I think it's better to be safe then sorry, use the parts that you know will hold up to the performance your looking for.

 

Exactly! Why in the world would you be a cheap a#% if your building a 600+hp RX7???!
Don't complain about the price of apex seals if you want big hp.

 

Im saying tune the car right, and 2mm oem apex seals will hold any power a 2 rotor will make. You will not reach the PHYSICAL limit of oem apex seals from a 2 rotor. I dont care what you say or what you have built. Show me an engine where the apex seals exploded from extreme horse power, I know you wont because it doesn't happen. I don't see anyone else typing what I have. Im not saying ceramics are a waste because oem seals are just a good. I know that ceramics are better but op wants to know what kind of power the oem 2mm seals will hold, my answer is any amount of power his engine will ever see.

 

And your answer is wrong boy wonder, lol. Go sit this one out and let the big boys post. And your post proves Im right. You've done nothing but spew out what so and so told you. You have NO personal experience with power levels this high and what it takes to get there.

 

Straight from someone that has more experience than all of us X2... Word for word he states "reached their thermal limits." Oh and guess who's engine it's from...

https://www.rx7club.com/showpost.php...3&postcount=84

 

I know, your right when op hits 400hp his apex seals will explode from shear awesome force that Mazda could never have dreamed of. I dont have as much power as you, and dont care. Once you show me an example of 2mm oem seals shattering from HORSE POWER(not other things like detonation, or lean conditions), I will believe you that anyone who makes high hp numbers is doomed to structural failure of the apex seal. I will also admit that Mazda sucks at engineering things like apex seals, and will tell everyone that my half-bridge FD is inferior to there car because my apex seals can't handle crap for power. Show me proof, thats all there is to it. I want to see proof, show me proof so I don't have say things people tell me due to my lack of inferior experience. I know what it takes to achieve high hp, money. I know plenty of people who have high horse cars and dont know alot about anything. I just want proof, if you can't provide then leave it. I can prove Im right based on you last engine that used Atkins seals, you should know oem seals go through an extra hardening treatment. What did you make, above 600? Did your 2mm seals explode? Your engine and many others proves 2mm seals will do there job.

 

Thermal limit, 3mm seals will do the same thing if thats the case. Im not saying Im more experienced by any means, Im simply saying 2mm seals will work for basically any 2 rotor application. Atkins seals by the way are not heat treated like oem Mazda seals. I have seen a 500hp FD at Defined Autoworks dyno day that did not have ceramics. I believe he is even on this form, his engine is fine. OEM examples please, lets compare apples with apples.

 

Are you kidding? He made nearly 800whp!!! The seals failed from the actual power being produced. No lean condition and no detonation! Now you're saying that OEM seals hardening surface would have been better? I thought your original argument was that no seals will fail due to horsepower???

 

^ I said in my second post that someone will provide a worthless example of a insanely powerful drag machine, and you did. I have also stated that Im talking in terms of power levels from us mere mortals, like 400- somewhere in the 600 range. An 800 horse 2 rotor proves nothing because any engine will fail at this level of power eventually. I really don't get it do you folks have trouble in reading comprehension? A 3mm seal would have done the same thing as your example, due to being the same material. A ceramic seal would be anyones only alternative. I do think that an extra step of heat treating would have made a difference, heat treating is everything with metal. The molecular structure of metal is altered all together from heat treating. Im not completely stupid, I know every thing has a physical limit, thats why I knew someone would show up with an uber car that no one could ever drive except on the 1/4 mile.

 

Too many double negatives... 400rwhp is fairly easy to attain. Hell, I've got it on stock ports and sequential twins @ 17-18psi.


If all you want is proof, than make your own and quit arguing a losing battle here. Put stock seals in your half-bridge, break the engine in, tune a mid-sized single to 20psi and crank out 600whp (on something *other* than a dynojet/pack) and run it like that. When your seals last years and years then come back to bump this thread with an "I told you so."

Until that point, it would seem that all you can do is hypothesize and argue with senior members who have been there, and done that.

Some people just cannot handle being wrong. Period.

 

^ Why do I have to, I personally know people who have. I don't understand, I keep saying it. I AM SAYING THAT OEM 2MM SEALS WILL HANDEL 99.9% OF ALL HP LEVELS OF A 2 ROTOR. Where is a double negative? I said us mere mortals who MAKE FROM 400-6 (using 400 as an average low, and 6 something as an average high) something can use oem seals with no problem. Im not trying to compete in terms of knowledge or experience. I said oem 2mm seals are strong enough to handle 99.9% of all 2 rotor power numbers, if this is not true then any one who is using 2mm seals prepare for them to melt/and or explode. I think in all of our arguing that we have lost the actual argument, 2mm seals will work in 99.9% of all 2 rotor turbo hp levels.

 

Howard coleman has talked about the combustion chamber temps of the rotary engine. a simple water injection kit will keep this under control.

