I don't get the fuss. You can already get lots of soft tops in diesel (Mercs, BMWs etc). Modern diesel engines aren't as noisy and rattly as they used to be, and for out of town driving, are the most economical option (even compared with electric assisted etc).

I drive a diesel (not a roadster), and whilst I would prefer the sound of a petrol, my wallet much prefers the diesel.

I thought most mass market roadsters were available in diesel form anyway. TT for example. Not sure but aren't Mercedes planning to do/already doing an SLK in diesel. Can't see the problem either.

EDIT: pixelmix got there before I

Because they want to be like Top Gear and hate diesels to get in with the cool kids.

Top Gear and cool kids...I don't think so... 😛

I heard a Touareg the other day with the V6 diesel - 4.2 is it? CR anyway and it sounded good.. really purred with just a hint of dieseliness in the background.

I didn't know there were any Merc diesel roadsters, I thought the TT was the only one.

Anyway petrols only sound good to me if they are great V8s, which is hardly in the same category. Otherwise they just sound like engines.

VW have offered the Eos in diesel, I think...?

Regarding sound - 6+ cyl diesels have always sounded nice. it's only the 4 cyl ones that have tended towards rattly.

And as for petrol engines not sounding good? - 3, 4, 5, 6 and 8+ cyl engines all have their own characteristics.

4s can sound fairly mundane, but can also sound pretty good under power. The old Peugeot XU9 JA/K from 205 / 309 GTi sounded nice and raspy under power... Subaru's flat 4 engine sounds pretty distinctive... Honda's V4 also makes a lovely noise.

Love the slightly offbeat turbine like wail of a 5 cyl. Always fancied a Fiat Coupe for the 2.0l 20v engine.

Diesel + 'Car enthusiast' = Does not compute.

Bloody horrible things diesel engines. **spits** Suitable only for HGVs, Taxis, and use as boat anchors.

VW have offered the Eos in diesel, I think...?

Yeah, my Mother in law has one, and I've driven it a lot. It only reinforces my dislike of oil burners. Wrong engine for the car, and not a good diesel engine anyway.

It is not the fuel they object to it is the way the engine delivers the power when driving. You get modern diesels with monster power and torque figures but they don't have the quick spinning response of a tuned petrol. Great for cruising or fast main roads, less fun for blast down the wiggly roads.

But the petrol engines they're using aren't exatcly tuned though are they. So nuts to that theory, it is just because it's still cool to whine about diesels and say things like they're for HGVs.

diesels...... slow smelly, ugly brutes....yuk.....

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[i]I drive a diesel (not a roadster), and whilst I would prefer the sound of a petrol, my wallet much prefers the diesel.

[/i]

Yeap, thats me too.

iDave. Nice one 😉

Diesels are great from getting from A-B efficiently with a bit of punch when you need it, but as a specific sports car I can't see how they have the flexibility and smooth delivery of power of a petrol.

Are diesels about compromise though? Do the Audi LeMans cars do so well at endurance racing because they are efficient? They could be a pig to drive quickly and no fun, but Audi wouldnt tell you that would they...

If I buy a sports car I want power delivered smoothly when I want it. Diesels just offer too much of a narrow power band, and then its all pretty much delivered in one lump regardless of what you do with your right foot.

I also don't see the point of a diesel in a sports car. Compared to petrol, diesels are heavier, have slower throttle response and produce torque rather than power.

Sports cars are probably driven less than ordinary cars so diesels don't make sense costwise either. IIRC the break even point for driving a diesel is about 15k miles per year. Less than that, the extra cost of buying a diesel car, plus the extra fuel cost makes them more expensive than petrol

I also don't see the point of a diesel in a sports car.

Some people only have one car, need to do 15,000mi pa in it, but want something interesting that can be thrown into a bends.

Diesel + 'Car enthusiast' = Does not compute.

Why so? It's just another engine.

You might like instant power delivery of a big NA petrol, but that doesn't mean I can't like engines and machines in all their various guises, does it?

Car enthusiast doesn't have to mean ragging it on a country road, does it?

but as a specific sports car I can't see how they have the flexibility and smooth delivery of power of a petrol.

So? Is there only one permissible way to enjoy an engine? Are their rules?

its all pretty much delivered in one lump regardless of what you do with your right foot.

That's just not true. Let's not have this argument again!

Lots of FAIL going on on this thread.

