Voodoo Theory

[Voodoo]

I really hope they go with the flat crank design!

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[TearTheHorizon]

Here is some news I just recieved. Currently, there are two GT500's (2013-14 body) at Romeo. From what I am told these are entirely (seemingly) stock GT500 cars. One is black and red, and the other is red and black. They are both vert's.

I am being told they are "playing around" out back between two buildings. (I am also told there is a spot like such they use during testing because the two buildings help hear the exhaust note.)
It was said these cars are not 5.8 vehicles.

It is claimed the exhaust note was very high pitch. One said it hurt to listen to with the two buildings reflecting the sound.

Perhaps the most interesting part: "...sounded like a whistle, but not like any turbo I have ever heard."

.....hmm.....

 

[pacettr]

I'm going out on a limb based on my initial impressions and some feedback in this thread.



GT350
5.2 Voodoo FPC
8500 RPM
525 hp

 

[Twin Turbo]

Here is some news I just recieved. Currently, there are two GT500's (2013-14 body) at Romeo. From what I am told these are entirely (seemingly) stock GT500 cars. One is black and red, and the other is red and black. They are both vert's.

I am being told they are "playing around" out back between two buildings. (I am also told there is a spot like such they use during testing because the two buildings help hear the exhaust note.)
It was said these cars are not 5.8 vehicles.

It is claimed the exhaust note was very high pitch. One said it hurt to listen to with the two buildings reflecting the sound.

Perhaps the most interesting part: "...sounded like a whistle, but not like any turbo I have ever heard."

.....hmm.....

So, not at all like this then.............



Many commented that sounded like the 5.8..............but I didn't think that would fit S550 :shrug:

 

[jjw]

Non-turbo sounding whistle = intake noise using individual throttle bodies and a non-silenced air box?
Or are these ecoboost gt500 replacement prototypes for further down the road that just sounds that unique?
Is there a good reason to run a FPC in an EB? I wouldn't think so. If there was, I wouldn't think it would change exhaust not all the much with the pulses being crammed through a turbine.

 

[TearTheHorizon]

Well every opinion is based on past expiriences, and we havent heard a factory turbo 5.0 to compare. Turbo technology is ever advancing also.

It would be great to see a mustang with a setup similar to current EB with nearly zero lag.

As to FPC with a turbo being better than a CPC with a turbo I have no idea. However I'm sure Ford will choose the most efficient route for the best power.

I have been told and reassured the 5.8 fits. I have also been told they are dropping the 5.8 nevertheless.

What other noises could be high pitched? I wonder what the 2.3 will end up sounding like. They could have used one of the drivetrain-less gt500 test cars and dropped that little motor in there.

 

[Dirk McGurck]

I'm going out on a limb based on my initial impressions and some feedback in this thread.



GT350
5.2 Voodoo FPC
8500 RPM
525 hp

Please, please, please.

 

[stable68]

I remember seeing a pic of a 2013 gt500 being driven behind a new ferrari around dearborn a little while ago, maybe that was the high pitched car? They both had manufactures plates on them i believe

 

[C00KIE M0NSTER]

I'm going out on a limb based on my initial impressions and some feedback in this thread.



GT350
5.2 Voodoo FPC
8500 RPM
525 hp

At 8500rpm Ford can make 525hp N/A with a cross plane crank, I think the horsepower number would be a lot higher with a FPC.

 

[TearTheHorizon]

I remember seeing a pic of a 2013 gt500 being driven behind a new ferrari around dearborn a little while ago, maybe that was the high pitched car? They both had manufactures plates on them i believe

No, these were two convertible GT500's. They may have that Ferrari for testing purposes though, but that's a separate event.

At 8500rpm Ford can make 525hp N/A with a cross plane crank, I think the horsepower number would be a lot higher with a FPC.

Agreed, if Ford's using a flat plane, 525 is low.
At 8500 RPM horsepower is made easy.

Remember that horsepower is just the end product of an equation.

HP = (TQ*RPM)/5252

So as you add rpm's you significantly raise horsepower.

 

[Red]

I don't see 8,500 rpm happening w/ the current coyote/roadrunner 5.0. Reason being mechanical stresses at that rpm.

