Keeping a direct injection engine healthy

lordrobs · 29 Jul 2018 at 10:17

We'll soon be getting a Polo from a family member (2016 1.2 TSI) and realising that A) going by past experience we will probably keep this car a long time (10 years maybe) and B) I know very little about direct injection, I was wondering how best to avoid the carbon build up that these seem to suffer?

It will be my wife primarily using it and she doesn't cover massive mileage so running it on V-Power is an option from a cost point of view but a little inconvenient. Would an occasional additive be an option? I keep hearing about Millers and well... I like their beer so I could give that a try

Or am I over thinking it and should just fill it up at the supermarket like 95% of the other identical cars on the road do?

I've done a bit of googling and am now completely confused but this forum knows their technical stuff so I'd appreciate your input.

Fusion · 29 Jul 2018 at 10:33

Wouldn't have thought it'd be an issue. Perhaps ensure occasional long runs or the odd fill up with V-Power if you're concerned.

tamzzy · 29 Jul 2018 at 10:42

You can't really keep the valves of a GDI engine clean, as the fuel never hits the back of the valve. Only option is to walnut blast them. Or can try "terraclean GDI" lol

Diagro · 29 Jul 2018 at 10:43

Carbon will build up no matter what you do, unless you run meth injection with some oil catch cans.

Best to to deal with it is to get the valves walnut blasted every few years, gets all the gunk off.

ianh · 29 Jul 2018 at 10:45

The carbon deposits for DI cars tend to be on the back of the valves, well away from the fuel/air mix, so fuel type makes no difference. If the car had no turbo then an occasional "Italian Tune-Up" (aka rev the nuts off it) will work a little bit to blow the residue off the valves but a manual clean is best. However on a turbo car like yours it's a different story as the amount of airflow created by the turbo massively reduces the amount of build up so it takes a lot longer to get so bad that it needs a clean.

When it comes to cleaning the only 100% guaranteed way to do it is a manual clean where the intake manifold comes off and someone scrapes away the deposits, all the other methods (except walnut blasting which is 90% as effective as a manual clean) make little to no difference.

So long story short, do nothing different, maybe look at getting it manually cleaned after 200k miles.

As an example, here is the valves of probably the worst Non-Turbo DI car - The Audi RS4 - which needs taking apart and manually cleaning approx every 30k miles.

and here is my own Audi turbo engined DI valves after 100k miles - Very little build-up in comparison - the pressure created by the turbo blows most (but not all) of the carbon build-up off the valves before it can build up.

lordrobs · 29 Jul 2018 at 12:50

Excellent info, thanks all

As for cleaning at 200k... with our current mileage we'll all be riding around in automated pods that we call up on demand by that point

Dangerous Dave · 29 Jul 2018 at 12:55

Running V Power will help keep the injectors clean which keeps the engine burning cleaner which should help but not totally eliminate the problem. The extra cost might not be worth it in the long run as a walnut blast isn’t that expensive.

I give my wife’s 1.6T Mini an italian tuneup every so often on the first couple of runs to the redline produces noticeable puffs of black smoke out the exhausts which I assume is carbon buildup.

A flat out run right up 3rd and 4th gear keeps the turbo flat out for a long time. Coasting back down then back on the throttle generally gives another significant puff before clearing up. I hope this will stop big build ups.

I never had this problem with my Golf as I drove it harder than my wife. The valves were pretty much clear at 120k, it was also ran on V Power from new.

Housey · 29 Jul 2018 at 13:27

ianh said:
The carbon deposits for DI cars tend to be on the back of the valves, well away from the fuel/air mix, so fuel type makes no difference. If the car had no turbo then an occasional "Italian Tune-Up" (aka rev the nuts off it) will work a little bit to blow the residue off the valves but a manual clean is best. However on a turbo car like yours it's a different story as the amount of airflow created by the turbo massively reduces the amount of build up so it takes a lot longer to get so bad that it needs a clean.

When it comes to cleaning the only 100% guaranteed way to do it is a manual clean where the intake manifold comes off and someone scrapes away the deposits, all the other methods (except walnut blasting which is 90% as effective as a manual clean) make little to no difference.

So long story short, do nothing different, maybe look at getting it manually cleaned after 200k miles.

As an example, here is the valves of probably the worst Non-Turbo DI car - The Audi RS4 - which needs taking apart and manually cleaning approx every 30k miles.

and here is my own Audi turbo engined DI valves after 100k miles - Very little build-up in comparison - the pressure created by the turbo blows most (but not all) of the carbon build-up off the valves before it can build up.

My B7 RS4 was one of the first cars in the UK to start showing this back in the day. Audi flew Zee Germans over to look at my car, it was with Audi for 6 weeks soon after I had it, which was due to emissions lights coming on and then some deeps dives found coking issues.

andythelandy · 29 Jul 2018 at 15:50

Pretty sure a 2016 TSI has 8 injectors 4 main ones direct and then 4 port injectors too.

Nasher · 29 Jul 2018 at 17:39

Yea more recent engines have gone back to using port injectors as well. Partly to help prevent this.

Buildup did seem to be pretty bad on VW DI engines.

Diagro · 29 Jul 2018 at 20:18

Don't bother with Vpower. Go use Tesco Momentum instead. Same fuel. Far cheaper

Frozennova · 29 Jul 2018 at 21:11

Diagro said:
Don't bother with Vpower. Go use Tesco Momentum instead. Same fuel. Far cheaper

No it isn't

Diagro · 30 Jul 2018 at 00:39

Frozennova said:
No it isn't

Heh,

Same 5% ethanol.
Same 99 Ron makeup.
Same performance when tested by tuners.

Basically the same fuel

Dr Who · 30 Jul 2018 at 02:57

Diagro said:
Heh,

Same 5% ethanol.
Same 99 Ron makeup.
Same performance when tested by tuners.

Basically the same fuel

different cleaning and additive package...

Diagro · 30 Jul 2018 at 06:36

Dr Who said:
different cleaning and additive package...

Very minor differences in terms of those though. Nothing that warrants £0.10-£0.20 Per L

Firestar_3x · 30 Jul 2018 at 07:55

Diagro said:
Very minor differences in terms of those though. Nothing that warrants £0.10-£0.20 Per L

How do you know which additives each company adds to the fuel?

Nasher · 30 Jul 2018 at 08:47

The difference is 99% marketing. All fuels have cleaning additives AFAIK.

They won't really clean this kind of buildup though.

Alibaba99 · 30 Jul 2018 at 09:13

Diagro said:
Don't bother with Vpower. Go use Tesco Momentum instead. Same fuel. Far cheaper

Completely different fuels and made in different refineries. The fuels are exclusive to the two brands.

Firestar_3x · 30 Jul 2018 at 09:23

Alibaba99 said:
Completely different fuels and made in different refineries. The fuels are exclusive to the two brands.

The base spec of the product is the same irrespective of the fuel brand, a refinery supplies multiple customers with base product, it is the additives package which changes.

Frozennova · 30 Jul 2018 at 09:26

Nasher said:
The difference is 99% marketing. All fuels have cleaning additives AFAIK.

They won't really clean this kind of buildup though.

It isn't just marketing