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Just to be clear, I don’t have much knowledge about engines, or am I a mechanic. I’m just a 30 year old guy who does some occasional DIY and I take care of my truck.

From all that I’ve read, the current Frontier has port injection. And I’m learning that the new 3.8 V6 Frontier will be Direct Injection. I’ve also heard a lot that DI engines are prone to carbon buildup as opposed to others such as... port injection.

in a nutshell, what does that mean long term wise? I know we don’t have a lot of info about the new engine, and aside from that, 9 speed automatics kinda scare me? That’s exactly why I passed on a Tacoma, I felt it had too much brains and not enough instinct.
 

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Many manufacturers are using dual injection. Port at low rpm, or constantly mixed to clean valves. Then direct at higher rpms for efficiency. My Focus just has Direct. Lots of hand wringing about dirty valves, but it could be hype from garages trying to make people spend money for cleaning they may not need.
 

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I've seen vid and articles about how bad valves foul with DI due to pcv valve gasses recirc back to the intake. Fouling starts as little as 30k mi. A good catch can is mandatory with a DI motor. its not just hype. IIRC Ford redesigned their v6 to be a mixed system because they were getting killed with warranty work with as little as 31k miles, and by 40k everyone was reporting issues. Ford was having to perform valve cleaning and replace heads in some cases.
Long term, IF its only DI, and IF there is no filtering of the pcv return (like with a catch can) then it will be a bad engine. HOWEVER they have been testing teh 3.8 for quite some time. its NOT a VQ block. Its also not the motor out of the GTR. The trans IS the same 9spd in the Titan.
In the next few weeks reviewers will be able to pull the engine cover to see how all the magic happens. I would be VERY surprised if Nissan doesn't at least have a catch can on there as they've been able to see everyone faceplant with early DI motors
 

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My 2008 Cooper Turbo S DI engine faceplanted at 102k. Coked an intake valve which then proceeded to drop the carbon ball into the cylinder one balmy day when the morning temp here in Maryland was -3F. Yes, it does get that cold here sometimes. Ruined the engine. DI is a disaster, if it isnt hybrid port / DI combination. I'd never own another one.
 

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all GDI motors have problems with carbon build up on valves and the hondas have an additional problem with oil dilution with gasoline

all the bells and whistles mean nothing if the engine gets trashed
GDI motors are manuafactures response to meet EPA mileage guidelines and the consumer will get screwed with a less long term reliable engine
Be thankful you have a regular ported fuel injection engine that gets 10 percent less fuel economy GOD BLESS my 2017.
and buyer beware of all GDI gasoline direct engines which means the 2020 frontier
could be a problem motor
 

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Fuel rail pressures are 6-900 psi on the GDI motors according to my Hyundai Mechanic son who recommends a catch can on the EGR line, mid grade gas at minimum because the GDI motors are running higher compression (11.5 on the I4's) and much more involved ECU of timing and valve timing, In a nutshell, the MPG's HP and torque go up but so does the complexity. Expect a price jump on the new trucks.
 

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Fuel rail pressures are 6-900 psi on the GDI motors according to my Hyundai Mechanic son who recommends a catch can on the EGR line, mid grade gas at minimum because the GDI motors are running higher compression (11.5 on the I4's) and much more involved ECU of timing and valve timing, In a nutshell, the MPG's HP and torque go up but so does the complexity. Expect a price jump on the new trucks.
10% increase in MPG, but 10% increase in per gallon fuel cost... hell to the yea!
 

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I would be shocked if the new 3.8 is direct injection only. As mentioned, most manufacturers are going to sort of a hybrid, with primary direct injectors and secondary port injectors to help clean / cool the intake valves.

A catch can might help, but since there also using VVT to run a sort of Atkinson cycle when at low load - your pushing exhaust directly back past the intake valves anyway - catch can or not

I would never buy a DI only engine. You might be the lucky one that lasts forever, but not likely.

And yes, the only practical advantage in a daily driver for DI is 3% increase in fuel mileage. Thank your local congressman for less reliable vehicles going forward.
 

