Alright guys,

This is my 2004 9N 1.4 TDi -

I've owned this car for nearly 2 years now (commuter) and it’s been very well maintained. The car is currently at 179.000 miles, still running flawlessly!

Encase you don’t know much about this engine;

3 cylinder PD

1422 cc

Turbo (has to be one of the smallest Garrett’s ever)

73bhp

195 Nm 144 lb-ft

61 mpg (all day long)

I have for a while now been looking for a 1.4 tdi tuning thread that can clarify different means of unlocking more power specifically from this engine.

Preliminary research into what to upgrade first looks like a generic remap that will bring the car upto 105-110bhp with 175 lb-ft or a customized remap which delivers 110-115bhp and 185 lb-ft.

I spotted a few people talking about those resistor kits that actually provided extra power, I don’t believe these are great for the longevity of any engine.

The remap gains are half as rewarding when carried out on the 1.9 PD tdi, the stock 150bhp you’re looking at a 45+bhp gain at stage 1 generics.

I know from experience the 1.9tdi can reach near 300bhp – one of 4 cars that made me shit my pants – ridiculous torque!

Does anyone know from experience if the injectors/turbo from a 1.9tdi are suitable for the 1.4tdi?

I am prepared to pop this engine to see what works.

If anyone knows cams/intercoolers/custom manifolds for this engine please share.

I will try my best to update any progress

Dark side developments had two cams made it may be worth getting hold of them to see if they have the specs or could get urs re ground. An audi a2 runs the same engine but is 90bhp out of factory and has a different turbo so may be worth looking into. Egr delet straight through de cat. Incjectors the 1.9 will fit but stock injectors will be fine up to 200bhp I'm sure, intercooler wise not much as in out of the box for polos but again dark side do a kit so get on to them.

Also be advised the clucth may not enjoy the new power and a single mass fly wheel and uprated clutch would do this engine a great deal

Edited 13 July, 201412 yr by mattieboi6n

Dark side developments had two cams made it may be worth getting hold of them to see if they have the specs or could get urs re ground. An audi a2 runs the same engine but is 90bhp out of factory and has a different turbo so may be worth looking into. Egr delet straight through de cat. Incjectors the 1.9 will fit but stock injectors will be fine up to 200bhp I'm sure, intercooler wise not much as in out of the box for polos but again dark side do a kit so get on to them.

Also be advised the clucth may not enjoy the new power and a single mass fly wheel and uprated clutch would do this engine a great deal

Nice one! I did see Darkside had a project 1.4tdi going but for some reason they stopped working on it and put the manifold/cam up for sale on their website.

I’m not sure if a cam would even make much difference with it being a 3 cylinder – it only revs to 4k’ish.

Will this engine handle 130+bhp? I think if I managed to reach this bhp, it would be a great car to drive!

I’m fairly sure the clutch is coming to the end of its days anyway, do you know what parts are a direct fit for this engine?

Also have you ever driven a car that has been converted from dual mass to single? This is quiet easy to stall moving off in 1^st without the accelerator – between 900rpm -1500rpm its very flat with no boost.

Cheers

I have driven cars with single mass conversions mostly tuned and never had a real problem. Even a stock car changed as the dual mass had it and never noticed the difference. They run 130bhp a lot and a cam will take it even further doesn't matter how many cylinders if u have 8 or 3 a cam opens the valves higher and longer so benefits for any engine, and is highly recommend to take the motor to the next stage along with a gas flowed head, I reckon 150bhp would be easly achievable with cam and head work with the normal kinda diesel stuff.

Uve gotta think these make 75 bhp but around 150 torque so double the horsepower will In theory double torque 300 torques in a car this size would be madness

Edited 13 July, 201412 yr by mattieboi6n

interesting me and me brother were talking about doin this to mine the other day

I've had my 1.4 TDi mapped for over 50k miles now (block is the same as in the 9n) and not had any problems, the injectors are a pig to change though, myself personally, I wouldn't bother dumping money into turning the 1.4 into a potentially unreliable motor, just a map and few tweaks to the air intake and intercooler will see enough to make the car quite spritely, any more and I say swap the engine, its just easier in the long run

maybe a free flow exhaust wont go a miss

Tbh, a custom free flow doesn't work for me, couple months ago my exhaust broke just in front of the rear box, although it sounded nice, it felt sluggish and down on power, fitting a new rear box rectified it, so it seems that it can be all to easy to cause a loss in power with the exhaust so think I'm staying standard

wow really.... just goes to show, some diesels act differently to some mods, i will need to replace my exhaust soon and was gunna add a full free flow stainless

This is exactly my problem, no one on enthusiast forums knows what works.

I’m hesitant to change the exhaust to a straight through as the back pressure might be completely wrong and result in a power drop.

I feel the same way about the intercooler, increasing the size might cause LAG with this tiny turbo.

I’m not too concerned about the reliability of the engine, just hope whatever mods I take up don’t cause the crank to snap.

you want as little backpreassure as you can get on a tdi. so anything after the turbo ideally wants to go if u know what I mean. The turbo provides all the backpressure your engine needs.

you want as little backpreassure as you can get on a tdi. so anything after the turbo ideally wants to go if u know what I mean. The turbo provides all the backpressure your engine needs.

So why would JonPDpolo's backbox being broken cause a powerloss? removing the backbox would surely decrease the backpressure mate

you want as little backpreassure as you can get on a tdi. so anything after the turbo ideally wants to go if u know what I mean. The turbo provides all the backpressure your engine needs.

So why would JonPDpolo's backbox being broken cause a powerloss? removing the backbox would surely decrease the backpressure mate

Without my backbox, it felt like the engine was working a lot harder to do the same job, felt loads better once I replaced it, as far as I'm concerned, the addage of less baffles/boxes in the way equals more power in petrol and large diesel, the same can't be said for the smaller engines

By the back box being removed without any additional to improve fueling to match the increased air flow, the polo would feel as if suffering power loss- modern engines are designed to monitor oxygen levels ect, and the change in data being received to the ecu would make this feel as if the car was not as fast.

In order to tune the 1.4tdi, the simplest way is to start at the top and work your way down - Injectors (darkside developments), Cam (darkside developments), inlet (porting), headwork (skim, de-coke, gas flow), turbo (pd150 or hybrid?), intercooler (Larger front mount), free flowing exhaust, then custom remapping to suit all modifications.

Alot of parts will have to be custom fabricated/adapted to suit as many are not available off the shelf.

Imagine the torque - would be brilliant. MPG and reliability will suffer however - the clutch and gearboxes are soft, and so are the engine mounts under heavy loading in my experience.

Best way to get the most power however is to buy a 1.9 polo 9n Tdi sport. They're awesome.