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Diesel v Petrol

4K views 111 replies 30 participants last post by  DrEvo 
#1 ·
Little debate to kick things off in the diesel forum...

Now I'm a die hard petrol fan, personally wouldn't own a diesel out of choice at the mo. But with all the advances in diesel technology (Just look at the Seats in the WTCC and BTCC and the diesel Le Mans racers) is there really a place in the world for both petrol and diesel?

Audi think that the diesel R8 will almost kill sales of the petrol version, so why do they make them?

Diesels offer more torque as standard, but is that just all talk?

Opinions more than welcome :D
 
#8 ·
Not from any of the ones I have seen, even with chips.. for the same sized engine.

Toyota made the 503e race engine, 1200 bhp from a 2.1 in qualifying spec, rally cars over 600NM of torque from a 2.0ltr.

Plus the engines are lighter :)

The torque characteristics will be highly dependent on the turbocharger.
 
#4 ·
Diesel for work petrol for fun its always been for me but diesels are getting very good now, id only really buy a diesel if i done a lot of miles and needed a workhorse tho. The sound lets it down for me

Really want to know what this R8 V12 diesel is gonna sound like tho.
 
#5 ·
I genuinely believe that Diesel and petrol is almost a dead technology ! The most interesting new development seems to be this water engine (the one you can drink the water that comes from the exhaust (I think lol).

Ok the cost of Diesel is hitting a rediculous £1.30 per litre, but as someone who travels a lot I can vouch for the fact that the savings are noticeable. I used to drive from RAF Kinloss (North coast of Scotland) to Nottingham over 5 years ago. The cost in my civic easily covered £120 - £140 quid. The other week I drove to Motherwell in the ZR TD at a grand total of £40 (take into consideration the rises in fuel prices since 2003).

When I tell people it is a Derv they act genuinely surprised. Ok, it does suffer chuggers syndrome when you first start it, but after a while it begins to run really well. The exhaust and 57i take over the tractor sound and you wouldn't know the difference !
 
#6 ·
Having owned a moderately modded R25 derv for 2 years now, i wouldn't even bother going back to petrol cars.

The shear feel of the torque as you plant your foot in any gear, is pretty addictive. Ican imagine what the T16 turbo feel, but i still get way over 35mpg while 'playing'!!!

I would recommend any petrol driver to drive even a moderately modded R25/ZRTD or even R45/ZS, and not leave with a smile glued there face.

Don't get me wrong, i driven tuned NASP petrol cars, but for the sheer smiles per mile, nothing beats the dervs push in the seat feeling.

Besides, diesel is not as flammable as petrol. I know which one i'd rather be in a crash in!!

Cheers
Dave
 
#7 ·
well at the minute i have the most powerful l series rover in the uk maybe the world at 178bhp and 312ft/lb. The engine is a very old design and that is its big problem. But saying a turbo petrol is quicker than a turbo diesel would be far from the truth, when you have vag engines runnning over 300bhp and 400ft/lb, and wat about the r8 diesel or 335d bmw (i know its twin turbo) but still proves that diesel is still devleoping were petrol has slowed down and lesser gains can be achieved. just my point of view.
 
#9 ·
After driving my Boss's Audi 2.0TDI I was very impressed.

The power is just "there", you can be doing 60mph, put your foot down more and it just pulls like a train. Gave me a grin or two thats for sure :D

2 things put me off owning a diesel though.....

Taking off power/speed, and they sound horrible.

Shame really.
 
#39 ·
Well as dave says, i would rather torque over bhp and revs any day. Alot more driveable and can be fun if you want it to be. Plus with running more torque it is easier to overtake, and easier to cruise along on motorways etc.
 
#40 ·
I have a 105 and a Rover 45 1600.
I have had my TD since about Jan and by golly the Derv doesn't half put a smile on your face when you first drive it.
Should be even better when I get my SDi injectors in.
When I drive my petrol's now I keep waiting for the turbo to kick in.

The 105(103 BHP) v TD (99 BHP)
The TD has loads more torque and that is the important factor.
BHP is nothing without torque.
 
