towing with petrol or diesel

[g_374369443]

Oh dear! Firstly, I have a diesel, its one of numerous diesels I have owned. Poisons coming out of the exhaust are irrelevant to the issue you were talking about.

So here goes. Reliability! Once diesels went hi Tech, then the reliability advantage dissapeared,indeed they do share a lot of the same electronics so its even Stevens there. But The diesel engine still suffers from soot build up, so the EGR valve is prone to failure, as is the turbo again due to soot build up, something that cannot be levelled on the petrol engine.

It appears because of its inheritance, low-down high torque characteristic, clutches and indeed the DMF, wear out far more rapidly than they do if fitted to a petrol engine!

So we already have two very costly units that brake more so on diesels, than petrol engines, turbo's at a grand and DMFs costing about the same it replace and fit.

Engine mountings, and gearbox mountings also suffer far greater wear on the diesel engine[more cost]Crankshaft pulley is another wear part,all those engine vibrations what not, another part that will need replacing far more often than that fitted to a petrol engine.

Then we come to the injection system [now this is hi tech and needs to be] The diesel injection system is an exceedingly expensive system, god forbid that going wrong,and again they go wrong more so than the cheaper petrol injection system does.

Now what about those new injectors themselves! To keep a head in the torque race [1800 odd psi going through them in the modern common rail]and as too not loose to much more ground in the BHP race, these things when they go wrong will indeed cost another small fortune around a grand for a complete set of 4 .

"last longer"!!!!! How long mileage wise do you want a engine to last? the modern petrol can go 200,000 miles with regular oil changes,and yet these new style service gaps and longer lasting oils for diesel [so to bring down service cost] are actually leading to all sorts of issues for diesel engines over 100,000 miles!.With wear levels in the camshafts, valves and valve gear now being worse than the same thing in petrols!

You said Seth..

"Diesels are less polluting than petrols,whether it be EGR OR SCR ,NOX gases have been done away with."

Diesel engines emit higher levels of NOX and you seem to have misplaced PM particulates! Although whilst i know what a egr is,[gas recirculating system ] That's not actually a gas! its a valve!.!

And incidentally modern petrol turbo's [not the monster bhp boys] have quite high toque settings at quite low rpm, so where on earth you get the peaky nature from I do not know! And given that a citroen xantia of circa 94/95? was tow car of the year with 92bhp and around 140 ft/Ib of torque, Then to go on about 225/232 ft LB of torque is being what everyone needs, is indeed rather misleading. The vauxhall vectra of 97-2002 had 151 ft/Lb of torque,and apparently was a decent tow car.

Matbe you are thinking of the BMW 2002 turbo [circa 1970s] or the saab 900 circa 1980! When you were thinking peaky all or nothing.

Like I said I like diesels I own them, but things are changing again, and now most investment is going into the petrol engine, just like most investment went in to diesel in the last decade.

Dustydog. LPG kits fitted to petrol cars, in a way it sort of doubles your mpg, as its only half the price of diesel/petrol.....

 

[g_374369443]

" g,

your post exclaims Diesels as playing "catch up" .would you please explain that to me.i,d be most interested."

Until the beginning of the 80's, and the introduction of the mass market reliabalish turbocharger, not much has changed in the diesel engine,when it comes to the car market.A slow smelly/dirty engined vehicle.

The better turbochargers that came onto the market, started the ball rolling.DI direct injection [very noisy for cars]was replaced by idi, [indirect injection] quieter, but less efficient took its place.

In the 90s, vnt turbo's [which helped to up the power and keep lag down came out, as did work on better DI injection systems [ie the common rail]that were not so noisy, and could work at exceedingly high pressures to get more power without becoming big fuel drinkers.

Thats where we are now. A lot of this technology is reciprocal, and is now getting used on petrol engines because of the emissions battle.

Now petrol cars are coming out with small charged engines, which are both powerful and torque from low-down without suffering from excessively high mpg.

