4 ROTOR

[Nizm0Zed]

And actually' date=' the Wankel operates more like a two stroke, especially if you consider the fact it needs oil mixed into the fuel for chamber lubrication, just like most 2 strokes.[/quote']

 

No, the only part the rotary has in common with a 2 stroke (other than petrol) is the oil added to the combustion mix.

It is a 4 stroke engine. It has 4 distinct stages of operation. Induction, compression, ignition, exhaust.

A 2 stroke combines the induction/compression in one stroke and the ignition/exhaust in another.

The rotary requires oil in the combustion mixture ONLY to lubricate the rotor seals.

otherwise there would be no way to lubricate them and it'd run dry, causing what is known as rotor chatter.

[Noddle]

All i know about rotaries is they sound really cool and they blow up really easy ..... blew up 3 of them before my rb days ;>

 

My understand of why these engines don't last, is mostly to do with the operator,

 

ie, did you warm it up properly , and cool it down properly before shutting it off ?

 

different metal expand at different rate,

 

Nigel

[Nizm0Zed]

rotaries can be very reliable engines, i personally know of several that have done over 100,000kms.

Like you said, look after it correctly and they are just as good as a piston motor.

Warm it up, cool it down, make sure it has lubrication for the seals, use mineral base oils not synthetics, good quality fuel, proper tuning, regular maintenance ect.

 

The things that kill a rotor is no lube in the fuel, hot oil temps (oil is used to cool the rotors), Poor tuning, no mechanical sympathy, poor quality rebuild/parts.

From that, all of those things (except fuel lube) apply to any engine.

There are also people that slag off rotors for blowing up and being unreliable because they heard of joe smith who rebuilds his rotor every year or 2 after a low amount of kms.

What they neglect to add, or just dont know, is that joe's engine is a comp spec highly strung motor that does a LOT of track time.

Same goes for a piston motor used in the same conditions. Full on competition racers rebuild after several runs/once a season. Same with rotors.

Otherwise its in a street car that blew up, because the owner straps the balls off it, it isnt tuned properly and was rebuild cheaply.

Again, a piston motor in the same situation will suffer the same problems, its just better at hiding it for longer.

[Gollum]

No, the only part the rotary has in common with a 2 stroke (other than petrol) is the oil added to the combustion mix.

It is a 4 stroke engine. It has 4 distinct stages of operation. Induction, compression, ignition, exhaust.

A 2 stroke combines the induction/compression in one stroke and the ignition/exhaust in another.

The rotary requires oil in the combustion mixture ONLY to lubricate the rotor seals.

otherwise there would be no way to lubricate them and it'd run dry, causing what is known as rotor chatter.

 

In that sense you're right, but let's not forget that a huge part of what makes a 2 stroke a 2 stroke motor by definition is that it makes power each time the piston reaches TDC. You could manually force air in and out of a 2 stroke and actually "seperate" the time in which they happen, but if it's still making power every 2 strokes of the piston, then it's a 2 stroke motor.

 

Just because a radically cammed 4 stroke bleeds it's cycles into each other like crazy doesn't make them less of a 4 stroke. They still take 4 full strokes to make their complete cycle.

 

A rotor doesn't really have a "cycle", which is why it's so hard to compare. The rotor never "moves back" and is always in a continual state of rotation. The only way you can call it a 4 stroke is by the fact that there's 4 distinct events, intake, compression, power, and exhaust.

 

Study aircraft turbine engines, they don't bother with specifying a stroke number because it simply doesn't matter. But the only way I can personally "make" a comparison, is it compare it to a 2 stroke that tends to always be doing something with no wasted time like a typical 4 stroke, and also requires lubrication internally. Much more in common than a 4 stroke imo.

[Weltall]

Before I bought my Z it was my goal to put a 20BT into and old Opel GT. Maybe I will someday. A 2000 pound, 650 horse toy just sounds like fun!

[helghast7]

rotaries can be very reliable engines, i personally know of several that have done over 100,000kms.

Like you said, look after it correctly and they are just as good as a piston motor.

Warm it up, cool it down, make sure it has lubrication for the seals, use mineral base oils not synthetics, good quality fuel, proper tuning, regular maintenance ect.

