Engines and stuff 1 of 2

Engines are fascinating. Thanks to the internet, most data is available also. So I wanted to see some more characteristics of VW engines and see how they compare against other well known aircraft engines.

The table below shows lots of different engines with some basic characteristics.

Engine	Max HP	at RPM	T (Nm)	Weight (kg)	Cooling	Bore (mm)	Stroke (mm)	Bore/ stroke	cc	Cyl	BMEP (bar)	HP/kg	X	st
AeroVee 2.1	80	3400	167.6	73	Air	92	82	0.99	2180	4	9.66	1.10	1.13	4
AeroVee 2.1 T	100	3400	209.4	80	Air	92	82	0.99	2180	4	12.07	1.25	1.04	4
Austro AE300	168	3880	308.3	185	Water	83	92	0.64	1991	4	19.46	0.91	0.47	4
Centurion 2.0	133	3890	243.5	134	Water	83	92	0.64	1991	4	15.37	0.99	0.65	4
Continental 200AF	95	2750	246.0	91	Air	103.1	98.6	0.86	3293	4	9.39	1.04	1.11	4
Continental 200DX	100	2750	258.9	91	Air	103.1	98.6	0.86	3293	4	9.88	1.10	1.11	4
Continental 240	125	2800	317.9	109	Air	112.8	98.6	1.03	3941	4	10.14	1.15	1.13	4
Continental IO-360ES	210	2800	534.1	138	Air	112.8	98.6	1.03	5912	6	11.35	1.52	1.34	4
D-Motor LF26	91.8	3000	217.9	58	Water	103.4	80	1.31	2687	4	10.19	1.58	1.55	4
DB 605	1800	2800	4577.7	756	Water	154	160	0.73	35763	12	16.09	2.38	1.48	4
Franklin 235	125	2800	317.9	93	Air	117.5	88.9	1.37	3856	4	10.36	1.34	1.30	4
Franklin 350	205	2800	521.4	135	Air	117.5	88.9	1.37	5784	6	11.33	1.52	1.34	4
GP 1600	55	3600	108.8	72	Air	85.5	69	1.21	1585	4	8.63	0.76	0.89	4
GP 1835	65	3600	128.6	74	Air	92	69	1.40	1835	4	8.81	0.88	1.00	4
GP 1915	69	3600	136.5	74	Air	94	69	1.46	1915	4	8.95	0.93	1.04	4
GP 2180	76	3400	159.2	75	Air	92	82	0.99	2180	4	9.17	1.01	1.10	4
GP 2276	80	3400	167.6	75	Air	94	82	1.03	2276	4	9.25	1.07	1.15	4
Grob 2500	95	3400	199.0	95	Air	100	78	1.29	2450	4	10.20	1.00	0.98	4
Hirth 3003 E	102	6500	111.7	51	Air	72	64	0.99	1042	4	6.74	2.00	2.97	2
Hirth 3203 E	65	6300	73.5	40	Air	76	69	0.95	626	2	7.37	1.63	2.20	2
Hirth 3701 ES	100	6000	118.7	54	Water	76	69	0.95	939	3	7.94	1.85	2.33	2
Hirth F23 LW	50	6500	54.8	30	Air	72	64	0.99	521	2	6.60	1.67	2.52	2
HKS 700E	60	6200	68.9	55	Air	85	60	1.58	681	2	12.72	1.09	0.86	4
Hummel 50 HP	55	3600	108.8	73	Air	85.5	69	1.21	1585	4	8.63	0.75	0.87	4
Hummel 60 HP	65	3600	128.6	75	Air	92	69	1.40	1835	4	8.81	0.87	0.98	4
Hummel 76 HP	76	3400	159.2	76	Air	92	82	0.99	2180	4	9.17	1.00	1.09	4
Hummel 85 HP	85	3400	178.0	76	Air	94	86	0.94	2387	4	9.37	1.12	1.19	4
Jabiru 2200	85	3300	183.4	63	Air	97.5	74	1.36	2210	4	10.43	1.35	1.29	4
Jabiru 3300	120	3300	258.9	83.5	Air	97.5	74	1.36	3315	6	9.82	1.44	1.46	4
JPX 4T60	65	3200	144.6	72	Air	93	75.4	1.19	2049	4	8.87	0.90	1.02	4
JPX 4TX75	82	3000	194.6	78	Air	95	82	1.05	2325	4	10.52	1.05	1.00	4
JPX 4TX90	90	3000	213.6	74	Air	95	88	0.92	2495	4	10.76	1.22	1.13	4
Jumo 213E	2050	3250	4491.7	940	Water	150	165	0.65	34989	12	16.13	2.18	1.35	4
Limbach 1700 E0	68	3600	134.5	73	Air	88	69	1.28	1679	4	10.07	0.93	0.93	4
Limbach 2000 E0	80	3400	167.6	74	Air	90	78.4	1.04	1995	4	10.55	1.08	1.02	4
Limbach 2000 EB	80	3400	167.6	76.5	Air	90	78.4	1.04	1995	4	10.55	1.05	0.99	4
