Cruzinaround

Then perhaps they're getting it wrong by Clearly stating FLAT 8. However...Even reviews from the typical resources like Motor Trend, Car and Driver etc, are entertainment. If they're gonna review it then what they say will be repeated. That said...I can't find any official specs on the F-type's supercharged 5.0 stating its not a flat plane 180 degree crank or that there may be a variation of it that is. Just referring to the AJ-V8 is a broad category because there have been several iterations of it for racing and consumer since the mid 90's. I find a lot of speculation about the current iteration and that it sounds like a flat 8. No confirmation either way....even on Jaguar forums.

But, I'll expand on this a bit....They further mention that the engine is equipped in the latest F-Type"R" Coupe. Which if I understand correctly...the "R" designation is for Race configuration. And Jaguar does in fact use a Flat plane designs for their Race engines. Perhaps there is where the slip ties back to the option mentioned. BTW the race variant with the FPC from Jaguar racing and used by TVR is coded as AJP-V8...just saying. ;-)

The Firing order specifications of the 4.2 liter V8 as of 2005 equipped in their "S" designated vehicles......being Bank1(1)Bank2(1)Bank1(4)Bank1(2)Bank2(2)Bank1(3)Ba nk2(3)Bank2(4) is not a FPC firing order....But there is nothing to reveal what is being used in the 5.0 liter "R" designated vehicles.

Anyhoo..now you know why I keep saying Flat 8. Until there is some confirmation either way I'm just a messenger based on what's available.

Besides if they are going to cram a V8 under the hood and keep in line with the UK pedestrian impact crumple requirements without negatively impacting the aerodynamics and still fitting it with an Eaton Supercharger...then the engine needs to sit lower to provide that clearance. So just speculating... that can be easier to achieve with a FPC. And happens to be something Ford needs to keep in mind when planning to take on the European Market...Hence....speculation about a FPC in their VooDoo project.

Just saying..

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jz78817

the only way a flat plane crank would reasonably lower the height of a V8 is by letting you widen the vee angle.

Cruzinaround

Well...then how acute or obtuse... that's a question to run by Jaguar, TVR and even Ford. But, If you know the FPC design you also know that omitting the counterweights and lighter internals come into play to counteract engine vibrations. The counterweight omission alone effectively lowers the engine profile without having to widen the VEE configuration. The Crankcase itself would not hang so low.....therefore lowering the engine height...without having to adjust the VEE angle from 90 degrees.

Just saying.

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Cruzinaround

I'll put it this way... the typical American v-8 burbling exhaust note that we grew up falling in love with and associating with the classic musclecars...is actually a sign of inefficiency.

My apologies to Mr.D for the tangent this took. In any case.... the 5.0 is a good platform for SC and boosting applications.

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jz78817

I'm not buying that in the slightest. On any V8 crank I've seen, the counterweights don't extend outside of the swing of the crank pins; there's no size to be saved.

Besides, a flatplane crank still has counterweights; here's one from a Ferrari F355:



nice beefy counterweights there. The difference with a crossplane crank is where the counterweights are.

if the difference amounts to even 1% in a street car I'd be very shocked. With the massive push to improve fuel economy, if a flatplane V8 was that much more efficient then more than just Ferrari would be using them. And the only reason Ferrari uses them is because they make their road cars sound like their race cars. The Ferrari V8s used in Maseratis use crossplane cranks.

Cruzinaround

Then you'll need to have a chat with Cosworth, Lotus, TVR, Porshe....about their FPC's

And typicallly there would be no need for counterweights in A FPC... Using a "balance shaft" is rare but for cars more tuned for consumer rather than the hyper segment it wouldn't be inconceivable to actually incorporate a balance shaft. It would be more efficient to use lighter weight internals.

But why don't you build both types and report back to us with your findings...then compare the power to weight ratio to a comparable CPC engine. ;-)

Here's what Lotus Engines are about....

http://www.projectm71.com/

I'll add they're more prone to vibrations where a CPC engine is not. So for a sports car its easy to counteract (or not since its a preference for some) those vibrations....for a consumer luxury sedan... a CPC is just more comfortable...not necessarily more efficient by design. And being that the majority of the Market is a daily driven coupe or sedan.... then a CPC would be more prevalent.... But, if you look towards performance then a FPC has the advantage. A normally aspirated FPC typically has a higher power to weight ratio by comparison to an equivalent CPC. Add boost to the equation and it gets more interesting.

