Are 'SDI's' diesels any good at MPG on motorway? - Now looking at Polo TDI's

Had a Arosa 1.4TDI which was ace but on the motorway it would come under boost at 70mph and start hitting the juice, but still was getting 50mpg+

I'm looking at a 1.9 SDI in a Polo but wasn't sure if it would be getting at least 50mpg at 70mph or if its constantly under load it'll do badly.

Anyone got any experiences using an SDI unit for a motorway hack?

 

It'll get the as near as dammit exact same as a 1.9tdi (all other things being equal, i.e bodyshell, engine condition, weather etc.)

Although it'll be revving higher than the equivalent turbo model, it'll need the exact same bhp to keep it going at a given speed, meaning the ecu is injecting the same amount of diesel, just needs the extra revs for the required air.

 

don't be so sodding tight.

 

youd be having to flog it to maintain normal motorway speeds

buy an s8 and prick some holes in the fuel lines. experience real man's fuel consumption

 

Get a 1.9TDI instead.

My theory was it's a bigger engine normally dragging a lot more weight around, Golf/Passat so stick it in a smaller car (Polo) and it's not thrashing itself all the time just cruising along:

 

Turbo diesels are usually more thermally efficient than NA varients, so I'd expect the TDI to be better on fuel all things being equal (gearing, constant speed etc).

 

NO!

I have driven both a SDI Mk5 and a 1.9 TDI MK5 (106bhp model so the base TDi) and the SDI was soooo slow it was dangerous!! you needed a country mile to pull out of a junction, wonder in to the middle lane of the motorway or heven for bid the fast lane to over take something doing 68mph... good luck! chnaging down to 4th just makes more noise!

yet in the tdi version, I got better economy as it wasnt thrashed, and there was power to over take, and pull out of junctions when needed, unless the car costs 50p run away very fast!

 

Not all of us earn as much as you...

Claypole is your TDI the 100hp variant? How easy is it to achieve such silly MPG?

Speed isn't too important as want to go economical as no point having a fairly quick car when the dual carriage way for pretty much 35 miles doesn't go above 70mph anyway.

Other option was an early mk4 gt tdi 110hp (non-pd) but are these worse on economy than the PD units? I would like a PD but firstly haven't got the funds to spend too much on the car in the first place and secondly whatever car I get is likely to be run into the ground by the time i'm done with it.

 

My gran can run backwards faster than these things can go flat out, if you get one though you'll soon learn how to get the most out of them ie. don't drive into a head wind, don't take passengers, don't have any excess weight in the car (which includes a full tank of fuel), don't go uphill, don't have any equipment on that can drain power and the most important of all never ever try to overtake someone

and that includes pushbikes

 

Mine's the red d and i so I think it is 100bhp?

Plenty fast enough when i was slaving at Ebuyer - 100miles a day on the motorway(s).

If you hammer it everywhere it will normally return about 47ish mpg.

If you take your time and chill out it's high 50's easily.

That 72mpg was on a long run on the M1 etc. dragging behind lorries and caravan's, anything to slipstream and bugger to stonechips.
As near to 56mph as possible.

I just think a bigger engine is better as it's not screaming away all the time at normal motorway speeds.

Just a bit more expensive as there's not as many about compared to the 1.4 ones.

Oh and I bought mine for the same reason, to drive it into the ground and not be bothered at stonechips, dents etc. It's has 110,000 on the clock now.

Had the timing belt and pulleys changed, rear discs and pads, 6 tyres and a set front springs and top mounts (one snapped due to speed bumps down the street) and that's about it for 50,000miles abuse.

 

Smashing advice Driven the same shape 1.2 petrol a few times and enjoy the car for its size and comfort.

Have to look at the market prices but having said that the 1.4's come in at 3,500 with mileage around the 75k but found some 1.9 TDI's coming in at 4,000 in similar spec and condition.

