German tank & truck petrol specs

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Trilisser, M. A.
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German tank & truck petrol specs

Post by Trilisser, M. A. » 08 Jul 2021 12:22

Does someone have data on the chemical composition and characteristics of wartime German petrol as used in tanks and trucks? Especially I would like to know the octane rating and whether TEL was used. According to Spielberger, e.g. the HL230 octane rating minimum was 74.

SIS 5
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Re: German tank & truck petrol specs

Post by SIS 5 » 08 Jul 2021 13:54

Hi,

very interesting questions. I can only give You an answer to Your last question about TEL.
In the year 1935 the I.G. Farben company acquired a licence for the production of TEL. The I.G. Farben company produced most of the synthetic petrol in Germany. So the so-called "Leuna-Benzin" later could get an octane rating until 100 and higher by adding TEL.

Regards

Bert

Trilisser, M. A.
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Re: German tank & truck petrol specs

Post by Trilisser, M. A. » 08 Jul 2021 15:56

It should be noted that both the nominally 87-octane B4 and 96-octane C3 fuels had the same amount of TEL added. However, the crux is that "motor fuels" (=for ground vehicles) had much lower octane requiments.

spannermann
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Re: German tank & truck petrol specs

Post by spannermann » 08 Jul 2021 16:57

Hi,
For most ordinary vehicles the octane rating is 74, and was often cast into the engine block, see photo of a BMW R75 motorcycle engine.

cheers PAUL
OZ74 BMW R75 ENGINE.jpg
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Richard Anderson
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Re: German tank & truck petrol specs

Post by Richard Anderson » 08 Jul 2021 17:40

"Is all this pretentious pseudo intellectual citing of sources REALLY necessary? It gets in the way of a good, spirited debate, destroys the cadence." POD, 6 October 2018

Yoozername
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Re: German tank & truck petrol specs

Post by Yoozername » 08 Jul 2021 19:43

Compression ratios in WWII (gasoline) vehicles were much lower than modern engines. I believe the Tiger engine was 6.8:1. The sherman radial even lower. So, octane ratings would also be lower. I believe the Germans also used ethanol mixtures (gasohol) and even methanol mixtures (in diesel) to raise octane and stretch out the fuel production.

spannermann
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Re: German tank & truck petrol specs

Post by spannermann » 09 Jul 2021 07:35

Hi,
Photo of a Zundapp KS 750 motorcycle engine block with OZ74 cast into it and the carburator data plate from a Stoewer lEpkw of 1940.

cheers PAUL
img_3210.jpg
pictures_0001.jpg
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spannermann
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Re: German tank & truck petrol specs

Post by spannermann » 09 Jul 2021 08:07

Hi,
Set of data plates on a 1942 Mercedes-Benz 1500.

cheers PAUL
P1240118.jpg
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Trilisser, M. A.
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Re: German tank & truck petrol specs

Post by Trilisser, M. A. » 10 Jul 2021 01:50

Yoozername wrote:
08 Jul 2021 19:43
Compression ratios in WWII (gasoline) vehicles were much lower than modern engines. I believe the Tiger engine was 6.8:1. The sherman radial even lower. So, octane ratings would also be lower. I believe the Germans also used ethanol mixtures (gasohol) and even methanol mixtures (in diesel) to raise octane and stretch out the fuel production.
Diesel engines don't benefit from high octane number, just the opposite. Diesel fuel is graded according to cetane number and cetane and octane numbers are inverse (the higher the octane number of a given fuel, the lower its cetane number is).

Compression ratio alone does not dictate octane requiments, IMEP does, though power increases through raising CR vs. raising boost (in supercharged engines) require higher detonation resistance for the same IMEP.

Yoozername
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Re: German tank & truck petrol specs

Post by Yoozername » 11 Jul 2021 01:35

I didn't specifically say that octane rating was meant for diesel engines, perhaps it reads that way. I mentioned , as an aside, they were trying to stretch fuel production capacity in both gasoline (using ethanol), and even diesel (using methanol). I was mostly mentioning the use of 'gasohol', and thought it was interesting. Adding ethanol does increase octane rating in gasoline. It also raises IMEP. I actually run all my cars by mixing E85, and E10 gasoline, to create E25. I have been doing this for over 10 years. No problems.

I would direct those people interested in reading about ethanol, and gasoline mixtures, to this paper available online.

https://journals.sagepub.com/doi/full/1 ... 4020943356

I quote....
Effects of ethanol fraction on IMEP values at stoichiometric conditions are seen in Figure 9. Analyses results showed that IMEP values were increased using higher ethanol content in fuel at stoichiometric condition. Trends of IMEP variations by different ethanol fractions showed similarity with those of engine torque and power values since IMEP is one of the main parameters of indicated engine torque and power. Simulation results of IMEP for gasoline E2.5, E5, E10, E15, and E20 fuels are 1.125, 1.128, 1.130, 1.133, 1.134, and 1.135 MPa, respectively. Maximum improvement in IMEP was 0.91% with E20 fuel compared to neat gasoline (E0).
figure
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