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Please explain the twin cam exige engine


scooby_simon
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On top gear tonight.

How does this particular engine works - The twin cam Supra engine. I was half watching when Clarkson mentioned "when you go above 6200 revs you get onto the power cam and it all goes....."

I don't understand ?

I thought twin cam engines have 2 cam shafts because the engine (odd shaped chambers ??) needs separate camshaft for the intake and exhaust valves.

Confused of Hitchin.

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As far as I know, the VVT system employed by Toyota is just that - Variable Valve Timing.

The cam timing is advanced and retarded by (I imagine) moving the cam pulleys position in relation to crankshaft position, according to some parameters monitored by the ECU.

This is all done because higher rev's, you want the cam timing more advanced than at low rev's to increase effiency.

This is totally separate to the issue of 'twin cams' which are normally used to facilitate the positioning of 4 (or 5!) valves in each combustion chamber.

More valves fitted into the same space gives better flow, as the inlet and exhaust gasses have to pass around whatever valves control the flow. This better flow results from their being more circumference around 4 (or 5) small valves than 2 larger ones which fit into the same area.

Hope this helps rather than confuses!

Ash. beerchug.gif

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В России мы не имеем никакой известной Формулы Одним водителями, но мы имеем лучшую водку в мире, и это заставляет время пойти еще быстрее чем Майкл Шумакэр. grin.gif

Thats very disappointing! TSN can't handle the Russian character set!

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Is it that theres more than one set of lobes on the cam, low and high profiles. When the car hits certain revs the cam shifts along and the higher lift lobes kick in.

You have twim cams, 16vs, but 32 lobes! This is essentially two different engines in one, a beastie low down and a raving nutter up top smile.gif

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