I'm not so quick to put down the D's. D's can be made to have a lovely flat, wide torque curve and then geared to suit. Don't forget, it's all about the gearing, the massive torque of a D can be scaled down to the same torque at the wheels as the petrol by using longer gears, which means that despite having a lower redline/powerband you don't need to shift any more often. Assuming both engines have the same rated bhp, gearing takes care of the rest and generally a well tuned D will have the flat torque curve that motoring enthusiasts dream about.

The immediacy of low rev torque available from modern TDis makes them a far more practical prospect for making progress in real world driving situations. By comparison, most petrol engines are not turbocharged and have to be revved quite highly before they can outperform a similarly specced diesel.

Petrol turbocharged cars suggest a good compromise between low down torque, high end oomph and reasonable fuel economy on paper but real world economy is far short of diesel returns.

molgrips - I can only base my experience of disel cars I have driven, and in fact any turbo charged car. They do not have the quick smooth throttle response that enables you to control a rear slide in a controlled manner with the same delicacy as a non turbo petrol.

Again gearing wise, I have yet to drive a diesel with the same wide range of gearing as a petrol sports car.

I'm only basing it on what I have driven, so great if there are diesel sports cars being produced now that over come these issues then fair enough.

FunkyDunc - stuff like the new twin turbo(1 small, 1 big) bmw diesel units have virtually zero turbo lag, due to the small turbo that requires very little spin up time/gas flow), and thus very quick throttle response.
They also pull extremely well from very low revs for the same reason, so gear range is less of an issue.

The 205bhp 2L unit feels like a big ol' na petrol.

So thats 2 £750+ turbos to fail, a £800 clutch, and it will still weigh 100kg more than the 2l petrol. All good selling points in a cheep'n'cheerfull roadster.

Don't forget, it's all about the gearing, the massive torque of a D can be scaled down to the same torque at the wheels as the petrol by using longer gears

True that. I was thinking about this when people were talking about their diesel chewing tyres because of the high torque. The ENGINE has high torque at low revs; for the same acceleration two differently fuelled cars will have the same torque at the wheels.

They do not have the quick smooth throttle response that enables you to control a rear slide in a controlled manner with the same delicacy as a non turbo petrol

Quite possibly. However I'm never ever likely to drive like that, so it's not much of an issue 🙂 Just because they don't suit what you want to do doesn't make them rubbish overall.

Why don't we just call it a different experience? It's like slagging off a 456 against an Orange 5. Different, but both good for slightly different reasons.

So thats 2 £750+ turbos to fail, a £800 clutch, and it will still weigh 100kg more than the 2l petrol.

Hmm.. a powerful twin turbo diesel is a completely different thing to a 2l NA petrol, isn't it? I think Glenh was comparing it to a "big" na petrol like some 3l V6. So if performance were equal you'd be using at least half the fuel in a diesel. An advantage that should not be ignored imo.

I was thinking of glenh's assertion that the BMW 2lt was a good option.

My 1.5l MG does 25-35mpg not far off a V6 3.8lt Nissan GT-R, the new fiat twin air does ~70mpg! Its not black and white that all petrols are one thing and all diesels are the other.

It is black and white that diesel is unlikely to ever be the fuel of choice in a lightweight sports car! OK its found a niche in LMP, but arguably becasue the format and rules let it. Lets face it, an LMP car isn't going to work on the B-roads that a roadster will!

For me any convertible car needs to have a 6 or 8 cylinder NA engine as a big part of the experience is hearing the induction noise and exhaust note when giving it some stick, but that's for my weekend fun car.

If all you care about is open top motoring and what some practicality and do alot of miles, I can't see the issue in a diesel soft top as it would be a good option for european road trips due to diesel being cheaper than petrol in many countries. The petrol 2.0 turbo VAG engine doesn't sound very good anyway.

Something to note, diesel is about to jump in price due to new environmental regs which will essentialy ban the use of HFO.

So all you smug people in your oil burners, you can add shipping to the list of things competeing for your fuel and pushing the prices up.

If anyone has tried the latest VW diesel engines as found in 2011 MY Golf, Passat etc, the whole rattle/noise thing is almost a thing of the past. There are rougher NA petrol engines around in my experience.

If they are offering it with the 7 speed DSG box, I would definitely buy one, as the DSG definitely masks a lot of the power delivery issues of a diesel and can be great fun to drive in sports mode and with paddleshift option.

Its not black and white that all petrols are one thing and all diesels are the other.

No, of course. However diesel is more efficient for a fact, which means either more power for the same mpg or more mpg for the same power.

A fiat twin-air does (on paper) 70mpg but it's tiny. Whereas a Passat bluemotion can approach that figure and is a big family car.

