This is the first of four supercars I plan on doing.

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Fafnir Motors Thor

General Info
Price: 604,500 USD
Production: ? cars
Layout: Front Engine/RWD
Transmission: Sequential Manual Gearbox w/ Paddle Shift

Dimensions
Curb Weight: 3,100 lbs
Height: 43.95 inches
Width: 75.7 inches
Length: 175.6 inches
Wheelbase: 96.2 inches
Front/Rear Track: F) 59.6 inches, R) 60.6 inches

Engine
Type: Twin Turbo V-10
Displacement: 8.424 liter
Bore: 4.03 inches
Stroke: 4.00 inches
Valvetrain: OHV, 4 Valves/Cylinder
Horsepower: 1,092 bhp
Torque: 1,150 ft-lb
Rev Limit: 6,000 RPM

Performance
o-60 mph: 2.76 sec
0-100 mph: 4.22 sec
1/4 Mile: 9.51 sec @ 159 mph
1 mile: 25.3 sec @ 227 mph
Top Speed: 256 mph
Lateral Accel: 1.06g
Braking: 105 ft
Slalom Speed: 78.5 mph

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Shiva AG Rakshasa

General Info
Price: 647,000 USD
Production: ? cars
Layout: Front Engine/AWD
Transmission: Sequential Manual Gearbox w/ Paddle Shift

Dimensions
Curb Weight: 2,588 lbs
Height: 43.3 inches
Width: 77.2 inches
Length: 169.3 inches
Wheelbase: 104.0 inches
Front/Rear Track: F) 63 inches, R) 63.7 inches

Engine
Type: Twin Turbo V-12
Displacement: 7.995 liter
Bore: 3.78 inches
Stroke: 3.62 inches
Valvetrain: OHV, 6 Valves/Cylinder
Horsepower: 1040 bhp
Torque: 768 ft-lb
Rev Limit: 5800 RPM

Performance
o-60 mph: 2.5 sec
0-100 mph: 4.34 sec
1/4 Mile: 9.63 @ 157 mph
1 mile: 24.3 @ 224 mph
Top Speed: 253 mph
Lateral Accel: 1.02g
Braking: 95 ft
Slalom Speed: 77.6 mph

**

Amaterasu Motors Tsukuyomi

General Info
Price: 647,750 USD
Production: ? cars
Layout: Mid Engine/RWD
Transmission: Sequential Manual Gearbox w/ Paddle Shift

Dimensions
Curb Weight: 2,591 lbs
Height: 44 inches
Width: 78.5 inches
Length: 169 inches
Wheelbase: 104.7 inches
Front/Rear Track: (F) 64 inches, ® 64.5 inches

Engine
Type: Twin Turbo V-8
Displacement: 6.9 liter
Bore: 4.2 inches
Stroke: 3.8 inches
Valvetrain: OHV, 4 Valves/Cylinder
Horsepower: 1046 bhp
Torque: 872 ft-lb
Rev Limit: 7500 RPM

Performance
o-60 mph: 2.75 sec
0-100 mph: 4.31 sec
1/4 Mile: 9.65 sec @ 157.98 mph
1 mile: 24.35 sec @ 225 mph
Top Speed: 254 mph
Lateral Accel: 1.15g
Braking: 105 ft
Slalom Speed: 85 mph

Engine seems... underpowered. You give almost 1100 bhp, but those specs say much much less.
Keep in mind that for high performance automotive engines, longer bore and stroke means bad, it means more weight, more firction, more time moving the piston for the strokes. Keep in mind higher performance engines have very short strokes, this would be better reduced to 70mm stroke then the 100mm it has now.

Keep in mind as well that the best automotive engines on the market don't get more then 100hp per liter. And to get that they use 5-6 valves per cylinder, and torque is actually less for high power engines in this application because they rev higher and higher revs usually mean less torque.

With what you have, assuming a normal turbo set up, you're looking at 500 bhp maximum on the best fuel money can buy. And your engine will not last running that for very long, so for something to be driven for more then a few hours ever, you're looking at tuning it down to 300-400 bhp.

Up the rev, lower the stroke, up the valves, and you can push 800-900 bhp out of this with the right induction systems, but you'll lose a good 50-100 hp by the time it reaches the wheels.

FR =/= good turning performance. Always remember that you are setting your car to have most of the weight off of the wheels of power. The more power you have, the less it will be able to do more then go in a straight line at any real speeds.

259 mph seems real fast for the design pictured. I just don't think it's aerodynamically capable of doing that. Real speed machines hold a much different shape, take a look at the Dauer 962 for instance.

0-60 and 0-100 times look a little low. I'd add half a second to the first and maybe a full second to the 100.

I couldn't honestly tell you why boring out the engine to fit bigger cylinders and lengthening the stroke works, but it does. I'm basing all my designs off of RL cars, in this instance the Hennessey Venom 1000TT.

I could point out any number of engines where this is not true on, the Saleen S7 (1,000hp version) on a 7.1L twin turbo V-8 being one of them. Oh, and the Hennessey 1,092hp TT engine being the obvious example as it is basis for this car.

The Viper's engine runs 510hp on an 8.3L with street car gas and without turbos.

This isn't a Veyron, it isn't meant to have insane turning performance period, much less at "real speeds." If I wanted good turning performance I'd have gone with AWD.

Well, you'd have to talk to the one who did the model for that, then. I don't know what he envisioned the top speed being, although he did say in the comments section that he imagined it being a very powerful and fast car. The reason I used the image was because it looks cool.

