3mm seals..........
 

I was told that for my third gen engine that you dont want 3mm apex seals for one, why is this
because your original rotors and all turbo rotors come with a 2mm apex seal
now when you get 3mm apex seal you need to cut a bigger groove, this then
weakens the wall of the rotor and with all the boost that is not good. So
what I use is 2mm but 2 piece apex seal instead of the 3 piece in which
mazda uses. these apex seals are so strong that they will with stand up to
32 psi of boost guaranteed.

What do i really want?????????????

Sorry, I cant really answer your question, I actually had one of my own... How hard is it to change these seals?

^

2mm

The 2mm 2-piece are generally good up to 350hp. There's a LOT of 400+HP using 2-piece or even the 3-piece Mazda seals.

The only problem with 3mm seals is that they cause more friction, thus requiring a little more lubrication for optimal performance. They're stronger, and seal really well at low RPM's (because of their weight); they withstand a little better to detonation. Ceramic 3mm seals require no extra lubrication.

2mm 2-piece are a superior design. The pros are that they are easily available and they're reasonably priced. The cons are that they're (or so I hear) a little more prone to cracking due to detonation.

Just FYI, the actual combustion process takes place within the leading edge of the indentation in the rotors; very little force is exerted to the seals (aside from holding the 1000+psi of combustion pressures). They (apex seals) don't push the rotors; the indentations do. When a motor pings/knocks/detonates, then the seals are forced to hold 10,000psi+ of pressure, far exceeding their rated capacity, forcing them to expell the excess pressure in one way or another (by-passing, cracking, shattering, chipping, ect...). http://www.mazdatrix.com/faq/boost.htm

2mm 2-piece seals for up to 350hp. Anything much over that, and you'll want to consider 3mm seals, even 1-piece seals.

i used to work at atkins rotary and i would talk to a guy occasionally on the phone that put 45 pounds of boost on 2 peice 2mm apex seals, and had no problems.

The boost/HP limits of 2mm versus 3mm seals is pretty much nonsense. There are high HP (>500RWHP) cars using both sizes.

3mm seals can be an economical option if you have otherwise good rotors with worn apex seal grooves. Machining them for 3mm seals is cheaper than buying new rotors.

Some shops recommend 3mm seals to guard against breakage under detonation. But the truth is that you can break 2mm or 3mm with enough detonation. The 3mm might take a little more, but you need to be careful wih detonation no matter what seals you use.

I know one shop that won't use 3mm seals because they found that they chattered too much. The 3mm seals are also heavier and tend to float over the cusps at high RPM (probably not an issue with light ceramics, but it can be a problem for the metal seals). Some experienced builders on here have said that 2mm seals make more power, presumably due to better sealing (and less floating).

If you are having an engine built by a shop that prefers 3mm seals, it probably makes sense to go with their recommendation. Or find another shop if you decide that you must have 2mm seals. If they recommend 3mm and you go 2mm, you might get an "I told you so" if you have trouble with it. Lots of people are running 3mm seals, so they do work.

I am just an enthusiast (not an engine builder with tons of experience to draw on), but from what I have gathered over the years I prefer 2mm seals for my engines.

There are many threads and many opinions on this topic. It is worth doing a search and reading what people have to say. I have shared my impressions from reading the discussions and talking to engine builders, but it's possible that I got something wrong or missed some important points. I recommend that anyone who is trying to decide between the two do their own research and draw their own conclusions.

-Max