Petrol Or Diesel.... What's Better?

[coconutmonkey]

HI,

Still in the process of buying a new car with no luck yet.....

What's better in the long run.... desiel...... or petrol..............

Thinking about economy,reliability, etc. And about the future of fuel prices..... even with LPG or NGV

Mostly driving in BKK though some long distance trips throughout the year.

Thinking of D-Max, Mu-7, Wish, or any other spacious car for family and transporting some equipment

Really lost as to find the best car; they're all about the same price......

Any comments welcome and cheers in advance

[BigSnake]

HI,

Still in the process of buying a new car with no luck yet.....

What's better in the long run.... desiel...... or petrol..............

Thinking about economy,reliability, etc. And about the future of fuel prices..... even with LPG or NGV

Mostly driving in BKK though some long distance trips throughout the year.

Thinking of D-Max, Mu-7, Wish, or any other spacious car for family and transporting some equipment

Really lost as to find the best car; they're all about the same price......

Any comments welcome and cheers in advance

For my baht I will stick to B5 Diesel, cheaper fairly clean, fairly good milages to the litrs, don't care for the LPG or NGV, I for one I have some safety Issues with these two.

[BSJ]

Today's diesel engined vehicle is as good or better than many petrol vehicles. For reasonable performance tick the box for the turbo option. But if your just tootling around your estate to survey the scenery a non-turbo would suffice.

Service it regular and it will probably outlive you!

[mdechgan]

Before I would have said diesel, but currently the prices of petrol especially gasohol have gone considerable down compared to high speed diesel. I think the prices per kilometer are almost neck to neck. The mileage is also pretty much neck to neck depending on engine size.

Petrol: really high rpms, and great throttle response. Lots of difference between city (poor) and highway (really good) mileage. Also lots of power loss like when going over briges and crossovers, going uphill and the a/c turned on or heavy loads. Lots of mainentance like electrical, tuneups, valves, etc .

Diesel: lots of torque, mileage is pretty much the same city or highway and heavy or light loads. Not much power is lost when going uphill or with a/c turned on. Rpms and throttle response is slow. Compared to a petrol engine it takes forever for a diesel engine to reach 3 - 4,000 rpms. Diesels are also noisier. But the diesel engines have very little maintenance compared to a petrol one. Just fill up and go.

This is comparing my sedan to my pickup. It will vary between models and engine size.

I agree with "bigsnake" to not recommend going NGV or LPG just yet for a petrol. Most cars were not designed to be NGV or LPG fuelled from the factory. So many problems will exist, like space lost and the difficulty of tuning a multi point programmed fuel injection car for LPG or NGV and engine wear. Do not trust those cheapo 30-40,000 conversion shops. The only NGV/LPG car I would recommend is the optra which is warrantied and installed from the dealer for NGV/LPG use. Diesel conversions are more easier to since they mix the diesel with LPG/NGV instead of running pure like petrols.

[coconutmonkey]

Before I would have said diesel, but currently the prices of petrol especially gasohol have gone considerable down compared to high speed diesel. I think the prices per kilometer are almost neck to neck. The mileage is also pretty much neck to neck depending on engine size.

Petrol: really high rpms, and great throttle response. Lots of difference between city (poor) and highway (really good) mileage. Also lots of power loss like when going over briges and crossovers, going uphill and the a/c turned on or heavy loads. Lots of mainentance like electrical, tuneups, valves, etc .

Diesel: lots of torque, mileage is pretty much the same city or highway and heavy or light loads. Not much power is lost when going uphill or with a/c turned on. Rpms and throttle response is slow. Compared to a petrol engine it takes forever for a diesel engine to reach 3 - 4,000 rpms. Diesels are also noisier. But the diesel engines have very little maintenance compared to a petrol one. Just fill up and go.

This is comparing my sedan to my pickup. It will vary between models and engine size.

I agree with "bigsnake" to not recommend going NGV or LPG just yet for a petrol. Most cars were not designed to be NGV or LPG fuelled from the factory. So many problems will exist, like space lost and the difficulty of tuning a multi point programmed fuel injection car for LPG or NGV and engine wear. Do not trust those cheapo 30-40,000 conversion shops. The only NGV/LPG car I would recommend is the optra which is warrantied and installed from the dealer for NGV/LPG use. Diesel conversions are more easier to since they mix the diesel with LPG/NGV instead of running pure like petrols.

Wow, great response.... if you don't mind me asking, woud you go for an Isuzu MU-7 or a toyota wish?

