I'm looking for an economical run around for commuting purposes. Slow is ok!

From what I've gathered so far the 1.9 SDI Fabia can give up to 70 mpg on a run and about 50 mpg in general use. Is this right?

What kind of MPG will the 1.4 MPI 8V give?

Thanks all,

Nick

I've no experience of the 1.4 but you won't get near the sdi's mpg.

I think the 1.4 MPI 8v is good for about 40 mpg in the real world.

The 1.9 SDI has exactly the same book combined figure as a 1.9 TDI PD100......57 mpg. And if you drive a PD100 at the same pace as an SDI you'll get low 60's mpg without too much trouble.

But then with the SDI there is no turbo to fail and no DMF problems......and you can run it on pure vegetable oil, which lowers the fuel bill considerably.

Edited 13 March, 201313 yr by booke23

The old 1.4 MPI I had, I would get around 40mpg, but my brother in law seems to get between 40 to 45mpg, but he has a different style of driving.

I own a 1.4MPI and usually get around 40MPG, it costs between £45-50 to brim and lasts me around the 300 mile mark.

You'll work hard to get below 70 with an SDI on the open road. Even in town it hardly dips. The SDI isn't actually slow - it will cruise at over 70 all day long up hill down dale. The thing is that it isn't quick to get to that speed; moving into a fast traffic scheme on a roundabout takes practice - on the other hand it is impossible to stall.

You can't compare running costs on a petrol and diesel using mpg, it's like comparing how many liters of beer you can drink before passing out compared to how many liters of vodka and trying to decide which is cheaper based on volume consumed, it doesn't work.

Work out how many miles you do per year, then work out the cost per mile for each using the current fuel prices and mpg figures provided (I get 41mpg over the last 20k on a 1.4 mpi if it helps), factor in the timing belt/pump every 4 years/60k, mpi is 120k for the chain, allow for more frequent tyre/brake changes (diesel is front heavy), service costs (oil can be more expensive for a diesel), VED and insurance.

Previously when I did this the difference was something like 2-3p per mile on fuel only, that's £20-£30 per thousand miles based on my mpi vs TDI and SDI (I'll dig up the old thread when I get home). If you do do 10k a year then that's £2-300 less the 1/4 of the timing belt/pump cost would leave £100-200, on a TDI you have a turbo/DMF/Clutch to consider and it'd be wise to allow something for that, on an SDI/mpi the clutch is a lot less stressed so it should last a lot longer, you also have an SMF and no turbo.

My point being if you aren't doing a minimum of 15k a year you are unlikely to save much with a TDI, you stand a better chance with an SDI. Before you jump on the SDI though, calculate the loss on selling what you have now and any extra you need to pay for an SDI including any interest costs, if it's say £500 (quite a small amount) you are going to have to do a lot of trouble free miles to be able to make that back before you get anywhere near to saving anything and each of those miles is costing you so it's not just 25k. Pretty soon you have two tyres to add to that figure and are half way towards a timing belt/pump.

The thing I took away from the exercise is no matter what you choose you can expect to pay very similar amounts, if 3 identical cars were on offer at the same spec/price I'd choose the SDI.

Get the sdi. No contest

Based on what you're looking for I think SDI would have to be the way to go. Based on around 3 to 4 years of running our 1.4 mpi 8v, as a guide I'd say ours returned around mid 30's for more urban'y type driving & mid to late 40's for a longer steady motorway run.

A good indication of mpg in my fuelly signature.

Although I broadly agree with calculating cost per mile, there are a number of factors which complicate the issue.

If you buy a 1.4 MPI with 80,000 miles on it and do 10,000 miles a year, you'll have to replace the chain in 4 years.......so factor 1/4 the cost of that in your annual running costs.....and I'd wager it costs more than a cam belt change. VED for the MPI is £195 per year vs £120 per year on the SDI (and the TDI). Insurance must be much of a muchness on either car.

As for tyres/brakes wearing out quicker on the diesel......maybe, but I think that is much more down to driving habits.

As for the extra cost of buying the car you choose....MPI or SDI, it depends on what you have at the moment. If your car is old and costly to run because it is old, then you are going to have to replace it anyway. So perhaps this issue may not be a factor at all.