It is black and white that diesel is unlikely to ever be the fuel of choice in a lightweight sports car!

Surely that depends on your criteria? One of my main criteria is fuel economy, so the TT or VW roadster would definitely be high up on my choices.

My Ibiza diesel handled quite nicely. Not the best ever, and it wasn't going to win any races, but then I wasn't racing it. It put a smile on my face and that's all that matters. Or was I wrong to be smiling?

So all you smug people in your oil burners, you can add shipping to the list of things competeing for your fuel and pushing the prices up.

I thought that only applied to the heavy marine diesels - ie engines the size of your house...

I wouldn't have thought road diesel would contain much heavy end hydrocarbons

I thought that only applied to the heavy marine diesels - ie engines the size of your house...

He's suggesting just that the ban they will start using diesel meant for cars, ignoring the fact there's other marine diesel fuel options.

I thought ship engines burned some kind of tar-like sludge left over when everything else had been taken?

He's suggesting just that the ban they will start using diesel meant for cars, ignoring the fact there's other marine diesel fuel options.

Serves me right for skim reading 😳

I thought ship engines burned some kind of tar-like sludge left over when everything else had been taken?

Yep - HFO, heavy fuel oil

VW offers a convertible zzzzzzzZZZZZZ and in diesel (quick Nurse hes slipped into a coma!)

Haven't you owned a few VAG Diesels now Hora?

Diesel+convertible is just wrong. Who wants to hear a rattly diesel engine on a nice summer's day with the top down?

And yes diesels have come a long way but a 6-cyl diesel still sounds rattly next to a 6-cyl petrol - depends what's most important to you of course.

VW offers a convertible zzzzzzzZZZZZZ and in diesel (quick Nurse hes slipped into a coma!)

What a beautiful post, Hora, an absolute delight to read. Delicately worded with fine subtle wit and yet graceful and elegant. You display such profound insight into the subject delivered with such warmth and joy that it's impossible not to love you.

And you contribute to the topic so well too!

Who wants to hear a rattly diesel engine on a nice summer's day with the top down?

My engine doesn't rattle unless idling cold. Idling warm it sounds a bit pants. Crusing along it just hums nicely. Got no problem with it. Listening to the engine isn't why I want a convertible anyway.

Haven't you owned a few VAG Diesels now Hora?

Oh aye and I'll be buying my bro in laws mkVI Golf TDI off of him when he finishes the lease.

No way would I buy a diesel 'sports car' or diesel convertible though just as you'd be silly to buy a V6 2.5 Cmax. Interesting concept but not fit for its purpose really.

I moved from a 270hp, 270lb/ft v6 that revved to 8.5k to a 240hp, 400lb/ft 1.9l weasel and the only thing I miss is the sound, although the diesel actually sounds alright through a 3" pipe, actually tell a lie two things I miss.... doing 75 in second gear. I think the diesel is quicker in most situations, and the delivery is excellent too, peak torque comes in like a sledgehammer at 2100rpm and power builds nicely towards the redline, means you actually have a choice to drive it on the torque and short shift or like a petrol and screw it, I'm not actually sure which way is faster but I like the torque burble.

Would I trade 56mpg for 16? Nope, diesel is the future, for now... 😀

Interesting concept but not fit for its purpose really

No? If I use it for semi-brisk driving along a windy road on a sunny day, will I not enjoy myself?

Gotta decide what its purpose is, haven't you?

You'd enjoy yourself at Legoland. I'd be climbing the walls.

I moved from a 270hp, 270lb/ft v6 that revved to 8.5k

What car was that? I've got a 286bhp 3.0 Straight 6 that can still return around 30 mpg, so that sounds very thirsty for the power.

I also don't see the point of a diesel in a sports car. Compared to petrol, diesels are heavier, have slower throttle response and produce torque rather than power.

Refers Captain Manwairing to previous post with Audi R10 TDI and maybe the Peugeot 908

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Yyyyyyyyyyyyyyyyyyyyyaaaaaaaaaaaawwwwwwwwwwwwwwwwwwwwwwnnnnnnnnnnnnnnnnn.

Gachet it was a 3.1l VR6, the way I drove it that was my average, granted if I really tried I could get mid twenties.

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Diesel MEV Rocket.

240hp 1.9? Whoooa - do hope you have uprated your clutch etc. Is that a standard tune VAG?

