I have a 13B 4 port turbo with the Hitachi 18S-2S series 5 turbo. I need to make power ONLY at 5252RPM.....it's going into a plane, and the prop/speed reduction unit does all the work. I need 300HP@5252RPM. I'm tryin' like crazy to keep from porting/returboin' the engine, but I reckon ya'll are gonna tell me to do just that, so what say ye, 'O Masters of the Rotary? Thanks!

 

HHhhhhmmmmmm.....mayhaps I ask the impossible?! FLOL!

 

Look, I know it's for an airplane, but please don't be silent because of that!!!! The fact is that rotaries are far more suited to aircraft use than even car use because of their RPM limits and their great PTW ratios. The only real issue is the speed reduction unit, & that's why I want to keep the RPM's down to where the torque matches the horsepower......it'll make the best performance for the bucks! So c'mon, you piston-eatin' guru's......tell me what I wanna know, you know what I wanna know, so tell me what I wanna know....FLOL!

 

www.rotaryaviation.com



I think they run them at 6000 RPM though.



Your turbo is probably too small but might work with a compressor upgrade.

 

i think everyone is scared to advise on this one because some sort of failure here is alot more serious than popping then engine in your car. Basically, a T2 engine with an S5 turbo will be able to pull 300 crank at 11+psi with a full exhaust. I dunno how much intercooling is an issue for planes, and i also dunno much about sustaining that much boost for that long.

 

Be not afeared of giving advise....I was a parachute-rigger for 12 years in the Marines, and my aircraft is already equipped with a ballistic parachute recovery system. I've already been to the rotary aviation sites, but generally they're behind the curve with regard to the latest rotary mods and especially turbo work when it comes to the 4 ports.......as to the intercooling, the only issue would be on take-off, but that is only a matter of a few seconds; after that, the top speed of 300MPH will provide all the cooling necessary. Taxiing to the take-off point would be done while the engine is at minimal power to keep it idling. The take-off run is about 2 minutes long, after which the boost can be turned down as much as half for cruising

 

Please identify "full exhaust".......and for the record, the side number on the turbo is Hitachi 18S-2S. I think that is the Series 5, but I'm not positive.





The remark about the rotary aviation sites was not meant as a ding.....actually, it was Tracy Crook(rotaryaviation.com)that got me so interested in rotary-powered aircraft, but he's more into carb set-ups, lower power and the new Renesis configs.

 

this is pretty much maxed out, stock s4 engine, stock s4 turbo, 3inch exhaust, greddy 2 row intercooler, and a boost controller tryign to keep the boost up at 14 psi, but after about 5k the boost starts to go down, the turbine is too small to keep the flow up at hihger rpm.

you might want to look into s lightly bigger turbo then your goal would be possible.

 

Remember that a larger compressor will make the power you want at a lower boost pressure, making less heat. It seems like my turbo doesn't make nearly as much heat below 10 psi as it does above 10 psi.

From memory (I could be off a little), heat increase is

(absolute intake temp)*(p2/p1)^0.283.



I don't know for sure, but I would think that a bigger turbine also would be advantageous for reducing heat loads (I've only really dealt with P-trim turbines. I will say, regarding AR, that I melted a 0.70 AR housing but had no problems with a 0.84 AR. I wouldn't necessarily count this as proof of smaller AR increasing EGT)

 

Ssssoooo.....basically, in order to push the envelope from 265HP to 300HP I'm looking at a whole new turbo, right? No way to just mod the existing turbo? Will replacing any one piece do the trick without having to chunk the entire old turbo? Yes, I know I'm redundant, but I like to be sure of these things. Thanks!