FMII Conversion to Vband
 

I've been reading the turbo track reliability thread and started thinking about the FMII kit I have. Is it possible or even worthwhile to convert an FMII kit to Vband? The Vband setup just means two vbands correct? One at the turbo to downpipe junction and one at the downpipe to exhaust?

Thanks for any help!

You can't convert and FM2 to v-bands. Their manifold does not allow it. The only makers on the market who sell v-band manifolds regularly for the miata are Abe@Artech and Fab9.

If you are using good inconel studs, then you do not need to convert to v-band. As the v-band solution was to solve stretching studs, which has now been solved with inconel studs.

V-bands move the problem downstream, Inconel solves it. Buy my stud kit and enjoy life.

Thanks guys. The FMII kit I have came with Inconel studs. So it sounds like i am good to go then?

Perhaps. I still had issues with the FM inconel studs. First time, a stud backed out through the nut. Andrew's solution is to use Resbond to lock the stud in place, which I spec'd during the first install (not done by me personally). I reinstalled the troublesome stud, again using Resbond. This time the stud pulled out of the manifold, taking out the threads in the process. Ultimately I bought the M10 inconel stud kit from Trackspeed Engineering, had the manifold drilled and tapped and have enjoyed life ever since (give or take a few failed transmissions).

If you haven't installed your FMII kit yet, get the bigger studs and potentially save yourself a lot of heartache in the future. It's infinitely easier (and much less expensive) to do beforehand.

Thanks for the info! Does the turbo flange need to be to be drilled and tapped as well for the larger studs?

No, that part should be good as is. I'm not saying that the FM inconel studs are useless, by the way - far from it. Before they were released I had even more serious issues with OEM-style studs, including having one break off flush with the manifold (that was a fun fix). They're just fine for an aggressive driver on back roads, and possibly fine for the track with standard FMII levels of power. For my, somewhat bonkers, build they weren't enough.

i guess technically you could convert it to vband, if you swapped manifolds, exhaust housings and downpipes. and swap to EWG, or find a vband exhaust housing with a IWG which might be difficult. Just to answer your question.

This depends on the turbo you're using. Some of them have enough clearance for M10 studs, others do not. My GTX2863R would require extensive grinding to clear 10mm studs (enough so that I would worry about the remaining wall thickness after doing it).

FWIW, I've done a lot of track days on my 8mm FM inconel studs and they've held up fine.

--Ian

Fair point. My turbo is a GT3071R, so it might be better endowed, hole-wise. Having to drill the turbo flange makes the conversion more difficult, as I'd imagine you'd have to basically disassemble the turbo in order to keep the clean parts clean.

Thanks for the great info guys!

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V-band for the downpipe? While it doesn't solve the point of failure at the turbo/manifold interface, it would sure make r&r-ing the turbo a relative piece of cake.

That was the point.