As I say.....sometimes the situation is complicated!

Join the SDI club. The mpg is vastly superior. I've had one for 8 years, it's still on its original exhaust after 147000 miles and there has been minimal repair costs. I use 50.50 sunflower oil in winter, anything over 75% in summer which keeps the fuel costs down though there is a small economy penalty using sunflower or veg oil. The only thing is that the SDI is slow to warm up fully whereas the petrol will warm up faster, I use a fan heater in the car for defrosting which warms it up enough inside until some heat comes through.

MPI short journeys. SDI longer journeys.

For SDI turn on the air con to help clear the windscreen and wear a coat and gloves

MPI short journeys. SDI longer journeys.

For SDI turn on the air con to help clear the windscreen and wear a coat and gloves

Air con-something missing from my classic. The coat,hat and heated pad for the seat are obligatory.

I want an SDI engine in my next van after having one

in one of my old Fabias. Great engine.

check out the feully website. It has real calculated figures for almost any car.

Although I broadly agree with calculating cost per mile, there are a number of factors which complicate the issue.

If you buy a 1.4 MPI with 80,000 miles on it and do 10,000 miles a year, you'll have to replace the chain in 4 years.......so factor 1/4 the cost of that in your annual running costs.....and I'd wager it costs more than a cam belt change. VED for the MPI is £195 per year vs £120 per year on the SDI (and the TDI). Insurance must be much of a muchness on either car.

As for tyres/brakes wearing out quicker on the diesel......maybe, but I think that is much more down to driving habits.

As for the extra cost of buying the car you choose....MPI or SDI, it depends on what you have at the moment. If your car is old and costly to run because it is old, then you are going to have to replace it anyway. So perhaps this issue may not be a factor at all.

As I say.....sometimes the situation is complicated!

What happens if you buy an mpi with 21k on the clock? That's what I did. Either way lets go with your figures

Mpi genuine timing chain kit is about £35 but requires more labour to fit, a genuine Gates/Skoda inc pump is about £100 more, you're looking at the best part of £400 from a dealer for a diesel (it makes the maths simple), assume the extra hundred covers the additional labour for the chain and book them at about the same. Using your 10k a year intervals you hit 4 years and have to do it again, you loose 20k's worth of potential savings, that cost comes out at £100 a year or 1p a mile which is 50%-33% of the fuel saving you make in a diesel. So lets use your car example for both options, you need to do that belt at 120/160/200/240 for a diesel, the mpi is done at 120/240. That's a bill of £400 for the mpi to do 120k and a bill of £1200 for a diesel, using the 2-3p saving figure from a previous thread that's 40k of use to break even at 2p or 26.7k at 3p but as you point out it's not that simple. You could however save £1600 - 2,800 over 12 years, that's between £133.33 and £233.33 per year but here's why you won't.

Firstly I don't know how long you've been driving or keeping track of fuel prices but 30 years ago petrol and diesel were about the same price and you had a few pumps at the petrol station that pumped diesel, that gap has got bigger because demand for diesel has grown massively, it's now not in surplus and now pretty much every pump has diesel available, now look at new car registrations, they are massively in favor of diesels because everyone who does 10k thinks a diesel will save them money because of the mpg, as long as demand is high and in this case increasing then the gap will continue to grow, as it does your cost per mile increases and that saving per mile decreases, in theory petrol should decrease as demand falls. Clearly a PD is designed with a minimum of 15k annually (4 year/60k for belt change), this has to tell you something but if not let's look at 10k a year. Obviously I don't know your driving habits but 10k/ 365 /2 comes out at approx 13.5 miles average outward journey and the same back, on a cold day (5c ish) a TDI won't hit coolant temp in that distance, it's also worth remembering that it's after the thermostat hits 90c that the engine actually reaches optimum temp so you won't return optimum mpg. The PD lump is really thermally efficient so you'll want a/c to heat it and clear the windows otherwise you'll be cold for most of your journey. A/C doesn't help fuel economy.