And frankly, Howard uses his car for everything, and beats it on the track regularly. Not to mention his years of rotary road-racing experience. I also have no problem trusting someone who uses his vehicle in an application closer to mine. Different types of racing put different stresses on an engine. ErnieT even mentioned his charge temps were insane. Perhaps this is why the oems are not good for his application. Control the charge temps and there should be less problems.

I don't see any reason a 13b with oem 2mm seals with ai couldn't make 500whp all day for years. keep the temps down and things last longer.

 

Just to add fuel to the fire, Dee from Reactive racing went low 8s/high 7s on the factory 2mm 2 piece apex seals This was straight from his mouth when I met him around 05/06. Of course I never saw the engine internally so I can only go on what info he gave me.

Still, for that power level, there are other better options than the factory 2mm seals . Very few people I believe or trust in this business as a lot of people like to go by what they hear instead of what they have seen/experienced as Ernie said. However, Ray Wilson is one of the few I never question and if he said they reached there thermal limits I will take his word for it

 

^ I will never argue that there are better options. I want to go ceramic in my next engine for rpm reasons. Im just saying 2mm oem seals will do the job.

 

I personally say go ALS as they are proven at beyond that HP level and the creators of those seals are researching and developing other ground breaking parts for the rotary engine. However, I have no personal experience with the ceramics but hear nothing but great things.

 

^ I have a friend with a 13b powered s14. He used ceramics, and that allowed him to rev to 9300 rpm, with dry-sump system. I know the ceramics are lighter and can take more heat. Im going to use ceramics with my next build.

 

Hey, Ernie. You can keep people in check without acting like a giant ***** while looking down your nose at everyone in this thread.

 

FDWarrior, you just don't quit, do you?

 

i believe d-cups is asking as he is upgrading to a single greddy t88 setup and wants to get a rough idea of how much power he can make before he has to pull his motor apart and rebuild it etc etc etc.

 

Sorry dude, its fustrating when people want accurate information on here and get heasay and what so and so told them. Then say Im wrong even though I've experienced it first hand. Whatever.

 

For what it's worth it doesn't seem to me as if you are coming across in a combative, negative manner. I, and I would assume 95% of the members here over age 22, are glad to read the posts of a veteran as he shares his experience.

It is foolish to say, "Show me apex seals that broke from HP alone; not detonation, going lean, etc..." HP = heat.

Thanks for chiming in with actual experience. It is a great benefit to those of us who are still climbing the HP ladder.

 

i think we need to appreciate the fact that the turbo'd rotary is a race engine.

many of us consider a 400 rwhp FD a medium output configuration. after all, turn up the boost with the correct build, fixturing and tune and we are looking at 500-600 and beyond.

consider what's going on in a 400 rwhp rotary...

400 is 460 flywheel divided by 159 cubic inches and you get:

2.89 hp per cubic inch!!!

a handbuilt, dry sump, titanium rod LS7 makes 505 flywheel w 427 cubic inches.
that's 1.18 hp per cubic inch!!

now consider the Combustion Chamber Pressure in the rotary making 400 rwhp and almost 3 hp per cubic inch. CCP equals HEAT.

so we are tooling around w a real serious race engine when we are making 400 rwhp... not some moderate tune deal.

the weak link in the motor is the apex seal... compared to a piston engine. this is not to say rotaries are doomed but they have to be built, fixtured and tuned just right. do it right and you get to ride the race horse.

while apex seal manufacturers would like you to believe they have the latest and greatest there's really no getting around the fundamentals. steel seals are steel seals and given enough CCP they are going to eventually bend/warp. not necessarily break... if you are properly tuned and use AI and make lots of CCP you will eventually warp your steel seals. they may continue to make pretty good hp but you will be losing some compression.

if you run a bit lean they will really warp and eventually break. if you run too wide an exhaust port the seals will loose cooling and warp.

you can heat treat your steel seals but they are still steel and they will warp. properly composed ceramics don't warp. i am currently building my 09 motor w NRS ceramics.

the thread started worried about steel seals... they work very well if properly supported. ceramics aren't a necessity for most.

i do generally agree with the poster that said that most of the time when seals fail it is because of a mis-tune situation. i also believe that there is a point where (especially steel) seals just can't cope w the tremendous CCP encountered. if for example, someone is running in the 8s w steel seals i can assure you his motor comes apart after each weekend and the steel seals are replaced w new steel seals. there is a point where steel doesn't cut it in the rotary combustion chamber.

hc

 

Hey I'm not questioning your expertise. I'm very curious about this subject myself and it is good to have someone with your experience on here.

 

Ernie, what fuel were you running and I assume you had some form of AI also when the seals showed that wear.

 

If your car is not a daily driver then go with Aviation seals. They will not break and will handle detonation that stock seals wont. Stock seals are fine to a point, but not worth the risk on a high HP RX-7 (400+).