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Deleted member 9101
Guest
The run of the mill 3.5 is an impressive motor... The 3.5 HO is even better. What's awesome about thr EcoBoost engines is they are just a tune away from making quite a bit more power.
VK56VD vs the "competition"
- Thread starter leeleatherwood
- Start date
The run of the mill 3.5 is an impressive motor... The 3.5 HO is even better. What's awesome about thr EcoBoost engines is they are just a tune away from making quite a bit more power.
broncobowsher
Adventurer
Dig into the VK56 and it gets even better. I have one in the living room as a lamp. I was really impressed taking it apart to build the lamp. I'm sure I will miss some of the design elements, but here we go...
Deep skirt block with cross bolted 6-bolt main caps, all 5 of them. Steel caps, not cast.
Forged crank. Full counterweight (even the old 426 hemi skipped the center 2 counterweights and the drag racers had to weld them on). under cut fillet radius, hollowed throws, induction hardened journals, micro polished. The crank is a work of art.
Reverse flow cooling. Heads first then the cylinders.
MLS head gaskets.
The modern variable cam timing and the variable intake lift and duration.
The pistons and rods were nice looking parts as well.
This thing has all the dream race parts that were never mass production. And it has a good V8 sound as well.
Deep skirt block with cross bolted 6-bolt main caps, all 5 of them. Steel caps, not cast.
Forged crank. Full counterweight (even the old 426 hemi skipped the center 2 counterweights and the drag racers had to weld them on). under cut fillet radius, hollowed throws, induction hardened journals, micro polished. The crank is a work of art.
Reverse flow cooling. Heads first then the cylinders.
MLS head gaskets.
The modern variable cam timing and the variable intake lift and duration.
The pistons and rods were nice looking parts as well.
This thing has all the dream race parts that were never mass production. And it has a good V8 sound as well.
leeleatherwood
Active member
Awesome info, are you talking about VK56DE (Like in 1st Gen Titans) or VK56VD (Newer titans, Infinitis, Armadas, etc)?
I have plans within the next 5 years to VK Swap a 350z or 370z and turbo it, so the the info you provided is pretty exciting.
Dances with Wolves
aka jk240sx
broncobowsher
Adventurer
VD but most of it applies back to the first gen. Except the VVEL system First gen had two different variable cam. Early years were single adjustable and after 08(?) went do dual variable cam.
There is even early and late VD. Early has a traditional thermostat and a single variable cam. Late had dual variable cams and computer controlled thermostat.
There is even early and late VD. Early has a traditional thermostat and a single variable cam. Late had dual variable cams and computer controlled thermostat.
leeleatherwood
Active member
Is it possible for tuners to change the valve duration by using the VVEL system? I think it would be possible to decrease duration, but not increase it. If the camshaft has 0 lift at a certain degree, then multiplying it by anything from the VVEL will always result in 0.
I know that Nissan uses the VVEL to alter valve duration, but I am curious if any tuners are actually modifying those parameters to get increased power. My guess is that because really only Nissan and I think BMW? Have VVEL systems, that nobody is doing it because they either dont know about it, or dont understand it.
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broncobowsher
Adventurer
I don't think you understand how the VVEL system works. There is no traditional style camshaft.
Don't know about the 56, but the VQ37 I have heard of tuners adjusting the max lift limit screw. Combined with a tune.
My understanding is these engines tend to throttle the engine via the amount of valve opening once they are up to speed and not the actual throttle valve itself. Something about pumping losses and a manifold full of vacuum.
If you want more power, open the exhaust. The difference between the 375HP van and the 390HP truck is all in the exhaust from the cat back.
Don't know about the 56, but the VQ37 I have heard of tuners adjusting the max lift limit screw. Combined with a tune.
My understanding is these engines tend to throttle the engine via the amount of valve opening once they are up to speed and not the actual throttle valve itself. Something about pumping losses and a manifold full of vacuum.
If you want more power, open the exhaust. The difference between the 375HP van and the 390HP truck is all in the exhaust from the cat back.
leeleatherwood
Active member
There are still camshafts, they just use an electronically controlled linkage to adjust the ratio between camshaft lift and valve lift.
If camshaft lift is 0.5", but the linkage ratio is 0, the valve lift will be zero. 0.5 x 0 = 0.
But if the linkage ratio was 1.5, then valve lift would be 0.75". 0.5 x 1.5 = 0.75
Using this method they can control valve lift and duration.
