Anyone tried experimenting with coating/treatments like WPC and cryogenic treatment? Was reading around and saw that side seals are an issue when it comes to pushing big power out of a renesis because they end up wearing out so quick. Tried searching on this forum for people trying treatments on side seals but couldn't find anything. Cryogenic treatment and WPC have been proven to help strengthen parts, reduce friction, wear, heat, which is amazing in the case of a side seal. Less friction, wear, and heat would lead to a longer lasting seal which is a definite win. Anyone?

 

I have also been curious about it but haven't done it yet

 

Atkins has their cryo seals for the rx8. However on a rebuild I could not get compression using:
- Cryo apex
-Cryo side
-solid corners

Then attempted another rebuild ~70psi (rough idle, stalling)
- Cryo apex
- Cryo side
- Mazda corners (after seeing other rx7 users complaining about low compression with solid corners.)

Then gave up and bought all mazda oem seals again to get 110psi. Maybe the atkins are more finicky sideseal tolerance wise? Atkins wouldn't provide help in terms of what gaps the cryo seals wanted compared to the oem side seal tolerance guide.

Brettus could speak more in terms of what the bottlenecks are at the 400hp range.

 

Interesting, I wouldn't have thought just cryo seals alone would cause low compression. They could have a different tolerance though like you mentioned although it shouldn't be by much. I've been keeping up with this one build on motoIQ and they've cryo treated/wpc treated just about any part and seal. Check it out.

https://motoiq.com/project-fd-rx7-re...ryo-treatment/

Cryogenic treated parts in the build - e-shaft (may be wpc treated too, unsure)

Cryogenic + WPC parts in the build - rotors, apex seals, corner seals, side seals, stationary gears, irons

 

Without numerically comparing and engine testing, which nobody has done as far as I know, it is a toss up. Cryo helps with heat and seal wear, but depending on the process you become more brittle and would likely wear out the housing more. I'd rather a safer softer 350$ seal set that wears out quickly compared to my $1500 housings and irons.

Did they every balance that assembly after? It sounded like they weren't going to balance at all, which seems like an oversight.

 

Don't think they balanced it, at least I can't find it. Bummer. As for the irons and housings you could treat those too, they did the irons but not the housings. Could be for some reason but I doubt a cryo treat would hurt.

 

This write up has some condensed claims for cryo treatments: https://hekimianracing.com/cryogenic...ics-explained/

I was reading up more last night and some places claim that to get a sealing benefit you must cryo treat both the piston ring and cylinder wall.....however they also mention that cryo machines better. So is the sealing going to be better from the cryo or from the tighter machined surface? In rotary applications we dont machine the housings, so that benefit may not apply to us.

Apparently different methods of cryo can also lead to mixed results in terms of becoming more brittle. Some claimed that older methods were more brittle than others.

 

I personally don't buy into the cryo treatment stuff. At least the WPC seems to have some positive observable results - albeit those results where not in a rotary engine.