Now about that tyre comment, in theory you're right, driving style does have a direct impact on tyre wear. I'm self employed and as such the cost per mile is all that's important when it comes to a car, i've logged a few hundred thousand miles in VAG diesels, 2 1.9PD's and a 2.0PD along with various other diesels and petrol's, that's not just fuel, it's everything right down to the screen wash. I've used Conti PC, Michelin PS and FS, Toyo T1R's, Vredestein Sportrac's, Pirelli P900/9000's and a load more besides, the PD lump is cast iron, the mpi is alloy, more weight at the same speed requires more braking force to stop, also more front end weight causes tyres and brakes to wear quicker, remember on a FWD car the front wheels are powered, steer and have the majority of the brake force directed to them, admittedly driving style could improve or worsen tyre wear but my personal style is smooth and focused on economy, when it's not I'm on two wheels or in another car. The one thing I can say with confidence is PD's are front heavy, they wear tyres more quickly than a lighter car running the same tyre.

VED difference is £75 a year or 0.0075 pence per mile on 10k usage. Service costs on an mpi for oil/filter are circa £15 non genuine and 60k intervals on plugs that cost £8 a set, air filter, I'd personally not go with anything other than Quantum for a PD and you're looking at 3x the cost for an oil and filter. Personally I do my own service work with the exception of wheel bearings and anything that'll require an engine lift or gearbox drop so I don't have dealer rates on service costs, I seem to remember the Leon costing £200+ last time round but I wasn't paying, in general diesels from any marque do cost more to service from experience when I had cars under warranty.

As to the purchase cost i'm guessing you understand the concept of cost to change? When you realise the depreciation and the true cost to change then work out how many trouble free miles you need to do to recoup that loss it's often not financially viable to change, this is why figures like mpg and VED are used to tempt people to buy cars, they're not indicative of the true cost per mile and true cost of ownership yet people buy based on them and don't see the level of savings they think, they just spend the money in a different way.

Insurance wise I went from paying £286 for a highly modified (+50% remap, induction, custom interior, a few grands worth of interior retrofits/custom stuff, suspension, intercooler, exhaust system etc.) inc an SP30 to paying almost £500 for a 1.4mpi. An SDI was from memory about £50 more, a TDI significantly more but not as much as the Leon. Admittedly this included a non fault write off of a parked car and the theft of a 1k hard top on the Roadster (again non fault) but the difference in both more than justified the VED.

Like you say it's not clear cut but with a petrol you pay less up front usually, less to fill it and it costs you less to maintain it, each mile in fuel terms only does cost more. With a diesel due to the demand you pay over the odds, more to maintain and insure it and those belt changes are a large hit in one go. For such low mileage and given the choice I'd suggest a small petrol over a diesel every time. Given the choice between both cars at identical mileage/condition/price I'd probably go with an SDI for my usage (2k+ a month) but for 10k the mpi is easier to work on and while slightly more expensive per mile on fuel it holds it's own in other areas making it closer to my previous diesels than I would have thought at the time. I can't directly compare as fuel prices have increased year on year.

Firstly I don't know how long you've been driving or keeping track of fuel prices but 30 years ago petrol and diesel were about the same price and you had a few pumps at the petrol station that pumped diesel

Unfortunately I'm old enough to remember when Diesel was cheaper than Petrol, and was also priced by the gallon! I remember the day sometime in the late 80's that petrol hit the shocking price of £2 a gallon (43p/litre), although I wasn't old enough to drive then.

Like you say it's not clear cut but with a petrol you pay less up front usually, less to fill it and it costs you less to maintain it, each mile in fuel terms only does cost more. With a diesel due to the demand you pay over the odds, more to maintain and insure it and those belt changes are a large hit in one go.

I don't disagree with you.....It's just the calculation has to be applied to the individual.

For instance in my circumstance my Fabia TDI will cover about 10,000 miles per year.........however I almost exclusively use it to commute to work....40 mile round trip....so the majority of the mileage is done with the engine hot.....my average calculated MPG over the last 6 months is 61 mpg. So potentially I spend about £500 less on fuel per year than if I had an MPI doing 40 mpg. I do my own cambelt changes, so the cost every 4 years is just over £100.

Of course if someone was doing 10,000 miles a year in short trips, I'd probably advise a small petrol for the reasons you mention.......as I say, it has to be an individual calculation.