Petrol or diesel?

Granty312

Active Member
Oct 7, 2018
73
6
Hey,

Currently driving a seat Leon TFSI, Bluefin chip remap to 240bhp (2005 on 55 plate) and bluefin chip was done by previous owner.

I love the car, but the MPG is a real issue. On a long drive I get about 25mpg 30mpg max doing 62mph with cruise control on. Around my area which isn’t a busy city I get around 17. Would a Diesel Version of this car be much better all around and more beneficial? On a full tank I get about 270miles. Hoping to go diesel if it’s worth the change.

Any information will be very helpful!
 

Pew.

Active Member
Mar 23, 2012
1,451
142
Scotland
Diesels only worth it if your doing a lot of miles, a lot more than the average 10-12k a year.

Diesel is more expensive and to outway the cost Vs mpg, Its 6-10k miles to benefits from the extra per litre according to money saving expert.

Servicing aadiesel is more expensive and insurance is 10-15% higher (according to research by money expert)

That's terrible mpg on your petrol, it should not be that low by any standard and I'd get that looked into if I were you....
 
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Granty312

Active Member
Oct 7, 2018
73
6
Diesels only worth it if your doing a lot of miles, a lot more than the average 10-12k a year.

Diesel is more expensive and to outway the cost Vs mpg, Its 6-10k miles to benefits from the extra per litre so if your going to be doing the same amount of miles as you have been in your petrol, you won't save any money in fuel costs due to higher mpg.

Servicing aadiesel is more expensive and insurance is 10-15% higher (according to research by money expert)

That's terrible mpg on your petrol, it should not be that low by any standard and I'd get that looked into if I were you....

The thing is I’ve done 5000miles in about 3months. I cover a hell of a lot of miles because I enjoy driving. Everyone I know with a diesel seems to benefit a lot from it. My mechanic said this is probably about average for this car? What do you recommend I do to try and improve this?
 

Pew.

Active Member
Mar 23, 2012
1,451
142
Scotland
Your mpg should be in the mid 30's if you aren't driving heavy footed and especially sitting on the motorway with cruise control.

First of all I'd remove the bluefin map and see what mpg you get on the standard car. Assuming of course he gave you the hand held device when you bought the car? If he didn't, are you sure it's a bluefin map?

If it shoots up then you know it's the map, if it remains low then i woukd check out your spark plug, Fuel injectors given the age of the car and make sure your tyre pressures right. It might also be worth replacing a few sensors, not 100% on your engine but typically most sensors are an easy to access and relatively cheap to replace such a the MAF.....
 

Granty312

Active Member
Oct 7, 2018
73
6
It’s definitely a bluefin remap as I have the control at home for it which he gave me with the car. The car also has an induction + dump valve on.

I drove from bath too Scotland with cruise control on motorway and I could get a max of 33mpg whilst driving on cruise control with 62mph. Anything over 70mph and I was down below 30? This seems very bad, would a diesel do much more or not really?

I put in some green stuff on a full tank fill up which helped clear the injectors, which didn’t do a lot. Service history is fully up to date from seat. Does tyre pressure make that much of a difference? Although they are all up to the correct psi.
 

RADIOTWO

Active Member
Mar 6, 2018
488
94
North Derbyshire
It’s definitely a bluefin remap as I have the control at home for it which he gave me with the car. The car also has an induction + dump valve on.

I drove from bath too Scotland with cruise control on motorway and I could get a max of 33mpg whilst driving on cruise control with 62mph. Anything over 70mph and I was down below 30? This seems very bad, would a diesel do much more or not really?

I put in some green stuff on a full tank fill up which helped clear the injectors, which didn’t do a lot. Service history is fully up to date from seat. Does tyre pressure make that much of a difference? Although they are all up to the correct psi.
We have a 2 Lt 184 DSG and get about 45mpg round town and get close to 65 on a run (even at 70mph)
 

Pew.

Active Member
Mar 23, 2012
1,451
142
Scotland
A good diesel would yes previous, my Leon 2.0tdi (mapped) returned 68 driving from Glasgow to Liverpool and back.

If you've done 5k in the last 3months then I could assume you'll do around 20k a year? If so then diesel will be cheaper.

