specRX7_22

this topic came up on the Rotary Performance section of this site. has this ever been done.... and what would be involved in converting a 12a to diesel? im not asking cuz i wanna do it... lol, definately not. its just interesting cuz ive never thought of it before.

Project84

You would need very high compression, so that means different rotors. All the internals would need to be beefed up for the kind of power it would make, so I would go with the 3 window e-shaft bearings, hardened stationary gears, clearance everything, 3rd gen corner seal springs, high pro oil ring springs, additional housing dowels, oil thermo pellet mod, oil pressure relief mod, new front and rear counter weights to balance the rotating mass, and a high compression starter to get that beast fired up. Thats all I can think of for now, but I'm sure someone else could tell you more.

Fennix_sr

what kinda power would that beast be pushin or would it be less?

Project84

diesel will make way more power.

wwilliam54

problem with diesel rotary is that diesel engines use knock to burn the fuel
and we know how bad knock is on a rotary

Project84

But its not knock on a diesel because its calculated. With gas, its usually because of a lean mixture or low fuel grade, which leads to an uncalculated, therefore mis-timed detonation which is powerful, but destructive.

wwilliam54

good point

id love to see this working well
cuz I wanna see a deisel DKM rotary

onepointone

how about apex seals??? those would need to be some strong bastards...

VashtheStampede

calculated shmalculated.

the reason diesels can get away with the high compression is that they ingest AIR ONLY, not an air/fuel mix. this is compressed to extreme pressures, then at the point where you would spark out mixes, they inject the fuel. knock/detonation is bad because it is uneven and creates undue temps(/pressures?). but in a desiel, it isnt knock or detonation because the flame propogates evenly from the point of fuel injection.
we wouldnt even make it to the compression rated that diesels hit before the air/fuel mix burst into flames (on a heated running engine) let alone to a properly timed spark.

at least... thats how i understand things.

Manntis

Just adding the direct injection fuel rail would be a PITA, nevermind beefing up ALL the components (seals, gaskets, rotors, and housing) By the time you're done it's an all-new engine, so why not just start with a Diesel rotary rather than convert a gasoline one?

OoMazdaSpeedoO

well holy sh*t they actually make a rotary diesel? me and a few friends joke about such a thing but I never knew they already made one
where could I find more info on this heh

racermike

Can't you also "compress" the air (turbo or super charger) before the engine compresses it more, to get to pressure. Diesels are only in the ~20 range instead of ~10.

There was also once a 2 rotor engine where the rotors were different sizes. The big one was for "pre-compression" and it's output was directly the input for the smaller rotor, only the smaller one "firing".

Rotor13B

I'd like to see this 2 rotor you speak of, maybe a pic or a name?

Manntis

try a google search, there's a ton of info on Diesel rotaries out there (including that stupid design that uses a large rotor as the World's Worst Supercharger Design to precompress the air before sending it to a smaller rotor for combustion)

onepointone

i dont get how you "pre-compress" air. wouldnt it "un-compress" as it travels to the next chamber???

specRX7_22

heres a link to the thread in the Rotary Performance section i was talking about. apparently someone raced one.

https://www.rx7club.com/forum/showth...hreadid=145897

NanaimoRx-7

RPI’s plans are to deliver an upgraded Series 70 two (2) rotor production engine to SAFE Boats this coming fall for further testing in a 17 foot jet drive boat. Production of the Series 70 250 HP engines could occur as early as next year. RPI intends to begin field testing of the Series 70 four (4) rotor 500 HP version of the engine in the spring of 2003”.

Also, underway in New Jersey is the development of a Series 580 two (2) rotor 1000 HP diesel fueled prototype development engine. This effort to provide a 1000 HP diesel fueled rotary engine for the marine and power generation markets is being led by John Mack, RPI’s Vice President and Chief Engineer. Plans call for the testing of this engine early this fall.

Holy Crap.

VashtheStampede

its called a two-stage diesel

85RX7GS

iTrader: (1)

Manntis

no, because it's compressed with part of it's volume already in the other chamber (through a port where the leading spark plug normally would be). When the second rotor moves away from that port it traps the air, already compressed, and compresses it further - hence the large rotor is acting as an inefficient supercharger.

rotary emotions

Guys, may I fresh up some memories? The engine that had a big rotor/chamber for compressing and a smaller for working, was made by ROLLS ROYCE.
As for diesel rotaries, the ones that are available nowadays are not suitable for automotive use. Running kerosine into those isn't that much different then running diesel fuel.

inittab

Look Ma.... no distributor


* SmartPlug ignition system!
* Wankel Rotary
* 1 rotor
* 8.5:1 compression ratio
* 650 cc
* Diesel fuel
* Distributorless
* Proprietary fuel injected

jhillyer

Yes, anything to raise the final compression to ignition range.


Hey Ma! How's this work? 8.5:1 with no compressor? Oh, do tell about your fuel injection. Is that top-mounted silver thingie a pump?

SERIES 1 XLR8

i thought about this a while ago. Strange concept though. I'd like 2 c it working! It would cost a bit though.

ray green

iTrader: (14)

Deisel fuel = $1.53 gal, plus torque. Both good for my 7.

Ray