Thread: 3.6L TDV8

Originally Posted by Dougal

I wouldn't expect their turbos to run the whole time.

Please explain! The 3.0 produces 500nm within half a second of take-off using its single VVT primary turbo (TDV8 with 2 VVT) so I'd expect the 3.6 to be in the same league.

The TDV8 3.6 has greater lag from takeoff (hence why the 3.0 is only around 0.1sec slower to 100kph, and is faster to 60kph) - but greater mid-range acceleration.

Cheers,

Gordon

Originally Posted by gghaggis

The TDV8 3.6 has greater lag from takeoff (hence why the 3.0 is only around 0.1sec slower to 100kph, and is faster to 60kph) - but greater mid-range acceleration.

Cheers,

Gordon

I have commented in the past that in a drag race between my 3.9 Classic and my 3.6 Vogue the Classic would win for the first second or two, then the Vogue would just walk away.

Originally Posted by Graeme

Please explain! The 3.0 produces 500nm within half a second of take-off using its single VVT primary turbo (TDV8 with 2 VVT) so I'd expect the 3.6 to be in the same league.

The 3.0 has two sequential turbos.
A very small one to start spinning up very early and a larger one to take over.

The 3.6 has two equal turbos. It is essentially 2x 1.8L turbocharged 4 cyl's sharing a crank. One turbo has to cover the range of engine rpm and boost, so compromises exist. This compromise is in low down boost.

Originally Posted by Dougal

The 3.0 has two sequential turbos.
A very small one to start spinning up very early and a larger one to take over.

I would have thought your statement to be correct and logical however Wikipedia says

The 3.0-litre design, known as the Gen III, superseded the 2.7-litre, and uses parallel sequential turbochargers and an uprated commonrail injection system incorporating fuel injectors with piezo crystals fitted nearer to the tip to reduce engine noise and a metering mode to reduce oversupplying fuel, decreasing fuel consumption and unused fuel temperature over the 2.7-litre model. The parallel sequential turbocharger system utilises the larger of the two turbos when the engine is running at low revolutions; once the engine has reached 2,800 rpm, the smaller turbocharger is used to push boosted air to the larger turbo’s intake port, prior to the small turbocharger’s boosted air is redirected to the intercooler 300 milliseconds later.

The issue with Wikipedia is that anyone can put information so the information may not be reliable.

Garry

Originally Posted by garrycol

The issue with Wikipedia is that anyone can put information so the information may not be reliable.

Garry

That bit ^^.
Whoever edited the wiki page has it wrong and has written a terribly confusing piece that's full of errors any makes no sense in many parts.
"unused fuel temperature"?

The 3.0's primary VVT turbo is indeed the larger one doing most of the work with the fixed geometry secondary turbo only used to top-up the smaller one.

Originally Posted by Dougal

One turbo has to cover the range of engine rpm and boost, so compromises exist. This compromise is in low down boost.

I believe its at the top-end that the compomise is made, if any, remembering that they are VVT providing fast spool-up when needed. But regardless, the turbos are always in use excepting perhaps not as much as might be preferred just above idle so stating that the turbos would not be running all the time is way off the mark.