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Old 10-18-2012, 08:27 AM   #61
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Yes.
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Old 10-18-2012, 10:26 AM   #62
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Quote:
Originally Posted by AllSystemsNominal View Post
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
I really don't see the addition of some epoxy stopping a throttle shaft from breaking. I did it with the expectation that it will keep my engine from eating the screws, not keep the shaft from breaking.
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Old 10-19-2012, 08:47 PM   #63
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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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Old 10-20-2012, 02:56 AM   #64
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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
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Old 10-20-2012, 03:57 AM   #65
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Quote:
Originally Posted by AllSystemsNominal View Post
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 epoxy doesn't keep them from breaking. Emilio's broken at least one (that I know of) OEM throttle shaft with JBweld applied. He broke it after he made that post, hence my "A lot happens in a year" comment.

The only thing that keeps it from breaking is better/stronger/thicker metal.
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Old 10-20-2012, 04:27 AM   #66
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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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Old 12-03-2012, 01:14 AM   #67
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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
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Old 08-27-2016, 07:39 PM   #68
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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.

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Old 08-27-2016, 07:48 PM   #69
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Yes, I have also seen the return springs break.

Scott Fraser
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Old 08-27-2016, 08:31 PM   #70
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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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Old 08-27-2016, 11:28 PM   #71
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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.
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Old 08-28-2016, 12:51 AM   #72
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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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Old 08-28-2016, 12:58 AM   #73
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Quote:
Originally Posted by x_25 View Post
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.
Here's the one I did back in 2011 or 2012. Lots of 7000-7500rpm track miles on this one with no problems. I can't remember exactly which epoxy I used but I'm 100% sure it was one of the $5-6 Home Depot/ Advance Auto options.

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.

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Old 08-29-2016, 05:22 PM   #74
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Quote:
Originally Posted by emilio700 View Post
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.
Really Is there retrofit parts? I never took mine apart but after breaking the throttle spring on my second run day 2 at Solo National finals last year I looked at it and saw how shitty the design of their non failsafe return spring was. They sent me another spring they had laying around and just looking at it I think it will have a finite life. It's pretty much in a crack initiated state just from the manufacturing process and I still don't have a spare.

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.
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Old 08-29-2016, 06:10 PM   #75
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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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