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Post by AtariGuy on Jul 18, 2018 2:06:34 GMT -5
90GTVert has done some extensive cam measures on project taotao. It'd take me almost an hour just to sift through all that data he has, but he does have the cam charts both for stock and for an a9 profile cam. Just keep in mind not all cams out in the market are a9 - and chinese quality is... well they don't say "it's made out of chinesium" for nothin...
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Post by 90GTVert on Jul 18, 2018 6:08:26 GMT -5
I haven't done that for the 139QMB. That was on my GY6. Not sure if it will apply. It seems that not all A9 cams are even the same for the same engine platform, so the best bet would be to take your own measurements if you're serious about this. What I did is shown in the link. 49ccscoot.proboards.com/post/228887/threadMy HOCA A9 cam for a GY6 150 was 229°in/241°ex @ 0.050". They're looking for advertised duration, which should be @ 0.006". Don't have that handy. Give me a few and I'll see if I still have the data I collected to figure that out. Again though, you should probably check your own setup. EDIT : Advertised looks like 292°in/294°ex. I did not specifically take 0.006" measurements, but I have the whole list that I took in 5° crank rotation increments so I can estimate where it was pretty close.
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Post by magoconnor on Jul 18, 2018 6:30:03 GMT -5
Ok cool, I tried plotting in the new info on this calculater www.exx.se/techinfo/runners/runners.html#It said the intake runner should be 30cm when target rpm is 9000. I know this is not fully accurate, but does it seem like I'm in the right ball park? I will pull the cam today, but Im little unsure on what to measure?
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Post by Happypancake! on Jul 18, 2018 15:15:38 GMT -5
Sounds about right
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Post by magoconnor on Jul 18, 2018 16:40:47 GMT -5
Cool man, glad Im finally moving in the right direction. the new calculator plots in the the cam duration by it self, so thats pretty good. It also sets it at 0.006 so that much be pretty accurate when brent also came to that number. I think Im gonna go with 30cm and see how it goes.
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