ot car special editions

In

You can get decent poke out of a 3.0 Essex with a bit of work. Nice and
strong too. Better basic design than the lump in my Sierra, that's for
sure.. just not so emissions friendly.

Then again, the exhaust on mine's fucked at the moment, give it a decent bit
of welly and it makes the eyes water...


--
Pete M

Ford Capri (ressurection starts soon)
Sierra V6 2.9 4x4 Twin Turbo Estate
COSOC #5
Scouse Git extraordinaire. Liverpool, Great Britain

 

I thought he was dead!

 

Heh. "...greatly exaggerated."

 

If you're achieving that power by bumping up the revs, sure.
But my query is based on the assumption that Diesel makes more torque
at the same revs, then by definition it makes more power at the same
revs. [1]

If the Diesel's making, say, 110bhp at 3000rpm, and the petrol engine's
making the same power at 6000rpm, then there's twice as many bangs
happening for the same power. So I guess what I'm actually asking is
"does the Diesel use more fuel per cycle than its petrol equivalent,
and if so how and why?"

[1] (torque * revs) / 5250 = power

 

I must admit I've not looked fully into the science of it, but just
observing the consumption figures I'm seeing in the real world. As
Diesels have increased performance, their economy has certainly dropped.
Conversely, modern petrol engines are getting better on economy, but
their performance is falling. BHP in Petrol engines is certainly
increasing, but the actual performance of the car is not. This is
generally mostly to do the with increasing weight of the cars though,
along with the weaker fuel mixtures used to meet emission regs.

At the basic level though, all that's happening is simple energy
conversion - carbohydrate and oxygen being burnt, the heat being
converted into motion. Only so much energy can be obtained from a given
amount of fuel.

 

But they invariably are, driven day to day, rather than being constantly
thrashed.

If you take both fuels, and continue to compare them by volume, diesel has
approximately 11% more hydrocarbons per litre, than petrol, therefore it has
11% more 'energy' to generate power with, per litre. So you inject less and
can compress it at a higher rate than petrol, to get the equivalent energy
force in return to force the piston back down.

If fuel was sold by weight rather than by volume, they'd be on more level
terms than they currently are with regards to bang per buck.

That's not a rule - I have a Golf Mk3 TDi... more performance and more
economy, than the Turbo Diesel and non Turbo ones they did at the same time,
all of which are 1896cc, the main difference being mine is a direct
injection, thus the extra power and economy over the other two models, is
obtained because what fuel is injected into the engine, is burnt more
efficiently.

Part of it with mine, is it has a stonking amount of torque from about
1400rpm upwards, whereas the more conventional diesels need revving harder
and higher to get the same level of grunt flowing.