When to start in a new DI engine

[JHZR2]

As some know, Im getting an additional car soon, and it is a turbocharged DI gasoline engine. I have had great success running a variety of adds from 2 cycle oil to FP60 to schaeffer's soy ultra to redline SI1 and amsoil PI.

I have been of the opinion in the past not to use fuel adds for the first while as the UCL component could hamper breakin. Whether this is true or not is surely TBD.

Given the desire to prevent deposits, etc. any suggestions on when to start with adds in a DI?

Thanks!

 

[JAG]

The only fuel additive that I'd guess has a decent chance of reducing/preventing IVD deposits in a DI engine is Red Line Sl1 because Red Line states some of its detergents survive combustion. They'd end up in the blow-by, then the PCV system, then past the intake valves. I don't know when to tell you to start using fuel additives but no later than 2K miles is my guess.

Getting a good oil catch can should be a high priority. Did you get a BMW 135i?

 

[Shannow]

I additise my Direct Injection diesel mostly for the injection pump, cetane improver, and injector cleanliness.

Given that a proper DI, the fuel should never get to the walls (we know it does, due to dilution), I reckon that adding lubrication to the fuel will be either hit and miss or not effective.

Injector cleaning I'd say is a must. Last DI (diesel) I saw with a "burned out" piston looked more like impingement erosion to me, being very clean around a very rounded edged hole.

I'm starting to form an opinion that in a DI engine, it's the oil vapour in the PCV flow that can either be your friend or enemy, as the only solvent to see the back side of the valve is oil vapours.

 

[StevieC]

The best way to fix the valve deposit with DI engines is to by pass the PCV from running directly back into the intake air flow and run it to a catch can first and then run from there to the air intake. This will drastically reduce the oil laden vapors and stop the gunky buildup on valves.

Nothing you put in the fuel, and no oil is going to stop intake valve deposits because the fuel is sprayed right into the cylinder and doesn't have a chance to clean the valves like in the normal population of engines.

Edit: Don't forget to check for a breather line as well, most cars today are using breather lines and PCV's like my Santa Fe. They only use the PCV during idle and the breather line during higher RPM's. It's important to do both or else you will miss the majority of the vapors!

 

[JHZR2]

Originally Posted By: JAG


Getting a good oil catch can should be a high priority. Did you get a BMW 135i?


Getting it very soon!

 

[Nederlander75]

Shell claims their adds survive the combustion process as well so that may be a good aid along with all the others mentioned. The beef tallow derived adds will also help as an upper cylinder lube to mitigate the impact of DI dilution. All of course in theory, even the profs dont know yet what to do.

Congrats on the ride.

 

[JAG]

Originally Posted By: JHZR2
Originally Posted By: JAG

Getting a good oil catch can should be a high priority. Did you get a BMW 135i?

Getting it very soon!

Cool. You'll become addicted to the power!

 

[JAG]

Originally Posted By: StevieC

Edit: Don't forget to check for a breather line as well, most cars today are using breather lines and PCV's like my Santa Fe. They only use the PCV during idle and the breather line during higher RPM's. It's important to do both or else you will miss the majority of the vapors!

It may have changed on the N55 BMW engine but on the N54 the PCV route that is used under low load is internal to the head (or intake manifold...I forgot) and it uses a cyclonic separator. So unfortunately nothing can be done about inserting a catch can to that route. That can only be done on the high load PCV route.

 

[StevieC]

The high-load route is the most important in this dual type setup. The PCV has negligible oil vapour flow compared to the high flow route so it's all good...