Here are mean piston speed, max piston speed, and peak acceleration values for some current engines. Acceleration relates directly to the forces acting on the con rod, wrist pin, piston (and also crank, bearings, bottom end, of course, but the con rod, pin, and piston are more highly stressed and 'generally' fail first). Piston speeds are used as a general indicator of overall mechanical loads and stresses, but also relate directly to friction (and heating due to friction).

Mean piston speed is a trivial calculation, depending only on stroke and rpm; calculating max piston speed and peak acceleration is more involved (though still easily doable) and requires con rod length.

In the following table (sorry, I couldn't figure out how to align things in columns), speeds are given in meters/sec; peak accelerations are given in g's. To convert meters/sec to feet/min: multiply m/s by 196.85 to get feet/min.

Engine@ redline: mean piston speed / max piston speed / peak accel

SRT Viper 8.4L V10 @ 6,250 rpm: 20.95 / 34.5 / 2,895
Chevrolet LS7 V8 @ 7,000 rpm: 23.70 / 39.23 / 3,704
Audi FSI 4.2L V8 @ 8,000 rpm: 24.75 / 40.61 / 4,324
BMW S65 V8 @ 8,300 rpm: 20.81 / 33.83 / 3,673
Honda B16B I4 @ 8,500 rpm: 21.93 / 35.70 / 3,979
Honda F20C I4 @ 8,900 rpm: 24.92 / 40.60 / 4,745
Porsche 911 GT3 3.8L Boxer 6 @ 9,000 rpm: 23.25 / 38.12 / 4,559
Ferrari 458 4.5L V8 @ 9,000 rpm: 24.30 / 39.81 / 4,756

Coyote 5.0 V8 @ 7,000 rpm: 21.63 / 35.56 / 3,323
Road Runner 5.0 V8 @ 7,500 rpm: 23.18 / 38.10 / 3,815
"Voodoo" 5.0 V8 @ 8,500 rpm: 26.26 / 43.18 / 4,900

Clearly, a Voodoo 5.0, using the same 92.7 mm stroke and 150.7 mm rod length dimensions as the Coyote & Road Runner 5.0's, at 8,500 rpm is off the charts, stress-wise. It won't live w/o frequent, expensive, and involved maintenance.

To put the Voodoo 5.0 @ 8,500 rpm values in some context, here are some racing engines (I used 'nominal' values for stroke, rod length, and RPM):

F1 2.4L V8 @ 19,000 rpm: 25.14 / 39.78 / 8,983
Nascar 358 CID V8 @ 9,400 rpm: 25.88 / 42.03 / 5,154
NHRA Pro Stock 498 CID V8 @ 10,500 rpm: 33.34 / 54.51 / 7,570

Note that the Voodoo 5.0 @ 8,500 rpm has higher piston speeds than the F1 and Cup engines.

From my reading, F1 and Cup engines are designed to last around 800 miles, roughly, before major teardown/overhaul/scrapping. The NHRA PS engine? Count on maybe 25 passes (6+ miles) -- and be prepared to go through valve springs like no tomorrow. And all the pieces you're tossing (whether F1, Cup, or PS) are the best available for their purpose and very expensive (I'm not talking expensive as in $50k for an engine either -- far higher than that).

Many/Most of the engines above use titanium rods. NHRA PS engines use a fair amount of beryllium pieces (cubic $ and toxic) -- most probably F1 also.

Re the 458 Italia engine for a moment: I never found its rod length, even after quite a bit of searching. To make the 8,500 rpm Voodoo 5.0 as credible as possible in comparison, I used a 'short' rod length (rod/stroke = 1.69) for the 458. A longer rod, for a given stroke, decreases both max piston speed and peak accel. I'd expect the 458 Italia rod/stroke ratio to be at least 1.80. Therefore, I expect the actual values for the 458 Italia are lower than those in the above table.

Enough for one post, but I have more to come later -- you poor bastards, lol.

On edit: Also clear from the table is that the Viper 8.4 reciprocating assembly is relatively unstressed, at least to this first level of analysis. The basic dimensions point to rev'ing it quite a bit higher -- to 7,000 rpm, maybe a bit more. The BMW M3 engine is also relatively unstressed, though not as much so as the Viper's.

 

[JGillis]

Thanks for the great post, Red. You make a good case and I learned more than a few things from it.

 

[BlueVenom]

Where did you all come up with 8500 rpm? Sounds like an unrealistic leap from the current halo car. Current GT500 only allows over-rev to 7000 rpm right?

