Is the IS 350 engine...
 

Is it direct injected or port injected?

In my other thread on the 200t, I was asking (worrying) about carbon build up with the 200t, as I mainly drive around town and don't do long highway trips often. Some of the things that I have seen say that the V6 350 is also DI, and makes me think that this would also suffer equally as much as the 200t?

Can someone explain the differences in this regard, would love to learn more just in general as this is all very interesting!

Thanks guys!

T

The 2.0t and the V6 have both direct and port injection.

All cars will have carbon build up to a certain extent. DI engines are little worse since they don’t have the port injectors spraying fuel which has detergents to try to clean/prevent/breakup carbon deposits. Oil catch cans on DI engines help because that oil mist isn’t falling on the valves it’s being caught. There’s absolutely no way to completely avoid carbon deposits no matter what. All you can do is minimize by using gas that has a lot of detergents if you have port injection and use oil that has a better rating for vaporizing. ILSAC GF-6 is also going to address this issue because LSPI (low speed preignition) is an issue with turbocharged small engines. SN Plus certification is the stopgap for LSPI until GF-6 comes out next year.

Thanks guys for the quick reply!

So, with the exception of power would you say that the 350 V6 and the 200t are about equal then in terms of carbon build up given they are driven in the same way?

Another interesting question is this.. as I understand DI is used under high load (driving hard) and gives better performance as the gas is pushed directly into the cylinder chamber (by passing the valves). Then, port is a lower pressure spray that hits the tops of the valves under light load. (grandma driving).

So, if that's the case... then, would it make sense to say that softer driving around town is whats cleaning the valves vs. more harder driving?

Yeah for the most part driving normally and not hard will use the port injectors more often as well as cruising. .

I've never seen anyone have a carbon build up issue on the 3.5 V6. I absolutely would not worry. If you get the refreshed model with the new 3.5 (2GR-FKS) it even runs a cleaning cycle to wash away build up, should any occur.

I'm less familiar with the 2.0t. I would not expect significant carbon build up, as it still uses PFI with the DI. Not sure if it runs the cleaning cycle as well.

The Toyota system uses both PFI and DI at lower RPMs, and just DI at higher RPMs.

Hard to answer that, because the engines are completely different in design and one is obviously turbocharged.

I believe heavy load + high RPM is direct only, with lower load and RPM ranges being either completely port injection or a mix of both. Not sure if there is any available documentation on which injection methods are used at what times, would be interesting to get some hard info on it.

Cars w/ sportier intents will tend to be more problem prone on the whole than normal cars. They'll need to push more power, be more responsive. And the gadgets mfrs give these cars to do that introduce other problems. So if you want something maintenance free, you really have to get something like a Corolla, Camry, Prius, etc.

W/ a modern sports sedan, you're going to have to pay to keep having your fun, whether its tires, oil, brakes, insurance, gas, etc. You cannot buy a sports sedan and just expect to cruise problem and maintenance free. Somethings gotta give. No free rides.

Just enjoy your purchase and maintain it. Stop worrying! The cost and risk of this and that comes w/ the territory of the car you bought.

Totally, totally agree. In the past I owned a 2004 BMW 330 CI and LOVED that car! As soon as the CPO ran out, I traded it for an Acura MDX, and then eventually ended up with Lexus RX. (Now the IS)

Some of my questions are coming from truly wanting to understand how the new engines work, and some of it comes from maybe wondering if I should have gotten the 350 vs. the 200t (in terms of overall reliability). There is a fraction of me that even wonders about buying a 350, and then selling this 200t because of the fear that this engine is going to be too finicky to keep up over time and is prone to more carbon build up.

The long story short is.. that myself, and my business are going through a "restructure" so whatever car I end up with now.. I will need to keep for 7 years to ride out a long wave of change. I dont care about "more power" or anything like that (350) BUT I do care about long term reliability.

The reason I started this thread was to talk about the carbon build up vs the two engines. If they both use the same systems, and operate DI and Port Injection the same way than I would have to assume they are going to be about equally as reliable in that sense.

Each day that goes by becomes harder to make any type of change. I mainly want to just keep the car I just bought and feel confident. But, I also want to be SURE. Tires, the valve thing for the turbo, etc.. fancy oil, gas, etc.. all that I am fine with. Other repairs, or turbo issues, carbon etc.. are all things I dont want to deal with just because I kept the 200t vs. "should have got" 350 V6.

T

You honestly should have gone with the ancient and battle tested super reliable 3.5L V6. The AWD IS 300 would have been a good compromise. I say this because you seem like a worry freak, no offense haha. I haven’t seen anyone on the forums (we are a tiny fraction of the IS owners out there) have actual engine or transmission issues yet, but I don’t think anyone here is at high mileage since 2016 was the first IS with the I4 Turbo.

LOL, no offense taken. Hey, your right! I am ;-)

Buying used is harder.. it becomes a game of getting the color, condition, and history as well. The car I got.. well, everything is perfect and looks BRAND NEW! but, its just not the engine I wanted. So, I guess its kinda a leap of faith thats all. I'm sure I will be fine, but I did want to know more about the two engines and how the injection works and if they are both basically the same in regard to carbon :-)

It will probably be more expensive to sell your car and get a 350 and have a difference in gas use over the life of the vehicle than it is to have an engine cleaning to get rid of carbon deposits in the future.

Since the 2GR-FKS 3.5 V6 as seen in the IS, RC, and GS has such a high compression ratio, runs on premium gas only, and is generally tuned for a sportier application than, say, the variant of the same engine used in other Lexus models like the ES or RX, doesn't that mean it would run hotter than other versions of the engine? And, if it runs hotter, that could aid in burning off particulates that would normally cause carbon build-up. I'm just theory-crafting here, so feel free to check my logic on that one. :D

I think the turbo engine is probably going to see higher temps anyway.

I would prefer the 350. Carbon build up will probably happen to both engines, but the turbos usually have alot more other worries down the road...

For starters, the design of a turbocharger: It has to work at extreme temperatures of hot exhaust gases, while the turbocharger shaft is lubricated by engine oil. This means there is more demand to the oil quality. Engine oil deteriorates faster under extreme heat. A turbocharged engine will not forgive low oil level, poor-quality oil or extended intervals between oil changes. Most turbocharged cars need high-quality synthetic oil and have shorter maintenance intervals. Some also require premium gasoline.

Turbo engines tend to have more problems in many cars, although there are turbocharged engines that are reliable. A turbocharged engine has more components than a naturally-aspirated (non-turbo) motor. These include an exhaust wastegate setup, intercooler, boost control system, vacuum pump and a more complicated crankcase ventilation (PCV). A turbocharger itself is not uncommon to fail. The more parts, the more can go wrong.

At higher mileage, as the cylinder walls and pistons rings wear out, higher combustion chamber pressure results in increased pressure inside the engine crankcase. This can result in oil leaks that pop up from many places and are difficult to fix.

Having driven my IS200t for two years, when i took it for servicing at the dealer, i was pushed a "de-carbonizing" package with in-cabin air filter cleaning of some sorts to "refresh" cabin air. I politely declined, but thinking that there may be carbon buildup since they recommended it, i went to a workshop to check whether that was necessary and the mechanic after checking said it was very clean and for a two-year old car de-carbonizing is wholly unnecessary. However, he added that twice a year, if i like, i can add a can of aftermarket detergent, those fuel additives that one drops into during refuelling to help in cleaning. He said those are just to help clean the fuel injectors and wont do anything to add power despite what the can claims. :)