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Diesel vs Petrol

3K views 42 replies 14 participants last post by  tim008 
#1 ·
I'm sure there's been plenty of these threads put up over the time. But I wanna ask:

Would a 2.0l TD ZR, be more economical than my 1.4l R25?

And I bet there is a much more complex answer than yes or no.

I do a 30 mile round trip each day which is about 80% A roads @ 50-60mph.
 
#3 ·
Yes, the diesel will be much more economical. The diesel you have allot of torque, you do not need to thrash the diesel unlike the 1.4. I learned to drive in a MG ZR TD and I found it a much more relaxing car to drive, I could change gear at low revs and still have plenty of poke. My 25 1.4 103PS is much slower, I often have to take it to 3500k - 4000k+ to keep up with traffic or get up to speed on a slip road etc. Due to that it does like to drink the fuel, 240 ish miles on 3/4 tank is not brilliant to be honest. If I had the money I would get rid of my car & get a diesel now, the engine is much better I think. The power delivery is better, it revs lower for the same effort and strangely at 70MPH the diesel is quieter I found with no annoying droning/boomy noise like the K series makes. Go for a diesel I say :).
 
#9 ·
I have the same issues going up hills at all, I found in the ZR I could keep it in 4th and still keep a bit of momentum & have quite a bit of boost if I ever rarely dropped down a gear. The diesel is a much harder car to stall, the clutch has more bite I found and it would just pull away with ease. Have a test drive and see what you think.
My missus is going to apply to get PPI back, so.....:bgrin:

I'm not sure whether to get a slightly damaged ZR from a salvage place like copart.
 
#11 ·
My missus is going to apply to get PPI back, so.....:bgrin:

I'm not sure whether to get a slightly damaged ZR from a salvage place like copart.
Go for it, damaged cars can become bargains, I bought mine as a Cat C from a company for £250, spent allot of money on it, but it is low mileage at 51k (now 52k). MG ZR TD prices are not that high to be honest though.
 
#8 ·
The R25 1.4 petrol should achieve high 30s mpg, the diesel driven in a similar fashion will probably return 60+ mpg.

It isn't always quite that simple though as the diesel will require more frequent servicing (for example, MG Rover recommended 12 000 miles between oil changes on the diesel, but 15 000 miles for the petrol).
 
#25 ·
constant speed on the right high speed roads and a diesel will sip fuel, start gunning it or doing a lot of cold starts and it'll suffer quite a bit.

Diesel very much worth it for those with a commute on decent roads, around town though they can lose some of the advantage, lots of stop start etc
 
#30 · (Edited)
on a standard 400 diesel 50mpg is doing okay, imo - it's not good, it's not bad, it's about where i like it

Might sound weird but it makes sense really. It's all about compromises.

When creating callibration for me it's a case of - Emissions - Economy - Performance = Pick 2

Nobody ever goes for emissions :lol:

That said, I like to be realistic - i don't trust book figures but if they were to be trusted 50 would be where most people would be at, probably more if they drive like a gran but for normal usage around 50, so whilst I love to hear reports of people getting 60+mpg I like to be quite conservative in my own opinion, if you drive like the designers expect you to drive and get 60mpg there has to be something wrong cos when the cars were being sold that would have been a right talking point.

Just my two cents, not explicitly disagreeing with anyone here but something to consider.
 
#33 ·
I am only going by the actual figures that have been quoted to me. I have no reason to doubt their accuracy.

If a 25/ZR with an L series diesel really is only capable of mid 40s mpg, that removes any claim that the dervs are cheaper to run - Parkers quote an average of 38mpg for the ZR120 petrol, and with fairly hard driving, I have averaged just over 40mpg (on odometer miles) from my 120 over the 8 years and 90k miles I have had it, which is about the same as the Parkers figure which is based on actual miles.

As I said, I would find a figure of around 50mpg from a 2 litre diesel in the same car deeply disappointing at best.
 
#34 ·
I am only going by the actual figures that have been quoted to me. I have no reason to doubt their accuracy.

If a 25/ZR with an L series diesel really is only capable of mid 40s mpg, that removes any claim that the dervs are cheaper to run - Parkers quote an average of 38mpg for the ZR120 petrol, and with fairly hard driving, I have averaged just over 40mpg (on odometer miles) from my 120 over the 8 years and 90k miles I have had it, which is about the same as the Parkers figure which is based on actual miles.

As I said, I would find a figure of around 50mpg from a 2 litre diesel in the same car deeply disappointing at best.
Some members assume their MPG will be stratospheric with the diesel motors. In reality, unless you do a longer commute the petrol models can actually cost less to run, especially if you factor in the fuel price differential.

The MPG from your 120 is actually very good, i'd actually say it's above the norm from that particular engine.

It's all swings and roundabouts really. There are other advantages with the diesel, their tunability being one of the main attributes that attracted me. One things for sure though, these people that toddle around town in a diesel and do 4,000k per year are subscribing to a false economy...

EDIT: The L series is actually capable of more than "mid 40's", it's just that people rarely achieve this in the real world. Drive at 50-55mph and you'll see the figure climb quite nicely, but there are very few people that will drive in this manner.
 
#38 ·
I'm not saying that a diesel engine is 100% reliable, 100% of the time.

Just the fact that problems are more prevailant with the K, there is much less of a worry/niggle in the back of the mind running the L series, rather than a K series.

Cheers
Dave
 
#41 ·
Back to the OP's original post I have owned a 1.4K-series and would average 35MPG but I did used to put my foot down a lot.
Now I own a SDi which is modified and average 45Mpg and again I do like to put my foot down.

I always prefer a petrol to a diesel but my SDi is way faster than my 1.4, with both engines I had no real issues except general servicing.

If you want to save money get a diesel. I did have a Turbo petrol which was achieving 28MPG, from my experience Parkers figures etc are generally at least 10% off what I have ever managed in my cars.

Pointis you can blast around in a Derv and still get over 40MPG whilst you drive like a grandad in a petrol to achieve similar.
 
#42 ·
This basically, I loved my 1.4, great little car with a pokey engine that you could have some great fun in, but it was useless with any decent weight in it or up hills and to enjoy it properly you needed to give it some beans which drained the mpg but the derv acts like hills don't exist and can pull silly amounts of weight effortlessly whilst being thrown about and still keep its mpg. If you don't mind sounding like a tractor at idle it's a no brainer really...
 
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