*EDIT: Cleaned up presentation and updated my mussing, along with including some more from comments*

This is part of my ongoing mussing into SR4 vehicles, creating new ones, and filling in the gaps within the vehicle rules. This part has no vehicles or rules in it however, since it is focused on the vehicle tech in 2070. It will eventually be tied into an idea I had for helping create a more living SR 2070 world with information on how the varies technology functions according to RAW.

First lets talk about torque, horsepower and some of the basics of the internal combustion engine...


Past to present...


So how do you get more horsepower then? (horsepower being actual work, is more important then torque) Simple, if you can't increase one of the variables that produce horsepower (torque), you increase the other one (rpm). With a high rpm cam, you push the torque curve up the rpm band, netting more horsepower. However, you can only go so far before the engine will begin to have problems operating at low rpms. To counter this, things like the original VTEC (multi stage cams) and VVT were invented, allowing engines that could rev to high rpms while still being smooth and usable at low rpms. They also had the added benefit of helping optimize fueling and ignition timing.


All of this leading us up to 2070, with my predictions below (some with additional details in spoilers).
1) Average production car engines will produce something between 70 and 80 ft/lbs a liter
2) Inline engines with 4 and 6 cylinders (I4 & I6) will be the most common, with 6 cylinders being preferred where possible for their inherent stability and smoothness.
3) RPM ranges will be one and a half to double what they are today (10k to 14k), with high performance engines reaching higher (14k to 16k) and sport bikes in the 16k to 20k range.
4) Engines will be built out of highly advanced aluminum alloys and ceramics.
5) Instead of cams, the valves will each be individually controlled by solenoids, allowing total control of valve lift, timing, and duration.
6) The above, combined with dynamically changing intake runners and active exhaust systems, will result in very flat VE (and thous, Torque) curves, often at or near 100% VE throughout the rpm range.
7) Most engines will run on a mixture of petro (derived from bio-oil producing bacteria) and ethanol (type of alcohol) with an octane rating in the 110~120 range.
8.) Transmissions will be continuously variable transmissions for most production vehicles, with sequential manual or semi-automatic for performance vehicles.
9) The speed of the transmission combined with the direct neural interface will result in negligible time to shift gears (10ms or so) for non-CVT.
10) All vehicles that are not purely electric will be hybrid electric vehicles with advanced kinetic energy recapturing ability.
11) All vehicles will have some form of all wheel drive capability. At the very least, this will be electric motors powering the wheels not powered by its fuel engine.
12) Due to lighter/stronger materials, better design, and advances in friction reduction drive train losses will be half or better what modern vehicles exhibit (in the range of 5~10%).
13) Forced induction capabilities will be greatly improved by memory materials (allowing changes on the fly of compressor and turbine) and friction reduction.
14) This will allow a turbo to perform at the peak of fast spool-up and low end torque through high horsepower/flow for its given size, without surge.
15) Superchargers (positive displacement and centrifugal) will also gain most of these advantages, extending their power production and greatly reducing their drive power usage.
16) The easiest way to improve engine performance will become increasing displacement (longer stroke/larger bore) or rpm range.
17) Vehicles will weigh only about 75% as much as current cars of their size, while being stronger and stiffer.
18) Brakes, clutches, and other friction parts will use ceramics that have a high density, strength, heat capacity, and heat radiating capability.

Examples

A quick rundown of a 2070s vehicle then would be a hybrid electric/petro vehicle, making extensive use of synthetic materials in its construction. Its engine is roughlly half the size or less of modern day cars in its class, but able to rev far higher. It would provide power smoothly, while constantly adjusting to always use the least fuel and energy.

I'm not big on calculations or cars, and while this made my brain hurt a little, there's definately some interesting ideas. I like the speculative science fiction, especially in 4, 5 and 6.

While it takes quite a bit more power to increase velocity, rolling resistance and wind resistance isn't as much of a drain as you'd expect. IIRC, for a typical sedan at 75mph it only requires 20hp to maintain speed. But if you only had a 20hp engine you'd spend several minutes getting the sedan up to 75mph. The two biggest issue at high speeds are having a transmission that scales high enough to generate the rpms and having a suspension/control system that doesn't turn the car into a death trap. At 100mph+ a bad suspension won't keep the wheels in contact with the ground, which is another way of saying "cause the vehicle to spin out of control."

