No single reduction hypoid cut. They offer even longer one i think 2.05 or 2.07.for low height trucks with small tires.
Planetary on road were used till about end of 1990s.
Mb was last to shift to hypoid at 1997. But even till 2006-7 many of mb trucks had it. Now hub reduction is used only on work trucks
Why do so many Americans hate European trucks?
Discussion in 'Trucks [ Eighteen Wheelers ]' started by snowbird_89, Jun 10, 2011.
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We were still getting Actros's with hub Reduction up until 2016..Oxbow Thanks this. -
All brands still have them but you have specify them and pay extra.Oxbow Thanks this. -
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The most important thing must be to get service wherever you are. Can't be any good with the "best" engine if it's not running because of some mechanical or electronic issue. And when it is in service, there must be instant accessibility to spare parts. I don't thing there are any big difference between the engines from the big engine makers if you take the bolt-on emission things away.
Oxbow Thanks this. -
The goal of the Miller or Atkinson cycle is to have a high expansion ratio during the power stroke to get as much energy out of the combustion as possible, but without the high compression ratio during compression stroke.
This is (usually) achieved by a high mathematical compression ratio combined with late closing of the intake valve. Either through the cam profile (Scania and I guess also Cummins) or with the IVA's (Cat).
Piston is already on it's way back up before the intake valve closes and pressure starts to build in the cilinder. The effective compression ratio is considerably lower.
The result is lower final compression pressure and lower peak combustion pressure and temperature, which reduced NOx.
A disadvantage of the late closing of the intake valve is that part of the cilinder charge (air) is pushed back into the manifold. Air that can not be used for combustion.
This reduces the power potential of the engine. As far as power potential the engine behaves like a smaller displacement engine.
Cat of course had a reputation to live up to, and wanted and needed the high power and had to compensate by running high boost pressures, to achieve the high power.
All in all, I think the Acert Cat was (still is) a very good basic engine, but made too complicated.
Scania, and it seems Cummins as well, only use it for the lower torque and power ratings, so they don't need the high boost. Simpler turbocharging system, no IVA's.
Back to the original question.
I haven't been around Scania's too much the last couple of years, but I found some information on Scania's website:
Sidenote: there must be an error in the displacement, all 4 have bore and stroke of 130/154 mm, yet on 3 of the engine the displacement is 16.3, on the other 16.4.
Based on these data, I think it is fair to say that if you want build a high hp engine, you would have to use the 730 as a base.
The 520 has a camshaft that is not favourable for high performance. If you put in a different cam, the compression ratio is too high.
Without seeing the actual cam-specs, the 580 and 650 will probably have a much better camshaft, but still (in my opinion) too high compression ratio for a high hp engine.
The high compression ratios will result in high cilinder pressures, which may cause head gasket problems, liners cracking, etc, whichever is the weakest link.
If you want performance, you would also want to get rid of the aftertreatment. Let the engine breath without restrictions.
Of course it all depends on how far you want to push it. Scania probably has better camshafts (for high performance) in the marine engines, and different pistons with even lower compression ratio.
If that still isn't good enough, you can have custom ground camshafts, better quality liners, o-ring or even c-ring head gasket system.
How much do you want, and how deep are your pockets?Last edited: Feb 16, 2018
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