Port and direct injection

[RonM_TX]

Because the part number is the same between the di heads and the di port fueled heads. Honestly, you cannot be this unintelligent. Having a single design is always less expensive than having (evidently) at least 3 designs that accomplish the same thing.

We know the following for certain: there was a substantial change to the head design on the 3.0l nano between its inception in the Lincoln lineup to its installment into the bronco raptor. The head is a completely different casting between the damb and rff valve actuators. The inclusion of port injection on a head that not only has di, but already has port injection prep built into the casting would be a trivial process change at longblock assembly. It makes more sense for Ford to consolidate the design into a single product rather than continue to have at least 3 variants of the same displacement engine with the same name.

How does a DI head differ from a PI head? If they are different how can they have the same part number? Are you talking about casting numbers instead of actual part number of the finished head?
Just asking as I got lost somewhere along the conversation.

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[Lion77]

There's different ways to implement Dual Injection. Some companies double up on injectors, so there the direct injectors that spray fuel right into the cylinder and there's a 2nd injector for each cylinder placed right at the end of each intake tract (port) and they use either / or depending on RPM and Load conditions to maximum benefit.

Some companies like Subaru, use 5 injectors for example on their 4-cylinder engines. There's just one single injector in the intake manifold further upstream shortly after the throttle body and its only purpose is fuel washing of the intake values. The other four go right into the cylinder like all other DI. That method is certainly cheaper and less complicated, but ONLY provides that singular benefit of cleaning the intake valves via fuel washing.

The dual injector method where there are two injectors per cylinder provides multiple benefits: 1. Fuel economy at lower load and rpm conditions and 2. fuel washing of the intake valves.

Here's my personal take on DI only (some will disagree), if you break in the engine properly to get good seal of the rings, use synthetic oils and stick to factory filters which do a much better job at limiting particulates than K&N's or other re-usable filters, DI can be reliable for the life of the vehicle, but you MAY need an intake cleaning at say 100k.

Again, I'll refer to my best friend from back in high school who is an army vett, he has a 2021 Explorer ST with the 3.0L, 130k, just uses motorcraft synthetic blend and factory filtes but does run it out to 10k intervals.

I've driven his ST and did not notice anything abnormal; it ran great. Just this week he is having a maintenance overhaul done as preventative measure, intake cleaning, drop the trans pan and change the filter / fluid, new plugs, air filter etc. Being formerly 19K and trained on armored vehicles (M1A1 main battle tank), he's a maintenance nazi.

I also believe my wife's Mazda Sky Active 2.5 Turbo in our 2018 CX-9 is DI only, we have 115k miles and it runs better than new cars off the lot (in part due to TriboTEX), gets better than the rated gas mileage, has no hesitation, pulls strong and consistent. Also, a vehicle I maintain rigorously. I use factory air filters and change regularly, factory oil filters and Mazda's Moly 5W-30 at 5k intervals. No detectable oil consumption over the interval and we drive about 22k-25k miles a year.

Mazda Skyactive engine carbon buildup ... are you at all concerned about GDI? : r/mazda

Mazda's Sky Active engine family is all DI since 2012 and I'm not aware of any reputation or mass problems with carbon buildup on the intake valves.

 

[Lion77]

As an additional thought on this, oil vaporization and improper break-in could both adversely affect that. Also filtering is HUGE. I had a 2007 Focus ST back when I was in college. It was Ford's 2.3L Duratec engine, bought it used at 104k, drove it to 175k before I got the S550 Mustang (my first new car ever). Someone bought it from me for a couple thousand and continued to use it (ran fine, I just wanted a sports car at the time).

That 2.3L Duratec had intake runner valves to change the flow path for low and high RPM, over time they were known to have the bushings wear out and would rattle / cause hesitation. Sure enough mine needed replaced at 140k, so I took the entire intake manifold off. That was a port injection engine, no DI.

It was FILTHY! Completely gummed up and caked, including the intake valves. It also used 1qt of oil ever 3k and I was dumb enough to use a K&N filter that clearly let through a high number of particulates. That got me to research filter performance more and what I found was that wile K&N's do flow better, their dust capacity is 1/3 that of a paper filter and once they clog up, they are MORE restrictive.