Roughly...
Petrol over 10,000 miles averaging 34mpg will cost £1698 if charged at 127p per litre (what I paid this morning)

Diesel over 10000 miles averaging 48mpg will cost £1267 if charged at 133p per litre (price at the garage near me just now)

The mpg I've used is based on my previous Leon TDI 150 (stage 1 184bhp ish) and my current Leon 1.8 (stage 1 245bhp ish)

The average are also the overall averages from my cars, not just long journeys or short trips, everything.
 

Granty312

Active Member
Oct 7, 2018
73
6
Yeah I do a lot because I end up going places faraway cus I get bored haha. I’ve just taken the remap off and to be perfectly honest, their doesn’t seem too much difference apart from the car is sluggish as hell. I’m definitely thinking off going to a diesel and remapping that so I gain the power and also the fuel economy? Would you say this is a wise idea?
 
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saveoursouls

Active Member
Jul 4, 2018
415
234
36
Manchester
I’ve owned petrol and diesels. I’m getting similar economy from my diesel as I did with my last petrol.

Only my last petrol was a Yaris 1.33 vvti, great little engine but not involving in the slightest.

I’m driving an older diesel a 1.9 TDI PD 105 bhp with plans to remap and it’s returning on average 49 mpg with a mix of motorway and roads. The Yaris returned 45 mpg average whilst being driven on the same routes.

Overall with the higher maintenance costs on the diesel it’s costing me a bit more but then if I wanted the same torque from a petrol....I’d be paying more for the petrol equivalent.

Depends on what you need, I needed / wanted a commuter / family car, something which has a bit of poke and looked sportier than the Toyotas I’ve owned in recent years. That and I like the way the diesel drives with the torque delivery.


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RADIOTWO

Active Member
Mar 6, 2018
488
94
North Derbyshire
I’ve owned petrol and diesels. I’m getting similar economy from my diesel as I did with my last petrol.

Only my last petrol was a Yaris 1.33 vvti, great little engine but not involving in the slightest.

I’m driving an older diesel a 1.9 TDI PD 105 bhp with plans to remap and it’s returning on average 49 mpg with a mix of motorway and roads. The Yaris returned 45 mpg average whilst being driven on the same routes.

Overall with the higher maintenance costs on the diesel it’s costing me a bit more but then if I wanted the same torque from a petrol....I’d be paying more for the petrol equivalent.

Depends on what you need, I needed / wanted a commuter / family car, something which has a bit of poke and looked sportier than the Toyotas I’ve owned in recent years. That and I like the way the diesel drives with the torque delivery.


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How can you say"Overall with the higher maintenance costs on the diesel it’s costing me a bit more but then if I wanted the same torque from a petrol....I’d be paying more for the petrol equivalent."
I have run diesels for many years and I would think its cheaper and not as much to service, all you have is the Oil and Air filter a Fuel filter every so often and you don't have to change spark plugs
 

saveoursouls

Active Member
Jul 4, 2018
415
234
36
Manchester
How can you say"Overall with the higher maintenance costs on the diesel it’s costing me a bit more but then if I wanted the same torque from a petrol....I’d be paying more for the petrol equivalent."
I have run diesels for many years and I would think its cheaper and not as much to service, all you have is the Oil and Air filter a Fuel filter every so often and you don't have to change spark plugs

Carbon build up on components such as EGR, Turbo. Injectors are expensive to replace, clutch wear is quicker due to the torque. You don’t have to change spark plugs but I need to change the glow plugs at a similar cost to spark plugs.

With more recent diesels you have DPF’S to contend with which are an expense and a hassle. Then there’s the higher fuel cost which somewhat negates the higher mileage.



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RADIOTWO

Active Member
Mar 6, 2018
488
94
North Derbyshire
Carbon build up on components such as EGR, Turbo. Injectors are expensive to replace, clutch wear is quicker due to the torque. You don’t have to change spark plugs but I need to change the glow plugs at a similar cost to spark plugs.

With more recent diesels you have DPF’S to contend with which are an expense and a hassle. Then there’s the higher fuel cost which somewhat negates the higher mileage.



