Weak part of engine....?
 

I was thinking with other engines some "weak" links coule be pistons, rods, sleeves, cams, retainers bla bla bla....and with rotory if you dont have all that crap what is the weak part of the engine that would prevent me from putting a t-78 with a 100 shot if i had a proper fuel system, street port & rebuilt, injectors, tuning and bolt ons?
Sorry if im missing some things its 4 am and i couldnt sleep because i was thinking about this

-Joe

Lean condition----->detonation------>failed apex seals------>low/no compression.

That about sums it up, pard. Now go get some sleep ;)

its weird they say the rotory can make any kind of power even 1000hp but then it doesn't last long

so imo that means it can't make big power because it won't last long when it has it.

I guess if everything was tuned perfect with 600rwhp the motor would last maybe 30k miles?
I think that not many people or shops know what they are doing with the turbo rotary yet so hopefully in the future it will get better.

I'm all confused about it too. I gotta find a place that knows wtf they are talking about.

The "weak" link in a rotary is the apex seals. They are the thing to go first, almost always. And the more pressure you put inside the combustion chamber, the more power you make. So by wanting more power, you're putting more pressure on the seals, and they wear faster. Basically, all you have to do it design apex seals that are resistant to detonation, stronger than the stock seals, won't fragment into a thousand tiny pieces upon blowing, and you've got youself an idiot proof rotary.

Now, in 100 years since the thing has been around, no one has been able to design seals that do all of that. But go for it, I'll buy them if you do.

My impression has not been that high horsepower rotaries wear out faster. It seems that if you can eliminate detonation, it will last forever. If you are running high boost, what engine internals are going to wear faster? It's not like apex seals wear out; 99.99% of the time detonation causes them to break.

Not that I have any experience here, I'm just going on theory. If you put more pressure on the apex seals by running higher boost, then over time they should theoretically be weaker, and so even less resistant to detonation. After a while, one ping and they're done.

I just don't see how the extra pressure on the apex seal is going to weaken it. It's not like it is being flexed or anything.

I'm inclined to agree with you. The more boost you run, the higher the internal pressure, and (octane of fuel held constant) the more tuning comes into play to keep everything hunky-dory. I think that's why high hp rotaries tend to break more.

It's all a matter of tuning. On piston motors when you want to make huge power, your biggest concern is the bottom end and how much it will take. A well kept rotary is actually capable of holding just about as much boost as you're willing to throw at it givin proper tuning and the right octane and you don't exceed the effeciency of the turbo.

I think it was the rx-7.com drag car that was runing for quite a while, runing high boost AND some sort of nitrous shot. I think that motor actually held together for quite some time and they only had to replace it when it blew a coolant seal.

Judging by that I'd say it's definatly possible, but you're going to spend a lot of cheese to have it tuned.

Meestor Kyle,

is that your FD in your sig, my man? Looks schweet :)!

OK, hold on, let me save myself from being overruled here.

In my first post I said that the apex seal is the weak point, which is still correct, I just have the wrong reasons. I claimed, (falsely, evidently) that more pressure = weaker seal. And it seems that more pressure = need near perfect tuning, otherwise seal blows.

Eh, you can't win em all.

thanks alot guys....if someone made those "bulletproof" apex seals think of the money you can make.....:)