Again, everything about this car is based off the Venom 1000TT, including the established 0-60 and 0-100 times, although this car is slightly quicker because it's a bit lighter. In fact, the Venom holds the world speed record for the standing mile with a speed of 225.213 mph which was completed in something around 24 seconds.

I'll go down paragraph for paragraph.

I know why it works, displacement = power. I said it a half dozen times in the building an engine tutorial. The problem comes around where you're running compression ratios so high, so thin cylinder walls that your car won't run for very long before it simply breaks. And beyond that you'll need to run special fuel, aviation fuel or even pure alcohol, which will be eaten up fast.

I'll address your example cars in order at the bottem, and why they're bad to use.

Viper's engine also runs more then the bare minimum valve set up for a four stroke engine.

Your lateral accecleration says otherwise. And AWD doesn't help turning performance, it just makes it safer to turn.

Fair enough on the picture. For supercars these days it's more about looking cool anyway.

Ok, on to your example cars. First that 1000 bhp Saleen S7, the concept version not actually released for sale. Where they bored the engine out, ran spiked fuel, and have effectivly limited the engine use time to a few hours. It's not a road car, not for sale, and the engine on it alone must cost a hundred thousand dollars.

Venom 1000TT, 0-60 is 2.9 seconds, 0-100 is 5.8, and if you go dig up the stuff they did to it, that engine has to rev at 5000 rpm to get the turbos spun up to give the boost to get it to 1000 hp. Beyond that the maintenence rate is horrid for even a supercar. It needs serious maintenence after only a few hours of driving, and all of it's performance records were taken with variable ration racing transmissions, which it kindly comes with. And on top of all of that, Hennesy reccomends to those it sells to to run avation fuel, and not to "let it out" so to speak, because it's designed to hit that power for performance figures and to sell, but it won't hold it.

Cars to look at for good performance from a real supercar that can hold itself in what it claims, are things like the TVR Speed 12, AM V8 Vantage, or even the Calloway Sledgehammer.

Well you bore out your cylinders for well bigger cylinders I mean shit that is just obvious greater compression under combustion as I understand it(displacement). You lengthen the stroke to increase torque not horses...not to say it doesnt increase horses but proportionally its really for beefing up torque. Also short stroke increase "side" wear on the piston because of the angle, so a long stroke isnt a "bad" thing in a high performance car... its just a different thing, it looks like old school big balling to me.

...

Damn, are you increasing the crank radius witht he increase in stroke length?

Because that aids in the increased HP you just have to watch the margin because just like shortening the stroke too far causes "side" wear so does lengthening the stroke AND increasing the crank radius.

No, they don't sell a separate version, what they do is make it an option for customers willing to pay for it. I've seen video posted on a car forum of a couple Saleen guys driving one in stop-and-go traffic on a traffic-jammed highway.

Actually, what I posted are the official fastest times. As for the other stuff, I'll gladly show your post to Hennessey and see what he has to say about it. However, even if what you say about the maintenance is true, it doesn't surprise me in the least because these cars aren't every day drivers, they're street legal race cars.

Um, 2 things.

1: I checked Saleen's website and a number of people I know who are big on that. It';s not even an option.

2: I got that information from Hennesy's website, you don't get more official then that.

And you still haven't addressed the 2 valves per cylinder thing. Which is going to hurt the car more serious then anything else I can find wrong with the engine.

All Vipers are listed as having 2 valves per cylinder. While you might be right on the issue, I'm going to take what I know about the car I'm basing mine on over the opinions of somebody I don't even know. I don't mean any offense by that, it's just how I've decided to do this.

Updated the Thor statblock and uploaded the Rakshasa's.

Sorry for the late reply, have been busy watching my nephew for my sister.
But while I was watching my nephew I gave Hennessey a call at their Texas centre, and they indeed confirmed to me that the 1000TT and 800TT use new 4-valve heads. I wasn't paying for the call, so it was worth it.
Apparently a number of major websites, supercars.net and ultimatecarpage.com being the two that come to mind for me, just assume they kept the old heads. Of course they can't keep the old heads, the extra pressure from the turbos would blow them off on ignition, but those two websites arn't always completely accurate. Good most of the time though.

As to the Rakshasa, my only problem with it is the engine. Physically speaking, I doubt you can fit a V12 in the front of that car, especially not one that displaces 8L. That's primarily an issue with specs-to-picture compatability, but it's an issue none the less. The front just doesn't extend far enough to fit such a large engine in length wise and have an AWD system, and to fit it transversely, you'd have to be steering with the rear wheels because the front ones would have no room to move.

Okay, I'll change that.

As for the renders, they aren't meant to be exact to scale images. They aren't even mine, I just borrowed them to show approximately what the cars in question look like.

And I've added the Tsukuyomi.

Are you saying it has two seperate V8 engines?

No, it has twin superchargers.

Superchargers don't give near as much boost as turbochargers, and while they do it they suck power from the engine, and stop working at higher RPMs. What's written now in the new engine, unless that's with a heavy N2O or WM50 injection system, and even then that engine will not last long, won't really work. As well, your peak power from that engine, which will be closer to 750 bhp, will be around 5000rpm, not 7500. And because they run lower RPM, superchargers have a tendency to run more torque in an engine, which is why you see them a lot in drag racers.

What you can do with that though, is this. Add a liter of displacement, drop that powerband down from 7500 rpm to 6500 rpm, and change your power and torque to between 750-800 bhp with 850-950 ft-lbs of torque.