Speed is not that big of a deal in the SRverse, at least by RAW. Let's start with the Honda Spirit, a standard city commuter with a max speed of 60mph. The Nightsky tops out at 75mph and the Comet, one of the most common sedans only gets to 85mph. I've got a Chevy Malibu, probably the equivalent of the Comet, and it has no trouble doing 85mph.

That ignores the RAW for high-stress driving. It takes Edge for most drivers to get a vehicle anywhere near their top speed. Let's face it, most non-riggers will only get 2-3 successes adding 10-15 m/turn to the speed. That gets a Westwind up to 75m/turn which equates to about 55mph in high-stress driving. Wheeeee. A high end rigger throwing ~20 dice only averages 7 successes, getting the westwind to 90m/turn or 67mph. Teenagers do better than that for whole minutes at a time in old pickup trucks according to "Cops" and "World's Stupidest Criminals" shows.

Fuel efficiency seems to be the key in the SR setting. Thanks to the rather phenomenal material tech, the vehicles should be very light. Going back to the Honda Spirit and it's 60mph top speed, it obviously doesn't need the same safety mechanisms. I really expect most vehicles, outside perfomance/sport, to be electric drive. Electric motors have max torque at low rpm, so plenty of take off and towing power, and can be ~90% efficient. Heck, IIRC the Prius doesn't even put the electric motor through the transmission; it runs 1:1 to the wheels. Only the gas engine runs through the CVT when it kicks in for high speed passing. Since SR has the potential for fuel cells, which are more efficient converters of fuel to electricity than a generators, I'd expect to see that be pretty common.

the sweet thing about electric is the're always at max torque.... regardless of rpm
also the most efficient hybrid is the series hybrid which is only driven by electric through transmission if you want although you could engineer one to not... this is powered by a bank of batteries constantly refiled by an ICE engine or other generator (solar wind regenerative breaking) so you can have a little engine like 20 or so hp powering the car which is all you need for going like 70mph and when you need to accelerate fast you have the reservoir of power from the batteries

oh ya and honda has broken the 100hp per liter limit since the early 90's

Actually, your numbers are way off on SR4 vehicle performance. Lets take our test driver, Dangerous Dan Davis (with a whooping 9 dice) and stick him in a Eurocar Westwind 3000. The EW3k gives +3 dice, so he has a dice pool of 12. On hard acceleration, he will get 4 success on average. That equals +20m/turn of acceleration, or 80. Netting him roughly 60mph in 3 seconds. That is pretty damn fast. However, SR4 has flat acceleration. So he will hit 100mph in 5 seconds. Now that is insanely fast (faster than every car currently in existence but the SSC Ultimate Aero TT). Hell, he will hit just shy of 180mph in 9 seconds. That is *CRAZY* fast!

And the Speed rating is not a vehicles top speed according to RAW. The speed rating is the top speed the vehicle can achieve without getting penalties on handling. How much over that is purely the GMs call. I use 25% over, with Accel cut in half, and all required successes for an action doubled in my games (since by RAW, it is the GMs choice). Which would mean in my games, based on my standard call, still according to RAW, the EW3k can hit nearly 225mph in 13.5 seconds.

If you do the math, the EW3k can run the 1/4 mile in about 8.028 seconds at ~159.568mph. Faster then every production car in existence.

Too crazy for you? Ok, let me pull out a slightly less crazy vehicle, the Chrysler-Nissan Jackrabbit. It is a gas/electric hybrid subcompact car.

Same guy driving, so he will only average 3 success a turn in this car. Base Accel is 35, +15 for his roll. That gives a base 50m, or roughly 12.5mph @ second of acceleration, up to the vehicles top "good handling" speed of 90mph. This cheap little subcompact will do 0-60mph in ~4.8 seconds and 0-90mph in ~7.2 seconds. That is fast enough to make it a pretty damn good sports car in acceleration by today's standards. Using my as GM choice (by RAW) of top speed = Speed rating x1.25, the car will top out at around 112mph. So we can figure out a 0-100 time to compare to current cars today, ~8.8 seconds.

