Learn me Ford Transit (EB, 3.7, diesel)

DWNSHFT said:

alfadriver said:

In reply to CyberEric :

The turbo can run more stoich under boost than the NA motor car.

I'd really like to know more about this.  In my limited, old-school understanding turbos run rich under boost hence mileage suffers significantly if you're in boost.  Alfadriver, I appreciate that you are a total subject matter expert in this area and I'm not doubting you.  But I'd like to know how technology has moved past my outdated understanding.  Direction injection?  Electronic boost control?  How does this play out in the market comparing torque, power and fuel mileage in, for example, a 1.6 turbo versus a 2.4 NA.

GRM, there could be a good story there.

Don't some of the smaller Ecoboosts run stoich basically all the time?

The next time I have to drive one with a scantool, I'll watch the equivalency ratio and see what happens.

Boost is weird, depending on the cam timing (which is now computer controlled) you might not be seeing the same mass flow at even 2-3psi as a naturally aspirated engine does at WOT because of the higher exhaust manifold pressure.  Logging my Volvo is interesting, I may be at "atmospheric" or even slightly into boost in the intake manifold, but the charge pipe pressure will be 6-7psi.  It takes exhaust pressure to spin the turbo up that much.

(For the tech weenies: the Volvo computer strategy uses a MAF but it also does a charge pipe referenced alpha-N calculation.  There is no intake manifold pressure sensor.  I don't know if anyone else does it this way.  Chevy might on the 1.4, given how they are similarly sensitive to dirty throttle bodies)

DWNSHFT said:

alfadriver said:

In reply to CyberEric :

The turbo can run more stoich under boost than the NA motor car.

I'd really like to know more about this.  In my limited, old-school understanding turbos run rich under boost hence mileage suffers significantly if you're in boost.  Alfadriver, I appreciate that you are a total subject matter expert in this area and I'm not doubting you.  But I'd like to know how technology has moved past my outdated understanding.  Direction injection?  Electronic boost control?  How does this play out in the market comparing torque, power and fuel mileage in, for example, a 1.6 turbo versus a 2.4 NA.

GRM, there could be a good story there.

The real question is- how does an engine make, say, 150hp continuously.  For a turbo, it can run under boost at lower speeds under boost, whereas an NA motor may have to run at high RPM to do it.  

So lets say that both engine can run stoich (lots of NA motors are actually made with "lesser" components, so can't run as high of combustion temps, but I'm ignoring that).  So just lowering the engine speed lowers the rotating losses enough to favor the turbo.  And then back the the components thing- turbos generally have better valve and valve seats- which are the first weak point in the chain of points.  Normally, the manifolds are the same temp, then for the boosted car, they have the turbo- which can deal with really high exhaust temps. Next temp sensitive component are the O2 sensors and catalyst- and the turbo has a 100-200F advantage just because of the turbo.

Basically, the whole deal is about managing combustion and exhaust temps.   Knock is a factor, but minor compared to exhaust temp protections.  And modern turbo's are really amazing when it comes to peak temps it can deal with- for this thread's subject, the 3.5T's turbo was well capable of over 1700F exhaust temp, and it's real time weakness were the valve seats.  NOT to say there was an issue- but when push came to shove, first enrichment was to keep the seats cool compared to the manifold or turbo components.  I was pretty surprised by that. (edit- this is why running closed loop with a WB is SO very valuable- you can dial that into a pretty tight temp window).

You compare some reasonably equal engines- a 1.6T vs a 2.4 NA.  The interesting thing is when you add in the 2.0l T, that doesn't have to try hard to move the vehicle.  For city driving, I would thing the 2.4 would be cheapest, the 1.6T best in the city, and the 2.0T best towing or at real highway speeds.  I know the latter has played out for us- I had a 1.5T Fusion that we took to New York, and it was easily out done FE wise by a 2.0T Escape.  

BTW, the 5.0l V8 truck engine exists just for the Mustang to have it.  It has no real redeeming value in a truck other than people who prefer the V8 for the v8's sake.  If the F150 didn't have it, there's no way the Mustang could afford it.  This isn't really that new, but back in the 60s-80s, the workhorse engines were big block V8s for and F or E 250 and up.