Who wants to hear a rattly diesel engine on a nice summer's day with the top down?

while a cold Diesel CAN rattle (older ones), once any engine warms up they can have a loverly low purr 😀

complements turbo whistle much better than a whiney petrol. :p

I also don't see the point of a diesel in a sports car. Compared to petrol, diesels are heavier, have slower throttle response and produce torque rather than power.

more laps per litre?

nowt wrong with excess torque, just gear it up.
bwap.

Amazingly I've done 28k on the standard clutch and flywheel without a hint of slippage. All that's done is turbo back exhaust, green panel filter, FMIC, hybrid turbo and custom map oh and water meth injection.

Here's a plot from when I first had it set up, the mapper insisted holding the torque back to preserve the clutch and I had to twist his arm to up it to this, it's also pre h2o/meth which helps it spool up much quicker, and after a few thou of the clutch holding up I insisted on letting the torque rip and if the clutch died I'd replace it.

[IMG] [/IMG]

[IMG] [/IMG]

What's the standard-tune fabia? 170? It'd be a bigger clutch than 'standard' anyway but bloody ell!

How much did the map/tune cost? You live in the Midlands?

Standard is 130bhp and 228lb/ft on paper but alot of the later BLT engine code cars are producing 150+ standard. Custom mapping was a little over £300 with a mk4 owners forum discount, they did the re-ee-map (bo) for free. I'm in Newport Wales. Some of the guys with the seriously tuned cars are running over 550lb/ft.

while a cold Diesel CAN rattle (older ones), once any engine warms up they can have a loverly low purr

complements turbo whistle much better than a whiney petrol. :p

Nah I've been in a few diesel convertibles and with the roof down at warm tickover it ain't pleasant

I like diesels in the right application though

You'd enjoy yourself at Legoland. I'd be climbing the walls.

Right. I like the idea, you don't. So it's not wrong, just different.

Easy speed at low revs is what I like, not revving the tits off a petrol. You seem somewhat boyish when it comes to cars, are you sure you wouldn't enjoy Legoland? 😉

produce torque rather than power

D'you actually know the relationship between those two things?

Agree with james. I couldn't stand a diesel mx5 but say a scaled-down 1.5 supercharged petrol YES!

+1 for a VAG remap in a hot hatch. I've got the Ibiza sport, 100ps standard now at 150, goes crazy at about 2500rpm, much more fun to drive than my old mk3 golf gti and easily on a par with my mk2. The noise is OK when you are driving. However I can't deny that its not ideal when you fire it up from cold and hear that tractory rattle...

@hora
[url= http://www.singletrackworld.com/forum/topic/fs-sram-x0-gripshift-left-hand-3-spd ]Click me[/url]

They do not have the quick smooth throttle response that enables you to control a rear slide in a controlled manner with the same delicacy as a non turbo petrol.

Agree with james. I couldn't stand a diesel mx5 but say a scaled-down 1.5 supercharged petrol YES!

Long distance journeys diesels rock. Every day use petrols ROCK.

O/T: On the gripshift- I just can't get my head around them. Sorry.

Long distance journeys diesels rock. Every day use petrols ROCK.

Not even 8.30 and the first hora bollocks appears.

Not going to get potty-mouthed again are we Drac? 🙄

I too like the hot Fabia above. If only to prove to boring petrol head drones like Hora that diesel doesn't necessarily mean slow 🙂 If I'd had more space I'd have kept my old 1.9 TD Passat and tuned that up 🙂

This isn't an argument about slow and fast molgrips.

I drive a petrol car quite different to a diesel. Its not just the sound. For a start I upshift alot quicker in a diesel. Probably where I am at 3rd gear in a petrol I'd already be upto 5th in a diesel in the same scenario.

Probably where I am at 3rd gear in a petrol I'd already be upto 5th in a diesel in the same scenario.

Hmm. What sort of speed is that? My car does over 100mph in 5th, probably more like 110.

I very much doubt that Hora unless your driving a sports car and I mean a proper one.

No way would I buy a diesel 'sports car' or diesel convertible though just as you'd be silly to buy a V6 2.5 Cmax.

Probably where I am at 3rd gear in a petrol I'd already be upto 5th in a diesel in the same scenario.

You have to drive the cars in very different ways and while all the diesels i have driven have short gears for 1st and 2nd they get much longer after that, longer than any of the petrols i have driven.

Yes, diesel gears are of course much longer after 2nd or so. Big jump between 2nd and 3rd on mine, but in 6th it's 2krpm at 70mph and just over 3krpm at 100mph!

Just goes against a roadster principle for me - I like them to be simple as possible, light as possible, and have cracking handling - Elise S1 or Elan style, Mk1 MX5 etc .. and bouncing them off the rev limiter is part of the experience.

