# How many horsepower?

rcgldr
Homework Helper
Is the timing at the Texas venue the exit speed, at the end of the mile run?
Unlike Bonneville, it's a standing start 1 mile drag run for speed (versus time).

Nissan Jon
Is the timing at the Texas venue the exit speed, at the end of the mile run?

As I understand the Bonneville records, they time over a measured mile; for instance the time between mile 6 and mile 7 of the 12 mile course. The Bonneville times are really the computed speeds over a mile, not the instantaneous speed.

I watched the motorcycles run there one year, it was a lot of fun to see.

Yes, your top speed is when you cross the trap line at the one mile mark.

Staff Emeritus
I don't think this is calcuable. We don't know the tire friction at 300 mph (and what do you use for tires? My H-rated Contis would turn to dust at 300!) and we don't know the weight distribution on these tires, especially as aerodynamic forces become large.

That said, why are you messing with an IC engine? You could presumably use a Leaf instead of a 350Z, right? So why not just use a ginormous electric motor in your 350z? Lots of HP, lots of torque. You don't need a charger, so you could take that out. 2000 hp is 1500 kW, and the Leaf battery is 30 kWhr. That will give you 72 seconds of power. That sounds like not much, but if you need more than 72 seconds of power, you're not going to be making 300 mph after a mile. The technical question in my mind is whether it's possible (and wise) to drain the battery that quickly.

mheslep
Gold Member
Where does one buy 1.5 MW polyphase induction motors at a power density suitable for race car, ie 4 or 5 kW per kg? The beast would have to include some method of cooling the rotor, as does Tesla's much smaller motor.

Staff Emeritus
Audi claims the electric drive in my A3 weighs 75 pounds. I believe it - it's a tiny little thing. It's limited to 102 hp, switching the engine on when it reaches that point because it can only run a few minutes at that level of power. An unreliable source (VW wouldn't lie, would they?) says it can do almost twice that. So that's well within the range you are discussing. Like I said, I think the bigger challenge is pulling that much energy out of a battery in a short time. You wouldn't want your car to pull a Samsung Galaxy at 300 mph.

mheslep
Gold Member
The battery ( and/or capacitor bank) would be purchased. I dont know of a commercial high power density 2000 HP e motor source.

Sure, the power density is doable, but with non trivial engineering and manufacturing chops. Tesla's motors for instance are 2.5 HP/lb (4kW/kg), and even higher power density is reportedly available, though these are built in the hundreds of HP range. Challenges include mechanical loads on the windings, with 200 lb-ft race car typical torque, and heat rejection when packing a lot of power into a small space, especially for the rotor. Guys like the OP have been machining high performance IC engines from scratch for a century. E-motors at 2000 HP and 3 HP/lb? Not that I know of. Dividing the load among multiple motors at 300 mph would present other challenges, like multiple gear boxes, and stable vehicle control.

Example GE 1.5 MW generator and gearbox, when high power density is not a design constraint:

Why mess with internal combustion? Because that's what I know. Why not electric power? Because I don't know anything about it. Lol

mheslep
Staff Emeritus
Because that's what I know.

That's actually a very good reason.

Nissan Jon and mheslep
I'm worried the amount of boost pressure necessary to generate said level of power would be too much for the stock motor. (assuming your engine, or the one you plan on purchasing is stock) From my knowledge of speed-machines, most cars running in the range you hope to achieve are running on 12+ psi, which few engines (apart from something to the likes of rb26s or 2jzs) can handle. At least for very long. Forged internals however, are always an option. Are you hard set on the vk56?

I'm worried the amount of boost pressure necessary to generate said level of power would be too much for the stock motor. (assuming your engine, or the one you plan on purchasing is stock) From my knowledge of speed-machines, most cars running in the range you hope to achieve are running on 12+ psi, which few engines (apart from something to the likes of rb26s or 2jzs) can handle. At least for very long. Forged internals however, are always an option. Are you hard set on the vk56?

Well, my shop represents Nissan motorsports, and I intended to stay with in the Nissan family. The only V8 option in the Nissan line up is the VK, however, as a testament to Nissan innovation, Nissan Supercar AU built a 714bhp Naturally Aspirated VK50, on almost entirely stock upper components and completely stock lower parts.

Now, I'll be far from stock. We'll be running primarily titanium parts, like: block sleeves, rods, pistons, ect., 320,000 psi head bolts, the works.

2,500 bhp is really easy to achieve, making it reliable is tricky, but cramming it all in a Z33 body will be the real challenge.

mheslep
rcgldr
Homework Helper
Another Ford GT, this time 279.9 mph. (280.1 at Arkansas). Despite the claim of no body mods, there's a 1 1/2" or so spoiler added to the rear, perhaps to direct air flow over the braking chute. The Ford GT body is based on a Lemans race car (Ford GT40), and is less prone to speed related issues (lifting of rear end or lifting of front end and blowover). My impression is that the 350Z body style is going to produce lift at high speed without some modifications. If there's enough excess power such as the drag cars, the entire body can be pitched nose down to produce downforce.

Nissan Jon
Now, I'll be far from stock. We'll be running primarily titanium parts, like: block sleeves, rods, pistons, ect., 320,000 psi head bolts, the works.
Oh, well you're set then.

Nissan Jon