Why rotary engines are better than piston engines!
12-08-2005, 02:21 PM
#51
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Originally Posted by rollerbldes
More information on thermodynamics:
The flaw in rotary engines is thermodynamic, because the four strokes
always take place in the same but separate four locations of the
chamber, so that intake (freezing), compression, combustion (5000F),
exhaust, are a steady state thermal load. Finding materials and
lubricants that can wipe past these extreme temperatures is beyond
today's technology, both from an expansion and friction aspect, and
probably will remain so. To make rotary internal combustion engines
work, lower compression and rich mixtures are used, making them non
economical both in fuel and duration.
Reciprocating piston engines perform all four strokes in the same
place so that both piston AND cylinder see an oscillating operating
temperature in which a boundary layer and expansion cooling make the
apparent temperature so low that cast aluminum and cast iron can
contained them, less expensive materials and higher thermodynamic
performance. It is not without reason that the Wankel did not
succeed. Its flaws were known more than 80 years ago but the unusual
configuration had many wondering whether a rotary engine might be
possible after all.
The flaw in rotary engines is thermodynamic, because the four strokes
always take place in the same but separate four locations of the
chamber, so that intake (freezing), compression, combustion (5000F),
exhaust, are a steady state thermal load. Finding materials and
lubricants that can wipe past these extreme temperatures is beyond
today's technology, both from an expansion and friction aspect, and
probably will remain so. To make rotary internal combustion engines
work, lower compression and rich mixtures are used, making them non
economical both in fuel and duration.
Reciprocating piston engines perform all four strokes in the same
place so that both piston AND cylinder see an oscillating operating
temperature in which a boundary layer and expansion cooling make the
apparent temperature so low that cast aluminum and cast iron can
contained them, less expensive materials and higher thermodynamic
performance. It is not without reason that the Wankel did not
succeed. Its flaws were known more than 80 years ago but the unusual
configuration had many wondering whether a rotary engine might be
possible after all.
12-08-2005, 09:27 PM
#52
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Originally Posted by RoXanneBlack8
stealthfox, ur officially a rotary moron. i have a rotary engine in my bedroom and i can lift it up by myself. i am 5'10 and weigh 150 lbs. there is not one v8 in the world i can even move off the ground. ur an idiot.
the transmission of an rx8 weighs as much, if not more than the rx8s entire engine.
a 1.3l engine with 238 hp is 183 hp per liter. thats virtually 3 horsepower per cubic inch. in order for a 5.7l v8 to make 3 hp per cubic inch it would have to make over 1000 horsepower. i bid goodluck to chevy trying to match that. o, by the way, make it a low emission vehicle and that gets 18 mpg city, with 10:1 compression and 91 octane.
"no advantages over a piston engine"?
3 moving parts compared to the thousands in an OHV v8 means more reliability. less parts that move are less parts to break. valve adjustment? timing belt replacement? warped head? thrown rods? spun bearings? blown head gasket? floated valves under high rpm? cracked piston? ever hear of these?????
not in a rotary
a 100 lb engine thats 2 feet long and 1 foot high will give better 50/50 than a 500 lb v8 thats 2-3 feet high. dont get me started on valvetrain noise or how they r just generally not smooth at all.
no wonder u got a v8 in ur 7. u didnt kno what u had, or u blew it up bc ur that retarded. thank the wankel god u dont have a rotary anymore. felix turned over in his grave when u decided to get a 7.
the transmission of an rx8 weighs as much, if not more than the rx8s entire engine.
a 1.3l engine with 238 hp is 183 hp per liter. thats virtually 3 horsepower per cubic inch. in order for a 5.7l v8 to make 3 hp per cubic inch it would have to make over 1000 horsepower. i bid goodluck to chevy trying to match that. o, by the way, make it a low emission vehicle and that gets 18 mpg city, with 10:1 compression and 91 octane.
"no advantages over a piston engine"?
3 moving parts compared to the thousands in an OHV v8 means more reliability. less parts that move are less parts to break. valve adjustment? timing belt replacement? warped head? thrown rods? spun bearings? blown head gasket? floated valves under high rpm? cracked piston? ever hear of these?????
not in a rotary
a 100 lb engine thats 2 feet long and 1 foot high will give better 50/50 than a 500 lb v8 thats 2-3 feet high. dont get me started on valvetrain noise or how they r just generally not smooth at all.
no wonder u got a v8 in ur 7. u didnt kno what u had, or u blew it up bc ur that retarded. thank the wankel god u dont have a rotary anymore. felix turned over in his grave when u decided to get a 7.
... and thank god i wasn't cursed with the spelling and grammatical skills of a 7 year old
-edit-
thank you for a new sig
Last edited by StealthFox; 12-08-2005 at 09:29 PM.
12-08-2005, 09:28 PM
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Originally Posted by Deslock
Stealthfox, you never responded... do you know how much any of those engines weigh? FYI, according to Atkins Rotary, the 13B block weighs 180 pounds (not fully dressed, obviously).
oh yeah also you need to take into account the fact that a 13b-rew is a very heavy system with its accesories and such and very complicated sequential turbo setup so removing that heavy ineffecient system that basically cooks itself gives you a lot of freed up weight to work with in a ls1 swap without weighing more or much more than stock. keep in mind the ls1 is an all aluminum block and its quite compact.