Limbach 2400 DFi	100	3000	237.4	76	Water	97	82	1.10	2424	4	12.31	1.32	1.07	4
Limbach 2400 DT	129	3000	306.2	86	Water	97	82	1.10	2424	4	15.87	1.50	0.94	4
Limbach 2400 DT.X	158	3000	375.0	86	Water	97	82	1.10	2424	4	19.44	1.84	0.94	4
Limbach 2400 EB	87	3200	193.6	82	Air	97	82	1.10	2424	4	10.04	1.06	1.06	4
Lycoming 233	115	2800	292.5	97	Air	111.1	98.4	1.00	3816	4	9.63	1.19	1.23	4
Lycoming 320A	150	2700	395.6	125	Air	130.2	98.4	1.38	5240	4	9.49	1.20	1.26	4
Lycoming 320B	160	2700	422.0	127	Air	130.2	98.4	1.38	5240	4	10.12	1.26	1.25	4
Lycoming AEIO 360	200	2700	527.5	136	Air	130.2	111.1	1.08	5917	4	11.20	1.47	1.31	4
Lycoming AEIO 580	315	2700	830.8	204	Air	135	111.1	1.16	9542	6	10.94	1.54	1.41	4
Lycoming IO-360A	200	2700	527.5	150	Air	130.2	111.1	1.08	5917	4	11.20	1.33	1.19	4
Lycoming O-360A	180	2700	474.7	132	Air	130.2	111.1	1.08	5917	4	10.08	1.36	1.35	4
Mikron IIIA	65	2600	178.0	65	Air	90	90	0.79	2290	4	9.77	1.00	1.02	4
Mikron IIIB	75	2750	194.2	69	Air	90	96	0.69	2443	4	9.99	1.09	1.09	4
Motorav 2.4 R	85	2900	208.7	85	Air	94	88	0.90	2443	4	10.74	1.00	0.93	4
Motorav 2.6 R	90	2900	221.0	86	Air	94	94	0.79	2609	4	10.64	1.05	0.98	4
Motorav 2.8 R	100	2900	245.5	84	Air	98	94	0.85	2836	4	10.88	1.19	1.09	4
MW B22D	95	3400	199.0	80	Water	93	81	1.04	2201	4	11.36	1.19	1.05	4
P&W R-2800 32	2850	2700	7516.5	1073	Air	146.05	152.4	0.72	45957	18	20.55	2.66	1.29	4
Revmaster R-2300	85	3200	189.1	77	Air	94	84	0.98	2332	4	10.19	1.10	1.08	4
Revmaster R-3000	115	3400	240.9	93	Air	102.4	90	1.02	2965	4	10.21	1.24	1.21	4
Rotax 912 ULS	98.5	5800	120.9	70	Water	84	61	1.49	1352	4	11.24	1.41	1.25	4
Rotec R2800	110	3600	217.6	102	Air	80	80	0.79	2815	7	9.71	1.08	1.11	4
Rotec R2800	150	3600	296.7	125	Air	80	80	0.79	3619	9	10.30	1.20	1.16	4
RR Griffon 65	2220	2750	5748.5	900	Water	152.5	167.6	0.65	36735	12	19.66	2.47	1.25	4
RR Merlin 61	1580	3000	3750.3	744	Water	137	152	0.64	26888	12	17.53	2.12	1.21	4
Sauer 1800 UL	68	3200	151.3	63	Air	92	69	1.40	1835	4	10.36	1.08	1.04	4
Sauer 1900 UL	75	3200	166.9	64	Air	94	69	1.46	1915	4	10.95	1.17	1.07	4
Sauer 2100 ULT	110	3000	261.1	76	Air	90.5	84	0.91	2161	4	15.18	1.45	0.95	4
Sauer 2200 UL	85	3000	201.8	66	Air	92	84	0.94	2234	4	11.35	1.29	1.13	4
Sauer 2400 UL Al	90	3000	213.6	75	Air	94	84	0.98	2332	4	11.51	1.20	1.04	4
Sauer 2400 UL Mg	90	3000	213.6	68	Air	94	84	0.98	2332	4	11.51	1.32	1.15	4
Sauer 2500	94	3000	223.1	77	Air	97	84	1.05	2483	4	11.29	1.22	1.08	4
Sauer 2700 UL	105	3000	249.2	75	Air	97	90	0.91	2660	4	11.77	1.40	1.19	4
SMA SR305	227	2200	734.7	206	Air	NA	NA	NA	5000	4	18.47	1.10	0.60	4
ULPower UL260i	97	3300	209.3	72.3	Air	105.6	74	1.60	2592	4	10.15	1.34	1.32	4
ULPower UL260iS	107	3300	230.9	72.3	Air	105.6	74	1.60	2592	4	11.19	1.48	1.32	4
ULPower UL350i	118	3300	254.6	78.4	Air	105.6	100	0.88	3503	4	9.13	1.51	1.65	4
ULPower UL350iS	130	3300	280.5	78.4	Air	105.6	100	0.88	3503	4	10.06	1.66	1.65	4
Vedeneyev M14PF	400	2900	982.2	214	Air	105	130	0.51	10131	9	12.18	1.87	1.53	4
Verner 133MK	84	5500	108.8	64.9	Air	97	90	0.91	1330	2	10.27	1.29	1.26	4
Verner 7H	110	2300	340.6	82	Air	94	85	0.96	4129	7	10.36	1.34	1.29	4

