I stand corrected. That's reasonable custom piston cost if you are say doing a custom stroker or bore.

I'm ARP / Damper / Oil Pump etc invested as well. I'd like to "set it and forget it" for a long time once she is built.

For everyone claiming these are quiet, quieter, less noise - or anything implying these aren't loud as fuck - can you please produce a video of cold start?

Because mine sounds like a tractor ready to plow.

Isnt that just normal for a BP? :noob:

That's because that's what motors making real power sound like.


I will say that my JEs in the 95 were dead fucking quiet. Spook-ily so.

I'll do it in the next few days. You're going to hear a lot of blower wine, nothing I can do about that, but you won't hear piston slap.

Every piston manufacture has options over there stock line of pistons. FM includes some of these options. Wiesco makes a piston based off of a stock piston and computer modeling. FM takes that and refines it through real world testing and calls it there own. Your getting a custom weisco piston rebranded as FM.

That being said, my off the shelf ones held 460whp just fine

I went back and forth with the same dilemma. I just couldn't justify the extra cost. I also noticed when I was looking Wiesco off the shelf pistons didn't have reliefs in the skirts for oil squirters. I don't believe super tech had notches either. I was also told by one machine shop that I should delete the squirters. I came to the conclusion i wanted to keep mine. After talking with a few people with built motors I decided on JE. I haven't found anything bad about Je's and the skirts are notched for squirters.

Does any happen to know the dome size (cc) on the turbo FM Wisecos and intended C/R? If it's listed I missed it.

The radial clearance for oversize valves seems to be taken into account on the FM Pistons where it is VERY tight on the OTS Wisecos using +1mm valves on a BP6D head.

All OTS Supertech Miata pistons are notched for squirters.

Here you go. Blower wine and exhaust are loud, but I have never heard piston slap. Granted it's not winter right now so can't say for sure but in summer it's silent.

Unrelated question:

Why does your oil pressure gauge show pressure before engine start?

Because I have oil pressure before engine start.

Because 2qt accusump.

I didn't realize that was a thing, although I'd thought it would be a good idea to have an electric oil pump to build pressure before engine start. This looks like a simpler way to accomplish the same thing. Very cool.

Yeah it's nice. Simple and effective. It's mainly there to supply the engine with oil in case the oil pump sucks air for any reason. Pre-oiling is also a feature which is nice.