have been thinking alot about buying a wee 1.4 tdi polo or lupo, the tax and mpg would be worth it in the long run, what about tunning?

specs?

as tunable as the bigger 1.9 's ?

I think with them 130 or so bhp is the upper limit before things start getting expensive.

thats still pretty nippy though isnt it for a wee 1.4

I'm looking at a 6n2 or lupo, id be chuffed with 120 tbh

^^ you aint going to get 120bhp with the standard turbo tbh, problem is with those is you are quite limited wiith choice because the exhaust turbine cannot be seperated from the manifold as it is cast as one piece..

the unit injectors on the 1.4tdi are capable of well over 140bhp without mods

you have to be carefull just how much you push out of them due to the magnesium alloy engine block flexing under load.. it is worth changing the pistons and rods for pd150 ones if you can get hold of them too. this is all fairly circumstantial anyway i suppose!!

although i must say it's kinda counter-intuitive to mod a eco friendly diesel like that, at the end of the day you need to use fuel to make power, so the economy you gain from a small engine is wasted..

The turbo is separate from the manifold in the 1.4 tdi's, its only cast into the exhaust on the 1.9's. Its a garrett gt1544 and according to garrett is capable of supporting 150bhp max, with max boost of something like 1.2 bar or about 17 psi.

I'd be wary of the clutch or driveshaft as a weakpoint

Edited 25 April, 201016 yr by Mediumr

Its not a technical point unlike the others above but : its a fantastic little engine! Especially chipped in a lupo!

Mm i have a 1.4 tdi 6n2 and am very pleased with it :-) they are nippy standard, they can be re-mapped to approx. 100bhp standard, and with an exhaust and remap your likely to be about 110-115bhp ..ish!

The turbo is separate from the manifold in the 1.4 tdi's

what like this one?? i've got 2 of them sat on the shelf in my garage for my lupo

Edited 25 April, 201016 yr by SkodaBoy

Right...from standard with a custom code remap youl be seeing between 100 - 110 bhp, with a good exhaust system with less restriction and the bore to give the optimum expulsion of exhaust/turbo gasses and a remap you will be seeing 120....believe there was a chap on here who had the said mods and a replacement k&n panel filter and was seeing close on 125 bhp.

The best bit about it is....the higher fuel consumption is only going to come by your own doing by putting your foot down more lol

A remap and exhaust system will actually make the car mroe fuel efficent and you will see an increased mpg.

but tbh 100 - 110 is more than enough from one of these to have abit of fun in....you certainly feel the difference without compromising reliability.

But as with all diesel engines its not about the bhp its about the torque and from this little 1.4 after a remap you will be seein a mountain of torque, with a remap anywhere between 240 - 260 is possible

Edited 25 April, 201016 yr by Monkey-man

A remap and exhaust system will actually make the car mroe fuel efficent and you will see an increased mpg.

no not really, all a remap will do is increase the engines ability to burn up fuel, the cruise/light load is largely unaffected tbh

in my experience, all 'big' exhaust systems do is make it noisy too, you dont gain much

what like this one?? i've got 2 of them sat on the shelf in my garage for my lupo

I stand corrected. There must be variants on them, not all are cast into the manifold:

http://cgi.ebay.co.uk/VW-Polo-Skoda-Fabia-...1-/320519907622

yes there are variants on them, but as far as i know all the AMF engines have a one piece jobby... some of the audi a2 1.4 tdi's have an 80bhp engine which has a different engine code, but off hand i can't remember what it is...

what i did on my old lupo tdi is swap out the impeller and cold-side turbine from a larger GT series vnt turbo.. it's quite tricky to do mind you, you'd be better off visiting a turbo specialist and getting them to do it..

also on the polo/lupo tdi one of the major bottle-necks is the intercooler, they are really poorly designed

A remap doesnt just increase an engines ability to burn fuel.

It also changes the power delivery. Rather than your having 'power peaks' there is a more progressive delivery of power giving smoother acceleration, but it also gives a sharper throttle response. When also having a remap done, the ignition timing is changed to give a more efficient burn, and it is this that has a positive effect on fuel economy. The only time it doesnt is due to the increase in power and torque drivers become heavier with their right foot

As regards to a larger diamater pipe then it deffinately helps the turbo breathe as its releasing the restriction placed on it by the tighter standard bore. But while having a larger bore...there is no point keeping the silencers and cat as this is also placing restriction on the turbo. But by removing both the silencers and the cat and coupling this with a larger bore diameter this certainly help and you will certainly feel a difference if you have had a decent system made. Youl certainly feel a little more poke, but the acceleration will be smoother and more controlled. I mean it is a 1.4 were talking about here so dont expect miracles.

But to say that "in my experience, all 'big' exhaust systems do is make it noisy too, you dont gain much " then in my experience you haven't driven many larger engined turboed cars, as this certainly makes far more of a difference than just noise.