And whilst they are not as good on mpg, as a good diesel, the gap has closed especially where urban cycles are concerned.

Given that petrol with stay cheaper by at least 10% and its going that way all over Europe too, if ever it got to a gap of 20%[good chance it will] Then diesel cars could loose the advantage they have had for decades due to their own success!

about torque and towing, let me remind you that torque is pulling power and bhp is work rate.

If you are taking on a mile or so incline of say 10% both cars are similar matches for weight, as are the caravans, one is supplied by a diesel engine of 150 bhp and 230 Ft/LB of torque,[which is about what a 150 bhp diesel has] the other is turbo petrol and has 180 bhp and 177 f/LB of torque.

Which one will get to the top first?

 

[seth1]

" g,

your post exclaims Diesels as playing "catch up" .would you please explain that to me.i,d be most interested."

Until the beginning of the 80's, and the introduction of the mass market reliabalish turbocharger, not much has changed in the diesel engine,when it comes to the car market.A slow smelly/dirty engined vehicle.

The better turbochargers that came onto the market, started the ball rolling.DI direct injection [very noisy for cars]was replaced by idi, [indirect injection] quieter, but less efficient took its place.

In the 90s, vnt turbo's [which helped to up the power and keep lag down came out, as did work on better DI injection systems [ie the common rail]that were not so noisy, and could work at exceedingly high pressures to get more power without becoming big fuel drinkers.

Thats where we are now. A lot of this technology is reciprocal, and is now getting used on petrol engines because of the emissions battle.

Now petrol cars are coming out with small charged engines, which are both powerful and torque from low-down without suffering from excessively high mpg.

And whilst they are not as good on mpg, as a good diesel, the gap has closed especially where urban cycles are concerned.

Given that petrol with stay cheaper by at least 10% and its going that way all over Europe too, if ever it got to a gap of 20%[good chance it will] Then diesel cars could loose the advantage they have had for decades due to their own success!

about torque and towing, let me remind you that torque is pulling power and bhp is work rate.

If you are taking on a mile or so incline of say 10% both cars are similar matches for weight, as are the caravans, one is supplied by a diesel engine of 150 bhp and 230 Ft/LB of torque,[which is about what a 150 bhp diesel has] the other is turbo petrol and has 180 bhp and 177 f/LB of torque.

Which one will get to the top first?

have i misread this or are we still at the same stage as we were in the 80,s because my 170 hp jtd fiat doesnt perform like a 2.0ltr diesel SD1.As you,ve explained yourself Diesel atributes are being used on petrols ,so whos a bit behind.

As ive stated you cant change the fundermentals of a Diesel engine,Diesel burns for longer,cylinder temp is higher,the physical max speed of a diesel is 4500rpm this makes for an engine lasting twice as long. Although petrols use a form of commonrail it totally differs from Diesel commonrail,i.e injector position,fuel pressures,injector actuation,fuel correction,fuel status.But inconjuction with commonrail and at least 50 years before it Diesels were using unit injectors,which funnily enough vw use today.(pd)Even this system outperforms your average multipoint,due to petrols inherent low flash point,low compression and weak spark ignition.

As for the comparisons ,Paper figures dont give the full picture,as im sure you,ll understand.

 

[seth1]

g,

what on earth are you talking about,your information is dangerous,commonrail 1800psi?were do you get that from?turbos failing due to soot build up,nothing to do with perferated intercoolers leading to turbo overspeed,EGR,S clogging up,poor fuel maybe?(dont tell me how to suck eggs)Injectors failing,nothing to do with fuel filters incorrectly fitted,not bleed up properly?,water in the fuel?(i,ll presume you,ve been on the commonrail course in Munich).DMF,admittedly not so hot,i own two that have done 100k no problem.Not just limited to Diesels .

 

[xtrailman]

Seth

I pulled my present caravan with both my audi, 180bhp/173 lbft.

and my old xtrail, 134bhp/131 lbft.

