00:00:00 --- log: started forth/04.08.02 00:00:06 To get economy, you shift at or just below max torque. 00:00:11 stronger cars it seems to be higher because they have more torque to overcome the momentum and inertia of the pistons 00:00:43 Yeah. They have larger bores for the pistons, and not as much piston travel. 00:01:14 i think they have the same piston travel 00:01:19 otherwise theyd do more RPM 00:01:39 Not necessarily. 00:02:00 A Dodge Viper, IIRC, gets its max power at 4000RPM. 00:02:03 :) 00:02:09 :) 00:02:12 It has a V-10 engine that displaces 8L of gas. 00:02:15 thats like ... mine! :/ 00:02:20 !!!!!!!!!!!!1 00:02:22 oh 00:02:28 it probably has longer travel then 00:02:42 Yes, it has a largish travel. 00:02:42 i think... 00:02:50 yeah 00:03:05 got a question 00:03:07 But the big thing about it is the size of the pistons, diameter-wise. 00:03:31 if you have very litle piston travel, is it true that i need the power to be able to utilize only a little bit of travel? 00:03:35 yeah 00:03:40 i have little diameter 00:03:42 The larger the diameter *OR* the longer the stroke, the slower it can run for the same torque output. 00:04:03 ah. 00:04:24 but still 00:04:48 if you configure my engine to have this really nearly-non-existant piston travel (like in the indy cars) 00:04:53 As a *wonderful* case in point, just look at those low-temperature differential Stirling engines. :) Tiny pistons, high RPM. Large pistons, slow RPM. 00:04:53 it wouldnt go anywhere 00:04:58 right? 00:05:02 oh 00:05:02 ;) 00:05:08 but look at my question 00:05:11 am i right? 00:05:13 No, that's not necessarily true either. 00:05:22 Power = Torque * Angular Velocity 00:05:45 If you reduce the angular velocity, you must increase torque. 00:05:49 (for a given power output) 00:05:58 Put another way, look at a simple lever. 00:06:07 yeah. 00:06:08 You can move a mountain with nothing but a stick. 00:06:15 yeah 00:06:20 But the closer to the mountain, the more torque you need. 00:06:20 but i need one hell of a travel 00:06:24 yeah 00:06:26 Exactly. 00:06:40 So the less travel a piston has, the more *push* it needs (e.g., the larger its diameter) to get the same output power. 00:06:49 *OR*... 00:07:09 The higher the RPMs needed, and an appropriate gearing on the back-end of the motor. 00:07:24 It's a trade-off. 00:07:44 thats the tradeoffs the indy cars take 00:07:53 they go like 14000+ RPM 00:07:57 Dodge gave the Viper a lot of push because it has large diameter pistons AND a long stroke (lots of leverage), and so therefore, it has massive torques for its engine size. 00:08:10 Indy cars, however, don't have the room to put such big engines on their cars. 00:08:42 So they have to go for very, very high-speed operation (approaching gas turbine speeds!), and use gears to transform the almost torque-less output of the engine into usable torque. 00:08:57 btw, do you know if you need some sort of special license for pistons starting at a cretain amount of cylinders? 00:09:16 No, you do not need any special license. 00:09:20 cool 00:09:29 There is no power limit in this country. 00:09:40 so i could put a V24 in the back of a truck, hook it up, and drive it without a problem? 00:09:57 In Japan, there is -- no street-legal car can exceed 280HP. This is why the last make of the RX-7s topped out at 280HP, and that's it. This is also why Nissan Skylines are also at 280HP. 00:10:16 Yep. Read about that. 00:10:25 arke: Son, you have a lot to learn. Early in the 20th century, Cadillac was experimenting with V32s. Where've you been? :D 00:10:33 o.O 00:10:34 ;) 00:10:57 wow 00:11:00 thats like 00:11:01 ... 00:11:02 wow 00:11:13 Yeah. As in, *LONG* engine blocks. 00:11:20 like 00:11:24 a meter and a half 00:11:41 Hey, they had to compete with Rolls Royce back then. 00:11:44 they put those things in tanks ;) 00:11:49 what did rolls royce do? 00:12:07 RR is a British luxury car manufacturer. 00:12:34 (and commercial airplane gas-turbine engine manufacturer too, interestingly enough. And invented, but never commercialized, the diesel Rotary engine.) 