New Light & Medium Duty News

[7Mary3]

The gorilla in the room is the Navistar/GM MD, what engine will those trucks have. The Duramax v8 and 6.0 is a given, what else.

 

Navistar/GM trucks will launch with the 6.6L Duramax/Allison only, no 6.0L gas option. Gas/CNG/LPG engine a year or so later, maybe for 2020 MY. Latest I am hearing on that is it will be an all-new engine platform, not a variation on the current 6.0L..

[jpd80]

 

Navistar/GM trucks will launch with the 6.6L Duramax/Allison only, no 6.0L gas option. Gas/CNG/LPG engine a year or so later, maybe for 2020 MY. Latest I am hearing on that is it will be an all-new engine platform, not a variation on the current 6.0L..

Do you think that GM would revive the old 8.1 Liter BB V8 but with a bit of current Gen 5 small block thinking

like VCT, AFM and Direct Injection.That could make for an easy and effective Medium Duty Truck engine..

Edited December 26, 2017 by jpd80

[twintornados]

Do you think that GM would revive the old 8.1 Liter BB V8 but with a bit of current Gen 5 small block thinking

like VCT, AFM and Direct Injection.That could make for an easy and effective Medium Duty Truck engine..

.

Talk about taking a step backwards in development...if GM wants to come up with a truly innovative path...they should revive Cadillacs' Northstar V8 program with todays advances in technology.

[7Mary3]

.

Talk about taking a step backwards in development...if GM wants to come up with a truly innovative path...they should revive Cadillacs' Northstar V8 program with todays advances in technology.

 

I think the Northstar or any similar engine would have about zero application in a heavy duty pickup or medium duty commercial vehicle. I large displacement 'no brainer' engine is what is called for. Maximum durability and high torque at low r.p.m.'s does not require DOHC, 4 valve heads, or elaborate turbocharger setups.

 

Wait and see what 7X is...........

[jpd80]

I notice that Ford's Medium Duty truck sales seem to have fallen significantly in 2017 versus 2016.

Could it be that Ford has filled the need of those mostly class 6 gasoline truck buyers?

 

Since Class 6 and 7 trucks are mostly loaded in service, there's little or no benefit to be derived

with forced induction gasoline, when larger capacity atmo engines tend to maintain leaner

mixtures under moderate load.

Edited December 26, 2017 by jpd80

[SteelyD]

 

I think the Northstar or any similar engine would have about zero application in a heavy duty pickup or medium duty commercial vehicle. I large displacement 'no brainer' engine is what is called for. Maximum durability and high torque at low r.p.m.'s does not require DOHC, 4 valve heads, or elaborate turbocharger setups.

 

Wait and see what 7X is...........

 

That 7.0 Lima in the MD's was a terrible engine wasn't it.

[Bob Rosadini]

 

I think the Northstar or any similar engine would have about zero application in a heavy duty pickup or medium duty commercial vehicle. I large displacement 'no brainer' engine is what is called for. Maximum durability and high torque at low r.p.m.'s does not require DOHC, 4 valve heads, or elaborate turbocharger setups.

 

Wait and see what 7X is...........

Agree on the simplicity-just go back to the 60's when the 401-477 and 534 Super Duties were a cost effective alternative to the big bore diesels of the day. I believe the early 534 was rated at 277 HP and 490 lb.ft at like 1800 RPM's. By the early 80's the EPA effectively killed these big gas engines, but with today's electronics, how efficient/effective could they be? With pushrods!

 

Now the other side of the coin, is not the Ecoboost success basically because of turbocharging? And are there ANY diesels today-other than small industrials-that are not turbocharged?

 

Again 7m-agree with your comment on "KISS"-but I do look at what turbocharging has managed to accomplish with the Ecoboost concept.

[jpd80]

If the truck's engine has enough basic capacity, then it maintains more airflow through the engine

with mixture strength around 14-14.7:1 Staying out of that 12.7 to 13.5:1 mixture strength adds

a lot to the engine's overall efficiency when carrying loads, something a GDIT engine can't do.