[culicine]

I own a honda civic 2.0, and get about 10km/l on 91 gasohol. Compare that to a new ford focus turbo diesel (easily chipped for more power), and it can return 17km/l ( could be up to 23km/l on the freeway). Performance between them would be roughly similar, though I'm led to believe the focus' big torque gives it great thout the gears acceleration. I know you were eferring to larger vehicles/pickups, but that's my take on those two sedans. Also the focus sedan how has a six speed auto which actually records better 0-100 times than the 6 speed manual version (tested in Malaysia).

[Jareddiving]

I dont understand the part where Mdechgan says it takes forever for a diesel to reach 3000/4000 rpms..

Because my diesel accelerates faster then the same car with petrol engine and the diesel is making less rpms.

[angiud]

I'm so happy with my Isuzu MU7 3000 TD!

(average 12 Km/lt)

[bino]

woud you go for an Isuzu MU-7 or a toyota wish?

No diesel option for the Wish... 2.0 liter petrol engine only.

[mdechgan]

Wow, great response.... if you don't mind me asking, woud you go for an Isuzu MU-7 or a toyota wish?

Different cars for different purposes.

I own a D-Max, but I really am looking for a Wish for BKK driving. I plan to buy a Wish soon. Its more of a family car and easier for my wife to drive on the streets of BKK.

[mdechgan]

I dont understand the part where Mdechgan says it takes forever for a diesel to reach 3000/4000 rpms..

Because my diesel accelerates faster then the same car with petrol engine and the diesel is making less rpms.

On pickups. Most diesel engines redline at 4,000rpm. On the highway at speed accelerate from from 3,000 - 4,000 rpm. Takes a long time. Compared to a high performance honda per se. It just means the throttle response is better for petrols. With exception if the the car is under powered. Diesels are designed to be stroker engine optimized for torque not RPMS. Thsi is my experience with diesel pickups not the ford focus diesels, etc.

[Lantern]

My 27 year old Diesel Toyota has been the most reliable vehicle I have ever owned. Had it for seven years now.

[Searcher25]

HI,

Still in the process of buying a new car with no luck yet.....

What's better in the long run.... desiel...... or petrol..............

Thinking about economy,reliability, etc. And about the future of fuel prices..... even with LPG or NGV

Mostly driving in BKK though some long distance trips throughout the year.

Thinking of D-Max, Mu-7, Wish, or any other spacious car for family and transporting some equipment

Really lost as to find the best car; they're all about the same price......

Any comments welcome and cheers in advance

My 2 baht:

I know many will disagree, but the truth is that diesel engines are not suited for idling long periods of time. "Blowback": unburnt diesel fuel seeping and/or clogging the engine is a typical symptom of a diesel engine that has had to idle too much . Diesels like to run at 80-90% of available power. If you were living up-country with lots of highway miles to run, a diesel is THE choice. They are brilliant engines when you need alot of torque and/or can run them at their 80-90% potential for most of the time.

See following link:

http://busbuilding.com/bus-conversion/dies...detroit-diesel/

For Bangkok driving, I would recommend a petrol engine. Much, much more forgiving when you must idle - BKK traffic. Not only on the engine but on you and your passengers in terms of noise and vibration.

By the way, I chose the petrol Fortuner over the Diesel Fortuner simply because my driving profile closely matches yours. If I were living up-country, I would of chosen the diesel model. And yes, I have driven both models (about a week a piece in city and up-country driving) before making my choice.

A further piece of, unasked, advice, if you want reliability over the long-term stick with Toyota or Honda. Let Izuzu/Mitsubishi/Nissan sell to those who have not done their homework.

[nakhonsi sean]

HI,

Still in the process of buying a new car with no luck yet.....

What's better in the long run.... desiel...... or petrol..............

Thinking about economy,reliability, etc. And about the future of fuel prices..... even with LPG or NGV

Mostly driving in BKK though some long distance trips throughout the year.

Thinking of D-Max, Mu-7, Wish, or any other spacious car for family and transporting some equipment

Really lost as to find the best car; they're all about the same price......

Any comments welcome and cheers in advance

My 2 baht:

I know many will disagree, but the truth is that diesel engines are not suited for idling long periods of time. "Blowback": unburnt diesel fuel seeping and/or clogging the engine is a typical symptom of a diesel engine that has had to idle too much . Diesels like to run at 80-90% of available power. If you were living up-country with lots of highway miles to run, a diesel is THE choice. They are brilliant engines when you need alot of torque and/or can run them at their 80-90% potential for most of the time.