00:12:54 why did they never commercialize it? 00:13:01 i know youve told me 00:13:03 but i cant remember 00:13:24 Materials science back then wasn't quite up to par. Apex seals would blow too quickly. 00:13:28 and my question was why did they have to make up V32 engines to compete with RR? 00:13:37 aah 00:13:40 when was this? 00:13:44 I'd like to see you apply 20+ atm. of pressure on a piece of metal about as thick as a pencil lead. :) 00:14:03 I'd have to pull the book out and determine the dates again. 00:14:08 And I'm too lazy to do that now. 00:14:13 guess? 00:14:23 70s? 00:14:24 80s? 00:14:41 re: Caddy -- they used lots of cylinders because it (a) was cheaper than improving burn efficiency to get more power, and (b) it provided a much smoother ride. 00:14:50 60s. 00:14:55 aah. 00:15:27 Oh, and (c) The car was much longer, and therefore, is a tangible and readily ascertainable symbol of wealth. 00:15:48 :) 00:15:51 The V32s back then only put out about 230HP too! 00:15:55 hmm 00:15:59 woah 00:15:59 lol 00:16:29 Compare that against a Mazda 13B, which is about as smooth as a V8, and is about half the length of a V8, and most definitely half the height of a V8....and puts out 240HP..... 00:17:00 13B = RENESIS = RX-8 right? 00:17:11 No. RENESIS is a kind of 13B. 00:17:15 aah 00:17:20 The 13 means it's a 1.3L displacement engine. 00:17:26 B means it's the second physical geometry. 00:17:31 Which is really a misnomer. 00:17:37 The 13B *should* be named the 13A. 00:17:52 Since it's the exact same geometry as the 12A engine (powerplant for the 1st generation RX-7s). 00:18:12 2nd gen is 12B? 00:18:47 But it gets even more confusing because Mazda has the 13G, the 13F, etc. all 3-rotor designs, and all 2.0L displacement. These engines are just one-offs though. 00:18:53 13B 00:19:08 The 1st gen RX-7 is 12A, the 2nd/3rd gen are 13B. 00:19:18 Just different variations of the 13B are used in each line. 00:19:48 RX-8 prototype was 3-rotor, right? 00:20:22 The 2nd gen started with the 13B-NA (Naturally Aspirated), then was upgraded to the 13B-RE (Rotary Engine ... duh!), then the 13B-RE/Turbo II, and then when the 3rd-gen came out, it was the 13B-REW (the W meaning "Wind", or "turbocharged"). Then the RX-8 came out, and is now the 13B-RENESIS. 00:20:29 No. 00:20:33 RX-8 has always been bi-rotor. 00:20:58 eh? 00:20:59 The Mazda Cosmo is the only 3-rotor car in Mazda's rotary line-up. 00:21:06 i thought RX-8 was 4 rotors o.O 00:21:13 No. 00:21:17 Where did you get that idea from? 00:22:23 dunno 00:22:28 All the way back to the RX-01 and RX-Evolv designs, it has always been a 2-rotor 1.3L displacement engine. 00:22:37 :/ 00:22:39 okie 00:23:09 Mazda DID experiment with putting a 20B engine in the 2nd gen RX-7 as a "preliminary concept" of what the 3rd gen RX-7 would be like. 00:23:20 (That's a 20B-REW, I might add). 00:23:36 But it never came to pass -- the 13B-REW is what ended up in the final production version. 00:23:57 But the 20B-REW is, like I said, in the Mazda Cosmo vehicle. 00:24:11 which was 1968 00:24:16 Mazda did make a 4-rotor engine, specifically for racing, called the R26B. 00:24:19 and then got 8.6 0-60 00:24:32 arke: No. You're thinking of the Mazda Cosmo Sport 110S -- that had a 10A engine in it. 00:25:11 I'm talking about the Mazda Cosmo (just, "Cosmo"), which is a luxury/sport vehicle. It's amazingly nice looking, all things considered. 00:25:25 I personally would never expect it to come from Mazda if I'd not seen it before. 00:26:15 Although the Cosmo Sport 110S kind of lives on today in a slightly different form. 00:26:51 RX-7/8? ; 00:26:57 It's called the Mazda MX-5, aka Mazda Miata. And, unfortunately, it comes with an otherwise great 4-cylinder engine. But the nice thing about the Miatas -- it has mounting brackets for a rotary. :) 00:27:32 Miatas are nice cars, and are definitely true roadsters. 00:27:42 I wouldn't mind having one myself. 00:27:48 me neither 00:27:54 they look great ;) 00:28:00 but thats interesting 00:28:01 Yes, especially the newer models. 00:28:10 they haev mounting brackets for rotaries.... 