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2.8 and 3.2 VR6 24V engines


blackpug
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Apart from cc's, what are the differences between these engines? ie Are many of the components shared? cheers.

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The 2.8 engine is a torque split engine with 25% up cam valve lifters. It also has skim pistons and a trail-scale dialogue crank. 169144-ok.gif

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Technically I would have to look in the manual although certainly a higher compression ratio in the 3.2. To drive they are chalk and cheese (almost) - I have had both. Lots more low grunt with the 3.2 and much more fun than 0.4 litres would lead you to suppose.

BTW, a parsec is a distance, not a time......

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Technically I would have to look in the manual although certainly a higher compression ratio in the 3.2. To drive they are chalk and cheese (almost) - I have had both. Lots more low grunt with the 3.2 and much more fun than 0.4 litres would lead you to suppose.

BTW, a parsec is a distance, not a time......

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znaika.gifyelrotflmao.gif

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Compression ratio, cc's and electronically controlled variable valve timing are the main differences 169144-ok.gif

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How does the valve timeing get adjusted on the 3.2? I've often wondered how on earth an engine manufacturer manages to adjust what is seemingly a solid lump of metal (the cam shaft).

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[ QUOTE ]

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Compression ratio, cc's and electronically controlled variable valve timing are the main differences 169144-ok.gif

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How does the valve timeing get adjusted on the 3.2? I've often wondered how on earth an engine manufacturer manages to adjust what is seemingly a solid lump of metal (the cam shaft).

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It's done by oil pressure.

In very basic terms, there are two inter-meshed rotors in a 'hub' at the ends of the camshafts - one rotor is attached to the camshaft, one to the sprocket. There are spaces between the teeth of these rotors which means they can move in relation to each other (thereby changing the cam timing). Oil is pumped into the spaces to force the camshaft to move relative to the cam sprocket.

1123032-R32VVT.jpg

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Wow thanks R32Ash, that was one of my big "must find out before I kick the bucket" life tasks! It must make profiling the cam extremely difficult, as the cam lobes would actually be a different profile at each side (if I'd understood the diagram correctly). I'd assumed the whole camshaft just lifted up or down, increased the time the vales were open for.

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I didn't think the R32 had variable valve timing of any sort..

and it just had a variable inlet tract only. You can see the variable inlet tract mechanism on the front side of the engine.

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It has both. I'll see if I can find some more pictures of how the whole system works. 169144-ok.gif

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