Pete. (l33t FS) said:

DWNSHFT said:

alfadriver said:

In reply to CyberEric :

The turbo can run more stoich under boost than the NA motor car.

I'd really like to know more about this.  In my limited, old-school understanding turbos run rich under boost hence mileage suffers significantly if you're in boost.  Alfadriver, I appreciate that you are a total subject matter expert in this area and I'm not doubting you.  But I'd like to know how technology has moved past my outdated understanding.  Direction injection?  Electronic boost control?  How does this play out in the market comparing torque, power and fuel mileage in, for example, a 1.6 turbo versus a 2.4 NA.

GRM, there could be a good story there.

Don't some of the smaller Ecoboosts run stoich basically all the time?

The next time I have to drive one with a scantool, I'll watch the equivalency ratio and see what happens.

 

Boost is weird, depending on the cam timing (which is now computer controlled) you might not be seeing the same mass flow at even 2-3psi as a naturally aspirated engine does at WOT because of the higher exhaust manifold pressure.  Logging my Volvo is interesting, I may be at "atmospheric" or even slightly into boost in the intake manifold, but the charge pipe pressure will be 6-7psi.  It takes exhaust pressure to spin the turbo up that much.

 

(For the tech weenies: the Volvo computer strategy uses a MAF but it also does a charge pipe referenced alpha-N calculation.  There is no intake manifold pressure sensor.  I don't know if anyone else does it this way.  Chevy might on the 1.4, given how they are similarly sensitive to dirty throttle bodies)

They try to.  As time goes on, the lower CO requirements almost require WOT stoich operation.  Which is a big deal for motorhomes and box trucks.

Funny- 20 years ago when I first did some turbo work, the assumption was that either fabricated or cast stainless manifolds were required.  Now someone developed some cheap iron alloys and turbo materials that can deal with +1700F running continuously.  

In reply to alfadriver :

TripleK was proud of the materials they used in my turbo, in 2003.  It was able to handle sustained 1700F EGT.  They had their own press release for it.  Peanuts for a racing turbo but amazing for a mass production turbo.   It's good to see this technology filter out into more high volume applications.

That was over 20 years ago.  20 years before that, turbos had a lifespan shorter than timing belts.

KKK was purchased by Borg-Warner, I do believe.

In reply to alfadriver :

Thanks for your thoughts!  [And that was fast, too!]

I used the 2.4 NA and 1.6 turbo examples because the manufacturers seem to have come to the same conclusion.  My Hyundai Sonata could be had with the base 2.4 NA or upgrade to a 1.6 turbo or a 2.0 turbo.  I wanted the 1.6 turbo but didn't like that the DCT clutches weren't covered by the warranty so I ended up with the 2.4.  I think other manufacturers offer similar options.  And it is telling that power and torque outputs are pretty similar for similar engines from different manufacturers.

I'm surprised that component temps are the limiting factor now.  I guess knock is so old-school.  That level of expertise at the manufacturer level is pretty awesome.  I bet most tuners aren't monitoring those other details so they might get big numbers but reliability, well, isn't warrantied.  :-)

In reply to DWNSHFT :

Look into the port flow (direction) and combustion chamber tech that Mercedes is using in their fours.  They have intense amounts of mixture motion (fast ignition is detonation resistant ignition) and it's curious how the injectors are centrally located while the spark plugs are off to the side, between the exhaust valves.  But they make 375-425hp from 2l engines and they use these engines in Sprinters.

An aside, one of our technicians drove a X6M (hot-valley twin turbo V8) and a new 2.3 Ecoboost Explorer back to back and felt that the Explorer was a lot more responsive.  Pure peak numbers aren't end all be all.

Trying to follow all this discussion...  I have a 2008 E350 with the 5.4.    Have had 202,000 carefree miles so far.   I tow any one of my 5 trailers every day.  The heaviest being the enclosed trailer at about 5,000 lb. loaded.   The van itself is pretty loaded with tools also.

If I needed to replace this fantastic workhorse what Ford engine should be the choice?

Thanks for the info on Ford DI. Very helpful!

I bought an abused 220k Ecoboost wagon during covid, did a little camper build, and have since put about 60k on it.