00:28:18 so you could put a 13b in it? 00:28:30 If you had the man-time and money to do it, yes. 00:29:03 If you go to any rotary engine car show, you're bound to see at least one. :) 00:29:20 ) 00:29:24 :) 00:29:45 oh yeah 00:29:55 one thing automatic trannies dont understand yet 00:30:06 is that a car isnt the best at redline 00:30:07 arghghg 00:30:20 CVT-equipped systems understand that just fine. :D 00:30:26 ;)( 00:30:28 :) 00:30:35 time to get an Audi ;) 00:30:40 Have you ever driven a CVT-equipped car? 00:31:14 no 00:31:22 would like to 00:31:31 They are weird -- as you accelerate, you notice the engine doesn't rev-up. You seriously start to wonder when you're going to start smelling smoke from the transmission's clutches. 00:31:56 It literally feels like you're slipping a clutch. 00:32:06 (except for the fact that you continue to accelerate smoothly) 00:32:12 heh 00:32:17 slipping clutch is weird 00:32:18 oh 00:32:20 did i tell you 00:32:24 if my clutch gets realy warm 00:32:35 (like, i go down a steep freeway and i engine brake) 00:32:36 it slips 00:32:40 but then it cools down 00:32:42 and its fine again 00:32:47 That's normal. 00:32:58 But it does suggest that your clutch may be wearing out. 00:33:11 Or maybe something related to the clutch's pressure plate. 00:33:34 well 00:33:52 we believe that clutch has been in there for almost 1200000 miles ;) 00:34:04 1.2 million miles? 00:34:10 Damn, maybe I should get a Colt Vista... :D 00:34:35 heh 00:34:40 that thing has driven ALOT 00:34:45 120,000 miles should not be enough to wear out a clutch though, but abuse (intentional or otherwise) will definitely do it. 00:35:06 well 00:35:13 i learned stick shift on it 00:35:13 Even so, with that kind of milage on it, I wouldn't complain. 00:35:23 ;) 00:35:28 Yeah, that'll be considered "abuse." :D 00:35:32 so ive abused that clutch quite a bit 00:35:36 .....unintentionally 00:35:37 ;) 00:35:45 but really 00:36:00 its only after going fast downhill for a while and engine braking 00:36:30 * kc5tja nods 00:36:33 and even then its only a little 00:36:51 if i floor it and engage hard, then its very noticeable 00:37:03 Yeah, that's also considered abuse. :) 00:37:05 (it revs to like 3500 immediately, etc.) 00:37:15 well, i dont do that much 00:37:16 ;) 00:37:27 Every little bit adds up. 00:37:30 but like if i want to pass somebody 00:37:38 so i press down harder 00:37:44 and it revs up a bit before it does its thing 00:37:47 i notice it 00:38:20 Crap. I'm hungry. And it's past midnight! 00:38:56 its called can of ravioli 00:39:00 cheap. easy. good 00:39:01 ;) 00:39:07 --- join: crc (crc@0-1pool228-30.nas19.philadelphia1.pa.us.da.qwest.net) joined #forth 00:39:11 hi crc 00:39:20 kc5tja: i had an idea 00:39:41 Hi arke 00:39:53 kc5tja: but to explain it, i have to read something 00:39:57 it relates to two-strokes 00:40:28 what's that? 00:41:14 http://auto.howstuffworks.com/inside-engines-roundup.htm -- firmly bookmarked in my browser now... 00:43:15 same here 00:44:17 what do they mean when a piston engine "knocks"? 00:46:26 it seems to be from too great compression 00:46:31 but i dont know the effects 00:46:33 and it interests me 00:46:59 A knock is a *pre*-detonation. 00:47:21 That is, the air/fuel mixture ignites on its own, *before* the spark-plug fires, while the mixture is being compressed. 00:47:25 In other words, it diesels. 00:47:33 yes 00:47:42 but lets say one of my cylinders knock 00:47:45 what happens? 00:49:15 Well, the explosion causes back-pressure on the piston. 00:49:28 Remember that it's still trying to *compress* the gas, but the gas is now trying to *expand*. 00:49:50 eh 00:49:59 and that force is exerted onto the crankshaft, right? 00:50:08 This essentially *doubles* the pressure put on that cylinder's connection rod and that part of the crank shaft. Hence, it's wearing that section of the engine out almost two the three times as fast. 00:50:30 This is why knocking can lead to snapped con-rods and damaged crank shafts. 