See following link:

http://busbuilding.com/bus-conversion/dies...detroit-diesel/

For Bangkok driving, I would recommend a petrol engine. Much, much more forgiving when you must idle - BKK traffic. Not only on the engine but on you and your passengers in terms of noise and vibration.

By the way, I chose the petrol Fortuner over the Diesel Fortuner simply because my driving profile closely matches yours. If I were living up-country, I would of chosen the diesel model. And yes, I have driven both models (about a week a piece in city and up-country driving) before making my choice.

A further piece of, unasked, advice, if you want reliability over the long-term stick with Toyota or Honda. Let Izuzu/Mitsubishi/Nissan sell to those who have not done their homework.

Better let all the European taxi drivers know! Sure they will want to switch to petrol when they find out!

My old Mercedes diesel has done almost 800,000 km, mostly in city traffic over the last 32 years and seems none the worse for it. Engine has never been rebuilt and is still going strong! Have a good friend in Amsterdam who drives a taxi. He normally drives his Mercedes taxis until the hit 1 million km. Says the trick is not to switch them off, keep them idling. When he finishes a shift he hires the car out to another driver. Basically his car is running 24 hours!

I think I would disagree on this advice. Diesels, in general, are much nicer to drive in traffic than petrol engined cars, far less cog swapping and much more relaxed. Also significantly more economical. The latest diesels are a world apart from the old bangers and are very refined and gutsy. Been driving a friends Ford Ranger around. The engine and gearbox are brilliant, by far the best of all the pickups. Seriously powerful, smooth and quiet.

[coconutmonkey]

HI,

Still in the process of buying a new car with no luck yet.....

What's better in the long run.... desiel...... or petrol..............

Thinking about economy,reliability, etc. And about the future of fuel prices..... even with LPG or NGV

Mostly driving in BKK though some long distance trips throughout the year.

Thinking of D-Max, Mu-7, Wish, or any other spacious car for family and transporting some equipment

Really lost as to find the best car; they're all about the same price......

Any comments welcome and cheers in advance

My 2 baht:

I know many will disagree, but the truth is that diesel engines are not suited for idling long periods of time. "Blowback": unburnt diesel fuel seeping and/or clogging the engine is a typical symptom of a diesel engine that has had to idle too much . Diesels like to run at 80-90% of available power. If you were living up-country with lots of highway miles to run, a diesel is THE choice. They are brilliant engines when you need alot of torque and/or can run them at their 80-90% potential for most of the time.

See following link:

http://busbuilding.com/bus-conversion/dies...detroit-diesel/

For Bangkok driving, I would recommend a petrol engine. Much, much more forgiving when you must idle - BKK traffic. Not only on the engine but on you and your passengers in terms of noise and vibration.

By the way, I chose the petrol Fortuner over the Diesel Fortuner simply because my driving profile closely matches yours. If I were living up-country, I would of chosen the diesel model. And yes, I have driven both models (about a week a piece in city and up-country driving) before making my choice.

A further piece of, unasked, advice, if you want reliability over the long-term stick with Toyota or Honda. Let Izuzu/Mitsubishi/Nissan sell to those who have not done their homework.

Better let all the European taxi drivers know! Sure they will want to switch to petrol when they find out!

My old Mercedes diesel has done almost 800,000 km, mostly in city traffic over the last 32 years and seems none the worse for it. Engine has never been rebuilt and is still going strong! Have a good friend in Amsterdam who drives a taxi. He normally drives his Mercedes taxis until the hit 1 million km. Says the trick is not to switch them off, keep them idling. When he finishes a shift he hires the car out to another driver. Basically his car is running 24 hours!

I think I would disagree on this advice. Diesels, in general, are much nicer to drive in traffic than petrol engined cars, far less cog swapping and much more relaxed. Also significantly more economical. The latest diesels are a world apart from the old bangers and are very refined and gutsy. Been driving a friends Ford Ranger around. The engine and gearbox are brilliant, by far the best of all the pickups. Seriously powerful, smooth and quiet.

Cheers Guys

Your posts are very thoughtful and thanks for taking the time to respond and help out.

There are so many conflicting views on this.... seems everyone has valid points and one is as good as the other..... any more thoughts very welcome..... please

[Gary A]

The diesel engine has more torque, lasts longer and will give a minimum of 30 percent better efficiency. No contest.

[MeetJohnDoe]

Still in the process of buying a new car with no luck yet.....What's better in the long run.... desiel...... or petrol..............

