Ecoboost engine question

Turtle n Peeps wrote:

johndeerefarmer wrote:
3.5 eco is not maxed out power wise. Lots and lots of guys are running tunes with 80 or more extra hp and 120 ft lbs of torque.
Ford overbuilt the 3.5 block so it can handle this extra power. I have heard of no tranny's failing but one guy lost a rear end probably becaus he towed 15k

That's like saying my blown SBC is not maxed out at 600 HP. I could always go 40% over on the blower and make 1,000 HP. :R

This is an easy formula:

When power goes up, duty cycle goes down.
When power goes down, duty cycle goes up.

How high of a duty cycle do you want? How much power you want?

Good point. But, I think most would agree truck manufacturers tend to engineer their OEM products from a very conservative position to keep the MTBF high (or, as you put it, duty-cycle). IMO, with hundreds of thousands of 3.5 Ecoboosts on the road, if there was a big worm in this engine it would have crawled out screaming by now.

I can see why Ford might be hesitant about putting the 3.5 Ecoboost in their F250/350 trucks. There's certainly the impression with a lot of folks that somehow 420 ft. lbs. of torque at 2500 RPM from a turbo-charged V6 is somehow mechanically inferior to the 6.2's 405 ft. lbs. of torque at (a much higher) 4500 RPM. Ford knew they were taking a HUGE risk even coming out with the 3.5 Ecoboost in their smaller 1/2 tons to begin with. Not from an engineering perspective, but from a marketing perspective. IMO, many of the concerns expressed here and elsewhere about the 3.5 Ecoboost were already on the Ford's marketing department's list of concerns long before the Ford engineers ever made their first prototype 3.5 Ecoboost engine.

Turtle n Peeps wrote:

johndeerefarmer wrote:
3.5 eco is not maxed out power wise. Lots and lots of guys are running tunes with 80 or more extra hp and 120 ft lbs of torque.
Ford overbuilt the 3.5 block so it can handle this extra power. I have heard of no tranny's failing but one guy lost a rear end probably becaus he towed 15k

That's like saying my blown SBC is not maxed out at 600 HP. I could always go 40% over on the blower and make 1,000 HP. :R

This is an easy formula:

When power goes up, duty cycle goes down.
When power goes down, duty cycle goes up.

How high of a duty cycle do you want? How much power you want?

There are guys with 40k tuned miles and no issues other than having to change spark plugs. How's that? :)

Oops, double post, sorry!

Turtle n Peeps wrote:

johndeerefarmer wrote:
3.5 eco is not maxed out power wise. Lots and lots of guys are running tunes with 80 or more extra hp and 120 ft lbs of torque.
Ford overbuilt the 3.5 block so it can handle this extra power. I have heard of no tranny's failing but one guy lost a rear end probably becaus he towed 15k

That's like saying my blown SBC is not maxed out at 600 HP. I could always go 40% over on the blower and make 1,000 HP. :R

This is an easy formula:

When power goes up, duty cycle goes down.
When power goes down, duty cycle goes up.

How high of a duty cycle do you want? How much power you want?

This.

It's probably the predominant reason (along with fuel economy) that many medium duty commercial trucks have lower output than the same powerplant is tuned to in personal-use pickups. Reliable service year-after-year is going to be easier to achieve at 250hp/610tq as opposed to 400hp/800tq.

johndeerefarmer wrote:
3.5 eco is not maxed out power wise. Lots and lots of guys are running tunes with 80 or more extra hp and 120 ft lbs of torque.
Ford overbuilt the 3.5 block so it can handle this extra power. I have heard of no tranny's failing but one guy lost a rear end probably becaus he towed 15k

That's like saying my blown SBC is not maxed out at 600 HP. I could always go 40% over on the blower and make 1,000 HP. :R

This is an easy formula:

When power goes up, duty cycle goes down.
When power goes down, duty cycle goes up.

How high of a duty cycle do you want? How much power you want?

3.5 eco is not maxed out power wise. Lots and lots of guys are running tunes with 80 or more extra hp and 120 ft lbs of torque.
Ford overbuilt the 3.5 block so it can handle this extra power. I have heard of no tranny's failing but one guy lost a rear end probably becaus he towed 15k

goducks10 wrote:

otrfun wrote:

goducks10 wrote:
My guess is that the 3.5 is maxed out with the 11,300lb tow rating in an F150. Add the extra weight of the F250/350 and the 3.5 would have a hard time reaching the 15,000+lb tow rating offered with the 6.2. It works fine in it's own element.

The 3.5 Ecoboost has 15 lbs. more torque than the 6.2, not to mention the 6.2 develops max torque at a relatively high 4500 RPM vs. the 3.5 Ecoboosts's much lower, diesel-like, 2500 rpm. I would think the limiting factor (ref tow capacity) for the 3.5 Ecoboost F150 is the 1/2 ton drivetrain and suspension.