00:51:04 :/ 00:51:07 it also takes a lot of energy away from the normal operation of the engine, and therefore, represents increased emissions, and decreased fuel economy. 00:51:30 a snapped con rod makes that cylinder not contribute, coirect? 00:51:49 That "knock" that you hear is the sound of the piston temporarily (and rather rapidly) changing directions. Not a good thing. 00:52:05 :/ 00:52:10 A thrown con-rod can actually destroy the entire engine. 00:52:27 The engine can throw it with sufficient force as to blow clean out of the hood of the car. 00:52:29 was about to say - it coult interrfere with the crank shaft path 00:53:01 oh 00:53:02 heh 00:53:07 how fun 00:53:18 Yes. 00:53:38 and if you have a V engine 00:53:43 and its mounted sideways 00:53:50 it could blow right straight into YOU 00:55:13 --- nick: Tomasu -> TomasuDlrrp 00:56:43 02:53 < arke> how fun 00:56:43 02:53 <@kc5tja> Yes. 00:56:43 02:53 < arke> and if you have a V engine 00:56:48 oops, ignore that 00:57:07 http://auto.howstuffworks.com/chrysler-concept3.htm 01:01:07 That's nice, but a pale imitation of the Bugatti 16.4. :-) 01:02:08 bleh 01:02:09 ;) 01:02:13 hmm 01:02:25 i think mitsubishi should redo the colt line 01:02:30 but this time, make them more l33t 01:04:27 I will say this about the Chrysler ME -- it is a gorgeous car. I think it's prettier than the Bugatti even. 01:04:46 But the EB has 150HP more power. 01:05:05 But, what really will determine all this is its power to weight ratio. 01:05:16 And I wonder if General Motors is planning a competitor to this kind of car. 01:05:30 Undoubtedly, they have a new CERV being designed to counter the ME. 01:05:38 ;) 01:06:28 The other thing: note how the ME412 looks amazingly like a future model of the Dodge Viper too. (:D 01:07:08 :) 01:08:29 aah 01:08:31 ive got it 01:08:44 heres my car 01:08:50 6-cylinder 2-stroke engine 01:08:56 backed by a CVT transmission 01:09:00 but, the good part is 01:09:12 fuel injection is not done the traditional way 01:09:24 but somewhat the way newer car engines do 01:09:46 the lower part of the cylinder is then free to act as a lubricating pan 01:09:52 eliminating the need to mix in oil 01:12:50 so, to recap 01:13:00 eliminate pressurization chamber 01:13:08 replace it with dedicated lube system 01:13:14 have fuel injection 01:13:48 OK, I stand corrected. Power to weight ratio of the ME-4/12 is 0.295, but is only 0.230 for the Bugatti. 01:13:55 Damn! That's damn impressive! 01:14:47 :) 01:14:54 what do you think about my idea? 01:15:00 I would use separate air injection AND fuel injection, personally. 01:15:21 This way, you can refrain from injecting fuel until you know the exhaust port is closed, and therefore, not leak out any unburned fuel. 01:16:07 You know what I find missing on their table of pwer-toweight ratios? A Corvette CR5. >:) 01:16:11 even better 01:16:14 ;) 01:16:20 Because I *know* that a CR5 is WAY more powerful than a ZO6. 01:16:56 :) 01:17:04 Still, the ME-4/12 is damn impressive. And it is a very, very nice looking car. It matches the front "Chrysler" logo (the winged logo) very, very nicely. 01:18:19 But here again, we see an engine with its power range from 2500RPM to 4500RPM -- exactly the same as the SVT-10 in the Dodge Viper. In fact, I would not at all be surprised if the official name of the engine is, in fact, an SVT-12. 01:18:45 Considering their very short production schedules, it would make the most sense to re-use the SVT engine design technology. 01:18:45 ;) 01:19:26 Still, if I were to build my own super-car, it'd have a Mazda R26B in it. 01:19:46 700HP of pure rotary fun, without turbos. Have a nice day. >:) 01:19:59 ;) 01:20:14 oh 01:20:19 BOTH! 01:20:28 No, not both. 01:20:31 Power to *weight*. 01:20:36 no 01:20:42 i mant somethinfg else 01:21:06 you know how hybrid cars just kinda switch between the engines on a certain condition? 01:21:28 Well, they don't exactly switch in a binary fashion, but yes. 01:21:30 And no, that won't work. 01:21:33 add a 2-stroke engine, described above. 01:21:36 and a rotary. 01:21:44 I wouldn't bother. 