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I've seen vid and articles about how bad valves foul with DI due to pcv valve gasses recirc back to the intake. Fouling starts as little as 30k mi. A good catch can is mandatory with a DI motor. its not just hype. IIRC Ford redesigned their v6 to be a mixed system because they were getting killed with warranty work with as little as 31k miles, and by 40k everyone was reporting issues. Ford was having to perform valve cleaning and replace heads in some cases.
Long term, IF its only DI, and IF there is no filtering of the pcv return (like with a catch can) then it will be a bad engine. HOWEVER they have been testing teh 3.8 for quite some time. its NOT a VQ block. Its also not the motor out of the GTR. The trans IS the same 9spd in the Titan.
In the next few weeks reviewers will be able to pull the engine cover to see how all the magic happens. I would be VERY surprised if Nissan doesn't at least have a catch can on there as they've been able to see everyone faceplant with early DI motors
Nissan's US stock prices are at a 5 year low because the CEO troubles, Corona virus and poor sales. Introducing a new engine that has DI problems would be a disaster for Nissan. Hopefully they won't take that chance.
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There is zero doubt it will be PORT and Direct Injected.
Please cite sources. I have seen no details on that. The only thing i HAVE seen is that it will be DI and have an integrated exhaust manifold and cylinder head.



Introducing a new engine that has DI problems would be a disaster for Nissan. Hopefully they won't take that chance.
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There has been enough research and problems exposed that i am hopeful nissan designed around that. But we won't Know till reviewers are allowed to do a deep dive, or nissan displays the new motor in detail. Given that none of the press have brought up the fouling of other DI's i suspect its not a concern. Or all of auto press have turned dumb and mute
 

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Id be amazed if they dont use dual port. I’ve been concerned about this as I have a gdi 2014 focus. Ford hopefully learned from the mini cooper issues, they apparently use valve timing to help correct. I can’t find a single post where anyone has had to do a cleaning in a 2012 and up Focus, many of which are over 200k. A ton are out there, many of which have had dct failures, very active forum, but no issues posted.
 

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Hyundai mechanic Son tells me that the biggest problems they see with GDI is Fuel Quality. The I4's are pretty much good (with exception of some 2012-2014 models assembled wrong at factory) for 200k plus with oil changes and good quality fuel. The Carbon buildup problem is exasperated by cheap fuel and commuter cars never reaching highway speeds or sustained mid-level rpm ranges. The catch can on the EGR is to keep oil off of the backside of the intake valve. (I never installed one on our Accent, 7 years and 97k miles and a scope down the intake runners shows nothing of concern.We used alternating tanks of regular and mid grade and monthly bargain fuel system treatment.)

The theory around his dealership is if you drive it like your stole it once in awhile your doing yourself a favor.

I wouldn't hesitate to buy GDI, its that new tranny that will keep me in my 16SV till the doors fall off OR the 5th model year...whichever comes first....Everybody is having CVT problems except Mazda...These High gear count conventional aren't far behind. (Although the FIRST thing I install on all of my trucks is an RV tranny cooler because a vast majority of all tranny problems are heat related.)

IMHO YMMV
 

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Fuel rail pressures are 6-900 psi on the GDI motors according to my Hyundai Mechanic son who recommends a catch can on the EGR line, mid grade gas at minimum because the GDI motors are running higher compression (11.5 on the I4's) and much more involved ECU of timing and valve timing, In a nutshell, the MPG's HP and torque go up but so does the complexity. Expect a price jump on the new trucks.
Some are much higher than that, the Cooper runs about 740PSI at idle and about 1900PSI on boost if I recall correctly, the 740 number is verified, and the HP fuel pumps fail all the time, mine went out at about 90k.
The Cooper Turbo is 11.5:1 static C/R and then 14PSI boost, which would be astronomical a few decades ago, but the GDI prevents predetonation as the fuel is injected just before the spark plug goes bang. Hence, no ping. If that part worked as designed, it would have been great, but all my Cooper woes were 100% engine related, I never had to fix anything else up to 103k when I dumped that raging turd.
 

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Please cite sources. I have seen no details on that. The only thing i HAVE seen is that it will be DI and have an integrated exhaust manifold and cylinder head.

The source is just my own belief.
Nissan wouldn't release a new engine that's DI only at this point.
 
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