The audi was easily the quicker of the two, on the flat.

But both were great tow cars, no doubt the xtrail would pull better up hill.

But the audi torque curve was flat from 1950/4500 rpm max torque.

I believe it is the diesel that is peaky if you could say that of the two.

Even the 171bhp/266 lbft xtrail i have now, if you study the graph in the brochure, you will see good torque over 350nm is only available from around 1900/3000rpm.

The lastest 2lpetrol turbo engines will give MAX torque over a very long rev range.

 

[g_374369443]

seth. Sorry missed off a naught, 18,000 psi.

So diesel are more reliable to the fact they have a max speed of 4500rpm! poppycock, the cut of on my alfa 2.4 jtd till 4600 rpm! and revs onto 4800! modern ones can run even further!

How on earth you come up with diesels lasting "twice as long because of a max 4500 revs"! is fancy full,diesel itself does have a lubricating properties,but you are talking about how it was,not how it is now! I have told you why they now wear and break!

turbo's actually get clogged up, or rather the vanes get stuck and do not open up properly!this lead to overboost and the car goes into limb mode. overtime it get worse till either the vanes are damaged or the car is in constant limb mode. At best the turbo needs cleaning/servicing. not really much cheaper than a replacement.

Indeed this actually happens because of the fact that so many diesel have so much pulling power, that they do not get revved hard enough to keep the vanes operating freely!

EGR,gets clogged up "poor fuel maybe" where have you been!NO this is a mixture of oil and water vapour mixed with particulates that come out of your engine,and get recirculated into the air intake! This stuff is like glue but hardens. not really what you want going back into the engine, but as the erg valve gets clogged its more likely to stay partially open all the time, leading to more crap getting into the engine!

I am surprised, you cannot remember the 1.9 sdi engines that the VW group was still using till 2007. these non turbo diesel had a massive 68 bhp, and around a massive 98 FT/LB of torque! at a high 2800 rpm! so much for the massive torque advantage of the diesel.

Interesting you mentioning engine characteristics, but not knowing how much petrol engines have changed. So many of them today have max power at a much lower rpm 5000rpm, and use softer cams to up the torque whilst making it usable so much lower down the rev range,this seams to have slipped by you.

Any road as this was about towing,and your rather misleading post,please answer the question i set. should be right up your street.

regards gio.

 

[ProfJohnL]

Gentlemen Gentlemen please!

This is not really helping Andrew with his question.

Andrew, as you can tell by the replies that you have already had, is there no clear cut winner in the Diesel vs Petrol stakes.

As in so many cases there are good and not so good diesel and petrol engines, and you must not forget the rest of the drive train, so you are never going to get a copper bottomed solution to your question.

The significant fuel efficiency that diesel engines used to have over petrol, has been eroded by the improvements in petrol engined cars in recent years, and the cost savings that running a diesel have virtually been wiped out buy the greater hike in diesel prices over petrol.

There is no doubt that petrol engines are mechanically quieter and smoother, Purchase prices and general service costs are less than diesel.

In my opinion and based on the current state of technology and fuel prices Diesels still have the edge for towing, but the case is much weaker than it used to be.

 

[Dustydog]

g

I'm fascinated by all these comments. I'm trying to imagine 18000psi.Mind blowing!

Anyway earlier you talked about LPG.

I still want to know how that will help me?

What vehicle can I buy capable of towing my 1700kgs TA and in all respects similar in overall reliability, performance and economy as my Sorento 2.5cdi? Obviously price new has to be around the

 

[DavidW1]

Dustydog,

Yes I agree 18000 psi is mindblowing and so are turbo oil seals failing and allowing the engines lubricating oil to become fuel and thus the engine to run uncontrollably and sieze up dramatically. Known by some as the engine lunching it's oil.

Dodgy EGR valves have been mentioned but as well as their recycling and "green" effect they are also there to allow cooling of the combustion gasses in the mid power range - when they stick they can allow much hotter exhaust temperatures through the turbo, slap bang in the range that is most used by us tuggers and slap bang is what the poor old turbo eventually does!

