1,200-hp Hennessey Cadillac CTS-V Coupe offered

I usually use a simple "rule of thumb" formula for determining if a car has too much power -- at least for 0-60, 0-100 and 1/4 mile runs. This formula is:-

0.7 x Tire Width (mm) x Number of Driven Front Wheels x Vehicle Weight (lbs) / 3500 + Tire Width (mm) x Number of Driven Rear Wheels x Vehicle Weight (lbs) / 3500*

Eg. A Corvette would benefit from extra HP up to about 0 + 275 x 2 x 3200 / 3500 = 503 hp

Eg. A FWD Cobalt would benefit fro up to about 0.7 x 235 x 2 x 2900 / 3500 + 0 = 273 hp

Eg. A Nissan GT-R would benefit from up to about 0.7 x 255 x 2 x 3830 / 3500 + 285 x 2 x 3830 / 3500 = 390 + 627 = 1017 hp

Based on this rule of thumb, the Hennesy CTS-V Coupe mounting 345/30 R20 rear tires has a power handling limit of 0 + 345 * 2 * 4200 / 3500 = 0 + 828 = 828 hp. Anything more really just produces additional wheel spin, and really does not have a tangible yield in acceleration times and can in fact make the car harder to launch and control.

Also, you'll noitce that FWD cars have about 30% less power handling than RWD due to weight transfer away from the front wheels during acceleration and AWD cars have essentially unlimited traction for "sane", mass produced, engines. Also, heavier cars actually handle more power simply because they have more mass pressing down on the same tires.

* The formula is really an over simplification as it is really torque to the wheels not power at the crank, contact patch, coefficient of friction and weight applied rather than just the width of the tire. But using a 3500 lbs correction constant, assuming the typical grip of summer compound tires and correcting for FWD lift, this rule of thumb is within +- ~10% of actual values and is easier to apply.

Very interesting info on assessing power/torque.

But what do you think of this Hennessey production car? The look, your impression/feeling?

We know you think it is over powered based on your formula, but what about their interruption of this Cadillac and their top performance version?

I have always liked the CTS coupe. And the overall look of the Hennessy car is not rodiculously over the top which helps preserve the car's clean looks. Personally, I'll skip the hood louvers because I don't like the clutter from the slats. If I have to do a hood vent I'll prefer a cleaner implement like that on the C6-R race cars or the Shelby Series-1.

One thing I'll really like to see on mechanically supercharged engines is a hydraulic supercharger coupling. Basically, it is a fluidic drive as opposed to a belt-n-pulley. The fluidic drive allows a variable bleed valve which can reduce the supercharger drive ratio in response to rpm, throttle position and/or altitude. This is actually a very neat arrangement as it is actually more compact than the fat belt drive.

This is actually a 75 year old concept. As far back as 1941, the Messerschimitt BF109's Daimler-Benz DB601 (later DB605) inverted V12 SOHC-48v engine has a fluidic supercharger drive for automatic alttitude compensation by continuously varying the super charger ratio. That engine, believe it or not, also has a Bosch Direct Petrol Injection system instead of carburettion typically on allied engines like the Merlin. Unfortunately, due to the low quality of German Gasoline in WWII they had to resort to larger displacements, lower compression and lower boost to generate the same amount of power.

Sheesh! That coupe sounds like a jet...! I would be completely happy with a stock V6 coupe, I've never been one to run a car hard or race around all the time. IMHO this Caddy Coupe is the best looking car to come out in a long time. Really miss all the coupes from days gone by. It is great to see the Camaro & Caddy Coupes on the road, very, very good-looking cars.

everything is great except for that overstated cheese grater on the hood... something a little more flush would clean it up.

It's an over-the-top car, I think the over-the-top hood is fitting. I wouldn't be surprised if it's mostly functional, providing more space for extra bits on the top of the engine, and providing venting for the heat produced by 1,200hp. I hate hoods, scoops, and vents like that when they're not functional, but when a car is just flat out that extreme to need it, I like it.

Over the top car indeed....

One thing to consider in the Formula of over powered is how sticky the tires are....

I wonder if the AWD system of the CTS regular could be beefed up enough to handle the power from the CTS-V or even this monster. I would think it would be freakin awesome if this was AWD.