A "gear-head" friend of mine who does allot of his own work on trucks once told me with petrol, you can count on 150k miles of useful engine life (with regular maintenance) but with a diesel you can get double that or something like 300k. Apparently, something about diesel engines makes them more durable than petrols.

[Plus]

Speaking of taxis - they all run on converted LPG or NGV, and they cover a lot more distance than your average car - there's no reason to doubt their reliability. Many of their LPG installs are really basic, for under 20k. 30-40k buys you proper head injectors. Converting diesel to LPG use cost somewhere over 150k, last year it was available only for Isuzu/Colorado engines.

Newer taxis run on NGV, now Toyota has factory fitted NGV model. GM either didn't see its Optra to taxi fleets, or it wasn't accepted by drivers, have no idea why.

[mdechgan]

Taxis in Bangkok have their engines overhauled every 1.5 -2 years. We use the same machine shop and the owner told me he makes most of his dough from taxi companies because LPG just destroys the engine. You have the see the engine parts when removed. Just horrible damage to everyone engine. The valves burned, corrosion heat damage everywhere, but relatively no carbon deposits. From an engineer mechanic' point of view LPG combustion is different from petrol. LPG has higher temperatures, less lubrication, more toxic corrosion unique to LPG combustion, but fewer carbon deposits. Just look at a burner on a picnic stove. That's how red and corroded the engine is inside. FOr true LPG you have to use special copper lead bearings against corrosion, special high temperature oil for LPG, special injectors, ECU mapping changes, fuel air mixture changes, even special spark plugs. One won't notice the damage until the engine is overhauled. Some shops compensate for LPG by installing a dual system where regular petrol is used solely for starting and acceleration.

I don't have en experience with NGV, all I know is that the lines at NGV stations are really long.

I have seen some diesel LPG conversions and engines that were in really good condition. I think its because diesel/LPG systems mix the LPG and diesel together before combustion (kinda like a mixer tank) instead of pure LPG.

petrol - LPG conversion = definate no no. The machine shop and even the auto mechanic said don't try it unless you want to overhaul the engine often. But engine overhauls in BKK are still cheaper with the fuel savings, that's why taxis use LPG.

NGV = don't know, long lines though and you will barely get 200km per tank

diesel/LPG = I think diesel/ngv/lpg conversions will be the way of the future. Biodiesel sucks.

[Plus]

Some shops compensate for LPG by installing a dual system where regular petrol is used solely for starting and acceleration.

What are you talking about? What dual system?

Every LPG install here can switch between petrol/gas, and most installs won't start cold on LPG.

Mine needs to start and run about 1.5km before LPG system is ready to take over. Cold LPG start for me is simply not possible. Installs with cold start usually include extra oil injector to add to LPG, there are pretty much standard issue.

Engine overhauls here are generally not recommended because it's cheaper to put a new second hand engine instead. I have no idea how taxis can afford overhauls every 1.5-2 years. Maybe it's replacing a few selected parts. The shop where I did my conversion services all of its installs and I've never heard them saying anything about overhaul, never seen them doing it, and there are plenty of taxis and vans there, too.

I have never seen diesel+LPG conversion here personally and I inquired at several shops - it's not done, except for fitting Colorado NGV system on Colorado/Isuzu trucks. Diesel owners usually go for engine swap and then LPG conversion.

Things might have changed in the past year but I haven't heard anything personally.

>>>

On the topic of diesels slow trottle response - one thing you CANNOT say about latest pickups is that they have slow acceleration. Something like Fortuner can easily pull away from any petrol car from 140km/h. I guess the trick is in swtiching gears earlier, and so acceleration slows down only in the last gear, which would be over 160km/h, from practical observation. Ford Focus has six gears to go through, I guess it would never run out of breath up to 180, and that's when 2l Civic should have an advantage.

Regular cars with 1.5-1.6l displacement are very sluggish over 140km/h comparing to current diesel trucks.

[mdechgan]

Overhauls for a neo or altis cost about 10k+. Taxis can afford them because most taxi companies have their own mechanics and supplier deals with parts and machine shops. Maybe 2 days max. This company I know has a fleet of almost 200 cars. Yes they can afford it.

There are many types of LPG installs from cheap to professional. Just beware of the cheap ones.

As for diesel LPG conversion they are all over the place. My co worker just installed one on his older pickup (strada)and its really efficient. The car is currently making runs from Patttya to BKK everyday. He saved a bundle on fuel bills. However I don't think there is a system for the newer commonrail diesels.