It also changes the power delivery. Rather than your having 'power peaks' there is a more progressive delivery of power giving smoother acceleration, but it also gives a sharper throttle response. When also having a remap done, the ignition timing is changed to give a more efficient burn, and it is this that has a positive effect on fuel economy. The only time it doesnt is due to the increase in power and torque drivers become heavier with their right foot

i think you need to re-read your diesel engine combustion theory tbh, there is no 'ignition' per se, although the injection timing can be advanced and retarded dynamically on the pd and common rail units with mapping.. the throttle response of a diesel engine is a product of how much fuel you whack in, there are no other variable factors other than the signal on the boost modulator valve... or put simply in laymans terms, there is no limit to how fast a diesel engine can run, the way it's governed is by the volume of fuel injected...

ok power and fuel... to make power you need to use fuel, if you turn up the fueling (in this case by advancing the injection timing) you also need to increase the air by turning up the boost.. hence you are consuming more fuel.. on diesels unburnt fuel comes out as black smoke

as i said before, part throttle and light loads are generally unchanged in terms of mpg and power on mapped cars

But to say that "in my experience, all 'big' exhaust systems do is make it noisy too, you dont gain much " then in my experience you haven't driven many larger engined turboed cars, as this certainly makes far more of a difference than just noise.

dont be so condescending mate, i've driven dozens of different turbo cars of all shapes and sizes petrol and diesel.. dont get sucked into this bigger is better trap... ys i agree that a large diameter pipe can theoretically flow more volume, but that extra sectional area also reduces the speed at which the gas is flowing because the pressure is lower in the pipe... there is a fine balancing act in choosing the right pipe, but i would say anything over 50mm tubing is too big in this application.. as you say, its only a 1.4... also i dont agree with your sentiments on silencers either, a decent silencer shouldn't affect the power output by a significant amount, also diesels dont have a cat as such, they have a particulate filter, and cars built to EU4 emmisions regs wont pass the smog test at MOT without it

A remap and exhaust system will actually make the car mroe fuel efficent and you will see an increased mpg.

no not really, all a remap will do is increase the engines ability to burn up fuel, the cruise/light load is largely unaffected tbh

in my experience, all 'big' exhaust systems do is make it noisy too, you dont gain much

I see what your saying here, but an engine that is able to produce more power is by definition more efficient. Like you said, a remap (and most other mods for that matter) allows more fuel to be burnt. But if the engine is not used to its full potential, the same power is able to be achieved at lower levels of fuel input. Essentially a tuned engine is a highly efficient engine, if only people drove them as such. Think of it as an elite athlete, they expend a fraction of the energy a fatty might to perform the same work. Its all about how the cars are driven in the end.

the same power is able to be achieved at lower levels of fuel input.

that's exactly my point, it's impossible to get something for nothing. you dont magically get more power for any given quantity of fuel.. the BSFC (brake specific fuel consumption) figure of any given engine is a constant and wont change just becuase you've whacked a huge exhaust on there or had a remap.

dont be so condescending mate, i've driven dozens of different turbo cars of all shapes and sizes petrol and diesel.. dont get sucked into this bigger is better trap... ys i agree that a large diameter pipe can theoretically flow more volume, but that extra sectional area also reduces the speed at which the gas is flowing because the pressure is lower in the pipe... there is a fine balancing act in choosing the right pipe, but i would say anything over 50mm tubing is too big in this application.. as you say, its only a 1.4... also i dont agree with your sentiments on silencers either, a decent silencer shouldn't affect the power output by a significant amount, also diesels dont have a cat as such, they have a particulate filter, and cars built to EU4 emmisions regs wont pass the smog test at MOT without it

Now i didnt say put on the biggest pipe possible did i???

I just merely pointed out that an increase in the bore diameter will increase the flow volume hence taking restriction from the turbo. I never disagreed that having too big of a diameter would have the opposite effect. As members on here have pmd me and vouch for the advice i have given them, i have said that having too big a diameter for the size of the engine will only cause the exhaust gasses to be slowed down in the exit throught the exhaust system, and then what will happen is they slow down to such a degree that they will rise and float at the top of the system. I didnt say and am not being sucked in to the 'Bigger is better' way of thinking, i was just merely pointing out that the bore diameter on the standard system WILL have a negeative effect on gas flow and increasing the bore size will release that restriction being held by the standard system. However i didnt say how big to go and i would agree with you to the point that having too big a bore is going to reduce the speed that exhaust agses leave the system, however to say that there is no point in doing it as your not going to see that big a gain. Then you have really contradicted yourself there as there will be a gain none the less and a benefit to the running of your car so why would you not do it????

I mean on a petrol engine, the first thing that most people will think of doing is replacing the standard restricted air intake system with an Induction kit to deliver colder air into your piston chamber and optimise fuel combustion to give higher bhp. This is only a very slight increase on all engines in the polo model range, but would you still recommend that they dont do this as its only a 'slight gain'??

