LTProject

I had a interesting conversation with a local turbo builder about the CFM that a rotary flows. It started with i brought him a Garret TV7301 off of a detroit diesel truck, and told him i was putting this on my rotary. He, at first, thought the turbo was to big but spent some time on computing the cfm of my engine and called me back with a shocking quote. Now he says that the turbo is to small by his calculations. I was just wondering if any of you guys had heard of the CFM that a rotary produces ported and w/o. This would explain why bigass turbos work well on the olwankel.

RICE RACING

Not much different to a good 2.6lt piston engine that has similar rpm range.

It is not so shocking ? Infact it is shocking how little cfm a 13b will flow compared to a race prepared 2.6 like a Nissan GTR engine that has been modified with bigger cams and a ported cylinder head and an upgraded rev limit.

What did your turbo guy use to make his cfm calculations, what data did you provide him with? If you post the data I can do a calculation for you if you want a second reference.

Bridgeported

Second reference? Rice Racing will be the only reference you need! His word is golden (ie: rotary god)

LTProject

Ill be talking to him on monday again, ill get him to give me his calculating numbers. I remember him saying that the 13b would flow like 1200cfm. Hes not very familure with the rotary, but all he did was used something like the firing of all the rotors and the degrees off crankrevs yadyadyad. Like i said im going to have him explain it to me again on monday so ill be back and you guys can add to his responce.

RICE RACING

Ok well get back to us and I or others may be able to help you out.

The CFM will depend on

IC efficiency
Ve of the engine
Capacity (engine type)
RPM for max power
Pressure ratio you want to run

They are the basics I will need if you want me to do a good calc, If you do not have the IC Eff or Engine Ve simply tell me the mods, manifolding (and any flow mods, IC pipe sizing) you wan to run inc exhaust spec (turbine type/size a/r "this will effect the VE) and IC type (stock air to air, Ice bath etc etc) type of porting you will run, and I will give you a rough answer

LTProject

I do know my turbo size its a TV7301 Garret. Compressor .78 , turbine 1.08. the compressor wheel is 3.00minor and 4.20 major. the turbine wheel is 3.30 minor and 3.80 major. My local turbo guy said (with his calcs) it would flow about 850cfm at 7.5psi. on another note i know he said he was using a 100% Ve since it was a turbo engine. The engine is a Hayes, 8.5 comp, big street port, and upgraded bearings and apexs with clearence for higher rpms. Anyway ill be back with more on monday, this **** is very interesting, and over looked too much.