Cars in existence today that have 0-100mph times of 8.8 seconds or slower include: Ford GT, Porsche 911 GT3 RS 997, Porsche 911 Turbo 996, Lamborghini Murcielago 6.2, Lamborghini Gallardo, TVR Tuscan S, Ferrari 360 Challenge Stradale, Chevrolet Corvette, etc etc...

Seriously, you have no idea just how fast the vehicles in SR4 are capable of accelerating. I actually put a max cap on acceleration success of Running Accel/10 (round up).

Learn to read bro. Honda is no where close to breaking 100 ft/lbs of torque per liter in a naturally aspirated engine. That is assuming you know the difference between Torque (a rating of force) and Horsepower (a rating of work, derived from Torque and RPM).

Also, Honda was no where near the first to build an engine making over 100hp per liter and they did not create the technology that they called VTEC (that was GM).



Wrong bro. Sorry, but electric motors are not 100% efficient and their efficiency varies throughout their RPM range. Some are more efficient at lower RPM and some are more efficient at higher RPM. Here is an example from the Tesla

[img]http://img179.imageshack.us/img179/8360/tesladynohq2.jpg[/img]



4, 5, and 6 are all extensions of current or currently being researched technology. There is little to no science fiction in my mussing.

Other then the several tons of armor they probably would be pretty light....

Little be higher than that actually, bout 25~30hp. But the same sedan at 150mph will require 200~240hp to maintain that speed.

Well, a lot of speculative fiction (like Shadowrun) uses current or currently researched technology as a basis. That said, I'm not big on cars, so I didn't know that.

I know what a liter is but what is "ft/lbs"? Why the mixing of unit systems?

ft/lbs is a measurement of distance moved per unit of force. In this case, the number of feet an object of arbitrary mass could be moved in a given direction.

You get the same sort of thing with PSI which is pounds force per square inch. This is a measure of force (in pounds) against a square inch.

It is not a mixing of unit systems. Ft/lbs is the actual measuring unit of torque. Torque is the actual power produced by an engine. It basicly equals how much force the twist of the engine crank has. Then you have engine RPMs, which is of course how quickly the engine crank turns. From those two you get horsepower, which is a measure of how much work the engine can do (how many times the crank spins combined with how much force each spin has).

Horsepower = (Ft/lbs of Torque * RPM)/5252

The idea of a 150mph sedan is pretty funny since with that wind resistance it doesn't control well outside a properly banked track with pristine paving and a fortune in after market mods, aka NASCAR.

True performance vehicles with SR capabilities already exist. The Corvette Z is roughly on par with the Westwind (500hp, 200mph top speed =~ 277m/turn) and vettes are economical compared to Italian exotics.

The big point you miss is that by RAW none of that speed exists if people shoot at you. The "acceleration ratings" are walk/run ratings in combat, not a true acceleration. Dangerous Dan got to 60mph in 3s but next round he needs the same successes just to stay at 60mph. Ostensibly that is so drones have similiar combat movement as runners. Which is fine but it nerfs full sized vehicles.

Doesn't matter what you do on a dynamo or test track if the car can't get you out of the firefight. SR sucks at James Bond/Steve McQueen car chases.

I think we're reading the rules differently. I took the rules on accel as the limit on how much speed you could gain per turn, not your actual speed from turn to turn.

Understandable misconception. The acceleration stat has nothing to do with rates of velocity change. It lists itself as the walking and running speeds per combat turn.

Steering things back on topic, compare how your car compared with something made in 1946, and see how much less bizarre the cars in SR4 look.

In my group we used the same logic, while it is a walking running rate, we assume the rate builds on itself turn after turn.

There is only a little one line bit from the BBB IIRC. I'll have to re-read it when I get home from work. But if it works the way you two are talking, they totally NERFED vehicles moving from SR3 to SR4 and I'm for sure going to correct that problem in my vehicle rules I've been working up.