Bore - Stroke ratio

I somehow had the impression that the bore/stroke ratio was an important parameter. Engines with longer stroke had more torque, while engines with shorter stroke had less torque and more rpm. This was completely wrong.

An engine with a large bore has more area or space for valves than an engine with small bore. This means that with larger bore/stroke, the engine can have larger valves and therefore will more easily be filled with air. That is basically it, that is the only important factor. The torque of the crank does not change with larger stroke (considering equal displacement). There also are some secondary effects; larger stroke means faster piston speed and more friction, larger bore means more forces on the cylinder and the bearings etc etc. Things that are important for detailed design, but does not really mean anything if the design is done properly.

The bore/stroke ratio is only valid for comparison of engines with equal displacement because the area is proportional to the square of the bore. To compare engines with different displacement some modification is needed. What we are looking for is a ratio of the area (available for valves) over the volume of the cylinder, the displacement. To be able to compare different sized engines, this ratio has to be non dimensional.

The modified bore/stroke = A^3/V^2 = (Pi/4)*bore^2/stroke^2

With this modified bore/stroke ratio, all the engines can be compared on equal basis. This is not a bore stroke ratio anymore, just a representative non dimensional number. This is done in the table below.

Engine	Max HP	at RPM	T (Nm)	Weight (kg)	Cooling	Bore (mm)	Stroke (mm)	Bore/ stroke	cc	Cyl	BMEP (bar)	HP/kg	X	st
Vedeneyev M14PF	400	2900	982.2	214	Air	105	130	0.51	10131	9	12.18	1.87	1.53	4
RR Merlin 61	1580	3000	3750.3	744	Water	137	152	0.64	26888	12	17.53	2.12	1.21	4
Austro AE300	168	3880	308.3	185	Water	83	92	0.64	1991	4	19.46	0.91	0.47	4
Centurion 2.0	133	3890	243.5	134	Water	83	92	0.64	1991	4	15.37	0.99	0.65	4
Jumo 213E	2050	3250	4491.7	940	Water	150	165	0.65	34989	12	16.13	2.18	1.35	4
RR Griffon 65	2220	2750	5748.5	900	Water	152.5	167.6	0.65	36735	12	19.66	2.47	1.25	4
Mikron IIIB	75	2750	194.2	69	Air	90	96	0.69	2443	4	9.99	1.09	1.09	4
P&W R-2800 32	2850	2700	7516.5	1073	Air	146.05	152.4	0.72	45957	18	20.55	2.66	1.29	4
DB 605	1800	2800	4577.7	756	Water	154	160	0.73	35763	12	16.09	2.38	1.48	4
Mikron IIIA	65	2600	178.0	65	Air	90	90	0.79	2290	4	9.77	1.00	1.02	4