Also...advances in engine internal coatings and treatments also provide for smoother running engines on both sides of the coin and typically the FPC does not have as long a piston shaft by comparison and also does not promote head soak due to the firing order. Everything matters.....when all is considered.

But, hey maybe they don't use a FPC. But, if they do... there are certainly a lot more reasons to do so for a specialty vehicle like a Shelby or a Mach1 in a new s550.

BOOM

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jz78817

none of them use flat-plane cranks on street-legal cars.

bollocks. #1 Ferrari apparently didn't get that memo. #2 even 4-banger crankshafts have counterweights.

any gains in "efficiency' you would get by moving to a flat-plane crankshaft would be more than canceled out by the increase in rotating mass added by a balance shaft. Not to mention the drag of driving said balance shaft.

why don't you ask for something realistic?

Lotus hasn't offered a V8 for a long time. I don't care about that. And when they did, it was a relatively small-displacement engine.

No it isn't easier. A flat-plane V8 is two 4-cylinders sharing a common crankshaft. a non-counterbalanced 4-cylinder has a significant second-order vibration. a 90° flat-plane V8 has an even more intense second-order vibration which is the vibration of one bank multiplied by the square root of 2.

the difference in efficiency (if it exists) is not enough for anyone to give a crap.

only because as the displacement (and moving mass) of your engine goes down, the penalties of using a flat plane crank also lessen.

this is entirely incorrect. The "smoothness" of an engine has to do with its inherent mechanical properties. Coatings and treatments don't enter into it at all.

This is about as wrong as can be. look, when you set up a V8 with a flat plane crankshaft, you're looking for a reduction in rotating mass and a high rev ceiling. The rev ceiling is fairly hard limited by peak piston speed. peak piston speed is partly dictated by the ratio of connecting rod length to crankpin radius. meaning, if you want a high-revving engine, you want a long conrod compared to the crank throw. which is what F1 V8s used to do, run a long conrod with a short stroke and rev up to 19,000 RPM.

like what? Make two people happy while the rest of the buyers of those cars bitch because their "awesome" flat-plane V8 is vibrating the fillings loose from their teeth?

Cruzinaround

Then jz....its just a waiting game isn't it.

Until then it can be anyone's guess.


I prefer to lean towards a FPC

http://www.projectm71.com/Cross_FlatPlane.htm

Either way... Voodoo FPC or not... I'm waiting to see

Cruzinaround

BTW jz....What is your definition of street legal...because Porshe has been popping FPC's in their RS series cars for decades...all street legal...albeit tuned for racing, but certainly street legal. This is applicable to just about every Manufacturer that dabbles in racing. I'll add that the innovation in actually making that same transition to a specialty Mustang is the fact that this is not typically done in a working man's car. Its something usually only seen in the high end specialty cars from the Manufacturers that dance with the supercar and hypercar segment...also a segment not typically attainable by the average Mustang owner.

If it weren't for the specialty cars daring to push the envelope you'd never see these innovations make their way into the more attainable cars like Mustangs. Just like the Specialty car for the Mustang genre would be a Shelby GT350, GT500 and the MAch 1 which is rumored to be toying with a FPC. If they are...then its possibly a new variant on the FPC and possibly used in racing already. As with all things innovative you have a good deal of speculation...especially when the Manufacturers are keeping a lot of the details...MUM. Sort of a tactic that we see Apple computers doing very well until they WANT a very strategic leak at just the right time.

Just Saying...

Mr. D

All you have to do is compare performance of the cool sounding "Old School" burbling V-8 engine to a 5.0L Coyote to prove that! My little supercharged 282 (4.6L) will run away from any Corvette 283 CID with a cool burbling exhaust sound! Here's a tip! Want to sound cool on Cruise Night? Unplug the wires on two cylinders! SMILE!