I'm sure you could build an equally fast diesel - but sometimes it's just not the point. Part of the fun of owning a roadster is having the option to take it apart a bit yourself for me.

Both are great in their applications.

The sound, you can't beat a decent petrol engine- **** mpg. One life, live it.

The sound, you can't beat a decent petrol engine- **** mpg. One life, live it.

So when are you getting your Diesel?

Aaaah, the likkle car drivers cry cos they can't get their special sound, ahhh bless em

Probably where I am at 3rd gear in a petrol I'd already be upto 5th in a diesel in the same scenario

Thats funny my last manual diesel would do well over 100 in 5th where as the fast petrol megane we have wont go any faster than 80 in third.

Isn't that totally missing hora's point???

Your diesel might do 120 in 5th, but you'll probably already be in 5th at 30...

... whereas in a petrol you might hang on in 3rd until the redline, perhaps somewhere around 70 or so 😉

Try the gearing on the 107/C1/Aygo- I got a hire 107 upto 5mph in 2nd 😀

One life, live it.

LOL!

This is a mountain bike forum full of people with all sorts of fascinating lifestyles and hobbies, and you think the measure of whether or not they are living their lives depends on the fuel they choose for their car? Any idea how ridiculous that sounds? 🙂

FWIW if you want to live life through a motor vehicle you can scare yourself just as much in any fast car. Haggling over torque curves is pathetic.

Your diesel might do 120 in 5th, but you'll probably already be in 5th at 30...

What? Diesels are geared longer, so you COULD be in 5th at 30 if you want, but you don't have to be. Plus, in 5th at 30 it will still pull away nicely, reducing the need to be rumaging around in the gearbox all the time.

It's all about driving style. At the end of the day, if you're a boy racer and you want to thrash the tits of your engine then petrol is for you. However, roadster driving does not have to be like that, does it? Making progress on a windy road with the top down can be a relaxing passtime, where a diesel would excel.

Would anyone like me to find out at what speeds the limiter kicks in for each gear on my car? Are you that interested in truth? 🙂

you think the measure of whether or not they are living their lives depends on the fuel they choose for their car? Any idea how ridiculous that sounds?

Even more so when he's owned diesels and is waiting for another.

He's suggesting just that the ban they will start using diesel meant for cars, ignoring the fact there's other marine diesel fuel options.

Basicaly the problem is............

HFO is a niche product, they don't sell much of it, most of it gets used in the refinery for stuff like distilation (via steam generation).

The cost of upgrading it to meet a lower sulphur limit would be prohibitive, as the heavier the fuel the higher temperature/pressures required for hydrotreating.

More likely to re-cycle it through the cracker again and turn it into something else. Still not cheep but considerably cheeper than building new equipment. Plenty of refineries already do this and no longer produce HFO for sale.

The problem is there isn't much else that can go into ships economicaly, and its unlikey that anyone will hydrotreat HFO as its cheeper to use FGD and burn it in static engines. Current thoughts are ships will run on a HFO blended with lower sulphur fuels wilst offshore (limit is IIRC going to be 4.5ppm), switching to diesel within the more stringent areas (english channel, north sea, irish sea, north american coast).

Right, well what are the relative volumes? How much diesel will be taken out of the market?

Your diesel might do 120 in 5th, but you'll probably already be in 5th at 30...

Diesels allow you to drive along feisty roads with only a few gear changes where as in a petrol you will be using a simillar amount of revs just a lot higher up.

Diesels allow you to drive along feisty roads with only a few gear changes

That is certainly my experience.

Diesels are geared longer, so you COULD be in 5th at 30 if you want, but you don't have to be. Plus, in 5th at 30 it will still pull away nicely, reducing the need to be rumaging around in the gearbox all the time.

That's precisely what I said... 🙄

ie, I was pointing out that in a diesel you were likely to have short shifted to use the torque available at low revs

Right, well what are the relative volumes? How much diesel will be taken out of the market?

If shipping was a country it would emit more CO2 than Japan (the 6th largest emitter).

Imagine a country the size of Japan suddenly going form using negligable diesel to using it for everything from heating their houses to Blast Furnaces.

That's precisely what I said...

You seemed to be saying that you would have to be in 5th at 30. Which would be silly

Don't 🙄 me!

Imagine a country the size of Japan suddenly going form using negligable diesel to using it for everything from heating their houses to Blast Furnaces.

Hmm.. seems to me that 'they' won't let the price of diesel suddenly triple. World economy would collapse!