Motorav 2.6 R	90	2900	221.0	86	Air	94	94	0.79	2609	4	10.64	1.05	0.98	4
Rotec R2800	110	3600	217.6	102	Air	80	80	0.79	2815	7	9.71	1.08	1.11	4
Rotec R2800	150	3600	296.7	125	Air	80	80	0.79	3619	9	10.30	1.20	1.16	4
Motorav 2.8 R	100	2900	245.5	84	Air	98	94	0.85	2836	4	10.88	1.19	1.09	4
Continental 200AF	95	2750	246.0	91	Air	103.1	98.6	0.86	3293	4	9.39	1.04	1.11	4
Continental 200DX	100	2750	258.9	91	Air	103.1	98.6	0.86	3293	4	9.88	1.10	1.11	4
ULPower UL350i	118	3300	254.6	78.4	Air	105.6	100	0.88	3503	4	9.13	1.51	1.65	4
ULPower UL350iS	130	3300	280.5	78.4	Air	105.6	100	0.88	3503	4	10.06	1.66	1.65	4
Motorav 2.4 R	85	2900	208.7	85	Air	94	88	0.90	2443	4	10.74	1.00	0.93	4
Sauer 2100 ULT	110	3000	261.1	76	Air	90.5	84	0.91	2161	4	15.18	1.45	0.95	4
Sauer 2700 UL	105	3000	249.2	75	Air	97	90	0.91	2660	4	11.77	1.40	1.19	4
Verner 133MK	84	5500	108.8	64.9	Air	97	90	0.91	1330	2	10.27	1.29	1.26	4
JPX 4TX90	90	3000	213.6	74	Air	95	88	0.92	2495	4	10.76	1.22	1.13	4
Hummel 85 HP	85	3400	178.0	76	Air	94	86	0.94	2387	4	9.37	1.12	1.19	4
Sauer 2200 UL	85	3000	201.8	66	Air	92	84	0.94	2234	4	11.35	1.29	1.13	4
Hirth 3203 E	65	6300	73.5	40	Air	76	69	0.95	626	2	7.37	1.63	2.20	2
Hirth 3701 ES	100	6000	118.7	54	Water	76	69	0.95	939	3	7.94	1.85	2.33	2
Verner 7H	110	2300	340.6	82	Air	94	85	0.96	4129	7	10.36	1.34	1.29	4
Revmaster R-2300	85	3200	189.1	77	Air	94	84	0.98	2332	4	10.19	1.10	1.08	4
Sauer 2400 UL Al	90	3000	213.6	75	Air	94	84	0.98	2332	4	11.51	1.20	1.04	4
Sauer 2400 UL Mg	90	3000	213.6	68	Air	94	84	0.98	2332	4	11.51	1.32	1.15	4
AeroVee 2.1	80	3400	167.6	73	Air	92	82	0.99	2180	4	9.66	1.10	1.13	4
AeroVee 2.1 T	100	3400	209.4	80	Air	92	82	0.99	2180	4	12.07	1.25	1.04	4
GP 2180	76	3400	159.2	75	Air	92	82	0.99	2180	4	9.17	1.01	1.10	4
Hummel 76 HP	76	3400	159.2	76	Air	92	82	0.99	2180	4	9.17	1.00	1.09	4
Hirth 3003 E	102	6500	111.7	51	Air	72	64	0.99	1042	4	6.74	2.00	2.97	2
Hirth F23 LW	50	6500	54.8	30	Air	72	64	0.99	521	2	6.60	1.67	2.52	2
Lycoming 233	115	2800	292.5	97	Air	111.1	98.4	1.00	3816	4	9.63	1.19	1.23	4
Revmaster R-3000	115	3400	240.9	93	Air	102.4	90	1.02	2965	4	10.21	1.24	1.21	4
Continental 240	125	2800	317.9	109	Air	112.8	98.6	1.03	3941	4	10.14	1.15	1.13	4
Continental IO-360ES	210	2800	534.1	138	Air	112.8	98.6	1.03	5912	6	11.35	1.52	1.34	4
GP 2276	80	3400	167.6	75	Air	94	82	1.03	2276	4	9.25	1.07	1.15	4
Limbach 2000 E0	80	3400	167.6	74	Air	90	78.4	1.04	1995	4	10.55	1.08	1.02	4
