ultimate vtec??

[GHOST 2.2]

many of my friends who have rx7s complain of POOR gas milage. plus it is not easy to fix a rotary engine. It is also not easy to find a shop who does rotary fixes.

most of my friends also say that rotary engines are a money pit. my homeboy spent 7 grand to fix his turbo rx7. he doesnt even race it.

but yea i like how the engines sounds n how a lil motor can put out a lot of power. but the reliablity is horrible.

[owequitit]

Actually.....Some of what you said was incorrect....

In theory, with the correct parts, a rotary engine will be incredibly more reliable than ANY piston engine. Thus being, fewer moving parts. Only 14 moving parts in total...


But Check out that Coates engine, it's pretty incredible. Like I said, takes the rotary Idea and sticks it onto the piston.





Rotaries rule!

Most efficient engines on earth, as far as least power lost...

Don't get me wrong. I am one of the biggest rotary fans on this site. My statements have nothing to do with my personal preferences, they are based on reality and the laws of physics. There is no such thing as a mechanically perfect system. Every thing has advantages and disadvantages, that is why there must be compromises in engineering.

Theoretically, yes a rotory is much more reliable. In reality it is not. Some of it is design, some of it is materials strength, some of it is the way you have to drive it.

How are you measuring efficiency?

they are not the most efficiant motor on earth. as far as i'm concerned a turbine engine has it beat...

That sorta depends on how you are measuring efficiency too... Turbines do have some distinct advantages, and they are just about perfect for their application, but they have many distinct disadvantages too.

[verothacamaro]

'Standard' Piston Engines have much great Parasitic Loss, than a standard Rotary....Thus making the Rotary more efficient. Now I do agree that Rotaries consume more fuel in the process, but the technology to make rotaries very fuel efficient is very expensive for mass production. The hydrogen powered car will most likely be a Rotary because, like I said previously, less power loss, and fuel will be in abundance.

The statement that Rotaries are hard to fix is a complete myth. No one wants to because they have no clue what they are doing. You can disassemble and assemble and rotary in less that 5 hours. I've done it, simple.

Your conventional engine has too much in the place of it. Valve cover, Timing belt, retainers, valves, springs, etc...


Now take for example Mitsubishi Eclipses. A sports car with a Turbo 4 cylinder. Average lifespan is 127k Miles before a real tuneup or rebuild. (there are exceptions)


How many Economic, Point A to Point B Rotary cars are there?.......few to none

As opposed to your everyday Civic...


Rotaries were put in Sports cars (More times than not)

Sports cars are driven Very hard.

Early 80's RX-7's were known to last well over 150k Miles with no problem. Then Comes the Turbocharger.

How many 4G63-T Do you know that havent had any problems over 100,000 miles?

And so comes the principle question....Is the rotary unreliable? Or is the fact that it's a performance engine, thus being driven hard on a regular basis?

N/A to N/A, A Rotary has a great chance of withstanding a significant lifespan.

Turbo to Turbo is just a matter of time before something goes wrong, on either end.

Supras are diffrent...they aren't from this planet

Dont forget that Ferraris engines have a lifespan of only 20k miles before a complete tuneup is required....

haha blah

[owequitit]

'Standard' Piston Engines have much great Parasitic Loss, than a standard Rotary....Thus making the Rotary more efficient. Now I do agree that Rotaries consume more fuel in the process, but the technology to make rotaries very fuel efficient is very expensive for mass production. The hydrogen powered car will most likely be a Rotary because, like I said previously, less power loss, and fuel will be in abundance.

The statement that Rotaries are hard to fix is a complete myth. No one wants to because they have no clue what they are doing. You can disassemble and assemble and rotary in less that 5 hours. I've done it, simple.

Your conventional engine has too much in the place of it. Valve cover, Timing belt, retainers, valves, springs, etc...


Now take for example Mitsubishi Eclipses. A sports car with a Turbo 4 cylinder. Average lifespan is 127k Miles before a real tuneup or rebuild. (there are exceptions)


How many Economic, Point A to Point B Rotary cars are there?.......few to none

As opposed to your everyday Civic...


Rotaries were put in Sports cars (More times than not)

Sports cars are driven Very hard.