 

The things that kill a rotor is no lube in the fuel, hot oil temps (oil is used to cool the rotors), Poor tuning, no mechanical sympathy, poor quality rebuild/parts.

From that, all of those things (except fuel lube) apply to any engine.

There are also people that slag off rotors for blowing up and being unreliable because they heard of joe smith who rebuilds his rotor every year or 2 after a low amount of kms.

What they neglect to add, or just dont know, is that joe's engine is a comp spec highly strung motor that does a LOT of track time.

Same goes for a piston motor used in the same conditions. Full on competition racers rebuild after several runs/once a season. Same with rotors.

Otherwise its in a street car that blew up, because the owner straps the balls off it, it isnt tuned properly and was rebuild cheaply.

Again, a piston motor in the same situation will suffer the same problems, its just better at hiding it for longer.

 

 

 To an extent this is correct. However, and the old me would hate me for saying this, they really just aren't that reliable regardless of what you do, and those cars that make those high numbers are nonturbo, which means no fun. Its the reason I want out after 6+ years of playing with them. As much as mazda has improved the design over the years, and as much as the aftermarket has improved the design even further, they just can't take the abuse that regular piston engines can. Period.

 

These engines as much as I love them, were bred to race, and thats it. Its why they do so very well on the track but mazdas sales struggled throughout history and their reliability isn't very good. Over the time I've spent around them I learned that a happy wankel is a wankel on the track. Theres nothing like a WOT pull through the gears of a nicely built rotary, at least not something that we would ever be able to experience in our "normal" lives lol(F1 lol).

 

But on the street its a constant checklist of things to remember to do, not do, keep an eye out for and so on and so on. They are certainly not budget friendly, my last engine rebuild for my FD cost me roughly 4k with medium porting, which was just parts and labor of the actual rebuild. They don't tolerate knock even in the slightest and are extremely unforgiving when it comes to tuning and like stated elsewhere they they run very rich by nature, which is also the reason they shoot flames out of the back, which to clear things up and answer questions, yes turbo'd rotaries do that naturally and without any help, no need for any silly spark plug in the exhaust or what not. My car can spit up to 2 foot flames at times on decel and between shifts.

 

But if you don't mind the negative side of things, there are also many advantages to them such as their ungodly powerband. A properly set up rotary can see most of its power from about 4k all the way to 9k and with proper balancing weve seen as high as 12k on some cars. Mine hits full boost at around 3500 and stays that way until my 8500 redline, its quite fun to outshift sports bikes, I sometimes like to picture the look on their faces through their helmets when I've only shifted once for their 3 shifts lol. Another plus is the weight and size, even some 4 cylinders have some trouble beating them in size, especially when you relate it to power. And my personal opinion is the most fun thing about them is the flames lol. God thats so fun to see peoples reactions.

 

As for the 4 rotor questions, no matter what route you do, its not cheap. If you do it the real way theres a company in either Australia or New Zeland (i forget which) that sells custom 20b and 26b eccentric shafts for about 10k, after that you need i believe 2 special side housing plates, and the rest can be taken from any other 13b engine minus the rx8 housings, though the rx8 rotors are the best for n/a use since they have the highest compression at 10.1, custom oil pan, you can't do a sick 20b/26b n/a without Peripheral porting it, which is very expensive, and for the 26b you need all custom intakes and exhaust setups and a fully mapable stand alone. Add that all up and you get very empty pockets and an engine that sounds exactly like the 787b or mad mikes FD.

 

The other "fake" way as mentioned earlier has been done plenty of times before by japanese rotary companies such as FEED and RE- Amemiya. Much cheaper then the other way but still not cheap, you basicly need 2 of everything including computers, wire harnesses and what not.

 

I loved the car, had a blast in my time, but im ready for something more reliable that once i dial it in, can hit the track time after time with no worries besides the normal things and still drive home everytime. Plus with the amount of money I've put into my FD, total including purchasing the car, i could have bought a nice s30, made it rust free, installed a complete track suspension and brakes, rb swap with AEM, and probably at least a 4 point cage and been racing for years.

 

Sorry if I rambled much.