Last edited by StealthFox; 12-08-2005 at 09:37 PM.
12-09-2005, 06:16 AM
#54
stop flooding ur engines
Last edited by RoXanneBlack8; 04-30-2011 at 08:37 PM.
12-09-2005, 07:09 AM
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Originally Posted by StealthFox
go to rx7club.com and go to the v8 swap section and they'll have all of that information for you in abundance.
oh yeah also you need to take into account the fact that a 13b-rew is a very heavy system with its accesories and such and very complicated sequential turbo setup so removing that heavy ineffecient system that basically cooks itself gives you a lot of freed up weight to work with in a ls1 swap without weighing more or much more than stock. keep in mind the ls1 is an all aluminum block and its quite compact.
oh yeah also you need to take into account the fact that a 13b-rew is a very heavy system with its accesories and such and very complicated sequential turbo setup so removing that heavy ineffecient system that basically cooks itself gives you a lot of freed up weight to work with in a ls1 swap without weighing more or much more than stock. keep in mind the ls1 is an all aluminum block and its quite compact.
However, your post prompted me to go back this morning and look again; I found weight numbers in some more recent threads:
- 13B block: 180 pounds
- 13B fully dressed: 260 pounds
- 13B-REW fully dressed: 327 pounds
- LS1 fully dressed: 460 pounds (I've seen it listed at 450 elsewhere)
Anyway, the t56 is lighter, offsetting some of the additional weight of the ls1 in the common V8 rx7 swap. And while I like the rotary, I'm not arguing against swapping in a ls1/t56... it has many advantages. But I couldn't find anything to support your statement that the rotary is "almost as heavy as some small block V8 engines". From what I've read, both the 13B and 13B-REW are significantly lighter than the LS1. How much do the 302 and 327 weigh?
On a side note, I haven't found the 13B-MSP weight anywhere, though I'd guess it's not much different from the previous 13B.
12-09-2005, 05:09 PM
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A RX-7 converted to V8... WHY? I thought the whole point in getting a RX was the rotary engine. If you wanted a V8 might as well get a hemi or something.. I bet a 6.0L Corvette can smoke that V8 RX-7... It is a bit heavier at 3180lb and 49/51 weight ratio.
12-10-2005, 11:11 PM
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Originally Posted by RoXanneBlack8
someone block this guy from the threads
12-10-2005, 11:19 PM
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Originally Posted by Deslock
Yeah, I've sifted through that engine swap forum before. Many said the swap added 100 pounds vs an 13B-REW, a few said it added 30-40 pounds, and some said there was no weight gain (but some of these people had swapped out many other parts on the car for lighter ones).
However, your post prompted me to go back this morning and look again; I found weight numbers in some more recent threads:
Anyway, the t56 is lighter, offsetting some of the additional weight of the ls1 in the common V8 rx7 swap. And while I like the rotary, I'm not arguing against swapping in a ls1/t56... it has many advantages. But I couldn't find anything to support your statement that the rotary is "almost as heavy as some small block V8 engines". From what I've read, both the 13B and 13B-REW are significantly lighter than the LS1. How much do the 302 and 327 weigh?
On a side note, I haven't found the 13B-MSP weight anywhere, though I'd guess it's not much different from the previous 13B.
However, your post prompted me to go back this morning and look again; I found weight numbers in some more recent threads:
- 13B block: 180 pounds
- 13B fully dressed: 260 pounds
- 13B-REW fully dressed: 327 pounds
- LS1 fully dressed: 460 pounds (I've seen it listed at 450 elsewhere)
Anyway, the t56 is lighter, offsetting some of the additional weight of the ls1 in the common V8 rx7 swap. And while I like the rotary, I'm not arguing against swapping in a ls1/t56... it has many advantages. But I couldn't find anything to support your statement that the rotary is "almost as heavy as some small block V8 engines". From what I've read, both the 13B and 13B-REW are significantly lighter than the LS1. How much do the 302 and 327 weigh?
On a side note, I haven't found the 13B-MSP weight anywhere, though I'd guess it's not much different from the previous 13B.
12-11-2005, 06:11 AM
#62
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StealthFox, I'm not interested in covering the pros and cons of rotary vs piston (I already said that there are advantages to the LS1/t56 swap). Our discussion is getting somewhat circular (from posts #37, 41, 50, 53, 55, and 61):
- you: Rotary is as heavy as some small block v8s
- me: How heavy are those engines? I've read that the 13b block is 180 lbs
- you: All that info is at rx7club
- me: 13b block is 180 lbs, 13b fully dressed is 260 lbs, 13b-rew is 327 lbs, ls1 is 460 lbs. t56 tranny is lightweight, offsetting some of the ls1 swap weight gain. What do the 302 and 327 small blocks weigh?
- You (while quoting my numbers!?): I was talking about the ls1. 13b-rew setup is as heavy as some small blocks
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