One can't compare a 3.0 turbo diesel with a honda jazz. But if you compare an isuzu with a 3.0 V6 accord.

Even if you compare a 2.5 dmax with a 2.4 liter accord the accord still wins.

[Brigante7]

The diesel engine has more torque, lasts longer and will give a minimum of 30 percent better efficiency. No contest.

I agree 100%, I have a diesel Mondeo in the UK, best car I've ever had, fast, smooth, reliable and very economical.

Brigante7.

[Plus]

Overhauls for a neo or altis cost about 10k+.

Sounds more like regular maintanance to me than overhaul, the word itself is scary - proper overhauls cost over 100k.

As for diesel LPG conversion they are all over the place. My co worker just installed one on his older pickup (strada)..

I'm still sceptical - we had a whole thread on old Mitsu conversion here just over a year ago, LPG+diesel was NOT an option then, only engine swap.

[mdechgan]

Overhauls for a neo or altis cost about 10k+.

Sounds more like regular maintanance to me than overhaul, the word itself is scary - proper overhauls cost over 100k.

At the dealer yes. At the local garage or your neighborhood friendly mechanic no. My mechanic only charges me 5-7k (labor) to remove and install a new engine.

[coconutmonkey]

Hi Guys,

Thanks for all the ideas on this topic of fuel choice....

Anyhow, I'm down to a car choice between a Toyota wish 2.0 gasoline, or a fortuner 3.0 desiel. Could even go a fortuner 2.4 gasoline..... hmmm.

Any suggestions about which would last longer (Desiel?), be more reliable (Desiel?), get better resale value (Desiel?), and be cheaper to run on the road over say, a 10 year period (Desiel?)

Cheers

[gobs]

Coconut, you answered already by yourself to your enquiries...

So good luck with your new DIESEL vehicle!

[coconutmonkey]

Coconut, you answered already by yourself to your enquiries...

So good luck with your new DIESEL vehicle!

Cheers

[WinnieTheKhwai]

Hi Guys,

Thanks for all the ideas on this topic of fuel choice....

Anyhow, I'm down to a car choice between a Toyota wish 2.0 gasoline, or a fortuner 3.0 desiel. Could even go a fortuner 2.4 gasoline..... hmmm.

Any suggestions about which would last longer (Desiel?), be more reliable (Desiel?), get better resale value (Desiel?), and be cheaper to run on the road over say, a 10 year period (Desiel?)

Has the Toyota Wish been updated recently or is it still the one based on the old Altis? If it hasn't been updated then I wouldn't go for it; get the Fortuner or wait for an updated Wish.

[coconutmonkey]

Hi Guys,

Thanks for all the ideas on this topic of fuel choice....

Anyhow, I'm down to a car choice between a Toyota wish 2.0 gasoline, or a fortuner 3.0 desiel. Could even go a fortuner 2.4 gasoline..... hmmm.

Any suggestions about which would last longer (Desiel?), be more reliable (Desiel?), get better resale value (Desiel?), and be cheaper to run on the road over say, a 10 year period (Desiel?)

Has the Toyota Wish been updated recently or is it still the one based on the old Altis? If it hasn't been updated then I wouldn't go for it; get the Fortuner or wait for an updated Wish.

Hi Winnie,

There's a new wish 'sport tourer', though it still doesn't have aircon ducts in the back..... and I find Thailand to be hot enough..............

So, here's the news................ NEWS BREAK! After all this procrastination.....

I'm going for the Fortuner, desiel! Yeah, I said it! A bit expensive around Bangkok, but the cheapest fortuner against the only descent wish model, and there's alot of driving around in the price difference.

Thanks everyone for all your good ideas. Cheers guys

[Ahnsahn]

There's a new wish 'sport tourer', though it still doesn't have aircon ducts in the back..... and I find Thailand to be hot enough..............

So, here's the news................ NEWS BREAK! After all this procrastination.....

I'm going for the Fortuner, diesel! Yeah, I said it! A bit expensive around Bangkok, but the cheapest fortuner against the only descent wish model, and there's a lot of driving around in the price difference.

Thanks everyone for all your good ideas. Cheers guys

Cool! I've decided to go for the Isuzu Mu-7 diesel (vs the Fortuna - I'm not in the busy BKK area) http://www.sonirodban.com/mu7.html I'm counting on the longevity of this engine to last for at least 15 - 20 years. Edited June 6, 2009 by Ahnsahn