Fiesta 1.4 diesel tdci MPG

[Heepsy92]

Hi guys. I bought this fiesta last month for a daily run around and mainly for work as I travel a lot for work ranging 300-500 miles a week.

Before I was using a celica tsport which I managed to average 30-33mpg so with buying this fiesta I thought I'd be doubling that mpg however the fiesta doesn't seem to get much more than 49mpg that's over the last 1200 miles. Got a fuel log app that works out mpg and other useful info instead of relying on the in car computer. Now I've not used the AC, haven't used CC and windows open roughly 1cm open for fresh air.

I'd say my driving style is rather decent as I drive my girlfriends pug 206 sometimes and always manage 60+ mpg.

Just wondering if there's anything I can do to improve mpg. Oh and I only used Shell v power.

Thanks

[Ticktock]

I have the 2006 1.4TDCI and I'm manage to get 54 mpg around town with a light bit of hammering. I do get better on longer runs though. 1 thing that did make an improvement was a new air filter when I changed it, it added about 3 / 4 mpg, the old one was caked in filth.

[Heepsy92]

forgot to mention its a 2010.

Ill be giving the car a service soon anyways as it will be hitting 30k miles so hopefully that might help.

[dave_k]

Give a good service, oil, oil filter, air filter, fuel filter, get a few good quality tanks of fuel through it, get rid of any extra weight your lumping around in the boot, adjust tyre pressures to correct settings for 1-3 people in the car (assuming that it is the case), make sure the tracking is ok. calculate using the two click method (google it). report back in a month or two let us know exactly what your getting should be around 55mpg with cautious long haul driving.

[m1tch]

The 1.4 TDCi is the 8v version, the HDi engine in the pug is the more fuel efficient 16v version, I have however modded my car slightly to get better MPG, mine averages mid 60s on the motorway (or slightly higher on flatter motorways and longer drives).

Basically I have found 2 things that make a difference:

1. air filter, swapping out the stock airbox to a cone filter makes a massive difference to throttle response and means that you use less fuel to maintain speed.

2. Injector cleaner - get some diesel purge and run it neat through the system, you WILL notice a marked improvement as it really does clean the system out.

[Heepsy92]

So would it be beneficial for a re-map to improve mpg?

[GaryPL]

Some people report gains in MPG after a remap (although not universally so), but also factor in the cost of a remap and you'll have to do thousands, if not tens of thousands of miles to make back the expense.

Also, some cars don't take too well to them, so you could potentially be looking at increased wear on literally any part of the drive train.

[m1tch]

The remap will give you gains on fuel economy due to the extra power it gives - basically if you have good throttle response and slightly more torque lower down you are able to keep the car rolling with less throttle. I found with the stock airbox the throttle was slightly 'muddy' whereas with my airfilter setup its now crisp, I don't have a remap on mine and its improved it no end on a stock map - seeing high 70/low 80 mpg on the trip computer (working out at mid to high 60s using the brim to brim fueling method).

For me the air filter only added a few £s onto my insurance and didn't cost much at all - its probably already paid for itself, with a more expensive remap its worth it if you are after more power only. Also if you remap for fuel economy then there is a chance the MPG will drop as it would depend on your driving style. The 1.4 TDCi is known to remap well, but is only worth it if you have other supporting mods such as an intercooler (to keep the intake temps down as you wind up the boost).

For me, I would simply give the car a good service, change the air filter over and run injector cleaner through the system and leave it like that. My old car, a Clio 1.5 DCi (80) had more power than my Fiesta and had much better fuel economy (low 80s) - its even got the same KP35 turbo!. The 8v 1.4TDCi just isn't able to get that sort of fuel economy unlike the 16v version. The other option for more power AND economy is the larger 1.6 TDCi but that's a DV6 engine with a HUGE number of issues.

[Mel90]

Hey David,

Which air filter did you use for your car? I was gonna have a full induction kit but having trouble figuring out where to fit it as the engine bay seems really small?

[m1tch]

23 minutes ago, Mel90 said:

Hey David,

Which air filter did you use for your car? I was gonna have a full induction kit but having trouble figuring out where to fit it as the engine bay seems really small?

I got a really generic CAI with cotton air filter, it cost something like £30, I too didn't think it would fit and I actually cobbled together a pipe using other OEM parts to fit onto the 60mm MAF. I did manage to get the generic 3" CAI and filter to fit - it basically looks like the same as the K&N setup, key thing is to try and get the filter to tuck behind the rocker cover at the back (where the EGR pipe is). I do hear the pipe knock every now and then when turning the engine off (I have also blocked the EGR and disabled the doser valve, below is a link to my small project with various changes to the stock airbox to see what the difference was. Key outcome was that the stock airbox is quite restrictive, there were some gains by removing the snorkel from the airbox plus modding it a bit but nothing was as good as a cone filter. 

There isn't anything at the back of the engine unlike some as the exhaust is at the front rather than at the back with the firewall, power and throttle response has improved dramatically vs the stock airbox to the point I am getting the check engine light come on due to the large flow of air through the MAF.

 

[Mel90]

Ok thats brill thanks for your help had a little look at your thread and might go for the green cotton air filter as I just mainly want the car to sound better will look at getting it remapped when the funds allow.

[m1tch]

3 hours ago, Mel90 said:

Ok thats brill thanks for your help had a little look at your thread and might go for the green cotton air filter as I just mainly want the car to sound better will look at getting it remapped when the funds allow.

Just be aware that it won't sound the same as a petrol engine with an induction kit - the 'induction roar' comes from the vacuum the engine generates, a diesel produces no vacuum meaning you don't get the same induction sound. With the cone air filter on mine the engine does sound better, it has a deeper idle noise and you can hear the turbo spool up.