Based on this, and after watching the video. I am pretty sure you cant just program in more duration if the camshaft doesnt have it available also.
broncobowsher
Adventurer
It's not a ratio adjustment. it's how much of the snail shape is exposed to the lifter bucket compared to how much of the base circle.
At low lift, mostly on the base circle and only the first bit of the snail is used.
At max lift, less of the base circle and more of the snail is used.
If the ratio changed you would have a fixed (or really close to it) duration and variable lift.
But this isn't a ratio change, it just shifts how far up the ramp before the ramp reverses and closes again.
If max lift is 10mm the snail rolls from the base circle up to the 10mm lift mark, and backs up again.
But if it is only trying to reach 5mm of lift, the snail only goes half way to the 5mm mark before reversing.
The eccentric that would be the intake cam is at max lift at the 5mm mark at the same position as the 10mm mark. But since the 5mm lift starts later and ends later it has a lot less duration.
Adding duration means the snail has to spend more time holding the valve off the seat. That means the VVEL has to be set to get on the snail sooner which pushes the snail further down on the valve and you get more lift.
Just think of the snail as a regular camshaft lobe but it doesn't make a full circle. The rotation is replaced by an oscillation. The lobe starts opening the valve then backs up again. If the oscillation were 90° of the camshaft, it will always be 90° of rotation. The VVEL just changes if the first 30° is on the base circle and 60° is on lift, or if the first 60° is on the base circle and only 30° is on lift.
At low lift, mostly on the base circle and only the first bit of the snail is used.
At max lift, less of the base circle and more of the snail is used.
If the ratio changed you would have a fixed (or really close to it) duration and variable lift.
But this isn't a ratio change, it just shifts how far up the ramp before the ramp reverses and closes again.
If max lift is 10mm the snail rolls from the base circle up to the 10mm lift mark, and backs up again.
But if it is only trying to reach 5mm of lift, the snail only goes half way to the 5mm mark before reversing.
The eccentric that would be the intake cam is at max lift at the 5mm mark at the same position as the 10mm mark. But since the 5mm lift starts later and ends later it has a lot less duration.
Adding duration means the snail has to spend more time holding the valve off the seat. That means the VVEL has to be set to get on the snail sooner which pushes the snail further down on the valve and you get more lift.
Just think of the snail as a regular camshaft lobe but it doesn't make a full circle. The rotation is replaced by an oscillation. The lobe starts opening the valve then backs up again. If the oscillation were 90° of the camshaft, it will always be 90° of rotation. The VVEL just changes if the first 30° is on the base circle and 60° is on lift, or if the first 60° is on the base circle and only 30° is on lift.
hurley842002
New member
My Xterra is right at 160k on the 4.0, I’m hoping to start slowly sourcing parts for a VK swap, love the idea of that engine in a vehicle the size of an Xterra.
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Sent from my iPad using Tapatalk
bigskypylot
Explorer
I like the Ecoboost but given the choice, I'd take the VD, 5L Coyote and the 7.3L Godzilla. My buddy that has wrenched for Ford for 28+ years said they area good engine for the most part but he would never own one out of warranty, He drives the F150 V8 and it gets respectable mpgs. Now if you weren't concerned about warranty issues and had some towing to do and didn't need a Super Duty, you can't go wrong with the 3.5
bigskypylot
Explorer
I like my VK56DE, it gives the X some get-up-and-go 
I like my VK56DE, it gives the X some get-up-and-go
Out of curiosity -- are you tsill running the stock fuel tank? And if so what kinda mileage are you getting? It seems VQ40 gets 300 miles to a tank, that's gotta be worse with a vk swap no?
bigskypylot
Explorer
From what I've heard, they area really well-built engine. The rods are forged but are a bit on the narrow side. I'm looking at building my motor at some point. It's a 2015 with 5,700 miles on it. I have the JWT CS2 cams along with the NGK R8 coils and that sound is great, especially through the JBA 6400-s Long tubes, resonated b-pipes and Armada Cat-back which is also resonated before the exhaust tip. It's really mild at highway speeds until you get on it then the whine of the blower combined with the exhaust is music to the ears lol
bigskypylot
Explorer
Yes, stock fuel tank. I'll be adding an aux tank sometime this year. PhullD did a great job on his set-up and has been running trouble free for over a year and a half. I also have two five gallon cans and will be installing a Titan Trail Trekker II in a couple of weeks. Im getting around 12 mpgs and many more smiles per gallon