j patterson

THAT is a really good question!

RDCR

And are they Porsche approved?

Macster

My understanding is Techron has both a liquid and vapor deposition phase and in some way this can add to the oil's contamination. This increases the dilution of the oil and brings with it deposits that will lead to an increase in acid formation in the oil.

Thus the recommendation to change the oil after using Techron as an additive or to use it just before an oil change.

Macster

While it is true DFI engines do not have the injector in the port and thus there is no fuel spray that helps remove deposits from the back of the intake valves, Techron can still help to keep this area clean of deposits.

Under some engine operating conditions at some point combustion gases are allowed to enter the intake manifold. These gases contain Techron in a vapor form. This vapor contacts the cold intake valves and this vapor then works to help remove deposits from the valves.

While I have no experience with gasoline direct injection engines I ran a VW Golf TDi for around 140K miles. This engine of course has direct diesel fuel injection.

This engine was notorious for accumulating carbon/coke build up in the intake manifold to the point this was eventually get so bad as to prevent the engine from operating at any RPMs.

The build up arises from the routing of exhaust gases to the intake -- done on purpose to foul the incoming air and lower combustion temperature to reduce NoX. The problem is this exhaust gas is full of soot. Combine this soot with the crankcase ventilation fumes which are full of oil vapor from blowby and toss in some water vapor and the soot and oil and water vapor combine to make a muck that builds up and hardens and which can get so bad to actually block air flow into the engine.

What I did to avoid this build up was to use a good brand of diesel fuel (I tried some fuel additive but got tired of dealing with it and just stuck with a low sulphur diesel fuel), and I used a good oil (Mobil 1 0w-40) and changed it every 5K miles. The oil came out of the engine as black as the ace of Spades. I also avoided extremely low RPM engine operation. Many TDi owners liked to drive the car around at engine speeds scarcely above idle to of course conserve fuel.

While this is commendable it is under these low RPM conditions the build up occurs.

Without going overboard I kept the engine RPMs a bit higher and once in a while used the upper RPMs of the engine to around 4K.

I never had to clean the intake system and just before I sold the car I checked the intake manifold. While it was dirty coated with a layer of soot and oil there was no build up at all.

Were to buy a car with a DFI engine (and at some point I think I will) I think I would follow the same path. I would use a good oil and change it at reasonable intervals (5K miles seems reasonable to me), and avoid extremely low RPM operation.

Flat6 Innovations

Nothing I do is Porsche approved. If a car comes to me under warranty, it won't be wen it leaves...

Never cared about approvals, I have my own.

sjfehr

The 9A1 engines in our late model Porsches [edit: do not] have both DI and port injection. Porsche's been a little tight lipped on specifics of when which injectors come into play, but it's become common for modern DI engines to use direct injection in conjunction with port injection to keep the valves clean. It's helped considerably to reduce the issues the early DI engines had.

Jake, my car's out of warranty, and I'm interested in your recommendations even if Porsche isn't

Flat6 Innovations

Porsche has yet to adopt the phased injection systems that utilize conventional and direct injection.

I have a pair of 2014 engines apart on the bench now, all you'll find are direct injectors with either of them.

I believe they may go this way in the future, as the head castings will accept either style of injector.

But, we've already beat them to it. Again.

sjfehr

The 2010 987.2 PET catalog is showing two different sets of injectors- one set part# 9A1-110-128-10 "High pressure injector" injecting into the block and fed from the high pressure pump (9A1-110-315-02/03), and another set 9A1-605-124-00 "injector valve" injecting into the intake manifold and fed from a fuel line that isn't labeled clearly but I thought was the low pressure fuel line. I haven't torn engines down so I have to take your word for it, but I thought this meant two sets of injectors- if that's not what this is showing, what's going on inside these engines?

e: oh dammit, I see what was screwing me up: Boxster uses one set and Boxster S uses the other.

Flat6 Innovations

Some engines for base models don't have DFI at all. These use conventional injectors only. The PET will often confuse models as it jams all components into one set of illustrated parts breakdowns.

Rob VN

I found that Techron caused increased lead levels in my UOA on my Cayman 2.7L. Once I stopped using Techron and did several oil changes the lead levels returned to normal. The car gets Shell Vpower fuel now.

LexVan

What were your lead levels before and after?

I've never detected high lead in my UOAs when using Techron.

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RDCR

I run chevron in my car about 90% of the time and my last UOA showed lead at 0.

Spokayman

Hmmm, I wonder why it would take several oil changes to lower the lead level in the oil. Should only take one, right?

LexVan

Did you also run any race gas during this period of elevated lead readings?

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