I'm building a turbo 12a what is the best side seal clearance. I'm replacing all the springs new corner plugs all new gaskets prolly doing an fd oil pimp and I'm doing an rb holley intake with efi. Anything else on top you guys would recommend I'm not trying to make crazy power just look cool waste money and in the end squeeze ever last hrsprs out of the stock engine, and I already have the turbo.
I'm already getting a champion rad and i have the front mount oil cooler
since it's 12a / "low compression" whats the max boost i can run to be "dead reliable" as possible I know that rb say 5 psi max on higher compression engines, I'm brideporting and I don't want more than 250hp just to avoid issues

 

.002" (max .005")

 

sweet, this is going to be so epic

 

0.002" is good, i've been using 0.0025" i don't want it too tight

as far as boost goes, it really depends on the tune. the actual AFR isn't super important, but you need to have no lean spots and such.
i have an Rx7 magazine with a dyno thing, and the AFR for the run varies by 0.2 afr from 4000-8000rpm.
it depends on if you have an intercooler, and temps and stuff too.

it should get richer with more boost too, so like 5psi you can run like 12:1, and as boost goes up mixture should get richer.

 

late response, why do you run so lean on rotary, can't you just retard timing like you do on normal engines, or is just so bad with detonating that you have to run leaner to get proper runing

 

12:1 is fairly rich - from a general standpoint.

14.7:1 is the stoichiometric ratio for gasoline (complete combustion). This means 14.7 parts air to 1 part fuel. More air is lean and less air is rich.


There are a number of reasons we run our motors rich (within reason). Heat and detonation go hand in hand so keeping the engine (and combustion surfaces) as cool as possible is critical. Richer is cooler and provides better lubricity.

Advanced ignition will absolutely cause detonation, but most rotary failures are from heat related pre-ignition. Due to the design of the rotary engine, there is always a combustion event happening and generating heat. The rotor faces never get a break (like the piston in 4 stroke), so it is critical to manage the heat.


Hope this helps,
Alex

 

Figured I'd throw in another two cents. I built mine with 0.003" clearances, but I also built it with the intention of the engine seeing a "reliable" 350HP one day. I do get a fair bit of gas in the oil, granted that's a multi-layered problem in my case.

Also a 12A wouldn't really be considered "low compression" by rotary standards (unless you somehow have some JDM 12AT rotors). 1974+ 12As are 9.4:1, meanwhile factory turbo 13Bs range from 8.5-9.0:1 which is important to keep in mind when comparing timing and other maps to more "conventional" turbo setups. Just some food for thought.

 

in that case what psi would you recommend om a .003 gap, racing beat doesn't recommend going above 5 on a na engine but im assuming that's an engine that hasn't been taken apart and clearanced

 

I have no hard and fast rule as far as power output to side-seal gap, although it's possible that some folks do. Three thou is just what I decided was the best fit for my situation based on the research that I could come up with.

Consider that NA engines don't have to put up with nearly as much heat as turbo engines do, and the more heat, the more things expand. What might be the ideal seal gap on an NA engine could very well be too small for a boosted application.