Limbach 2000 EB	80	3400	167.6	76.5	Air	90	78.4	1.04	1995	4	10.55	1.05	0.99	4
MW B22D	95	3400	199.0	80	Water	93	81	1.04	2201	4	11.36	1.19	1.05	4
Sauer 2500	94	3000	223.1	77	Air	97	84	1.05	2483	4	11.29	1.22	1.08	4
JPX 4TX75	82	3000	194.6	78	Air	95	82	1.05	2325	4	10.52	1.05	1.00	4
Lycoming AEIO 360	200	2700	527.5	136	Air	130.2	111.1	1.08	5917	4	11.20	1.47	1.31	4
Lycoming IO-360A	200	2700	527.5	150	Air	130.2	111.1	1.08	5917	4	11.20	1.33	1.19	4
Lycoming O-360A	180	2700	474.7	132	Air	130.2	111.1	1.08	5917	4	10.08	1.36	1.35	4
Limbach 2400 DFi	100	3000	237.4	76	Water	97	82	1.10	2424	4	12.31	1.32	1.07	4
Limbach 2400 DT	129	3000	306.2	86	Water	97	82	1.10	2424	4	15.87	1.50	0.94	4
Limbach 2400 DT.X	158	3000	375.0	86	Water	97	82	1.10	2424	4	19.44	1.84	0.94	4
Limbach 2400 EB	87	3200	193.6	82	Air	97	82	1.10	2424	4	10.04	1.06	1.06	4
Lycoming AEIO 580	315	2700	830.8	204	Air	135	111.1	1.16	9542	6	10.94	1.54	1.41	4
JPX 4T60	65	3200	144.6	72	Air	93	75.4	1.19	2049	4	8.87	0.90	1.02	4
GP 1600	55	3600	108.8	72	Air	85.5	69	1.21	1585	4	8.63	0.76	0.89	4
Hummel 50 HP	55	3600	108.8	73	Air	85.5	69	1.21	1585	4	8.63	0.75	0.87	4
Limbach 1700 E0	68	3600	134.5	73	Air	88	69	1.28	1679	4	10.07	0.93	0.93	4
Grob 2500	95	3400	199.0	95	Air	100	78	1.29	2450	4	10.20	1.00	0.98	4
D-Motor LF26	91.8	3000	217.9	58	Water	103.4	80	1.31	2687	4	10.19	1.58	1.55	4
Jabiru 2200	85	3300	183.4	63	Air	97.5	74	1.36	2210	4	10.43	1.35	1.29	4
Jabiru 3300	120	3300	258.9	83.5	Air	97.5	74	1.36	3315	6	9.82	1.44	1.46	4
Franklin 235	125	2800	317.9	93	Air	117.5	88.9	1.37	3856	4	10.36	1.34	1.30	4
Franklin 350	205	2800	521.4	135	Air	117.5	88.9	1.37	5784	6	11.33	1.52	1.34	4
Lycoming 320A	150	2700	395.6	125	Air	130.2	98.4	1.38	5240	4	9.49	1.20	1.26	4
Lycoming 320B	160	2700	422.0	127	Air	130.2	98.4	1.38	5240	4	10.12	1.26	1.25	4
GP 1835	65	3600	128.6	74	Air	92	69	1.40	1835	4	8.81	0.88	1.00	4
Hummel 60 HP	65	3600	128.6	75	Air	92	69	1.40	1835	4	8.81	0.87	0.98	4
Sauer 1800 UL	68	3200	151.3	63	Air	92	69	1.40	1835	4	10.36	1.08	1.04	4
GP 1915	69	3600	136.5	74	Air	94	69	1.46	1915	4	8.95	0.93	1.04	4
Sauer 1900 UL	75	3200	166.9	64	Air	94	69	1.46	1915	4	10.95	1.17	1.07	4
Rotax 912 ULS	98.5	5800	120.9	70	Water	84	61	1.49	1352	4	11.24	1.41	1.25	4
HKS 700E	60	6200	68.9	55	Air	85	60	1.58	681	2	12.72	1.09	0.86	4
ULPower UL260i	97	3300	209.3	72.3	Air	105.6	74	1.60	2592	4	10.15	1.34	1.32	4
ULPower UL260iS	107	3300	230.9	72.3	Air	105.6	74	1.60	2592	4	11.19	1.48	1.32	4
SMA SR305	227	2200	734.7	206	Air	NA	NA	NA	5000	4	18.47	1.10	0.60	4