One question I have: Anyone seen rules anywhere for how fast vehicles in SR4 can brake?



Your not the only group doing that. My group, and in fact all the groups in my area handle it that way. Pretty close to how it worked in SR3 also.

Also, you would roll dice for acceleration only if you were spending your action trying to get as much acceleration out of your vehicle as possible. If you were swerving and dodging stuff, your driving roll successes would be used to meet the GM set difficulty. In my games, I allow any excess successes to be used to add speed after meeting my set difficulty (since a good driver can get up more speed through a set of twisties then an average or poor driver).

Part of where all this comes from is that I am big into cars and actively road race (that being on a closed course road track, not public roads).

#5 is nothing new. it's used in racing and other one-of-a-kind vehicles AFAIK. it's just not reliable and cost-effective enough for production vehicles.

#8 is there a reason you would not want to use CVTs for production cars?


17/18; increasing speed of a given vehicle could be done in a large variety of ways, few involving the engine. reducing aerodynamic drag, better bearings, reducing weight. all of these are options.

It is.
Liter is a metric unit of volume. Ft-lbs is from that weird "Imperial" system. (IMG:style_emoticons/default/wink.gif)

So it should either be liters and Newton meters (Nm is the metric unit of torque, 1 ft-lbs = 1.3558 Nm) or ft-lbs and whichever of this zoo of Imperial volume units is appropriate in this context...

(IMG:style_emoticons/default/grinbig.gif)

Most of the stuff I listed is not new stuff, just extensions of modern research and development in vehicles. But things that were cutting edge in race cars 30 or 40 years ago are fairly common in production cars today and the same will be true for today to 2070.

CVTs have serious maximum load and force limits. They would be more then fine for electrics, city cars, and smaller cars. However, for any how power or performance vehicle they are not the choice since building them strong enough to handle the power is difficult. In addition, the way the sound and feel is not conductive to how a performance vehicle should sound and feel.

As for 17/18, you are correct in that those are ways. However, since we are talking about the "Engine Customization" mod, I tried to keep it engine related.

Exactly:

Acceleration
Vehicles have an Acceleration rating that determine their movement rates. Th e number to the left of the slash is a vehicle’s
Walking rate in meters per turn. Th e number to the right is its Running rate.

A drive or drone can attempt to move a greater distance by making a Vehicle Test (see below). Each hit on the test adds 5
meters to the vehicle’s movement rate.


I don't understand why SR keeps trying to redefine perfectly well understood words to mean completely different things in the game. It causes huge confusion. Of course, they redefine and use critical elements of the game mechanics differently in different chapters...

Ah, but what liter from what metric system are you talking about? There is no one "metric system" and in fact there are several. I'll assume that you ment the SI (International System of Units).

As for the Imperial system, no I don't use the Imperial system at all. I use 'U.S. Customary Units' and unless you do not live in the U.S., you do to. There are differences between the Imperial and U.S. customary units. Example, an Imperial ton is 2240lbs, while a U.S. customary units ton is 2000lbs.

(IMG:style_emoticons/default/twirl.gif)

Precisely, as that is the unit system used in Germany. I used the general term "metric system" as that seems to be the name Americans know rather than SI.
I'm well aware of that. Again, my choice of words was based on simplicity. I didn't want to write "Imperial/US customary" every time - AFAIK both systems have the same unit names even if there are differences in value...

Mars Climate Orbiter showed what happens when you mix up unit systems.

Sorry if you didn't catch it by the Jester and Crazy face, but I was just teasing you bro.

And after looking at the BBB again, I have to say that vehicles are *really* nerfed as written. Damn, if I'm going along at a speed of 200 in a EW3k (roughly 150mph) on a 75mph speed limit highway at 1am and I blow past a Star in his Chrysler-Nissan Patrol-1, crazy stuff happens. Since I decide to run (fake SIN plus double speed limit = go to jail), it becomes stressful or combat driving. Next round I punch it to accelerate even more and... move 80 meters... WTF?!