For me buying a used modern diesel is therefore a no no, in fact I would rather have the cane Sir.

On your LPG point - you are right there are no manufacturers other than posibly Volvo, Ford and Vauxhaul who will supply a new LPG vehicle. However if you consider nearly new there are numerous examples out there, via specialists, iether already converted or with the option to covert within the purchase price.

Google in LPG vehicles for sale if you are really interested, you may be quite suprised.

The only reason I have not gone that route on my current car is that it has fuel cooled injectors which do not lend themselves to running with LPG

 

[Dustydog]

David

Thanks for that . In truth for me to change from diesel is totally impractical. We spend a lot of time in Scotland and on the Islands.

As far as I can see there are only two LPG stations , Ullapool and Wick. Nothing on the Isles of Lewis or Harris. Seems to me if you live in a big city youi may be ok. Then we have Gordy Brunes next tax hit, yes you guessed it LPG. That's exactly what happened to diesel. As soon as too many of us jumped on the bandwagon up went the tax.

Hand on my heart I've looked at Google for LPG and there is nothing that will do what my Sorie does, well as far as I am concerned. What vehicle would you suggest?

I'm no technician but is there any reason why supercharged diesels arern't out there like petrol?

Cheers

Dustydog

 

[g_374369443]

Dustrydog.. Read here if you wish....http://en.wikipedia.org/wiki/Common_rail.

Commonrail, for cars, something that FIAT led the way on before selling the rights to Bosch.

It not entirely new, as trucks had a similar system previously, but certainly no where nears as advanced..

 

[xtrailman]

dustydog

I understand the supercarger is used to improve low down pull, some cars have a supercharger and a turbo.

If you go the LPG route you will lose boot space, or diesel tank capacity.

So really the way i see it, you have to buy a car larger than you actually need to get the same boot space. If boot space isn't a issue then no problem, except perhaps when you need specialised LPG servicing?

 

[g_374369443]

Dustrydog.. Indeed all things considered, I don't think an lpg run car is for you [me neither at the moment] but its nice to know all the options.

Diesel power is of course the better choice if merely because the maths still favour it, better MPG lower road tax ect ect.

The point was to show their is indeed a choice, be it diesel petrol or an LPG conversion on a petrol car.And as times change so do the varying practicalities of the options change too, and of course also whether you are buying new or old, they all change the equations, as does the size of caravan you intend to tow, or how you visualise what are the priorities you place on the car in question.

I mean today, LPG systems seem as reliable as either the petrol or diesel option, even boot space does not have to suffer,as the tank can be mounted in the spare wheel housing or even flung underneath, depending on the vehicle.But its not much of an option if the nearest lpg station is a 100 miles away.

The very fact you have considered all options means the chance are you will make a fine choice, unlike me who rushed in!

 

[Dustydog]

Dustrydog.. Indeed all things considered, I don't think an lpg run car is for you [me neither at the moment] but its nice to know all the options.

Diesel power is of course the better choice if merely because the maths still favour it, better MPG lower road tax ect ect.

The point was to show their is indeed a choice, be it diesel petrol or an LPG conversion on a petrol car.And as times change so do the varying practicalities of the options change too, and of course also whether you are buying new or old, they all change the equations, as does the size of caravan you intend to tow, or how you visualise what are the priorities you place on the car in question.

I mean today, LPG systems seem as reliable as either the petrol or diesel option, even boot space does not have to suffer,as the tank can be mounted in the spare wheel housing or even flung underneath, depending on the vehicle.But its not much of an option if the nearest lpg station is a 100 miles away.

The very fact you have considered all options means the chance are you will make a fine choice, unlike me who rushed in!

Thanks for that g

I suspect whatever is better today will be more heavily taxed by Gordies government tomorrow.