The M14PF is the longest stroked engine and the UL260s are the shortest stroked engines. Interestingly the VW engines are all over the place.

BMEP

From what I have gathered of information, the only meaningful parameter representing how well developed and tuned an engine is, is the Break Mean Effective Pressure, or BMEP. The BMEP is the theoretical integrated pressure needed to turn the engine at a certain power at a certain rpm. Max BMEP occurs at max torque, which typically is at a bit lower rpm than max power. BMEP is not the pressure inside the cylinder, but should be proportional to the physical integrated or mean pressure over the power stroke. Higher BMEP means a better engine in terms of engine output. Top fuel dragsters have an insane BMEP for instance. It also means that BMEP is a good number telling how far "pushed" the engine is in terms of tuning. This is not always a good thing, higher tuned engines tends to last shorter than lower tuned engines. More BMEP also means higher power pulses that the shaft, gear and propeller must sustain.

Turbo or supercharger will increase BMEP, which of course is the whole purpose of a turbo. Comparing naturally aspirated engines with boosted engines may not seem "fair". But power is power, how that power is obtained is uninteresting for an aircraft.

BMEP (Pa) = n * P / (D * N)   or when using P = T * N * 2 * Pi

BMEP (Pa) = n * T * 2 * Pi / D

n = revs per power stroke, 2 for 4 stroke and 1 for 2 stroke

P = power in Watt

D = displacement in m^3

N = angular speed in revolutions per second (Hz)

T = torque in Nm

The second relation shows that BMEP is proportional to torque per displacement.

