Yes.
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Originally Posted by AllSystemsNominal
(Post 940564)
Pretty sure I remember Emilio saying in a post that he does this on his track cars and hasnt had a TB shaft failure since
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The goal of it isn't to stop the shaft from breaking, it's to stop the screws from falling out when it does and getting eaten by the engine, smashed up against your head stabbing it in, scraping up the side of the piston (it's gonna bounce something fierce in there) or mashing into or under a valve and bending it.
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From the link on Miata.net i mentioned posted by "2002tiitomx5"
"It's an aerodynamically induced vibration fatigue issue. The metallurgy of the shaft is inadequate for the operational requirements you are subjecting it to. At high airflow rates the butterfly valve is open with differential air pressure on upper and lower surfaces. With the valve open and only supported by the shaft bearings, the shaft is then allowed to flex up and down at some high hertz rate eventually causing fatigue cracking at the weakest points." If there is truth to this maybe thats why the epoxy seems to keep them from busting so much. maybe it changes the flow of the air around the plate |
Originally Posted by AllSystemsNominal
(Post 941390)
From the link on Miata.net i mentioned posted by "2002tiitomx5"
"It's an aerodynamically induced vibration fatigue issue. The metallurgy of the shaft is inadequate for the operational requirements you are subjecting it to. At high airflow rates the butterfly valve is open with differential air pressure on upper and lower surfaces. With the valve open and only supported by the shaft bearings, the shaft is then allowed to flex up and down at some high hertz rate eventually causing fatigue cracking at the weakest points." If there is truth to this maybe thats why the epoxy seems to keep them from busting so much. maybe it changes the flow of the air around the plate The only thing that keeps it from breaking is better/stronger/thicker metal. |
Anyone track test the skunk2 TB yet ? Ive seen posts in the past of people who had larger throttle shafts made out of better/stronger metal made and they claimed they still bust
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If you bought one of the first throttle bodies and hear a whistle on tip-in I guess they have found a fix. Give them a Skunk2 a call or you can check what was said on miata.net
Scott Fraser |
Has anyone ever seen the return springs break on a stock throttle body? I know all about the shaft and screw problems, but I've never heard of the springs breaking. One of my friends had the springs break last time we were at the track, 3 weeks or so ago, and he just called to tell me that he had the exact same failure again today with a new (used OEM) throttle body. I checked the throttle body myself last time and the shaft and screws were perfectly fine- only the springs broke. I haven't seen any pictures yet of the one that failed today. We thought it was just a freak failure last time, but now I'm confused.
Details of the car: Brand new 99 chassis PTE build- the first spring failure was at the car's first event after the cage and engine swap. Today was the car's second time at the track. Unopened VVT motor with flat top and full exhaust Stock redline Roughly 140whp right now I'm not positive, but I think it just has mazdacomp rubber motor mounts. I'm talking about the two springs in the bottom left corner of this picture. The ones that wrap around the throttle shaft. http://www.miata.net/garage/manifold...anifold_04.jpg |
Yes, I have also seen the return springs break.
Scott Fraser |
I've seen two broken returns springs on stock TB's and three on Skunk2 TB's. Skunk2 changed the way the spring is captured after we and I think TSE sent them a broken spring. Fixed now on the Skunk2. OEM still a risk for sustained high revs.
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was there ever a workable epoxy or braising method found to retain the parts? (not so much worried about if it breaks, just don't want to ingest anything). Read a bunch of places where it was talked about, but no actual what was done. Don't want to get/make an adapter plate to run the Skunk2 on my 1.6.
And no, the answer is not 1.8 yet. I still don't trust my tuning ability and would rather sacrifice a 1.6 if I make a mistake. I am thinking epoxy over the screw heads/ends and then epoxy the plate to the shaft. I have some nice high temp/high strength stuff at work. |
Thanks for the input. After further disassembly, it looks like today‘s was a shaft failure, not a spring failure. Both screws currently missing. Dude is having some shitty luck...
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Originally Posted by x_25
(Post 1357035)
was there ever a workable epoxy or braising method found to retain the parts? (not so much worried about if it breaks, just don't want to ingest anything). Read a bunch of places where it was talked about, but no actual what was done. Don't want to get/make an adapter plate to run the Skunk2 on my 1.6.
And no, the answer is not 1.8 yet. I still don't trust my tuning ability and would rather sacrifice a 1.6 if I make a mistake. I am thinking epoxy over the screw heads/ends and then epoxy the plate to the shaft. I have some nice high temp/high strength stuff at work. I only did epoxy on the one side on this one. The next one I do will have epoxy on both sides of the butterfly. http://i2.photobucket.com/albums/y28...ps2euxu1bc.jpg |
Originally Posted by emilio700
(Post 1357019)
I've seen two broken returns springs on stock TB's and three on Skunk2 TB's. Skunk2 changed the way the spring is captured after we and I think TSE sent them a broken spring. Fixed now on the Skunk2. OEM still a risk for sustained high revs.
It won't at least suck parts into the motor like a broken OEM but I think the risk of suddenly stuck open throttle with my Skunk 2 is just as bad if not worse than OEM. |
Fwiw, we are working on a new throttle body. Drawings made just got to work out a few more details before we built the first prototype. But yes, I understand everyone's frustration that at this late stage there is still no thoroughly engineered and properly manufactured throttle body solution for the B series.
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Originally Posted by emilio700
(Post 1357390)
Fwiw, we are working on a new throttle body. Drawings made just got to work out a few more details before we built the first prototype. But yes, I understand everyone's frustration that at this late stage there is still no thoroughly engineered and properly manufactured throttle body solution for the B series.
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Originally Posted by LukeG
(Post 1421895)
Is this still happening? Checked your site and all I saw was the Skunk2 TB.
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Originally Posted by emilio700
(Post 1421902)
We have a drawing. Haven't printed the proto yet. Still looking at some options for a shaftless design, improved serviceability and such. One of many widgets we're working on so no ETA.
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Originally Posted by LukeG
(Post 1421903)
Cool, thanks. Saw you were out of the Skunk2 TB's on your site. More coming soon?
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Would it be possible to fabricate the butterfly shaft out of a stronger material and simply swap it out? I haven't seen this brought up yet. Buying a whole new throttle body seems overkill if a single part could be swapped out.
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