Looky what i saw the other day!!

Man of Honour
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Jez said:
And yes, it IS all about power at the wheels when talking about virtually identical cars in a drag race, all driven by professional drivers (etc etc).

Please explain why a 2000 BMW 528i Sport is faster to 60 than a 2001 BMW 525i Sport despite identical bhp outputs and identical gearbox.

Clue: The 528i has more torque..
 

Jez

Jez

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The two engines have identical PEAK power but not the same characteristics throughout the rev range. Hence one engine accelerating the car slightly faster when going through the best available gears. Power is simply a product of the torque vs the speed of the engine, so that higher torque at the lower end results in more usable power there.

The same does not apply to the 4.8 V8 vs the 3.0 TD though! The 4.8 V8 is a huge amount more powerful and will obviously result in higher acceleration.
 
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Jez said:
The two engines have identical PEAK power but not the same characteristics throughout the rev range. Hence one engine accelerating the car slightly faster when going through the best available gears. Power is simply a product of the torque vs the speed of the engine, so that higher torque at the lower end results in more usable power there.

The same does not apply to the 4.8 V8 vs the 3.0 TD though! The 4.8 V8 is a huge amount more powerful and will obviously result in higher acceleration.

I totally agree, but this 3l TD has two massive 20psi Garret turbos strapped to it!

All i'm saying is - that; for an engine with 80% more displacement, the times between the two (as stats on paper), and a car £6k less (more economical, and nothing in bhp that a £400 remap wont sort!), its a wonder why BMW bothered!
 

Jez

Jez

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I'd much sooner have the 4.8 V8 to be honest, turbo diesels have a very distinctive feel to the way they drive, which personally i dont like.

Different strokes for different folks, you'd have the diesel, i'd have the 550, hence why BMW bothered - market for both :)
 
Don
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It's not about peak power. It's about the area under the graph.

A car producing 100bhp from 3,000 to 6,000 RPM will be faster than one producing 200bhp from 6,000 to 7,000 with less than 50bhp below 6,000.

This is from 4-stroke vs 2-stroke theory as to why a 60bhp VFR400 is faster to 60mph than a 60bhp RGV250.
 
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