollow thinish walled tube filled with rubber. That 12mmish bolt is more than sufficient.

Voices of reason!

I used the PPF bolt in that configuration on purpose. It looks weak and would raise eyebrows by some. Yes, I'm a jerk.

A certified welder would say that I've yet to make a weld!

I've been an amateur welder for a long time, pre-Perestroika. My major weakness is metallurgy. In the last fifteen years, there have been zero failures on welds put into service. There have been issues with the base metal adjacent to the weld on a few occasions. Last year I laid down about 150lbs of filler. Even though I drive a Miata, penetration is not an issue.

AND... contrary to popular belief, the raised fulcrum shifter puts less force on things below the fulcrum, including shift forks and synchros.

AND and..... the heat treat and things not done to the nth degree is part of the Kool-Aid that doesn't apply to most real world cars. Did I mention that I've made five of these shifters in the past that have been in long term service? To make you squirm, on one I used a 90 cent tent spike as the extender on the lower ball. It's been on multiple cars for over ten years.

If this shifter does break, I'll fix it. A CNC, FEA, BFD shifter can still break. Don't get me wrong, I love exceptional design and fabrication, I just don't have the time or money for it.
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Old 07-30-2013, 12:04 PM   #12
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Quote:
Originally Posted by dvcn View Post
My major weakness is metallurgy. In the last fifteen years, there have been zero failures on welds put into service. There have been issues with the base metal adjacent to the weld on a few occasions.
Heat Effected Zone. Torch anneal the next part that has that problem after you fix it.
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Old 07-30-2013, 12:13 PM   #13
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I'm not saying I think the shifter will break or anything, but do you have an explanation for a raised-fulcrum shifter putting less force on components? That seems the opposite of how physics work. If you increase the moment arm and keep the torque constant, you will be putting more force on the end of the shifter vs a shorter moment arm.



If we assume tau is constant since we use the same force on the shift **** for both shifters, if you increase r, you increase the force.

Looks good though, I'll probably try it with the 6-speed and if I can't get it to work I'll splurge for the miataroadster one.
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Old 07-30-2013, 12:14 PM   #14
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Am i the only one who has broken a stock shifter in half?

Haven't broken my miata yet, but i don't need to rip the gears like i've had to on crappy nissans in the past.
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Old 07-30-2013, 12:16 PM   #15
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Quote:
Originally Posted by Leafy View Post
Heat Effected Zone. Torch anneal the next part that has that problem after you fix it.
I will try to remember to do that on small parts.

The failures have been with heavily abused industrial type things. The last (metal) failure was a 3/16" wall thickness pipe welded to a 2"d thick chunk of steel that was then attached to a 90lb jackhammer. It was then taken to a welding shop and it broke two more times.
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Old 07-30-2013, 12:21 PM   #16
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Quote:
Originally Posted by thenuge26 View Post
I'm not saying I think the shifter will break or anything, but do you have an explanation for a raised-fulcrum shifter putting less force on components? That seems the opposite of how physics work. If you increase the moment arm and keep the torque constant, you will be putting more force on the end of the shifter vs a shorter moment arm.



If we assume tau is constant since we use the same force on the shift **** for both shifters, if you increase r, you increase the force.

Looks good though, I'll probably try it with the 6-speed and if I can't get it to work I'll splurge for the miataroadster one.
The lower arm is disproportionally lengthened relative to the upper arm. Yes, if the lower arm was at stock length, the mechanical advantage would deliver a lot more force to the mechanism in the transmission.

The arm ratio of the raised fulcrum shifter greatly reduces delivered force while reducing upper arm throw. To match the stock shifter's delivered force, you'd have to manhandle this short shifter.

There is also a lot better feel and thus increased mechanical empathy for the transmission.

Last edited by dvcn; 07-31-2013 at 06:08 PM.
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Old 08-08-2013, 01:46 PM   #17
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DVCN by far has the best bang-for-buck ratio for a DIY Miata turbo of anyone in this forum that I am aware of. So much so his awesomeness has him sleeping with all of your girlfriends without your knowledge.

I tried out this shifter in person yesterday and it is fantastic. I would do the same thing in a minute. The throw and feel are both very nice and I like the position near the wheel. I want to do the same thing now with my track car (though I have a T56 trans). I seriously doubt it would ever break. The PPF bolt is overkill.
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