01:21:45 oh 01:21:47 why not? 01:21:48 Just stick with a 2-stroke. 01:21:57 2-strokes can easily handle high RPMs like a rotary can. 01:22:07 why wont both work? 01:22:18 rotary kills 2-stroke in high-end torque 01:22:25 2-stroke kills rotary in low-end torque 01:22:32 They can be made to work, sure, but now you've got the weight of two engines PLUS the mechanical linkage between them PLUS the normal transmission. 01:22:48 The solution is to use the engine where it's most killer. 01:22:48 :/ 01:23:06 If your engine excels in low-end torque, use it in the low-end. :) That's what a CVT is for. 01:24:33 then id want the rotary 01:24:39 i do like that whole double-clutch concept though. It's so devilishly simple. I really can't think of why I didn't think of something like that myself. 01:24:42 the one that handles 12000RPM 01:24:49 with a transmission to match 01:24:54 Well, what you want is a weight-reduced RENESIS then. 01:24:57 oh, yeah 01:25:00 wet double clutch 01:25:02 sw33t 01:25:18 yep 01:25:21 but with a matching tranny 01:25:28 one that handles those high RPMs 01:25:35 That can be done. 01:25:48 :) 01:25:57 hmm 01:26:04 not a CVT though, or...? 01:26:44 A CVT can work, definitely. The problem is, can the CVT handle the torque of very high power outputs? 01:26:57 thats my point 01:27:07 is it possible to create a CVT tranny doing that sort of stuff? 01:27:16 if most normal trannies cant even handle it 01:27:23 why a CVT? :/ 01:27:35 Well, what kind of power are you looking at? 01:27:48 uum 01:27:54 10500 RPM 01:28:03 That's RPM. 01:28:09 What kind of power are you looking at? :) 01:28:23 erm... 01:28:26 in HP? ;) 01:28:30 yes 01:28:36 or kW if you wish. 01:28:38 I can convert. 01:28:40 280 01:28:46 HP 01:28:54 Today's CVTs can handle 280HP without any issues. 01:29:07 So a CVT can be made to work, even if an initial gear-down is required to keep the oil cool. 01:29:07 when does it start becoming problematic? 01:29:44 I'd guess at around 400HP or so. 01:29:57 ahh. 01:30:25 However, I'd also like to say this much: it should be possible to use two CVTs in parallel to spread their load evenly across them too. 01:30:35 ooh 01:30:37 awesome 01:31:00 So if you can afford the space underneath the car (which I doubt you would be able to, BUT...), you should be able to handle up to 600HP or so with "a" CVT design. 01:31:55 Another possibility, I'd think, is a computer-controlled, 10-speed or 20-speed transmission too. 01:32:17 On my mountain bike, I can keep at a pretty consistent pedal cadence regardless of terrain usually. 01:32:35 And that's with only 8 usable speeds out of the 21 speeds that I have. 01:32:47 A proper 10- or 20-speed transmission would have that much more freedom. 01:32:55 hmm 01:32:59 and double-clutching would make it seem virtually transparent. 01:33:12 the main thing would be having an insanely torquey low range 01:33:18 yeah :) 01:33:36 Well, my RX-7 has hauled many heavy loads from San Diego to Oceanside and vice versa. 01:33:53 So believe me, low gears are never a problem. 01:34:45 well, RX-7 already has a very torquey first gear 01:35:07 yes, it needs one. 01:36:24 exactly 01:36:34 how fast does 1st go at some RPM? 01:36:56 The fastest I've personally gone in 1st is about 20MPH. 01:37:34 woah 01:37:36 But I never pushed the engine to its redline in 1st. 01:37:40 what RPM was that? 01:37:50 5000RPM. 01:37:54 o.O 01:38:05 I go 30mph 1st 5000rpm 01:38:32 In 2nd gear at 5000RPM, I'm doing almost 55MPH though. :) 01:38:49 2nd gear 5000rpm is exactly 50mph ;) 01:38:50 (well, on my 1st gen RX-7 that is.) 01:38:57 my second gear mph = rpm / 100 01:39:12 yeah, gear ratios are different for 4 speeds 01:39:17 i dont like 4 speeds :/ 01:40:07 Actually, I stand corrected: about 45MPH in 2nd gear. 01:40:20 Because at 3000RPM in 4th, I'm also doing 45MPH. 01:40:21 in 1st or 2nd gen? 01:40:26 1st, LIke I said. 01:40:32 oh 01:40:41 still more torquey than mine 01:40:46 Yeah. 01:40:50 what about 3rd hear 01:40:53 gear* 01:40:55 But the higher gears make up for it. 01:40:58 3rd gear 3000rpm is about 50mph 01:41:20