Top or bottom mount
#1
!!! NOT CONFIRMED !!!
Thread Starter
iTrader: (1)
Join Date: Oct 2008
Location: Cleveland Ohio
Posts: 67
Total Cats: 0
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
After searching I couldn't come up with the reasons to go top or bottom mount. I assume top mount for larger framed turbos, and bottom mount it if you can. I could see charge piping, waste gate, and downpipe being factors as well. where would a gt28 frame sit the best.
#3
Cpt. Slow
![](/mt2011/images_td/ranks/supporter1.gif)
iTrader: (25)
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 14,326
Total Cats: 1,181
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
You've pretty much got it. Bottom mount has sucky access but the downpipe routing is much better for heat and flow reasons. Top mount is the opposite, easy to access turbo/dp flange and depening on your imtercooler routing easier charge pipes, but the dp needs to do a ~110* turn straight out of the turbo, right next to heater lines, brake lines, throttle cable, and ocasionally electrical bits.
#4
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
The joy of bottom mounts is that you can easily mount the turbo on the manifold before you mount the manifold in the car. If you dont do a v-band on the turbine exit the downpipe can be a bit tricky to get on. As curly said, downpipe routing is great coming out of a bottom mount downpipe. Keep in mind with bottom mounts you also need to deal with your mixing manifold but its not really all that difficult to be honest.
Side/top mount will leave you more room for your AC/PS bits if you have them. For a GT28 turbo i'd go bottom mount, but I could be biased =P
Side/top mount will leave you more room for your AC/PS bits if you have them. For a GT28 turbo i'd go bottom mount, but I could be biased =P