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I think you need to rethink, as I have been running diesels for many miles and years and never had to change glow plugs,and never had to replace a clutch in 42 years of driving(admitting I am running a DSG) but like the low end torque, as also have towed many large trailers and caravans
 

saveoursouls

Active Member
Jul 4, 2018
415
234
36
Manchester
I think you need to rethink, as I have been running diesels for many miles and years and never had to change glow plugs,and never had to replace a clutch in 42 years of driving(admitting I am running a DSG) but like the low end torque, as also have towed many large trailers and caravans

That’s not my own experience, guess everyone’s entitled to their own opinion.


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KXL

KXL
Dec 15, 2016
1,581
197
London, UK
Might be a sign of the times....current Cupra 280/290/300s would get 25-30s mpg in city ish urban, highway driving on cruise control @ 62mph, I'm sure they would get high 30s, low 40s mpg. My 3cyl petrol 1.0 TSI (yes...only 110PS), got 57mpg, cruise control ~ 65-70mph with few customary 50mph roadworks zone, 200+ miles Lon to Manchester. Most 1.4 EcoTSI and 1.5 EVOs would perhaps get around the same or slightly lower mpg same journey. The newer petrols can be economical too!
I used to have a 2.0TDI (63 plate) Leon. Compared to my petrol Ibiza, only on highway journeys it's more economical than the petrol, in the city (and 40-50mph roads), the petrol on Ibiza is more economical. My journeys have always been similar in both cars. A similar Lon-manchester journey on the 2.0TDI would get me low 60s mpg. So it depends how many miles you do a year. Most would recommend, less than 10k a year, definately petrol, more than 12k a year definately diesel, 10-12k a year, flip a coin?
If you are cruising up and down dual carriageway and motorways doing 50-70mph, perhaps get a 184 TDI or 150 EcoTsi ACT. Both these engines should get in excess of 500miles a tank, the 184 TDI maybe even 600+. Imagine remapping these two engines...ahh.....if you don't like the rattly diesel, and want more power (or do less miles) then there is only the rare 1.8 TSI or even the Cupras :).

Regarding the DPF, I've had a 2.0TDI previously, did 5k miles a year (yes it was my first car, so didn't read the mileage / and semi aware of DPF issues), I didn't have any issues with DPF, despite doing 80% city (no short journies though), but when I was not in the city, I went 100+ miles at a time on 70mph roads. I did follow the advise to use only diesel from non-supermarket pumps (Shell/Esso/BP) with a 1 in 4 or 5 tank using Shell Vpower Nitro Plus / Esso Ultimate, and I was perfectly fine. If you do go diesel, please fill the first full tank when you get it with Esso or Shell's finest diesel, like descaling a kettle, it would give the engine a good clean!

Oh, just re-read the posts...my 1.0TSI sitting @ 62mph, I would get (on the readout) around 50-55mpg.if flat road..but with the 50mph roadwoks and some downhil and uphill, ended up with 57mpg for the trip. My 2.0 TDI sitting @ 62mph, the readout would be around 62-67mpg if flat road. If @ 70mph, 1.0 petrol would show 48-52mpg, and 2.0TDI would show 57-60mpg if flat road. Cupras might show 42+ mpg @ 62mph and 38+mpg @ 70mph if flat road on instant readouts? Cupra owners might need to confirm this.
 
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saveoursouls

Active Member
Jul 4, 2018
415
234
36
Manchester
Might be a sign of the times....current Cupra 280/290/300s would get 25-30s mpg in city ish urban, highway driving on cruise control @ 62mph, I'm sure they would get high 30s, low 40s mpg. My 3cyl petrol 1.0 TSI (yes...only 110PS), got 57mpg, cruise control ~ 65-70mph with few customary 50mph roadworks zone, 200+ miles Lon to Manchester. Most 1.4 EcoTSI and 1.5 EVOs would perhaps get around the same or slightly lower mpg same journey. The newer petrols can be economical too!
I used to have a 2.0TDI (63 plate) Leon. Compared to my petrol Ibiza, only on highway journeys it's more economical than the petrol, in the city (and 40-50mph roads), the petrol on Ibiza is more economical. My journeys have always been similar in both cars. A similar Lon-manchester journey on the 2.0TDI would get me low 60s mpg. So it depends how many miles you do a year. Most would recommend, less than 10k a year, definately petrol, more than 12k a year definately diesel, 10-12k a year, flip a coin?
If you are cruising up and down dual carriageway and motorways doing 50-70mph, perhaps get a 184 TDI or 150 EcoTsi ACT. Both these engines should get in excess of 500miles a tank, the 184 TDI maybe even 600+. Imagine remapping these two engines...ahh.....if you don't like the rattly diesel, and want more power (or do less miles) then there is only the rare 1.8 TSI or even the Cupras :).