Cheers mate

Dustydog

 

[seth1]

g,

sorry to differ with your post,but even adding a zero on, is still duff information,common rail actually runs at a max pressure of 1800bar but only on torque demand,most of the time it hovers around 900bar,not to be confused with psi.But i expect to be corrected on this.As for water destroying turbos and EGR valves that is laughable,i would expect you,d have heard of low sulphar fuel,to combat "soot"deposites.i would sugest instead of reading information of the net, try getting hands on experiance,or better still stick to what you do for a living as from what you,ve stated you quite clearly havnt kept up to speed with the modern Diesel.

The facts ive stated are not dreamt up,as these items are addressed to every day of my working week.As said none of this is benifical to the original poster.

 

[xtrailman]

1 bar = 14.5037744 psi

 

[seth1]

That is correct Ray,earlier in this thread emmissions was brought up.today ive found a direct comparison,the following is not my words but Fleet news.

extract one,-

Fiat 500 1.4 petrol turbo charged,-155g/km of CO2.

Citreon c2 1.4 hdi -119g/km of CO2(this is not NOX gases)

extract two-,"a properly tuned Diesel engine(not remapped) gives drivers more miles in the tank and erodes the price differential that Diesel drivers are suffering from.

Fact.

 

[g_374369443]

I am not going to turn this into an argument seth, and no doubt you have had a week to do some studying, and good for you.

And yet again you are trying to mislead people, I said vapour!and all engines have breathers fitted for this, and indeed water will be present in that vapour, as will oil. so stop trying to mis lead yet again.

You made the statement concerning "nox" and diesel apparent lower "nox" rating, now that you have done your home work and have found it to be incorrect,[as I stated] you have decided to go with CO2.

God that was difficult, everybody knows that, said it before C02 is mirrored by MPG ! The better the average MPG, the lower the CO2 !

What is clear is that last week, you really didn't know that much,after all you are now correcting me again on common rail pressure! I stated it ran at 1800 psi, thought I had missed a nought off, clearly not, should have been bar! But Its not something you knew otherwise you would have said so at the time!

I can only assume you thought it was less, as commonly believed,otherwise why did you not correct me when I said 1800 psi, by say "bar" actually!You didn't cuzz you didn't know, hell you also went on to compare lorry injection systems with VW PD system! When actually its common rail that mirrors the HGV system best. Again had you had known this, then you wouldn't have made the comparison with the PD, when the common rail system more closely related!

Tell you what, get hold of professional motor mechanics, or similar, better still carry on goggling any big diesel car forum, Vw, or MPV they are big sites.and learn something useful!

The amount of turbo related problem due to soot build up is 50 times more common than the old inter cooler going!When talking about diesels!

Hell diesel car mag mentioned it almost a decade ago, there concerns at the amount of sludge in the inlet tract!and the harm it could do!

And after that twall HGV sites, Not the same problem there, as HGVs use there full rev range, which keeps soot build up down.

 

[g_374369443]

Seth wrote. 08:57 PM That is correct Ray,earlier in this thread emmissions was brought up.today ive found a direct comparison,the following is not my words but Fleet news.

extract one,-

Fiat 500 1.4 petrol turbo charged,-155g/km of CO2.

Citreon c2 1.4 hdi -119g/km of CO2(this is not NOX gases)

extract two-,"a properly tuned Diesel engine(not remapped) gives drivers more miles in the tank and erodes the price differential that Diesel drivers are suffering from.

Fact.

WOW...! I glad to know that,,,,Hang on, did i not say something similar in this thread? you know at 10% dear its getting close, but if diesel became 20% dearer the balance would start to sway?!!!!!!!!!!!!!!

 

[g_374369443]

Except my humble apology Seth, just found the S max thread, so it would seem you do know a little about the common rail workings, although only as it applies to HGVs, as I found one of your answers to Garfield.

Like this one.

"Hello Garfeld,with respect mate,there will always be one problem car but the main problem you,ve got is not the car,but finding a decent service centre to repair it.