I think not, so saying not to change the exhaust system on the tdi for a bigger bore system as there is only a slight gain then this is abit stupid as the whole point to one of the questions the guy asked when creating this thread was to optomise power output from these engines, in which having a larger bore size over the standard system WILL benefit the running of the car and WILL see an increase in power output, however small. So by that very nature wouldnt you recommend that he does this??

And just for reference 5bhp is not a slight increase on one of these engines, thats a 6.67% increase over standard output, thats a fair old gain just by changing the bore on system for a small engine.

But after having my engine remaped, even with the bigger bore system i saw an increas of between 5 - 15 mpg dependant on how i drove and whether it was urban or extra urban driving.

Edited 26 April, 201016 yr by Monkey-man

having a larger bore size over the standard system WILL benefit the running of the car and WILL see an increase in power output, however small. So by that very nature wouldnt you recommend that he does this??

not necessarily no, too many people get hooked up in this bhp figure. you can't get something for nothing, if you are gaining a few bhp's at peak output you WILL be loosing it somewhere else. in my opinion you'd be far better off keeping the pressure high with a smaller exhaust to aid the spooling of the turbocharger at low revs..

with all the vw pd engines, it's not the fueling that is the limiting factor, it's the unburned fuel that comes out as black smoke that is the problem, the only thing that causes fuel to be unburnt is either there is too much fuel or not enough oxygen..

the best way to pick up more power (if any) is to maximise the amount of oxygen entering the engine so that all the fuel can be fully burned up, as i mentioned previously the standard turbocharger on the AMF engines already stuggles to cope on a standard chipped engine at certain places in the rev range..

also fitting an induction kit is waste of time, the standard airbox and filter however 'restrictive' it may be is more than adequate even for a modified engine, on the lupo's and 6n2 polo's it's very oddly designed indeed, the air filter is right underneath the front bumper near the floor. in fact i've never seen an induction kit for a 1.4 tdi that actually replaces the air filter, all the ones i've seen just replace one of the resonator chambers behind the intercooler with a giant cone, and if i'm honest i struggle to see how you could actually gain anything by putting one on there because you will have lost the ability to feed cool air to it

But after having my engine remaped, even with the bigger bore system i saw an increas of between 5 - 15 mpg dependant on how i drove and whether it was urban or extra urban driving.

on my current lupo tdi which has been chipped by revo it hasn't made much difference in the mpg output at all, if anything i suspect it's lost a bit, but maybe that's becuase i drive like my arse is on fire

Wasnt reffering to an induction kit on a tdi, especially the pd engines as it messes up you MAF sensor. But was just reffering to when people put an induction kit on petrol models.

This may be going off on a tangent here. But is the standard intercooler the best that you can do for the 1.4 engine as it seems to be in an awfully silly place. Is there nothing more efficent you can do?? Thought about putting an FMIC on but this would just be stupid as would this not increase turbo lag on the small 1.4 engines?

Edited 26 April, 201016 yr by Monkey-man

i was just thinking about the maf sensor this evening too, before my previous lupo i had a 6n2 tdi that i owned from new, i whacked a green filters induction kit on there and it lead to the premature demise of the maf sensor.

in regards to the intercooler it depends if you have aircon, *most* of the 6n2 tdi's have aircon so there is nowhere to put a FMIC, well i suppose the standard intercooler could be classed as a front mount as it is at the front of the car rather than at the side like it is on a 9n and a fabia.... the standard lupo intercooler is a fairly decent size as it is, but it has such tortuous bends going into and out of it, and the end tanks are not very well designed. it may be possible to cut the end tanks off and fabricate something better... the other option would be to use a water-to-air charge cooler. in theory a liquid can cool something more efficiently than a gas (air)

i dont recommend increasing the volume of the intercooler, as you mention it will only make the turbo lag worse...

there is also another tried and trusted method of boosting the power output of a diesel that nobody has mentioned yet, that is using propane gas as an accelerant to the combustion process, propane (lpg) will increase the rate at which the diesel fuel is burnt so it ups the power output due to more complete combustion and also reduces exhaust emmisions accordingly, the only trouble with it is there isn't many places you could stash the gas cylinder, the spare wheel well is favourite which i guess its ok on a 6n2, but the boot on a lupo is tiny.. i've seen a propane injection system used on a fabia vrs to great effect. a rough rule of thumb says that 0.5% + 99.5% air will give roughly 5% power increase.. you do have to be careful you dont push it too far, you can run into pre-ignition problems. normally diesel is injected at just be fore the the power stroke and is burned by the hot air created compression of a rising piston, but propane is injected into the intake tract in a similar way to a petrol engine which can ignite under compression before tdc on the compression stroke... crikey i dont know if i've explained that properly or not?

Edited 26 April, 201016 yr by SkodaBoy