Not bothered about mileage as honestly would rather get a cheaper high mileage as it'll be doing my usual 25,000+ miles a year on the motorway and i do the servicing myself anyway as its simple.

Have you had any issues with the 1.9 TDI engine as wouldn't expect many issues given its a low boost version?

 

If you are so skint that 15 a week on fuel REALLY makes a difference to your life then you really need to look into what's going wrong....

 

ummm he's running two cars - one of which is a mk2 vr6 FFS, so it is sensible to try and get a daily that has low running costs. imo better than being loaded one week and unemployed the next

 

I have an 02 SDi Caddy van as a daily which I have to rag pretty furiously to get going, but no matter how hard I drive it returns a bang on 45mpg (I track my mpg on the piephone).

Im sure the improved cd of a polo and normal tyres, not 215s, would yield 50mpg.

Another advantage is my 9A Jetta feels like a rocketship after the Caddy.

 

dont worry about high miles, if the tds are looked after they will do 200k+ with ease!! its all about vag oil, chnages every 6k / 6 months and being kind to it so letting it run down and not giving it any revs untill warm etc,

I know why your doing it too, I am the same, TDI for the daily doing 46-50mpg all day long and then a fun car for weekends and dry weather. if you can afford to do it it makes sense.

 

remember on top gear, clarkson had a 3cyl diesel fabia and it was rubbish on diesel

 

I have both a 1.7 SDI lupo and a 1.4 TDI lupo.

The SDI is painfully slow... borderline dangerous. Average 55mpg.
The TDI is pleasantly quick and vastly more drivable. Average 65-70mpg (making better progress)

If you stick to 70mph the 1.4 TDIs will do 70mpg. Anything higher and it drops fast though. e.g. 50mpg at 80. Over a 300 mile constant 60mpg following a trailer back from the 'ring we averaged 94mpg in the tdi.

 

Engine's been faultless. Changed the belts as I mentioned and 6 monthly oil changes and that's about all.

Spent a few quid when I bought it as the gearknob and gaitor were all ripped up as I suspect a lady owner (company car) ripping it with her nails.

Only "breakdown" was the engine warning light coming on not long after I got it but that was just a broken switch for the brake light, fixed after some help on here.

My only moan is the matt finish on the steering wheel spokes - it's just paint over a shiny plastic so it scratches off and looks a mess, scratched it all off one day while driving home. Safe driving.

 

If you can find one, get the Polo 1.9TDI with the Red 'D' AND Red 'I'
These are 100bhp, 65mpg, group 6 insurance, and as fast 0-60 as the non-turbo MK4 GTI.


If you drive it hard you'll still get 55mpg too!

 

15 a week? Where did you work that one out professor plum Given half your threads on here are about your life problems I think you can hardly talk about me looking into my own life As for being skint weren't you the one on the Dole??? PMSL!

Last year I did 30,000 miles, which on average I got 30mpg from a tank of fuel from the mk4. At todays prices (110p) that works out 5,145 for the year in petrol.

Doing the same but with 50mpg from a TDI and even accounting the extra 1p for diesel cost that is approx 3,000.

The net saving is 2,145 a year, which divided by 52 weeks equals just over 40 a week...So more than 50mpg will save me more not to mention cheaper tax and my insurance will drop by a lot given the business class and high miles on the mk4 isn't cheap to begin with.

I've had the 1.4 TDI in the Arosa and didn't find that economical really on the motorway as quite rightly said RIP-MK3 they showed on top gear.

Claypole cheers for the input

Might start looking around after the x-mas period to see what comes about as mk4 1.8t prices are really low to begin with and need to see one nearby for a test drive before i start deciding to sell the mk4 as need to consider having access to a car as the mk2 is off the road currently.

As others have said the mk2 vr6 is my weekend toy and would rather through money in fixing that up on the road than going into petrol coming out my own pocket in a car that won't get from A to B quicker than something like a Polo TDI.