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-   -   China 64mm TB knock-off (https://www.miataturbo.net/engine-performance-56/china-64mm-tb-knock-off-94579/)

bahurd 09-22-2017 05:08 PM


Originally Posted by .one lane (Post 1441310)
If someone that has a legit skunk2 TB we can compare dimensions/quality/bearing/etc. if you guys want.

I have both. I'll dig my Skunk2 out of storage and do some comparisons for the group in a couple days.


https://cimg6.ibsrv.net/gimg/www.mia...1b3ea934d8.jpg

chicksdigmiatas 09-23-2017 07:36 PM

I ordered one for science as well. We shall see.

julio 09-23-2017 09:02 PM

My Skunk2 doesn't have the lower right corner (in the pic above) milled off at an angle like that. Also less machining marks around the mounting holes and finish looks different on both the main body and the "cable cam" or whatever you want to call that part. Very similar otherwise. Not sure how old my Skunk2 is as I bought it unused off someone else but it looks like all the pics I've seen of them. Did they ever change the main body design at all?

bahurd 09-24-2017 11:52 AM

China SKUNK TB knockoff review
 
I mentioned ealier I had a SKUNK2 throttle body and had bought one of the China knockoff items that caused this thread [both 99-05 fitment]. Below is a quick comparison of both items [my SKUNK2 is used but cleaned up]. Any questions, or anything you feel I missed send me a PM and I'll try and answer it.

One of my customers happens to be a manufacturer of production throttle bodies so there's a few things I know wouldn't pass muster with them and that went into this.

1. Machining finishes & visual

The SKUNK2 is definitely a better finished product. The coating is much smoother vs the unfinished aluminum of the China knockoff. Also, the machining of the knockoff, while likely meets with whatever mfg tolerances they use it doesn't match up with throttle bodies I see at one of my customers who's in the business.

Several of the edges of the knockoff are sharp and they haven't taken the time to do much more than a cursory manual deburring. Definitely no thermal deburring process here....


https://cimg4.ibsrv.net/gimg/www.mia...1742725906.jpg


https://cimg5.ibsrv.net/gimg/www.mia...1ea9a9d856.jpg

2. TB Bore
One of the things you watch for in TB manufacturing is the actual finish of the TB bore and the transition areas where the angle changes and the butterfly is. You can clearly see, at least in this example, the China TB has some surface finish flaws especially below the butterfly. The SKUNK2 is well finished with no surface imperfections. I haven’t taken the time to do a profilometer check on the finish.

An area of concern is the intersection of the butterfly shaft and the throttle body bore. On both sides of the China unit the cross shaft flats are carried into the wall of the throttle body. As bearings wear and allows any movement of the shaft this could cause a problem where the shaft starts to dig into the body. The SKUNK2 unit carries the full diameter of the shaft out to this area and theoretically provides better support.


https://cimg0.ibsrv.net/gimg/www.mia...cc5d55c096.jpg



https://cimg2.ibsrv.net/gimg/www.mia...6586bbdfce.jpg


https://cimg1.ibsrv.net/gimg/www.mia...edaf9260c8.jpg



3. Pulleys
The SKUNK2 pulley is a fully machined piece of aluminum whereby the China TB is a plastic pulley. I haven’t disassembled the China TB to look at the internals where the pulley connects to the shaft but I expect the aluminum machined version is a lot stronger. Also, spring pressure seems the same although I haven’t checked with a guage.


https://cimg1.ibsrv.net/gimg/www.mia...67226e85e4.jpg

4. Butterfly shaft
Here’s where the 2 products differ significantly.

Cross shaft Ø:
SKUNK2 10.88
China TB 9.71

Across shaft flats:
SKUNK2 6.8
China TB 6.8

My unit is whatever version sold by SKUNK2 in 2014 so if there was a change I guess the China people haven’t caught up yet. If I was worried/concerned about the cross shaft breaking and destroying my motor this’d be the deal breaker. Also, the SKUNK2 product uses allen head screws vs phillips head screws to get ample tightening torque. I notice no threadlocker on the China screws so if you’re using one, best to add some red threadlocker before you install.


https://cimg6.ibsrv.net/gimg/www.mia...7d17c7f25.jpeg

5. SHAFT BEARING
Looking at the bearings, it appears both bearings are about 1mm difference in the OD and the difference in cross shaft is accommodated with a thicker inner race in the China TB. You can easily see the difference in the picture. Of interest is the difference in the tang that engages the TPS. I'm not sure why the significant difference and I haven't fit a TPS to the China product.


https://cimg0.ibsrv.net/gimg/www.mia...b238e6d48e.jpg

6. Misc
Most of the surfaces, but not all are identical, and close enough to the SKUNK2 to imply a copy [possibly of an earlier SKUNK product]. Things like the IACV cover plate are identical. The obvious things are in attention to details like sharp edges on machined surfaces, no coatings to protect from corrosion and removal of machining burrs.


https://cimg5.ibsrv.net/gimg/www.mia...2bbb05b518.jpg


The differences noted are what I see visually and can measure without a full disassembly.