The main issue with the Ecoboost is exhaust manifolds warping and breaking bolts which seems to happen anywhere from 50k to 150k. Access is not as good as in the trucks, so it's long and tedious but not that hard if you have some strategy for extracting broken bolts. The factory fixed this sometime in 2021. I think it's also worse in the vans because water drops from the base of the windshield onto the turbos. This is also the source of some other possible issues, like wet air filter, bad main electrical harness connections, and things on top of the engine like coil bolts that don't come out because water pools on them. Easy enough to prevent with any number of ugly homebrew water diverters, but something to watch for. (Various ziploc bags and iced tea bottles underhood might actually be a positive, showing the owner was aware of all this and proactive about it.)

Both the EB and the 3.7 seem relatively reliable and multiple hundreds of thousands of miles doesn't seem rare; the 3.7 obviously doesn't have the turbo and manifold to go bad, but does seem like it more frequently needs cats. 

The diesel is rather problematic. For emissions systems mostly I believe, but unlike the trucks the knowledge base just isn't there and the engine was only used in the Transit in North America, so I would avoid that orphan. The cheapest used Transits tend to be diesels; that should tell you something.

If you're in the rust belt watch the front subframe for rust. There are a couple of bolts that are a bear to get out to replace the front control arms or subframe, and it ends up all needing to be cut into pieces if you need to, for example, drop the trans pan. Transits seem to rust from the bottom up, but it doesn't look like any of the modern vans are particularly corrosion resistant.  

Other things to be aware of on the platform: tire size is limited to about a 245/75-16 and the speedo can't be fully corrected to that easily. Ground clearance and particularly departure angle on an extended van are worse than most alternatives. Passenger vans have the world's biggest side airbags that go all the way back and can't be disabled without also disabling the front row side bags, if you're looking to build stuff in the rear. The rear end is a full-float 9.75 and rear brakes go fast (like 30k) and can be expensive if you were to pay someone (But it also means that an F-150 eLocker should bolt right in). As has been stated, cooling is probably the towing limitation; having a rear air conditioner drops the tow rating, for example. 

They're a weird mishmash of Euro Ford and US Ford, resulting in stuff like the aforementioned windshield dumping water onto the engine or needing to take the subframe out to take off the transmission pan but in general they're pretty straightforward to work on and parts and info are pretty accessible. 

Transits do drive better than Sprinters or Promasters, and are in a different league from Econolines etc. especially in GRM qualities like steering and braking. A Transit would still be my choice of van, particularly now that prices are coming down a bit. 

In reply to pkung :

Fantastic! Thanks for all that info. Super helpful. Sounds like either a 3.7 or EB game s gonna be good enough. 

Re tire size, I cannot believe the small size Ford put on these vans! It weighs as much as a Econoline from what I can tell and has smaller tires. No me gusts. That would be something I would upgrade. I was reading on the Transit forums about people putting 245/70s at least, but needing to cut some wheel well pieces and rolling odor any bigger. They talked about using Forscan to update the speedo.

Yeah and off-roading will be out of the question given the lower ground clearance. My E250 was actually decent off road due to the ground clearance. I surprised the hell out of some 4Runner/Landcruiser guys in Death Valley once coming up a rough road.

The Transits rust a hell of a lot less than the Mercedes equivalent.

The control arms aren't bad to do if you have a swivel socket and some extensions, to get the forward brace out of the way.

The rear axle problem showed up as a groaning in low speed turns that got progressively worse then threw a traction control light. As I recall the worn part had a tone ring integrated?

pkung's comment about odd corrosion made me recall another odd repair :a plastic valve cover had to be replaced because the coil bolt hole stripped @ ~125k

As for off road, be aware that the lowest piece in front behind the plastic bumper on the EB is the intercooler. I stoved mine in once on a stump I didn't see in tall grass. It was bad enough that I kinked the rubber hose and the engine died, I thought I had killed it! Much heaving and I was able to reef it back into drivable shape and drove home.

I run 225/75/16 AT tires w/o any clearance issues. Good rubber is crucial for ice/snow or slippery surfaces 

In reply to petemc53555 :

Oh, hell, that happens on practically every 5.0.  The threaded inserts rip out of the plastic valve cover after the coil bolt rusts to it.

Clean up the threads, mix up some 5 minute epoxy, stick the insert back in the hole, and it's good for another 100,000mi.