duster44d
Well-Known Member
Has anyone started looking at what horse power a flat crank puts out and any thing for the v8 mopar as far as kits. They make horse power and rpm. A link if you do not know what im talking about.
Flat plane crank
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txstang84
Well-Known Member
They also require better harmonic dampening due to sinusoidal vibration compared to a conventional 90* crank. The reason flat plane crank engines typically do so well is because they spin high and through high flowing ports. The only domestic V8 I can think of that uses a 180* crank is the 5.2L Voodoo. And it does make 520 rated hp, but it also has 4 valve heads, and fuel doesn't shut off until 8200 rpm.
If I remember correctly the flat crank allowed for better tuning as the exhaust valve opening on each engine bank would be 180 degrees apart.
Probably sone tuning potential but not sure it 'do be worth it.
Probably sone tuning potential but not sure it 'do be worth it.
EchoSixMike
Well-Known Member
Severe balance/vibration issues, acceptable on a 3.0L Cosworth for couple hundred km, didn't work when they tried to use the same engine for endurance racing in sports cars.
Mopar tried to use a flat plane crank in their Prototype sports car project from the early 00's. Some W8 headed thing. They had cranks selling on racing junk a couple years back when Fiat bought Chrysler. S/F.....Ken M
Mopar tried to use a flat plane crank in their Prototype sports car project from the early 00's. Some W8 headed thing. They had cranks selling on racing junk a couple years back when Fiat bought Chrysler. S/F.....Ken M
It's a really old concept. I believe the 180 cranks originated with the Flathead Ford V8s.
txstang84
Well-Known Member
nah, the flatties were 90* cranks as well...just had 2 fewer main journals...
The euros have been building flat plane cranks in their V and boxer engines for decades, but they also build their engines to be like 2 engines joined at the crank...i.e., a V8 that's fed by two plenums and essentially 2 four cylinders sharing rod journals.
The euros have been building flat plane cranks in their V and boxer engines for decades, but they also build their engines to be like 2 engines joined at the crank...i.e., a V8 that's fed by two plenums and essentially 2 four cylinders sharing rod journals.
69_340_GTS
Well-Known Member
duster44d
Well-Known Member
That is the new ford flat crank design right.
txstang84
Well-Known Member
Yes. They took the coyote 5.0L engine, made a flat crank, increased the displacement, reground the cams, made a different balancer, upped the SCR to 12:1, enlarged the valves, changed the induction and exhaust and netted another 90 hp...
txstang84
Well-Known Member
That 5.2 Voodoo also has twin independent variable valve timing. Imagine if you had the capability, with a 360 for example, to swing your valve timing--intake and/or exhaust--25* from "zero"...50* total timing adjustment...completely variable. You'd get to change your ICL to bleed off some cylinder pressure under less than ideal conditions, or you could close up your LSA to enhance your mid-rpm torque.
The new LS and Hemis have variable cam timing, but you can't vary the intake vs exhaust events independently
The new LS and Hemis have variable cam timing, but you can't vary the intake vs exhaust events independently
duster44d
Well-Known Member
So 90 horsepower and you get an increase in rpm?
txstang84
Well-Known Member
You're cherry picking...read the REMAINING portions of my description.
The flat plane crank is only one part of the package.
flat crank
(left out of originial description): forged pistons/stronger rods
increased compression ratio
bigger cams
bigger valves
50* variable valve timing
FWIW, the conventional 90* cranks used in the first gen mod motors (4.6L) are capable of taking 8K rpms too, especially the 4V versions, but you have to have valvetrain and connecting rods to support it. The factory cams run out of steam somewhere around 6200 and the factory "cracked cap" rods are known to ventilate blocks somewhere north of 450hp.
Again, the crank is only part of the package and flat cranks have their own requirements as stated above...they create different harmonics due to their construction. Also take into consideration, the 5.0/5.2 platform is still a fairly new platform (5.0 debuted 2011) and the factory can readily absorb the R&D costs involved with developing all the pieces parts that go along with it.