The Driver 09-24-2017 12:02 PM

^Thats some post! Thanks, bahurd!

turbofan 09-24-2017 12:17 PM

:likecat:

ElyasWolff 09-24-2017 12:56 PM

Wow thank you!

chicksdigmiatas 09-24-2017 02:19 PM

Awesome post! Poscat!

ryansmoneypit 09-24-2017 02:24 PM

So an 100 dollar Throttle Body that needs 500 bucks worth of my time to fix? GAHH! Alright, gimme one please. I'm so sorry US manufacturing. I feel like a total pos.

chicksdigmiatas 09-24-2017 04:44 PM


Originally Posted by ryansmoneypit (Post 1441599)
So an 100 dollar Throttle Body that needs 500 bucks worth of my time to fix? GAHH! Alright, gimme one please. I'm so sorry US manufacturing. I feel like a total pos.

I have decided fixes when i get mine i will get allen butterfly screws and loctite them, then i will redrill the spring hole. Ill also measure and compare to stock unless someone beats me to it.

julio 09-25-2017 10:49 PM

My Skunk2 looks like the top pic. Bottom one is from Bahurd's post. Notice the bleed screw (or whatever that is) position is different on the bodies. Did they change these at some point? I assuming they must have. Curious which one is the current design. Think I've seen both in pics. Noticed mine doesn't line up the best with the lump on my squaretop.


https://cimg1.ibsrv.net/gimg/www.mia...39338a6ead.png


https://cimg4.ibsrv.net/gimg/www.mia...d57ea00526.png

bahurd 09-26-2017 06:59 AM


Originally Posted by julio (Post 1441877)
My Skunk2 looks like the top pic. Bottom one is from Bahurd's post. Notice the bleed screw (or whatever that is) position is different on the bodies. Did they change these at some point? I assuming they must have. Curious which one is the current design. Think I've seen both in pics. Noticed mine doesn't line up the best with the lump on my squaretop.


https://cimg1.ibsrv.net/gimg/www.mia...39338a6ead.png


https://cimg4.ibsrv.net/gimg/www.mia...d57ea00526.png

Diff between 1.8NA and 1.8NB throttle bodies??? What year car?

concealer404 09-26-2017 08:10 AM

Adapter is the only difference between NA and NB to the best of my knowledge.

My Junk2 also looks like Julio's. Car is an NB.

julio 09-26-2017 08:50 AM

Yep. Mine is an NB but they are supposed to be the same except for the bolt on adapter plate for the IAC valve like Concealer mentioned. I'll have to send something to Skunk2 and see if they will chime in. I'm curious now as to when these changed.

bahurd 09-26-2017 09:16 AM


Originally Posted by julio (Post 1441924)
Yep. Mine is an NB but they are supposed to be the same except for the bolt on adapter plate for the IAC valve like Concealer mentioned. I'll have to send something to Skunk2 and see if they will chime in. I'm curious now as to when these changed.

I noticed that when doing the comparison. The China TB looked pretty much like what yours does. Maybe you could measure the OD of the butterfly shaft [not across the flats, that’s the same]. You might find yours is the smaller diameter?

Not sure what Skunk changed over the variations but given the breakage problems that probably was one of them.

Like I said, mine is 2014 time frame so recent.

concealer404 09-26-2017 09:22 AM

Mine was purchased late winter/early Spring 2015.

julio 09-26-2017 09:47 AM

The shaft on mine measures 10.88 mm, flats for the TPS are 1.6 mm, paint marker on the allen heads etc. Don't see any other differences other than the bleed screw location. Weird...
I've got my original box with the labels etc and paperwork inside it but don't see any dates on anything at all so that's no help.

bahurd 09-26-2017 10:42 AM

Another of lifes many mysteries. Lends meaning to the term Junk2.

Looks like the important thing is the shaft diameter. :riaa:

780racer 09-27-2017 12:23 AM

So the consensus is the Ebay will break and cause your whole engine to blow up into sad cats, even with new allen screws and Locktite?

Just trying to understand some of the comments made since sarcasm is so easy to read on the internet.

Edit: Is the shaft being 1mm smaller for the valve going to cause it to fail?

bahurd 09-27-2017 09:02 AM


Originally Posted by 780racer (Post 1442151)
So the consensus is the Ebay will break and cause your whole engine to blow up into sad cats, even with new allen screws and Locktite?

Just trying to understand some of the comments made since sarcasm is so easy to read on the internet.

Edit: Is the shaft being 1mm smaller for the valve going to cause it to fail?

I don't know if that's the consensus.

If I had a lot of money in a built engine, and had "evidence" of failures caused from a smaller shaft I'm not sure I'd opt for something just because it's cheaper. If I was putting it on an essentially stock engine, for street use, with limited funds and had the ECU to take advantage of tuning maybe why not.


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