#59 ·
BHP is nothing without torque.
isn't that kinda stating the obvious considering bhp IS torque x revs / by 5252??? lol


how a car drives is all about the bhp power curve - i.e. how much power you have on tap throughout the rev range. the lack of revving in a diesel means that you never get as much BHP (as can be seen in above formula) and so diesels never quite have that same acceleration as a petrol which will rev higher.

my 1.8 zr with r140 kit pulls just as well as my mums TDi golf mk4 (100pd engine) throughout the rev range, however, when her car hits 4k and has to change mine just keeps on going and going and will leave hers standing.
 
#41 ·
tbh if I was buying an MG it would be between the 160 and TD, if the 160 was fool proof against HGF I would get the 160 but diesel is sweet, but the price of diesel is making it less "cheap" than it originally was.
 
#58 · (Edited)
The only advantages to the dervs were the mpg, but having driven both a 115TD and a 120 ZS the savings to get the same performance were negligable. I think it was £150 over 30,000 miles. That was 2 Years ago so since derv is now 12p more expensive than petrol I would imagine that the savings have dropped more.

Performancewise the 115 (when it was working) was phenominal. It still wasn't as good as the 120 though. The extra weight at the front created more understeer and the engine had to be worked hard all the time.

It would have been nice to test it against the 120 when it was working with the decat and other small mods but I never really got a chance.

Test drove the 2.2CDTI and 1.8i-VTEC Civics back to back. I regrete not going for the diesel, just a little bit. The torque was immense, and with recent re-maps it is supposidly being released as a Type R with the next Gen of 2.2's as seen in the New Accord.

Diesel is now a serious competator for performance, and with the green bandwagon the way it is, bio-diesel will be the way forward.
 
#60 ·
well its not really fair comparing a 100bhp heavy golf, to a 1.8 zr with im guesing 140bhp. a remapped l series with around 130-150bhp will be any match for the petrol versions of the mg/rovers.
 
#65 · (Edited)
the golf develops around 230NM torque (max) so it is no slouch for in gear acceleration.

also my zr (which i would estimate at around 130bhp due to needing a remap) was exactly the same pace as a Golf GT TDi 150 - which was the fastest derv they did in the mk4 series afaik - and that was from a 50mph rolling start in gear.

also consider that the standard in gear acceleration of the 120 and TDs is pretty much identical (both being a bit faster than the 160) the fact that the 120 will be significantly faster 0-60 does mean that in most scenarios it will outpace the TD - both in standard form.


the lack of rev range means that my petrol engine is in the high power band for a longer time than a derv that creates similar BHP which is when mine can take a lead - as you change gear, dropping down in power generated due to lower revs, whilst i am still flying ahead in front with more BHP being created for longer. also i find the power delivery far smoother in my car due to the absence of turbo lag and the fact that the torque curve is pretty much flat from 2k to 5k.

now that diesel is so expensive it is almost at a level where the increased efficiency is cancelled out by the cost of fuel, and if you consider the increased initial cost of a diesel model in the first place, i see no economic reason to purchase one.

At the end of the day though, the real killer point is... who wants to drive a car that sounds like a tractor ;)
 
#61 ·
Saying that, in my moderately modded R25 derv, i kicked the ass of a Mitsubishi Galant.

Not sure as to the model, as it was debadged, and had a large bore exhaust on it.

At the speeds we were doing, i know he was trying hard to shake me off, so just planted the pedal further into the carpet and left him way behind.

It's not something i normally brag abut, but checking the stats of all the models (Galant specs), and using the above examples, he should have left me behind. His face was a picture when i went past him :cool2:

Cheers
Dave
 
#66 ·
well to be honest 230nm is nothing for a diesel now, as a slightly modded l series diesel will be putting out over 300. i understand wat ure saying about rev ranges and having alonger power band, put a diesel will pull through the gears alot faster and has power and torque very low in the rev range, which means it can pull away very quickly. Turbo lag is not a problem with variable vane turbos, and even the new hybrids we are instaling on the l series gives very little lag.

and it only sounds like a tractor when at idle, put when ure up and going theres no problem, just the sound of 1.9bar boost whistling away.
 
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