Edited December 27, 2017 by jpd80

[Bob Rosadini]

If the truck's engine has enough basic capacity, then it maintains more airflow through the engine

with mixture strength around 14-14.7:1 Staying out of that 12.7 to 13.5:1 mixture strength adds

a lot to the engine's overall efficiency when carrying loads, something a GDIT engine can't do.

JP-please elaborate-too technical for this o'l boy.

[jpd80]

JP-please elaborate-too technical for this o'l boy.

Uh, sorry. A turbo engine would be on boost most of the time, meaning it has to run richer to protect against detonation....

A bigger naturally aspirated engine would probably cruise along with a load more easily, staying out of those richer mixtures..

Edited December 27, 2017 by jpd80

[Sevensecondsuv]

Basically gas engines need to run richer than stoich (14.64:1 air-fuel ratio) under boost to avoid pre-ignition (detonation). The extra fuel basically cools the compressed air charge. This can be significant - a fuel trim of 0.8 lambda (~11.4:1 air-fuel ratio) is common for port injected gasoline engines under boost. Direct injection mitigates this to an extent but doesn't eliminate the need for rich mixtures.

 

On the other hand, the diesel cycle engine doesn't have a fixed stoichiometric ratio. Thus turbocharging basically just adds "displacement" by forcing in additional air without need for an extra rich mixture to fight pre-ignition.

 

So for a gas engine running around at high load most of the time (like a medium duty application) naturally aspirated makes more sense since it'll run at 14.6:1 AFR vs the 11:1-13:1 mixture that would be required for a turbo gasoline engine running under boost.

 

Turbo works on the half tons because the duty cycle is low and they spend most of their time out of boost where they can run at stoich. It's also why we haven't seen ecoboost in the 250/350. Try loading up a ecoboost f150 with a big trailer though and it'll suck fuel as bad or worse than it's V8 peers/competition due to the boost enrichment.

Edited December 27, 2017 by Sevensecondsuv

[jpd80]

The big NA engine also gives bags of torque down low right where a MD truck needs it to lift a heavy load from rest.

There's a lot of good reasons to have a large NA engine in a MD Truck, big simple and less to go wrong under constant load.

Edited December 27, 2017 by jpd80

[Bob Rosadini]

Uh, sorry. A turbo engine would be on boost most of the time, meaning it has to run richer to protect against detonation....

A bigger naturally aspirated engine would probably cruise along with a load more easily, staying out of those richer mixtures..

thx-my SHO (2010) requires 91. Same for newer Ecoboosts?

[Bob Rosadini]

Basically gas engines need to run richer than stoich (14.64:1 air-fuel ratio) under boost to avoid pre-ignition (detonation). The extra fuel basically cools the compressed air charge. This can be significant - a fuel trim of 0.8 lambda (~11.4:1 air-fuel ratio) is common for port injected gasoline engines under boost. Direct injection mitigates this to an extent but doesn't eliminate the need for rich mixtures.

 

On the other hand, the diesel cycle engine doesn't have a fixed stoichiometric ratio. Thus turbocharging basically just adds "displacement" by forcing in additional air without need for an extra rich mixture to fight pre-ignition.

 

So for a gas engine running around at high load most of the time (like a medium duty application) naturally aspirated makes more sense since it'll run at 14.6:1 AFR vs the 11:1-13:1 mixture that would be required for a turbo gasoline engine running under boost.

 

Turbo works on the half tons because the duty cycle is low and they spend most of their time out of boost where they can run at stoich. It's also why we haven't seen ecoboost in the 250/350. Try loading up a ecoboost f150 with a big trailer though and it'll suck fuel as bad or worse than it's V8 peers/competition due to the boost enrichment.

Very good- I guess my SHO impresses me with its low end torque (it will climb a hill at like 1100 RPM without downshifting) yet when I hear 150 owners bitching about fuel mileage-while at the same time bragging about pulling ability- I get the picture.

[7Mary3]

Basically gas engines need to run richer than stoich (14.64:1 air-fuel ratio) under boost to avoid pre-ignition (detonation). The extra fuel basically cools the compressed air charge. This can be significant - a fuel trim of 0.8 lambda (~11.4:1 air-fuel ratio) is common for port injected gasoline engines under boost. Direct injection mitigates this to an extent but doesn't eliminate the need for rich mixtures.

