Quote:
Originally Posted by WingsofWar
Sorry i should have noted that owners have expressed dissatisfaction in the lexus forums with the carbon buildup and no aftermarket support. Clublexus.com might offer some answers. Im also in those forums when i owned a sc300 a few months ago.
port injection is only present are certain engine conditions. At mid-high RPMS Direct injection comes on only.
Both D4-S engines and DI engines have carbon issues, while D4-S can see more milage before you have to get the heads serviced by lexus and is covered under warrentie, some owners have extended warrenties because of this. DI only engines especially turbocharged/supercharged equipped cars build up soot reallly quickly. I read somewhere that 400hp 2GR-FSE Supercharged variant found in Japans Toyota Mark X has a bad shelf life.
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Now that is even more discouraging regarding DI. I am definitely going to be picky about my fuel picking the ones with more detergents and I will probably be running the maximum safe amount of alcohol too. Alcohol is a good solvent and it helps reduce carbon buildup, how much
.
I will be monitoring my intake to the valves whenever I make the switch to DI. That goes on my list of things to monitor like o-rings...
Quote:
Originally Posted by serialk11r
From the other threads, I am fairly sure that port injection is on most of the time, it only goes off at near max. throttle for maximum torque. At other times it's a mix to make the distribution of fuel in the cylinder as even as possible, to save fuel/emissions since these engines run stoichiometric A/F ratios for emissions. At mid rpm if the throttle is partially closed this should still apply. Maybe someone else can correct me if I'm wrong...
Of course if you only drive a D4-S engine say, on the track, you're mostly using just the direct injector, and that would be a problem.
@Allch Chcar what's up? I don't get the "whoa there cereal"...
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I think WoW explained it better now. I was saying don't get too go carried away with the port vs direct injection
. Just because they have port injected doesn't mean they still don't have carbon buildup issues. From personal experience.
Quote:
Originally Posted by WingsofWar
Your absolutely right! and based on logic that we should not be seeing carbon build up because of the port injection...but unfortunately its not true IRL. owners are still both D4S and DI engines are seeing similar early carbon buildups, with D4S being the lesser of two evils.
Its not entirely clear why they are getting carbon, but they do know that DI plays a major roll in it.
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Lack of detergents would be my guess. It's a common problem with cheap grade Gasoline regardless of fuel injection.
Either that or these Lexus guys are not giving it enough throttle
. This is why Rotaryheads recommend red lining once in awhile, it helps reduce carbon buildup, supposedly
.