My conclusion was, K&N's are suitable for track use (not a lot of miles, relatively clean), but not for anything in severe duty, daily use or harsh environments. Keep that engine well maintained and ALL of my collective experience says DI is not highly problematic, but it is more sensitive to maintenance mistakes by the owner (like not using good filters, not changing the oil, not using good quality oil, running the oil out too much, proper engine break in). Anyone can do those things, they just have to be informed. The Port injection didn't fix the gumming up of the intake valves in that 2.3L Duratec because of the filter and poor performance of the oil control rings (could have been the original owner didn't break it in properly or just not the greatest design, not sure as it already had 104k on it).

Also had a 2001 Impala 9C1, also port injected, also FILTHY intake as I had to do work on that care too! So, port injection isn't a fix all for maintenance issues, improper break in, sub-optimal oil and filter etc. Can it help in some instances? Sure, but the other things matter a lot MORE.

And there are examples of F-150's out there, one I found, Gen 1, with 448k miles, original engine, just rigorously maintained. Assuming you don't have a factory defect or major design flaw (like Ford's Gen 1 cam phasors in the EB engines which has since been fixed 2021 and newer), a lot of it up to optimal maintenance.

Sorry for the LONG and wordy posts, but it's a complex subject. That's just my view based on what I know and my personal experiences. Also, I think even my Mazda 3's 2.5L is DI only, it's 2 years old and has 49k on it, no issues at all, runs great, but I bought it new and broke it in properly (had 1 mile on the odometer).

 

[superj]

Our 2018 mazda3 with the 2.5 is di and is a great engine. We bought it with 30k miles on it and its got 50k now and runs perfectly. We use mobil1 in the cars and jeeps

 

[Lion77]

Yah the Sky actives we well developed GDI engines. So is the 3.0L Ecoboost.

My maintenance advice is same for all engines as port injection doesn't solve gumming up of intake runners, valves and components entirely:

1. Use factory paper air filters as their filtration of particulates is much better than " high flow types".

2. Use good quality synthetic, I prefer OE now just to avoid any potential performance issues, although there's lots of great synthetics out there. Most of carbon on intake valves isn't from the normal combustion process, it's from vaporized oil in the pcv system that cycles back into the combustion chamber as the PCV vents to you intake to contain and burn fuel vapors as part of the emission control.

3. Factory oil filters are in my opinion a must because many aftermarket don't have bypass or it's pressure set point is not specific to your mfgs engine design, they are not all the same!

4. Periodic fuel induction service can help keep intake valves reasonably clean, but I think the other 3 are more.important.

5. I'm a big advocate of using In Situ hydrogenated DLC coatings because it enhances ring seal at the micron level that has the effect of enhancing the performance of the oil control rings once it forms in the upper cylinder group. Been using this in both my mazdas since they each reached 10k.

6. Change your plugs as scheduled, cleaner combustion process means less fouling / buildup.

Oil cans are another mitigation strategy, but I'm not 100% sold on them especially for turbo engines. Here's why: i used UPRs dual valve system on a 2015 Mustang ecoboost before I got my GT a few years later.

The valves tended to leak a bit and not consistently open and close. If you run it on intake only side, your not filtering anything when in boost as single valve system works on vacuum only. Then if your can gets a bit overly full (i.e., you forget to empty it or vaporization rate is higher than you anticipated over a given interval) it can backfill and dump all the sludge right into your intake all at once, which is far worse!

On an on-road car, it's doable, but on an off-road truck? I'd imagine you would need to empty it ever 1k miles to make sure it never gets close to full unless baffled, but even baffles are limited in preventing backfilling.

Also, there is a factory baffle system in all Ford and Chevy Turbo engines (probably also in Jap cars too I' imagine) that does the same thing as a catch can but drains right back into the crank case, while not quite as good as a dedicated catch can, I think when paired with the above maintenance it's a good overall solution. That's just my 2 cents for what it's worth.

 

[Mystic]

Wow that's incredibly thorough, appreciate the thoughtful insight!

Yah the Sky actives we well developed GDI engines. So is the 3.0L Ecoboost.

