Also, the diff centres on MAN SL 200/SL 202s are interchangeable with Mercedes-Benz ones. The diff centres on the O 305-series and O 405-series are interchangeable. The vehicle weight has got no impact on the maximum speed by the way, at least as long as the road is totally flat. I'm absolutely sure that your final drive ratio was never available in Europe in the O305G, even the O307 had a maximum speed of only 98km/h with its fastest rear axle (and so did the O407 and O408 ). The O405 series had smaller wheels which had to compensated by a different geared final drive (of which the wheels themselves are a part too, of course). I don't know anything about diffs from the O405 in the O305G axle (I would assume that the axles were more or less identical anyway) but also don't forget that the diff is only one factor of the final ratio, as the reduction hubs add to it and they were available in different ratios too. In order to reduce the maximum speed to about 85 km/h I had to choose a 5.1 axle ratio. I'm going to include the engine_constfile with the correct torque values in the next update, but so far there's no plan to upload one just for this one file. My own O 305 G has a dry weight of 14,820 kg. I should note also that the O 305 Gs with third-party bodywork in Australia are much heavier than the ones built in Germany. Just for reference, an O 305 with a 5.22:1 final drive has a theoretical top speed of 87 km/h at 2,200 rpm and the same bus type but with a final drive of 5.937:1 has a theoretical top speed of 75 km/h. Regarding OMSI, I find that the achievable speeds are quite close to the numbers that you can calculate manually, and even a little bit lower than expected. Later deliveries (1986-7) were 3-speed 280hp units with 5.409:1 final drive and performed much better. These were adequate for our generally flat topography and allowed them to be used on freeway services. My city also at one stage had 3-speed 240hp O 305 Gs with the 5.263:1 final drive delivered new in 1979-80. My own O 305 G has an unusual specification with a 4.203:1 final drive to allow for a top speed of 110 km/h. I have seen O 305s with O 405 diff centres, O 405s with O 305 diff centres and so on. I understand that there are many combinations possible. I think this Bahnbus version is almost too powerful and accelerates too fast too, which might be down to Omsi again not calculating for example driving resistances correctly. As far as I remember Mercedes claimed that the articulation control is working reliably up to a speed of 95km/h but no O305G was able to go that fast with the factory adjustments.Īccording to the aforementioned brochure the following final drive ratios were available: 6.734, 5.921 and 5.263, the latter most likely only in combination with either the OM407hA or the 4-speed gearbox with a very low 1st gear. I chose the final drive ratio for a roughly 85km/h top speed, as apparently Omsi doesn't calculate correctly and the bus would be far too fast with the correct value. I've got the performance charts myself in a brochure from an exhibition in 1978 and the values in the engine_constfile should be correct. The standard ratio of 5.921:1 is good for only 75 km/h or so. The final drive ratio would likely be 5.409:1 as in practice, buses fitted with this ratio with a good engine can can achieve 85-90 km/h. I have the engine performance chart for the M-B OM 407 hA if you are interested, as my own O 305 G has this engine.
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