Don't miss the forest for the trees man, it's a pretty decent little power plant, but you're staking a claim of awesomeness simply on ONE aspect of a whole package.
The flat plane crank is only one part of the package.
flat crank
(left out of originial description): forged pistons/stronger rods
increased compression ratio
bigger cams
bigger valves
50* variable valve timing
FWIW, the conventional 90* cranks used in the first gen mod motors (4.6L) are capable of taking 8K rpms too, especially the 4V versions, but you have to have valvetrain and connecting rods to support it. The factory cams run out of steam somewhere around 6200 and the factory "cracked cap" rods are known to ventilate blocks somewhere north of 450hp.
Again, the crank is only part of the package and flat cranks have their own requirements as stated above...they create different harmonics due to their construction. Also take into consideration, the 5.0/5.2 platform is still a fairly new platform (5.0 debuted 2011) and the factory can readily absorb the R&D costs involved with developing all the pieces parts that go along with it.
Don't miss the forest for the trees man, it's a pretty decent little power plant, but you're staking a claim of awesomeness simply on ONE aspect of a whole package.
Might be able to put a flat crank in a 340 block. The stroke would have to be really short so you might only end up with 300 inches or so but it would scream. Might want to use a 48 degree block so the valvetrain would work better. Put some good heads on it, maybe W9 or the new Edelbrock heads. Probably cost $30K or more to build but it would sound killer. Definitely would get some attention.
EchoSixMike
Well-Known Member
The shop I moonlight at is sciencing out a 306" W8 head Comp motor. It's been held back because of a few mistaken assumptions; doing dyno pulls to 9000 rpm to save springs(it'll go to 10k and change, but springs last less than 5 pulls), it's at about 700hp. That's not where it needs to be to be competitive. Going back to step zero and flowing the heads, it turns out they're way short of what they need to be at about 365cfm at .800. Ported by a "real good guy" but no real flow testing....
Anyways, that problem is sorted and progress continues.
This guy has more $$$ in dyno testing than all save perhaps a few people(me too) here have invested in their motors(tall 5 digits). 90 degree crank (Winberg), so I strongly suspect that flat plane cranks are not worth the trouble associated with them. S/F....Ken M
Anyways, that problem is sorted and progress continues.
This guy has more $$$ in dyno testing than all save perhaps a few people(me too) here have invested in their motors(tall 5 digits). 90 degree crank (Winberg), so I strongly suspect that flat plane cranks are not worth the trouble associated with them. S/F....Ken M
txstang84
Well-Known Member
Not if you're the sole or majority contributor to the project, and certainly not when proven parts are already available. I don't know how much a custom crank would cost, but that would be your biggest hurdle. A custom cam is a custom cam...figure out your firing order, make a couple phone calls, pay your money.
Power is in the heads and only limited by the method by which you extract it (compression ratio, cam timing, RPM)...IQ52 has said it in these forums before, 3 things make power, cylinder heads, cylinder heads, and cylinder heads...
Power is in the heads and only limited by the method by which you extract it (compression ratio, cam timing, RPM)...IQ52 has said it in these forums before, 3 things make power, cylinder heads, cylinder heads, and cylinder heads...
Phreakish
Well-Known Member
Flat crank makes it a little easier to plumb a well scavenging exhaust that works up high. Especially with variable cam timing.
Yet it has balance issues and the valve train will never know what kind of crank lives beneath it, and so must be up to the task anyway...
As a result, a flat crank sounds different/neat, makes for a marketing buzzword, but isn't something worth investing in for performance unless it's in an entirely new engine. Especially for a crowd that tends to do most of their work under 7500rpm (and many of us at half of THAT).
Drool all you want over it, but few of us will be missing anything special.
Yet it has balance issues and the valve train will never know what kind of crank lives beneath it, and so must be up to the task anyway...
As a result, a flat crank sounds different/neat, makes for a marketing buzzword, but isn't something worth investing in for performance unless it's in an entirely new engine. Especially for a crowd that tends to do most of their work under 7500rpm (and many of us at half of THAT).
Drool all you want over it, but few of us will be missing anything special.
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