Concerns about the 3.5 Ecoboost duty-cycle and fuel economy aside, I believe the 3.5 Ecoboost's torque characteristics would provide much better realworld performance (to include towing) than a 6.2 in a F250/350 chassis. Torque does all the work. The 3.5 Ecoboost has more and at a much lower RPM than the 6.2.

IMO the 3.5 is maxed out for stress in the F150. Do you really think the 3.5 in a 7-800+lb heavier truck can pull a 15,700lb 5th wheel? Even in the HD F150 it's still 11,300lb max towing. And the HD F150 has payloads equal to the F250 in certain configs. So with your way of thinking the HD F150 3.5 should be able to tow 13,000lbs with the 3.5. Why didn't Ford up the tow rating in the HD F150? Just because it has more torque at lower rpms doesn't mean it's internals are up to heavier towing. Why would Ford waste their engineering money on building a 6.2 for their HD trucks if the 3.5 was up to the task.

In the context of this debate, I think you have to compare these two engines in the context of them using the same chassis and drivetrain. No, the F150 3.5 Ecoboost cannot tow 13,000 lbs. Why? Because the F150's 1/2 ton drivetrain and suspension won't support it, not because of the engine.

Would a 6.2 mounted in an F150 chassis support more tow weight? If you say, yes, than how and why? The 6.2 puts out less torque than the 3.5 Ecoboost. Torque tows trailers, not HP.

The 3.5 Ecoboost engine is designed to put out 420 ft. lb. of torque. The 6.2 is designed to put out 405 ft. lbs. of torque. IMO, torque is torque. Is 1 ft. lb. of higher displacement V8 torque somehow "better" than 1 ft. lb. of turbo-charged, V6 torque? If so, can you explain how and why?

The fact the 3.5 Ecoboost has more torque than the 6.2 is not even the real clincher. The real clincher is the fact the torque on the 3.5 Ecoboost is output at nearly half the RPM's of the 6.2. In the realworld this makes the 3.5 Ecoboost much more useful and desirable from a drivability perspective. This is why diesels are so, so addictive. This is also why the Ecoboost has been such a run-away success for Ford. The 3.5 Ecoboost does one heckuva fine job of emulating a diesel engine's torque curve.

otrfun wrote:

goducks10 wrote:
My guess is that the 3.5 is maxed out with the 11,300lb tow rating in an F150. Add the extra weight of the F250/350 and the 3.5 would have a hard time reaching the 15,000+lb tow rating offered with the 6.2. It works fine in it's own element.

The 3.5 Ecoboost has 15 lbs. more torque than the 6.2, not to mention the 6.2 develops max torque at a relatively high 4500 RPM vs. the 3.5 Ecoboosts's much lower, diesel-like, 2500 rpm. I would think the limiting factor (ref tow capacity) for the 3.5 Ecoboost F150 is the 1/2 ton drivetrain and suspension.

Concerns about the 3.5 Ecoboost duty-cycle and fuel economy aside, I believe the 3.5 Ecoboost's torque characteristics would provide much better realworld performance (to include towing) than a 6.2 in a F250/350 chassis. Torque does all the work. The 3.5 Ecoboost has more and at a much lower RPM than the 6.2.

IMO the 3.5 is maxed out for stress in the F150. Do you really think the 3.5 in a 7-800+lb heavier truck can pull a 15,700lb 5th wheel? Even in the HD F150 it's still 11,300lb max towing. And the HD F150 has payloads equal to the F250 in certain configs. So with your way of thinking the HD F150 3.5 should be able to tow 13,000lbs with the 3.5. Why didn't Ford up the tow rating in the HD F150? Just because it has more torque at lower rpms doesn't mean it's internals are up to heavier towing. Why would Ford waste their engineering money on building a 6.2 for their HD trucks if the 3.5 was up to the task.

otrfun wrote:

CarterKraft wrote:
My opinion... We don't need small displacement turbo gas engines in HD applications we need small displacement turbo diesel engines in HD applications.
Look at Cummins new 5.0 V6. 5.0 Cummins

Makes perfect sense! But . . . human nature being what it is most likely it'll be ruthlessly compared to the 6.7 850 ft. lb. diesels and called wimpy . . .

One of the first complaints about the new Ram 1500 EcoDiesel was that it *only* could tow 9,200 lbs. Doesn't matter it's only a 1/2 ton and gets 25-28 MPG when it's not towing.

Unfortunately you are right. Can't be the cool kid on the block with a V6. The eco-boost does well in it's class but it would be low man in the HD class and be laughed at by it's peers. Even though it might actually a better choice than the base 5.4 engine the cool kids would never give it a chance.

Water-Bug wrote:

jerem0621 wrote:

Engineer9860 wrote:
Now let me get this right..........

A direct injection turbo Diesel engine is workable in a heavy duty pick-up truck, but a direct injection turbo gas engine is not?

Yes! Everyone knows that 6 cyl can't work in a HD Truck..... Everyone knows that just asking for mains to freeze and cranks to break. :D

Hope that was meant as a joke. RAM Cummins is a 6 cylinder.

Of course it was... Very tongue in cheek. Cummins and inline 6 gassers have been powering trucks for decades.