Engine	Max HP	at RPM	T (Nm)	Weight (kg)	Cooling	Bore (mm)	Stroke (mm)	Bore/ stroke	cc	Cyl	BMEP (bar)	HP/kg	X	st
Hirth F23 LW	50	6500	54.8	30	Air	72	64	0.99	521	2	6.60	1.67	2.52	2
Hirth 3003 E	102	6500	111.7	51	Air	72	64	0.99	1042	4	6.74	2.00	2.97	2
Hirth 3203 E	65	6300	73.5	40	Air	76	69	0.95	626	2	7.37	1.63	2.20	2
Hirth 3701 ES	100	6000	118.7	54	Water	76	69	0.95	939	3	7.94	1.85	2.33	2
GP 1600	55	3600	108.8	72	Air	85.5	69	1.21	1585	4	8.63	0.76	0.89	4
Hummel 50 HP	55	3600	108.8	73	Air	85.5	69	1.21	1585	4	8.63	0.75	0.87	4
GP 1835	65	3600	128.6	74	Air	92	69	1.40	1835	4	8.81	0.88	1.00	4
Hummel 60 HP	65	3600	128.6	75	Air	92	69	1.40	1835	4	8.81	0.87	0.98	4
JPX 4T60	65	3200	144.6	72	Air	93	75.4	1.19	2049	4	8.87	0.90	1.02	4
GP 1915	69	3600	136.5	74	Air	94	69	1.46	1915	4	8.95	0.93	1.04	4
ULPower UL350i	118	3300	254.6	78.4	Air	105.6	100	0.88	3503	4	9.13	1.51	1.65	4
GP 2180	76	3400	159.2	75	Air	92	82	0.99	2180	4	9.17	1.01	1.10	4
Hummel 76 HP	76	3400	159.2	76	Air	92	82	0.99	2180	4	9.17	1.00	1.09	4
GP 2276	80	3400	167.6	75	Air	94	82	1.03	2276	4	9.25	1.07	1.15	4
Hummel 85 HP	85	3400	178.0	76	Air	94	86	0.94	2387	4	9.37	1.12	1.19	4
Continental 200AF	95	2750	246.0	91	Air	103.1	98.6	0.86	3293	4	9.39	1.04	1.11	4
Lycoming 320A	150	2700	395.6	125	Air	130.2	98.4	1.38	5240	4	9.49	1.20	1.26	4
Lycoming 233	115	2800	292.5	97	Air	111.1	98.4	1.00	3816	4	9.63	1.19	1.23	4
AeroVee 2.1	80	3400	167.6	73	Air	92	82	0.99	2180	4	9.66	1.10	1.13	4
Rotec R2800	110	3600	217.6	102	Air	80	80	0.79	2815	7	9.71	1.08	1.11	4
Mikron IIIA	65	2600	178.0	65	Air	90	90	0.79	2290	4	9.77	1.00	1.02	4
Jabiru 3300	120	3300	258.9	83.5	Air	97.5	74	1.36	3315	6	9.82	1.44	1.46	4
Continental 200DX	100	2750	258.9	91	Air	103.1	98.6	0.86	3293	4	9.88	1.10	1.11	4
Mikron IIIB	75	2750	194.2	69	Air	90	96	0.69	2443	4	9.99	1.09	1.09	4
Limbach 2400 EB	87	3200	193.6	82	Air	97	82	1.10	2424	4	10.04	1.06	1.06	4
ULPower UL350iS	130	3300	280.5	78.4	Air	105.6	100	0.88	3503	4	10.06	1.66	1.65	4
Limbach 1700 E0	68	3600	134.5	73	Air	88	69	1.28	1679	4	10.07	0.93	0.93	4
Lycoming O-360A	180	2700	474.7	132	Air	130.2	111.1	1.08	5917	4	10.08	1.36	1.35	4
Lycoming 320B	160	2700	422.0	127	Air	130.2	98.4	1.38	5240	4	10.12	1.26	1.25	4
Continental 240	125	2800	317.9	109	Air	112.8	98.6	1.03	3941	4	10.14	1.15	1.13	4
ULPower UL260i	97	3300	209.3	72.3	Air	105.6	74	1.60	2592	4	10.15	1.34	1.32	4
D-Motor LF26	91.8	3000	217.9	58	Water	103.4	80	1.31	2687	4	10.19	1.58	1.55	4
Revmaster R-2300	85	3200	189.1	77	Air	94	84	0.98	2332	4	10.19	1.10	1.08	4
Grob 2500	95	3400	199.0	95	Air	100	78	1.29	2450	4	10.20	1.00	0.98	4
Revmaster R-3000	115	3400	240.9	93	Air	102.4	90	1.02	2965	4	10.21	1.24	1.21	4
Verner 133MK	84	5500	108.8	64.9	Air	97	90	0.91	1330	2	10.27	1.29	1.26	4
Rotec R2800	150	3600	296.7	125	Air	80	80	0.79	3619	9	10.30	1.20	1.16	4
Franklin 235	125	2800	317.9	93	Air	117.5	88.9	1.37	3856	4	10.36	1.34	1.30	4
Sauer 1800 UL	68	3200	151.3	63	Air	92	69	1.40	1835	4	10.36	1.08	1.04	4
Verner 7H	110	2300	340.6	82	Air	94	85	0.96	4129	7	10.36	1.34	1.29	4
Jabiru 2200	85	3300	183.4	63	Air	97.5	74	1.36	2210	4	10.43	1.35	1.29	4
JPX 4TX75	82	3000	194.6	78	Air	95	82	1.05	2325	4	10.52	1.05	1.00	4
Limbach 2000 E0	80	3400	167.6	74	Air	90	78.4	1.04	1995	4	10.55	1.08	1.02	4
Limbach 2000 EB	80	3400	167.6	76.5	Air	90	78.4	1.04	1995	4	10.55	1.05	0.99	4
Motorav 2.6 R	90	2900	221.0	86	Air	94	94	0.79	2609	4	10.64	1.05	0.98	4
