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Lucifer's ultimate guide: 1.4tsi fundamental problems

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lucifer666

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Dec 17, 2006
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Cardiff
Article now located in the resources section of the site

General maintenance - 1.4Tsi Twin-charged fundamental problems

Hello twincharged owners. My name is Mark.....aka Lucifer and I have spent the last 4 years in ownership of a 1.4tsi Seat Ibiza. I have now at long last managed to conquer stage 3 tuning on this engine after several setbacks and much more money...
www.seatcupra.net www.seatcupra.net
 
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3. Turbo

The turbo is not necessarily an issue if it wasn’t for the known engine problems but there are 2 major features of this turbo that need consideration to avoid oil consumption.

The oil seals of the turbo are designed to hold the oil inside the turbo around the bearing rather than it leaking down the turbo shaft to the turbine and impeller (2 wheels at each end of the shaft). These are designed and balanced perfectly to take into account the forces applied on them in both directions. The internal force on the seal is made by the heat expansion inside the bearing and the oil pressure flowing through it. On the other side there is back pressure. On the intake side of the turbo it is the air hitting the wheel and the force of compressing the air to send to the intercooler. On the exhaust side it is the back pressure of the downpipe, catalytic converter, cat back pipe and silencers.

One rule of thumb with a turbo engine is that the best sort of exhaust is no exhaust at all; and no exhaust = no back pressure. Thus after market exhausts deliberately try and minimize back pressure, resulting in the oil seal losing the pressure balance it once had. On a normal car this is not usually too much of a problem and the seal could potentially hold the oil in with minimal seepage, but together with the second feature of this turbo, it simply cannot.

The second issue is the internal pressure inside the turbo. These turbos, as confirmed by their manufacturer, are designed with internal pressures of 40-60psi in mind. When measuring the actual pressure through the turbo even with a new engine it was found that it could raise to 70psi. This is because of the under piston oil jet system, which coats the pistons in clean cooler oil before they raise up into the bores for the next stroke. There are a few other manufacturers that have had similar problems.

Now if you imagine the engine and pcv problems being present as discussed earlier with high internal pressures and no back pressures then it becomes a very serious issue.

There is no SEAT solution to this problem as they don't want us to run sports exhausts to begin with, especially de-cat exhausts. I designed an oil restrictor bolt based on another VW variant. It has slightly smaller holes than the OEM one on the 1.4TSI and have I have logged the pressures at between 40-45psi. This results in a healthy internal pressure allowing a decat exhaust to be run safely with a healthy engine.

This is even more important to fit if you are using a hybrid turbo. The reason is the turbine wheel on the exhaust side is MUCH bigger and the housing has been bored out resulting in more flow but less back pressure. Thats great for performance but not good on the oil seal. For this reason, I have also had the oil seals strengthened in my hybrid turbo.



Solution:
Custom oil restrictor (if running decat)
Strengthened oil seals (as part of the turbo hybridization process)

NOTE: LOBA270 has normal oil seals, and is not suited to a de-cat exhaust, despite what they say!
 
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PART NUMBERS

I will be updating this section soon to include all the up to date part numbers and I will highlight the ones essential to solve the problems above or needed for tuning.
 
FINALLY

I hope this is useful for people who see the 1.4TSI as a mystery. I was one of these people to begin with. I have done my best to provide the most comprehensive and accurate account of these problems as well as all the solutions that are possible. The information gathered has been supplied by SEAT head technicians, ECU tuning companies, Performance engine builders, Turbo technicians and my own personal findings.

If there are any questions or comments that you feel the need to ask, please do.


LOOK FORWARD TO.............LUCIFERS ULTIMATE GUIDE 2: TUNING THE 1.4TSI

STAY TUNED
​
 
Excellent read! Are you sure about no upgraded timing chain? Or is every other source I have lying. Somewhere around - 11-12 there is supposed to be an upgrade.

Sent from my HTC One_M8
 
Good stuff mate, my rad OK at 5 years but I change coolant every year - 2L G12+ and distilled water. I change oil every 3,000 miles. Mine does not like sitting in traffic, I try to avoid this. Forged pistons OK after 32,000 miles. Running REVO stage 1 now but with big intercooler. VW/SEAT had no idea what they were doing with this engine, it should have been a classic, they F***ED up this whole issue, what a load of W*****S.
 
ibizaracebrake said:
Good stuff mate, my rad OK at 5 years but I change coolant every year - 2L G12+ and distilled water. I change oil every 3,000 miles. Mine does not like sitting in traffic, I try to avoid this. Forged pistons OK after 32,000 miles. Running REVO stage 1 now but with big intercooler. VW/SEAT had no idea what they were doing with this engine, it should have been a classic, they F***ED up this whole issue, what a load of W*****S.
Click to expand...

Agreed. Your forged pistons are better suited than mine to daily driving as they have high silicone content, really good all rounder with small tolerances and clearances. Reason I chose the low silicone is just because I intended going stage 3 running high boost. Good to hear your rad is ok
 
:-o

I'm using my car like a nun on a Sunday drive from now on. And definitely getting rid before the warranty expires!
 
looks like you have the CTHE engine as its the facelift car in your pic. If its not mapped and it is the revised CTHE engine you'll be fine. I would suggest changing the plugs to the bkr7eix regardless just because they are colder and make the engine run healthier.

Dont fill your oil above the hashed area to minimise crank pressures too, thats another tip.
 
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2010 Cave w/ Stage 2 without (!) Warrenty means getting rid? :p

Great guide! Lots of new information. Looking forward to your Stage2 "Readme" and still interested in your opinion about upgrading the stock turbo!
 
I agree, that made a good read thanks. I always liked the Ibiza cupra was thinking of getting one a couple of years back but most definitely won't be now at least until they change and 're design the whole engine lol
 
Wow, now that's a really cool guide! I'll post this on a Greek ibiza owner's forum if you don't mind.
Looking forward to your tuning guide. Is your car ready now? I hope mine will be in a few days as I had the mechatronic and clutches replaced.
 
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