 

[FordBlueHeart]

Where did you all come up with 8500 rpm? Sounds like an unrealistic leap from the current halo car. Current GT500 only allows over-rev to 7000 rpm right?

It's not an "unrealistic leap" for the engine he was talking about. It will take some engineering prowess to accomplish.

 

[Red]

Thanks J.

I did not come up w/ 8500 rpm -- others did. I feel it to be an unrealistic level, and did a little coding and web searching to back that up.

I'd like to add one or two interesting tidbits (interesting to me anyway).

If one wants 8500 rpm from the basic Coyote/Road Runner architecture, the stroke has to be decreased. The engine from the factory actually carries a pretty large 'arm' at 92.7 mm (3.650") for 'only' 302 cid displacement, imo. Deciding to limit the mean piston speed to 24.0 m/s gives a stroke of 84.7 mm. If we want to keep the same pin height (stroke/2 + rod length), the rod needs to be lengthened from 150.7 mm to 154.7 mm. Keeping the same pin height means you can use the same compression height for the pistons and, importantly, the same deck height for the block -- i.e. one 'could' reuse the same block and pistons, saving costs. More on this in a bit. Keeping the bore unchanged at 92.2 mm gives the following specs:

rpm: 8500
bore: 92.2 mm
stroke: 84.7 mm
rod length: 154.7 mm
displacement: 4,524 cc (276 cid)
rod/stroke: 1.826
mean piston speed: 24.0 m/s
max piston speed: 39.09 m/s
peak acceleration: 4,361 g's

Achievable numbers, though still a highly stressed engine -- no way around it at these rpm levels. The Road Runner (RR) is already a highly stressed engine, and everyone involved w/ its design and manufacture deserves much respect.

Anyway, first consideration has to be getting the above conceptual engine to live well past warranty period. To reduce loads/stresses, perhaps titanium or Carillo/Crower steel rods and perhaps titanium intake valves will be needed. RR already comes w/ forged pistons, but I'd have to think this conceptual engine would need new lighter weight forgings to withstand the significantly higher peak acceleration (4361 vs 3815). Definitely some very high quality valve springs. The crank will be stronger due to the shorter arm (assuming bearing diameters are unchanged - a big assumption, and other things being the same), so that's one thing in this engine's favor.

Consider next what it'll take to get the torque and power desired. Let's say 525 HP @ 8000 rpm is desired. As mentioned above, we can easily back out the torque required at that rpm: ~345 ft-lbf. For comparison, the Road Runner makes ~ 311 ft-lb at 7000 rpm (this conceptual engine needs to breathe, to say the least!). Backing out the brake mean effective presure (BMEP), I get ~190 psi. That is a very stout number, imo, but not unreachable. The RR (311 ft-lbf @ 7500) has a BMEP 155 psi. The 458 Italia, with 562 HP @ 9000 rpm has a BMEP of 183 psi. If you run the numbers for NASCAR and F1 mills, you get 215 - 225 BMEP. I don't know how reasonable, or unreasonable, it is to get 190 psi BMEP out of a street engine, special edition or not. Hard to raise the compression much w/o getting into radical cams. DI could really help here. The RR heads are really good, but they may need revision for this level of performance, I don't know. Another thing working in our favor will be reduced windage losses due to the shorter stroke. A dry sump could go a long way on this engine (plus an extra stage to put the case under a 'vacuum' would definitely help). My guess would be 20 horse for the dry sump.

But, if we're willing to move the 525 HP up to 8500 rpm, then the torque (at 8500 rpm) falls to ~324 ft-lbf, and BMEP (at 8500) falls to 177 psi. Will likely be an even more high-strung engine, but perhaps a more realistic design.

Finally, after all this typing ( ), I still have to think that Ford could enlist the Aluminator (for N/A applications, not the S/C version) as the "Voodoo" engine. Slightly larger bore (94.1 mm) would give 5.2 liters (rounded to nearest tenth of a liter). Block has 100 mm bore centers, so there'd be 5.9 mm left between head gasket bores at narrowest point. Again, kind of on the limit (of blowing head gaskets), but I imagine that could be handled. It's otherwise a proven unit making 500 HP and carrying a 2 yr/24,000 mile warranty. Increasing the warranty period to 5/50 (or whatever it is) may require some concessions in HP/torque.

Of course, if the "Voodoo" is available in only non-street legal cars (CJ, 302S, 302R), then all bets are off.

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