Regarding the DPF, I've had a 2.0TDI previously, did 5k miles a year (yes it was my first car, so didn't read the mileage / and semi aware of DPF issues), I didn't have any issues with DPF, despite doing 80% city (no short journies though), but when I was not in the city, I went 100+ miles at a time on 70mph roads. I did follow the advise to use only diesel from non-supermarket pumps (Shell/Esso/BP) with a 1 in 4 or 5 tank using Shell Vpower Nitro Plus / Esso Ultimate, and I was perfectly fine. If you do go diesel, please fill the first full tank when you get it with Esso or Shell's finest diesel, like descaling a kettle, it would give the engine a good clean!

Oh, just re-read the posts...my 1.0TSI sitting @ 62mph, I would get (on the readout) around 50-55mpg.if flat road..but with the 50mph roadwoks and some downhil and uphill, ended up with 57mpg for the trip. My 2.0 TDI sitting @ 62mph, the readout would be around 62-67mpg if flat road. If @ 70mph, 1.0 petrol would show 48-52mpg, and 2.0TDI would show 57-60mpg if flat road. Cupras might show 42+ mpg @ 62mph and 38+mpg @ 70mph if flat road on instant readouts? Cupra owners might need to confirm this.

Now and again I’ll treat her to some v-power and some fuel additives. I think she needs a good clean of the EGR and Turbo also as it seems the previous owner has done short journeys.

I’m inbetween the 12-13k a year mark making a petrol or a diesel and option, overall the diesels costing me more so far simply on manintenance as it’s older (2007) where as when I’ve had petrol engines they’ve been a bit newer. I think once I’m on top of the maintenance that the Diesel engine will make
some return.
 

KXL

KXL
Dec 15, 2016
1,581
197
London, UK
A good diesel would yes previous, my Leon 2.0tdi (mapped) returned 68 driving from Glasgow to Liverpool and back.


The mpg I've used is based on my previous Leon TDI 150 (stage 1 184bhp ish) and my current Leon 1.8 (stage 1 245bhp ish)

The average are also the overall averages from my cars, not just long journeys or short trips, everything.

I've often wondered what a remaped 2.0 TDI 150PS would return, both power and mpg, now I know :)...assume yours was a manual, hence the much better mpg? Apparently the 2.0TDI 150 DSG returned 4-5 mpg less like for like...compared to a manual
 

phillll

Active Member
Aug 7, 2018
14
16
Wirral
I was in the same boat as can sometimes commute a bit for the day job, went for a Cupra 290.
I see 28mpg quite often on the daily commute around town, and 40+ on the motorway.

I even managed 46mpg on the M6 o_O
 

KXL

KXL
Dec 15, 2016
1,581
197
London, UK
I even managed 46mpg on the M6 o_O

50mph roadworks? Or you were sat behind a large van / SUV / MPV and used the slipstream?
You know, I always tried this (or when a car overtakes on the fast lane and come into my lane after), and looked at the instant mpg at the same time, if I'm within 7-10 meters of a large high vehicle in front, my mpg numbers invariably increase :).
 

phillll

Active Member
Aug 7, 2018
14
16
Wirral
50mph roadworks? Or you were sat behind a large van / SUV / MPV and used the slipstream?
You know, I always tried this (or when a car overtakes on the fast lane and come into my lane after), and looked at the instant mpg at the same time, if I'm within 7-10 meters of a large high vehicle in front, my mpg numbers invariably increase :).

Yeah, 50 limit for some of it!
 
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