Andrius

Hi. I am one new lucky rx7 owner who bought somebodys else project. I am also drag racer, race car builder for more than decade with various engines building and chassis building experiences. I was recently looking on internet for rotary perfomance mod source and i couldnt find any. All merchant services only. Would you guys give me some link or direct me to someone who is building racing rotary and has no intention to make bussines or sell parts or whatever please? I just need some practical advice from garage people with experience. Thanks! Andrius

diabolical1

2 months dead ... but what the hell ...

assuming you haven't found what you wanted and moved on, it would help better if you just asked your questions. i'm sure someone here can give you the "practical advice" you seek.

Andrius

Thank you for answer. Ive got some help from people around the net already, but...since i am new to rotary engine ill ask spme specific questions here.

1. Why someone would use 3mm thick appex seals? Resistance to pinging? Assume id never have ping in the engine, would it make sense to have thick appex seal then?

2. Is 13b rotor different from renesis except higher compression ratio?
3. How different is renesis eshaft from 13b? or its the same?
4. Im going to supercharge two rotor engine, so i never have exhaust backpressures. Ignore detonation issues once again, only physical housing capability to hold boost is what? 10psi? 20? 30? Unmoded, bone stock 13b. And if i boost it up over that what first let go? Seals? Bearings?
5. Alkohol fuels. Say if i use E85 for instance (im sure somebody have tried that), stock ignition does handle it or it doesnt, and up to what charge levels?
Did anybody ever used MSD distributor controled ignition on rotary engine?
6. What type of port job is commonly used in high boost set ups? Bridgeport? Semi-p? Why?
7.Rotary timing reminds me two stroke engine timing - its all in exaust/intake overlap and duration. When you alter timing radicaly, high rpm gain pays low range loss or not? Where can i see any written stuff on perfomance timing of rotary? Books maybe? Anything?

Thanks! Andrius

WJMRTY

I am a rotary specialist , builder and racer with more than 35 years expearance and most of your questions are all to suit piston engines and not all relevant to a rotary engine .You first need to understand how a rotary engine works and what makes them break .You can pm me if you need some help and advice if you wish to ,I am happy to help if you want it

diabolical1

this is a topic that has been debated ad nauseum. i will answer the question like this: 3 mm apex seals were stock in most (there were some OLD 6 mm carbon engines, too) engines made before 1986. the newer 2 mm engines are what Mazda stuck with until the end of production of the 13Bs with and without turbo. i think that should mean something.

some people use the 3 mm seals in order to use out of spec rotors OR as "insurance" because they will tolerate more detonation than the thinner seals. in my opinion, it's sort of a crock, but there if you're dealing with inexperience, incompetence or any combination of the two in terms of the ancillary parts used (e.g.: fuel system, ignition system) or tuning, then that choice does have some merit.

just keep in mind that the 2 mm seals, in competent hands, have achieved some pretty incredible output levels.

yes. they are different. side seal locations, apex seals and slots are different. MSP rotors have an oil scraper seal to protect the oil seals from the exhaust.

they are different but interchangeable. the MSP shaft is similar in design to REW shafts in that there are gentle tapers at the bearing journals. they are also about 0.5 pound lighter.

i'm not sure what you're asking ... with the back pressure, detonation comments you threw in there. i think you're basically asking what boost levels the engine will survive and that will totally come down to the overall setup.

i simply don't know what supercharged rotaries are capable of on a large scale, because i never really held an interest in supercharging. sorry.

however, i would imagine, like a turbo rotary, if you assume adequate, fuel, ignition and engine management, then you can probably move the limits of the engine upwards with lower compression, intercooling and maybe some kind of auxiliary fuel enhancement (water, alcohol, etc.)

traditionally, forced induction mistakes are going to involve busted apex seals that grenade and take out housings and/or other things. however, in some cases you can break the housings themselves. again ... my response is based on turbos though, so ....

simple answer is yes. however, you will have to track down the details yourself because i have not used alcohol myself yet.

both have been used, and the simple answer is powerband.

Street Rotary is a good book that can get you familiar with the engines and tuning them. i chose not to link it because i have no stake in who you buy a copy from.

hope this gets you started.