Although the flywheel was well worn this must,nt be the problem,and neither is the egr,which i presume the dealer will stand.surly this cannot be that hard to elliminate."

Found the thread as Garfield has just returned from a long trip, car running fine again.

So I thought I would point this out to you, although in a later post, it appear you reasoned out that a worn DMF could indeed through the timing out, you seem to have disregarded the ERG valve! You know the one full of soot after 37k!

Yes indeed a partially opened ERG valve can make starting a problem, it supposed to be shut, and can make a car tick over erratic or stall or simply hard to start........

Might I remind you, of your certainty that it was the injection system,and indeed the dealer came in for some stick too.

What I find funny is on that thread you slated the common rail system, no doubt for being problematic,and on this thread where longevity costs are concerned, and me telling of the pitfalls that modern diesel cars can have, in later life to make them a more costlier alternative to the petrol engine.

Indeed you defended the common rail system on this thread blaming

things such as poorly fitted filters and not being bleed! Which is totally different to your reply on the other thread!

I can also understand why you know nothing about soot issues in cars, concerning ERG valves and sticking turbo vanes, simply because you work on lorries, and I have repeatedly stated how and why they have different results!

You are welcome to have the last word on our exchange of views, but I stick by the fact that diesel cars have lost a great deal of the advantage they once held in longevity reliability and cost issues. Any one buying one with 100k on the clock can end up with some huge bills,more than the equivalent petrol car. even if they have a full service history.

regards G

 

[Dustydog]

g & Seth

Can I pick your brains please?

Why do some diesels have spill pipes and what is it they do?

Are DMFs specific to diesels only.

I've towed with both fuels and at the end of the day I think it's down to what I can afford, what does the job best for me and of course old Gordys ever changing fuel duty laws.

Cheers

Dustydog

 

[Garfield]

When it's running, the 2.0tdci engine in our S-max is a fine thing that outperforms the 2.0 petrol non turbo which has similar max bhp due to something the engineers/ mathematicians among us know as the "area under the curve" in other words this Turbo diesel produces more average power through the rev range than the petrol. However the potential repair bills for the modern turbo diesel are horrendous.

I prefer a car that is reliable to one that has lots of "toys" and would sacrifice some fuel efficiency for better reliability and lower repair bills. Governments are utterly blind in pursuing fuel efficiency as a counter to global warming, as a result, manufacturers are producing less reliable / durable cars that get scrapped before their time because the technology used is too expensive to repair. the slightly dirtier exhausts and lower fuel efficiency of keeping an older car on the road has negligible effects on the environment compared to the effects of scrapping and building cars.

I bet my old 1989 golf GTI is still on the road, more reliable and far cheaper to run and repair than any new car.

 

[ProfJohnL]

G and Seth,

This thread is degenerating and has come very close to being personally abusive. It has lost virtually all relevance to the OP, and it is not the place to be scoring points.

Please stop now.

 

[Guest]

Its all down to what you can afford to buy and then run on a daily basis really

Our tow car is a 2003 Vectra 3.2 V6 with 200+bhp and 200+lb per foot of torque.We have had it for a year and its used daily. We have covered 18000 in this year towing for about 5000 of those miles. Without the van on the back (Challenger 500 se 1400 kg loaded) it averages 28mpg, and about 20 towing.Its got all the power we need for towing and happily cruises at 70+ on autoroutes in France and easily dealt with the Cevennes and the Pyranees this year.

The point I am making is that whilst the fuel cost is high, the purchase cost of

 

[Guest]

200 or so lbft of torque from a 3.2 litre petrol is pretty paltry compared to smaller diesel engines.

I'm a driver not a technician, my wfe drove diesel whilst I drove petrol in the past and I have now converted to diesel.

What I see here is a load of ====. I don't know any high mileage modern diesel that has the problems mentioned. My wifes BMW's were all fault free and others including my son in-law have done 20000 thousand miles on common rails with no turbo problems.