Make sure you also budget in the clutch upgrade as well as the remap as the additional torque will wear the clutch out much faster.

I would suggest blanking the EGR (£2), disable the doser valve (£0) and fit an induction kit (£30 ish), see how that goes, by just changing those bits the who car is much more responsive and it must increase or adjust the fueling for the additional air as the car does feel faster.

If you still feel you need additional power then go with a remap, but to be honest I am actually quite happy with just the air filter - remember to also add in the extra insurance costs, an air filter won't cost much, whereas a remap probably would.

[Mel90]

19 hours ago, m1tch said:

Just be aware that it won't sound the same as a petrol engine with an induction kit - the 'induction roar' comes from the vacuum the engine generates, a diesel produces no vacuum meaning you don't get the same induction sound. With the cone air filter on mine the engine does sound better, it has a deeper idle noise and you can hear the turbo spool up.

Make sure you also budget in the clutch upgrade as well as the remap as the additional torque will wear the clutch out much faster.

I would suggest blanking the EGR (£2), disable the doser valve (£0) and fit an induction kit (£30 ish), see how that goes, by just changing those bits the who car is much more responsive and it must increase or adjust the fueling for the additional air as the car does feel faster.

If you still feel you need additional power then go with a remap, but to be honest I am actually quite happy with just the air filter - remember to also add in the extra insurance costs, an air filter won't cost much, whereas a remap probably would.

Right ok how do you go about blanking the EGR and disabling the doser valve? Have you got a guide on how to do this? I was also told to take the silencer off the exhaust as this may help a little in getting a better sound from the car aswell.

[m1tch]

4 hours ago, Mel90 said:

Right ok how do you go about blanking the EGR and disabling the doser valve? Have you got a guide on how to do this? I was also told to take the silencer off the exhaust as this may help a little in getting a better sound from the car aswell.

THe EGR can be a bit fiddly, I will try and find a guide for you, the doser valve can be disabled by simply unplugging the connector on the side of it - I actually unscrewed the butterfly part of the valve and reinstalled mine. To fit the blanking plate you basically need to loosen off the 2 bolts holding the EGR onto the back of the engine and slip the plate in and retighten, its fairly fiddly - you need to remove the airbox but I think I did mine without needing to remove the fuel filter, did mine mainly by feel.

I have run a few 'debackboxed' diesels before, they would help with spool but will also fail an MOT, the turbo is very very small (KP35), and mine starts to spool at around 1,250rpm so very little is really gained when running a stock map.

[JoJo2222]

M1tch, 

Ive read all your posts regarding the air intake and filter mods. 

Do you have a guide to running diesal purge through the injectors neat?

Also did you ever test the cone filter on the end of the oem air-box with out the panel filter in?

its all been a great read and I hope to copy what you have done.

Thanks

jo

[Mel90]

22 hours ago, m1tch said:

THe EGR can be a bit fiddly, I will try and find a guide for you, the doser valve can be disabled by simply unplugging the connector on the side of it - I actually unscrewed the butterfly part of the valve and reinstalled mine. To fit the blanking plate you basically need to loosen off the 2 bolts holding the EGR onto the back of the engine and slip the plate in and retighten, its fairly fiddly - you need to remove the airbox but I think I did mine without needing to remove the fuel filter, did mine mainly by feel.

I have run a few 'debackboxed' diesels before, they would help with spool but will also fail an MOT, the turbo is very very small (KP35), and mine starts to spool at around 1,250rpm so very little is really gained when running a stock map.

Ok thats brill thanks for all your help have you ever had a front mount intercooler looks awesome I think with the writing on the front might have a look at having one fitted when the pennies allow!

[m1tch]

2 hours ago, Mel90 said:

Ok thats brill thanks for all your help have you ever had a front mount intercooler looks awesome I think with the writing on the front might have a look at having one fitted when the pennies allow!

DON't fit a massive front mount, the turbo is too small, you need much a larger turbo to really need a large front mounted intercooler, they do however look cool. My suggestion would be to simply buy the parts for the 1.6 TDCi which does have an intercooler - I believe they run an upright intercooler next to the radiator. If the intercooler is too large then you will get a lot of turbo lag (as the turbo has to fill the intercooler and pipework before it can even make any boost) - plus there will be a pressure drop across it.

The usual remap doesn't need an intercooler, its only if you are running the tiny turbo at larger (inefficient) boost levels you need to cool the intake charge down, as its a diesel not a petrol it doesn't have the issue with detonation on boost.

You can see in the below photo the pipe I am talking about (although would be fairly easy to mod the OEM pipe):

BTW, check out the OEM Renault Senic intercoolers on the 1.9 - those are quite large metal front mounts but again, don't get a large intercooler, look at some of the smaller intercoolers.

[dave_k]

Also remember that the vehicles in question are 2010 and 2011. Probably mid range mileage that are not really worth a lot on paper so weigh up the economics of spending money on intercoolers/ remaps etc etc and all labour costs and time and hassle involved. The cars are not worth too much especially s trade in so perhaps just better leaving as is and keeping it well serviced and cheap to run.  Sometimes you just have to put up with what you have and save the pennies towards something better next time round.

[m1tch]

2 hours ago, dave_k said:

Also remember that the vehicles in question are 2010 and 2011. Probably mid range mileage that are not really worth a lot on paper so weigh up the economics of spending money on intercoolers/ remaps etc etc and all labour costs and time and hassle involved. The cars are not worth too much especially s trade in so perhaps just better leaving as is and keeping it well serviced and cheap to run.  Sometimes you just have to put up with what you have and save the pennies towards something better next time round.

Mines a 56 plate, I am not going to bother going any further with mine, I am happy with the induction kit as its really pepped the car up in terms of drivabilty and MPG, I have the stock airbox and can return to stock within 5 minutes.