My maintenance advice is same for all engines as port injection doesn't solve gumming up of intake runners, valves and components entirely:

1. Use factory paper air filters as their filtration of particulates is much better than " high flow types".

2. Use good quality synthetic, I prefer OE now just to avoid any potential performance issues, although there's lots of great synthetics out there. Most of carbon on intake valves isn't from the normal combustion process, it's from vaporized oil in the pcv system that cycles back into the combustion chamber as the PCV vents to you intake to contain and burn fuel vapors as part of the emission control.

3. Factory oil filters are in my opinion a must because many aftermarket don't have bypass or it's pressure set point is not specific to your mfgs engine design, they are not all the same!

4. Periodic fuel induction service can help keep intake valves reasonably clean, but I think the other 3 are more.important.

5. I'm a big advocate of using In Situ hydrogenated DLC coatings because it enhances ring seal at the micron level that has the effect of enhancing the performance of the oil control rings once it forms in the upper cylinder group. Been using this in both my mazdas since they each reached 10k.

6. Change your plugs as scheduled, cleaner combustion process means less fouling / buildup.

Oil cans are another mitigation strategy, but I'm not 100% sold on them especially for turbo engines. Here's why: i used UPRs dual valve system on a 2015 Mustang ecoboost before I got my GT a few years later.

The valves tended to leak a bit and not consistently open and close. If you run it on intake only side, your not filtering anything when in boost as single valve system works on vacuum only. Then if your can gets a but overly full it can backfill and dump all the sludge right into your intake.

On an on road car it's doable, but on an off road truck? I'd imagine you would need to empty it ever 1k miles to make sure it never gets close to full unless baffled.

Also there is a factory baffle system that does the same thing as a catch can but drains right back into the crank, while not quite as good as a dedicated catch can, I think when paired with the above maintenance it's a good overall solution. That's just my 2 cents for what it's worth.

 

[superj]

I am surpised no one makes anything so you can do your own walnut blasting. Alot of other engines have things on amazon and ebay that you hook your compressor to and blast the valves and then the shop vac pulls it out. The kit for my 2017 titan v8 was 20 or 30 bucks on amazon and people were doing it in their garage.

Its walnut so if anything gets in the combustion chamber, it burns up. And it doesn't hurt the intake or valves. You still make sure both valves are closed though

 

[Lion77]

Wow that's incredibly thorough, appreciate the thoughtful insight!

It annoys some people; others appreciate the details and specifics. Can't please them all so I just do what I do and ignore the haters. The way I look at it, if you don't like what or how much someone has to say, just don't read it, right? But it's there for those that want that in-depth discussion.

 

[Lion77]

I am surpised no one makes anything so you can do your own walnut blasting. Alot of other engines have things on amazon and ebay that you hook your compressor to and blast the valves and then the shop vac pulls it out. The kit for my 2017 titan v8 was 20 or 30 bucks on amazon and people were doing it in their garage.

Its walnut so if anything gets in the combustion chamber, it burns up. And it doesn't hurt the intake or valves. You still make sure both valves are closed though

I wonder if there's a DIY walnut kit for the ST's that might be able to retrofit for RR applications? I'm sure the plumbing is unique to both on the intake side, but the base core of the engine is the same.

 

[Lion77]

Case in point regarding the factory baffle: 2018-2022 Ford EcoSport Crankcase Vent Valve - Gates EMH925 - Oil Separator - PartsGeek.com

Even the lowly EcoSport has one, so I see a catch can is very redundant, since the factory separator is doing the same thing, but instead dumping it back into the crank case vs. holding it in a can to be emptied. I'm sure cans will maybe catch a bit more as it's like adding a 2nd stage to a filter, but how much does it really matter, are we now straining at a gnat?

All of my collective experience and knowledge from studying engine design and implementing what I've learned has led me to the above recommendations as the optimal balance for most GDI applications. Some will disagree. There are always highly specialized applications also that can benefit some tweaks or additions to the above, maybe even a catch can in something like a track car / dedicated race vehicle, just like high flow filters have some applications too.

But when it comes to long term durability, I think filter quality matters a lot more than the ~10ish HP you might gain from a high flow, because at 100k, 150k, 200k... ring wear really starts to matter a lot, and you'll lose more power to wear / tear long term than any short-term gains. Also, if you run that truck hard regularly, keeping the factory-like-new-power takes a rigorous effort in maintenance and I'm of the opinion that should be the main focus for 90% of us.

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