Why do these dirty Diesels have to be so damn fast??

[Welshbeef]

DELETED: Comment made by a member who's account has been deleted.

Why do you keep trying to call posters here who own these and similar vehicles who keep telling you yes they do rev this high but somehow you get off telling them and me no your wrong "no it doesn't ".

[anonymous-user]

xjay1337 said:

Lots of st being posted by people who mainly say

"Diesels are st" or "they make no power above 3000rpm" or "they all smoke" or "they're all slow"

without actually owning one made in the last 15 years, let alone driving one.


In out and out performance many equivalent petrols are faster. But in gear performance, in the rev ranges you mostly drive at, 30mph in 3rd, 40 in 4th, etc, a diesel will have the initial get up and go that many naturally aspirated petrols lack.

Take a 320i (non turbo) to a 320d.
In gear in the middle of the rev range the petrol is miles slower.

But it's cool to hate diesels :')

You've made quite a few assumptions there about people's driving history and I don't understand why in your examples, you are comparing turbo diesels to NA petrols. I have first hand experience where a decent petrol with forced induction can create an almost flat torque curve from idle all the way to 7k rpm. Superior levels of torque to a wheezy old diesel and thank goodness that petrol engine technology has moved on enough to mean there's a real alternative.

Requiring 3 turbos and an array of EGRs/DPFs to in any way compete with a clean, powerful petrol shows just how st they really are as a design.

They have their place and work great for day to day in most heavy cars, combined harvesters etc.

[HoHoHo]

wormus said:

Nope. All diesely coughing and clattering stops by just shy of 5k



..in fact it's pointless revving it much past 4k.

My tri-turbo diesel goes past 5k revs

[anonymous-user]

Welshbeef said:

Exactly and another poster is saying said engine will not rev beyond 4,750 yet a number of actual owners of these cars have posted here saying hey have revved to 5.5k revs. Not sure why someone who doesn't own one or run one thinks he knows better than actual owners ? Maybe a vested interest in trying to make his point but doesn't like it when examples destroy his point.

See earlier dyno graph as an example, it may rev higher but power will drop off and it's ultimately a waste of time. That's why we change gear.

[anonymous-user]

Welshbeef said:

wormus said:

Welshbeef said:

My pre Lci revs to 5,500 rpm on the guvenor.
Tri Turbo revs higher

Nope. All diesely coughing and clattering stops by just shy of 5k



..in fact it's pointless revving it much past 4k.

Nope peak power in my car is 4,400rpm - are you talking about many decade old diesels or very low power diesels?

No. That graph is from an 05 535d with a remap.

[Palmers]

My diesel revs to 6.5k

[PixelpeepS3]

Merc 250 'bluetec' diesel did well in gear against the S3 a few days back... off the line it was a different matter but the difference on the move was a lot closer than you'd expect.

These kind of things that make you question your car choice sometimes

[Welshbeef]

wormus said:

See earlier dyno graph as an example, it may rev higher but power will drop off and it's ultimately a waste of time. That's why we change gear.

http://www.superchips.co.uk/curves/x35dx40d313PS.pdf

Still producing c300bhp beyond 5k revs so unless you think the next gear offers higher wheel ho then change up else... hold on

[Welshbeef]

http://www.superchips.co.uk/curves/F80M3F82M4withE...

This is a lovely Turbo petrol power unit which I've driven on track - fast everywhere perfect.

[RizzoTheRat]

DELETED: Comment made by a member who's account has been deleted.

This is the key point I think. I wouldn't be surprised if the large majority of drivers never get in to the upper third of their rev range, therefore the diesel is significantly quicker for them as they're not using all the petrol engines's power, and having the power/torque available in the middle of the rev range, where you spend most of your time, leads a lot of people to consider them a more relaxing drive.

Only having a visit a filling station every 600 miles is nice too, when I travel on petrol power I have to fill up every 200 or

[RizzoTheRat]

Palmers said:

My diesel revs to 6.5k

I think the diesel I did my first driving test in redlined at about 2800. It was a 5.8 liter naturally aspirated straight 6 though

[Fastdruid]

Palmers said:

My diesel revs to 6.5k

I'm surprised you didn't go with "my diesel revs to 8k" again despite the dyno graph clearly showing it only going up to 5800.

Oh look.

Palmers said:

The car shot a rod. A combination of the power and revs. Fortunately engines are cheaper than trying to replace parts so it has a fresh engine, a new rev limit of 5,800 rpm and less fuel / boost. This is a nice set up for now and I think it will stay that way for a while. Only thing it may need is a new manifold for the turbo to spool earlier.

[thebraketester]

Palmers said:

My diesel revs to 6.5k

Where its presumably making ~4bhp?

[Welshbeef]

thebraketester said:

Palmers said:

My diesel revs to 6.5k

Where its presumably making ~4bhp?

You need revs for power so suggest it's more than that my strummer had me a lot more than that.

[WinstonWolf]

Welshbeef said:

thebraketester said:

Palmers said:

My diesel revs to 6.5k

Where its presumably making ~4bhp?

You need revs for power so suggest it's more than that my strummer had me a lot more than that.

Try telling that to an ocean going liner...

[Welshbeef]

WinstonWolf said:

Welshbeef said:

thebraketester said:

Palmers said:

My diesel revs to 6.5k

Where its presumably making ~4bhp?

You need revs for power so suggest it's more than that my strummer had me a lot more than that.

Try telling that to an ocean going liner...

Exactly such massive HP from tiny RPMs - petrol engines wouldn't be of any use in oil tankers or locomotives

[Welshbeef]

Nanook said:

Welshbeef said:

Power is nothing without revs.


Actually let's take a locomotive or oil tanker they don't need many revs at all some barely do 100 rpm yet have tens of thousands of BHP so you don't need revs for power

Welshbeef said:

You need revs for power so suggest it's more than that my strummer had me a lot more than that.

Well an oil tanker proves you don't need revs to make massive power

Well an S2099 proves you need revs to make sports car power.


So which is correct? Both.

[RizzoTheRat]

Thread Title said:

Why do these dirty Diesels have to be so damn fast??

Surely one thing that everyone must be able to agree on is that oil tankers aren't fast

[Welshbeef]

DELETED: Comment made by a member who's account has been deleted.

Someone says you need power for revs - so I say no you don't ocean liner or locomotive

Then someone says you'd produce no torque at high revs - so I say you need revs to create power.



An oil tanker makes what 100,000 bhp? Tiny rpm 100rpm max
Best road car diesel 450bhp standard 5,500 rpm
Best road car petrol 1,300bhp Chiron 6,000 rpm

[Fastdruid]

Welshbeef said:

Exactly such massive HP from tiny RPMs - petrol engines wouldn't be of any use in oil tankers or locomotives

You do know that there were petrol locomotives?

You do also know that the majority are gensets, ie an engine driving a generator and the motors are electric. The engine speed they make power at is utterly irrelevant as they are geared to run at a fixed speed which corresponds to their most efficient range.

The only reason that there aren't any more is that diesel is more economic, nothing to do with anything else.