Early 80's RX-7's were known to last well over 150k Miles with no problem. Then Comes the Turbocharger.

How many 4G63-T Do you know that havent had any problems over 100,000 miles?

And so comes the principle question....Is the rotary unreliable? Or is the fact that it's a performance engine, thus being driven hard on a regular basis?

N/A to N/A, A Rotary has a great chance of withstanding a significant lifespan.

Turbo to Turbo is just a matter of time before something goes wrong, on either end.

Supras are diffrent...they aren't from this planet

Dont forget that Ferraris engines have a lifespan of only 20k miles before a complete tuneup is required....

haha blah

I understand what you are saying. I agree, rotories are not hard to rebuild, and one of the reasons they are money pits is because people do not know what they are doing with them.

OK, they have less parasitic power loss. It isn't that much less, and if we remove the valvetrain loss from a recip (with a solenoid activated valvetrain) we have effectively even the parasitic loss difference to almost zero. We are then left with the parasitic loss of the crank and bearings, the piston rings in the bore, the wrist pins and rods and bearings. Total drag surface area is probably pretty close to what you would find in a rotory with the eccentric shaft, apex seals and rotors, in contact with everything.

Also, my understanding is that the displacement figure settled on by the S.A.E. for rotaries is based on the displacement of 1/2 of the total # of rotors. So in the case of a 13B, the 1.3 liters is based on 1 rotor, since there are two. If a more conventional method was used (apparently there was a lot of debate over the method) it would actually displace about 2.6 liters. That would still give it somewhat high specific output, but it is less impressive than 1.3 liters.

Personally, I wouldn't use a Mitsubishi Eclipse as any kind of benchmark for durability.

Yes the 7's were generally beat on, especially the turbos, but like I said in a previous post. 200K out of a rotory is pretty good, and that is for a well maintained NA example. I know from plenty of experience that I have to fight like hell to blow an NA Honda BEFORE 200K.

I agree too about the 2nd gens. Everybody tends to lump 2nd and 3rd gen together. The 3rd gen is a ticking time bomb for many reasons other than the rotory itself. The car is inherently sound, but all the sub systems, were overly complex and poorly thought out. The 2nd gen is MUCH more durable. They seem to need rebuilt between 130-150K and you KNOW they had the snot beat out of them.

Again, like I said, there isn't anything wrong with Rotories, but they aren't the solution to making an engine that is more efficient than a recip piston engine.

[verothacamaro]

FD3S has ridiculous amounts of vacumn lines under the hood....the Sequential Turbo system was a little too ahead of it's time.....If the rotaries dont overheat, they'll last you a lifetime

I proved it.

[owequitit]

FD3S has ridiculous amounts of vacumn lines under the hood....the Sequential Turbo system was a little too ahead of it's time.....If the rotaries dont overheat, they'll last you a lifetime

I proved it.

True true. The FD3S was designed to not make this happen I think. Between the restrictive exhaust, close coupled cat that loves to melt, the plastic air water seperator tank, the somewhat small radiator, and the inflexible engine management, it seems to be hard to not get them to blow up do to overheating, or detonating. Sometimes both.

One of the coolest cars ever made. EVER. You just have to massage the wrinkles out and they will be fine.

[deevergote]

mmmm... I want an FD...

[bjaccord]

http://coatesengine.com/

Anybody check this out? It got mentioned and then the whole conversation went towards rotary motors, this is a rotary cylinder head. Its a freaking sweet idea, and you can have a cylinder head made for almost any engine, if you have the cash that is. Check it out. L8r

[v4lu3s]

there is a guy possibly in Greece who has done a valvetronic style conversion on multiple B series vtec dohc engines, dutchaccord knows the web page since he showed it to me, looks very cool!

[sj960]

I heard there is a system that actually uses solenoids to allow hydraulic fluid to modulate the valves.... supposedly gm is working on it.... that idea seems like it would be a lot more reliable than massive solenoids to directly open the valves...

[owequitit]

The problem with Hydraulic fluid is that it is heavy, thick, and generally doesn't allow for as fast a movement as pneumatics (compressed air).

Pneumatic valve trains have been in F1 for awhile now. It will most likely be the first one refined for production.