Motorav 2.4 R	85	2900	208.7	85	Air	94	88	0.90	2443	4	10.74	1.00	0.93	4
JPX 4TX90	90	3000	213.6	74	Air	95	88	0.92	2495	4	10.76	1.22	1.13	4
Motorav 2.8 R	100	2900	245.5	84	Air	98	94	0.85	2836	4	10.88	1.19	1.09	4
Lycoming AEIO 580	315	2700	830.8	204	Air	135	111.1	1.16	9542	6	10.94	1.54	1.41	4
Sauer 1900 UL	75	3200	166.9	64	Air	94	69	1.46	1915	4	10.95	1.17	1.07	4
ULPower UL260iS	107	3300	230.9	72.3	Air	105.6	74	1.60	2592	4	11.19	1.48	1.32	4
Lycoming AEIO 360	200	2700	527.5	136	Air	130.2	111.1	1.08	5917	4	11.20	1.47	1.31	4
Lycoming IO-360A	200	2700	527.5	150	Air	130.2	111.1	1.08	5917	4	11.20	1.33	1.19	4
Rotax 912 ULS	98.5	5800	120.9	70	Water	84	61	1.49	1352	4	11.24	1.41	1.25	4
Sauer 2500	94	3000	223.1	77	Air	97	84	1.05	2483	4	11.29	1.22	1.08	4
Franklin 350	205	2800	521.4	135	Air	117.5	88.9	1.37	5784	6	11.33	1.52	1.34	4
Sauer 2200 UL	85	3000	201.8	66	Air	92	84	0.94	2234	4	11.35	1.29	1.13	4
Continental IO-360ES	210	2800	534.1	138	Air	112.8	98.6	1.03	5912	6	11.35	1.52	1.34	4
MW B22D	95	3400	199.0	80	Water	93	81	1.04	2201	4	11.36	1.19	1.05	4
Sauer 2400 UL Al	90	3000	213.6	75	Air	94	84	0.98	2332	4	11.51	1.20	1.04	4
Sauer 2400 UL Mg	90	3000	213.6	68	Air	94	84	0.98	2332	4	11.51	1.32	1.15	4
Sauer 2700 UL	105	3000	249.2	75	Air	97	90	0.91	2660	4	11.77	1.40	1.19	4
AeroVee 2.1 T	100	3400	209.4	80	Air	92	82	0.99	2180	4	12.07	1.25	1.04	4
Vedeneyev M14PF	400	2900	982.2	214	Air	105	130	0.51	10131	9	12.18	1.87	1.53	4
Limbach 2400 DFi	100	3000	237.4	76	Water	97	82	1.10	2424	4	12.31	1.32	1.07	4
HKS 700E	60	6200	68.9	55	Air	85	60	1.58	681	2	12.72	1.09	0.86	4
Sauer 2100 ULT	110	3000	261.1	76	Air	90.5	84	0.91	2161	4	15.18	1.45	0.95	4
Centurion 2.0	133	3890	243.5	134	Water	83	92	0.64	1991	4	15.37	0.99	0.65	4
Limbach 2400 DT	129	3000	306.2	86	Water	97	82	1.10	2424	4	15.87	1.50	0.94	4
DB 605	1800	2800	4577.7	756	Water	154	160	0.73	35763	12	16.09	2.38	1.48	4
Jumo 213E	2050	3250	4491.7	940	Water	150	165	0.65	34989	12	16.13	2.18	1.35	4
RR Merlin 61	1580	3000	3750.3	744	Water	137	152	0.64	26888	12	17.53	2.12	1.21	4
SMA SR305	227	2200	734.7	206	Air	NA	NA	NA	5000	4	18.47	1.10	0.60	4
Limbach 2400 DT.X	158	3000	375.0	86	Water	97	82	1.10	2424	4	19.44	1.84	0.94	4
Austro AE300	168	3880	308.3	185	Water	83	92	0.64	1991	4	19.46	0.91	0.47	4
RR Griffon 65	2220	2750	5748.5	900	Water	152.5	167.6	0.65	36735	12	19.66	2.47	1.25	4
P&W R-2800 32	2850	2700	7516.5	1073	Air	146.05	152.4	0.72	45957	18	20.55	2.66	1.29	4

All the two stroke engines have low BMEP. The reason for this is they don't need to have all that much pressure because they have double the power pulses per revs compared with a 4 stroke. At the other end we find the RR Griffon and the P&W R-2800. Also here the VW engines are all over the place, but now there is a clear differentiation between the GP and Hummel engines in the lower end and the Sauer and Limbachs in the higher end. The AeroVee and Revmaster is in the middle somewhere. The AeroVee turbo, rumored to have 100 HP for take off and 80 HP continuous, have less BMEP than a comparable naturally aspirated Limbach 2400 DFi. Suggesting the turbo boost is very low. Also interesting is the ULPower UL350i which sits there at the lower end of the scale along the Hummels and GPs. Sadly the specs for the 2 stroke diesels, the Wilksch WAM and DeltaHawk is nowhere to be found, they would be interesting to see in there.

Engines and stuff part 2