 

On the other hand, the diesel cycle engine doesn't have a fixed stoichiometric ratio. Thus turbocharging basically just adds "displacement" by forcing in additional air without need for an extra rich mixture to fight pre-ignition.

 

So for a gas engine running around at high load most of the time (like a medium duty application) naturally aspirated makes more sense since it'll run at 14.6:1 AFR vs the 11:1-13:1 mixture that would be required for a turbo gasoline engine running under boost.

 

Turbo works on the half tons because the duty cycle is low and they spend most of their time out of boost where they can run at stoich. It's also why we haven't seen ecoboost in the 250/350. Try loading up a ecoboost f150 with a big trailer though and it'll suck fuel as bad or worse than it's V8 peers/competition due to the boost enrichment.

 

 

Yeah, what he said. Exactly why Ecoboost has no application beyond an F-150, at least in it's current form.

[jpd80]

I wonder if F150 owners who intend doing a fair bit of towing are steered towards the 5.0 V8,

especially now that it has a 10-speed auto.and better torque curve..

[Bob Rosadini]

I wonder if F150 owners who intend doing a fair bit of towing are steered towards the 5.0 V8,

especially now that it has a 10-speed auto.and better torque curve..

Might be but doesn't the 3.5 EB have the higher ratings-both payload and towing??

[hwyman3]

thx-my SHO (2010) requires 91. Same for newer Ecoboosts?

 

 

I have a 2016 Explorer 3.5L EcoBoost and I can run 87 in it.

[Sevensecondsuv]

Might be but doesn't the 3.5 EB have the higher ratings-both payload and towing??

It did on the 6-spd trucks, not sure about the 10 speed trucks. It does have more torque than the 5.0, so I don't doubt the tow rating. It'll really use fuel though and save you exactly nothing over the V8 if you load it up though. Horse power is simply air flow rate through the engine and if you're using boost to achieve those power numbers it will require a richer mixture than a naturally aspirated engine will. So for high loads NA is better fuel economy. Ecoboost achieves better overall economy by having reduced pumping losses vs a larger naturally aspirated engine when running at low load / duty cycle.

[jpd80]

It's the same reasoning as the Medium truck but with everything scaled down- engine size, truck weight and payload /towing

The only issue F150 has is meeting CAFE and that's why the 6.2 was stopped but still sells well in F250.

Edited December 27, 2017 by jpd80

[SoonerLS]

Might be but doesn't the 3.5 EB have the higher ratings-both payload and towing??

It did and still does on towing; the Coyote cuts out at 11,600lbs, while the EB35 goes up to 13,200lbs. Max payload is about the same for the EB35 and Coyote with the Coyote taking a slight edge (probably because the Coyote weighs less than the EB35).

Edited December 28, 2017 by SoonerLS

[Bob Rosadini]

It did and still does on towing; the Coyote cuts out at 11,600lbs, while the EB35 goes up to 13,200lbs. Max payload is about the same for the EB35 and Coyote with the Coyote taking a slight edge (probably because the Coyote weighs less than the EB35).

Now that is a surprise-the weight issue. Two turbos outweigh a bigger block!

[SoonerLS]

Now that is a surprise-the weight issue. Two turbos outweigh a bigger block!

I was surprised, too. It's not a huge difference (IIRC, it's around 50lbs); I'd guess that most of the difference is in the turbos and related plumbing. I can't find the actual engine weight specs at the moment, but the EB35 curb weights are heavier than the Coyotes in the same wheelbases, cab configs, and driveline configs.

[theoldwizard]

No, the 6.2 Boss is built at Romeo engine plant, Michigan

 

The 7X is going to be assembled in the Annex plant, next to Windsor Engine(TMEP)

apparently, that used to be a low volume line for the mod engines

So there is a possibility that both the 6.2L and 7x will be in production together for some period of time ! &x seems kind of big for F250/350.

[theoldwizard]

Uh, sorry. A turbo engine would be on boost most of the time, meaning it has to run richer to protect against detonation....

A bigger naturally aspirated engine would probably cruise along with a load more easily, staying out of those richer mixtures..

The joke about EcoBoost is that you can have Eco or you can have Boost, just not both at the same time ! For reasons stated above !!