After doing lots of homework I'm choosing to go with ra supers. They sound pretty good and they don't eat the rotor housing. One builder told me that they let pressure get by on the side on new rotor housings but I think he was just trying to sell me his seals. Now my question is how much boost and hp are people getting out of the Ra super seals? It's gotta be a lot if they can handle what most other seals can't apparently.

 

the gas leaking by comment, is partly true.

the reason we use 2 piece apex seals is because we need the seal to be able to change lengths as things heat up.

the 81+ mazda seals put the junction of the housing, apex seal and the triangular end piece as close to the end as possible, this does wear the rotor housing more, but it seals better. as the area that changes is very tiny

the pre 81 mazda seals are more like the RA's, where the end piece is more of a trapazoid and actually has to contact the housing. thus when this type of seal changes length, it changes height too, and has a much more area to leak between chambers.

the effect is probably about 1-2% in power and mileage, mazda changed a lot of other stuff for the 81MY so its a little hard to say.

 

Hmm. Is the 1-2% noticable in performance applications? That small leak create a bigger margins for detonation for any reason?Does the expansion of the seal actually eat the rotor housing contrary to what I have been told by my builder?

 

better chamber sealing = less detonation.

 

Maybe I should reconsider then. Any recomendations? I don't want oem.

 

oem

 

Oem.

 

i already said no oem.

 

I have been running RA super seals for 6 years and actually reused them once. I had a dyno sheet from a few years ago for 386rwhp on a T04S turbo. I've run up to 21psi on the T04S and 18psi on my current T04R turbo. For a heavily modified engine they are good because they can take detonation. For a more stockish one you might as well go OEM

 

What reason do you have for this?

 

No joke, OEM are the best; that is unless you want to throw down on ceramic seals.... but unless you are building a 600rwhp track beast for a professional racing team that can afford to replace irons and housings and rotors when the seals shatter into hundreds of metal destroying fragments, why?

 

there's many seals for many different applications, OEM seals are good for wear/mileage but i honestly don't recommend them any longer for any engines i build over 350WHP. RA seals supposedly are ok beyond that but i don't use them due to many varying responses from the community on them, i am now testing Goopy apex seals in higher horsepower applications but it will take time to gather enough information on them as to their wear, detonation handling and sealing characteristics.

just about every aftermarket seal company has 13B engines pushing an engine here or there at around the 1000HP mark with a few exceptions, i don't think i have seen Atkins seals push that high nor the stock OEM seals but i am sure even they are capable with a perfect scenario, others are more capable of it without a perfect setup.

in all honesty though just about any seal out there can handle up to 500WHP but some do it better than others with a cost. ceramics for example cause the least wear to the rotor and housing but they will destroy everything in that rotor chamber if detonation does take out a seal on a rotor.

RA/ALS/Goopy seals all supposedly have the most detonation resistance to breakage of aftermarket seals. which cause less rotor and housing wear though? that still is in the air. ALS/Goopy though have some of the best horsepower figures on multiple engines so far. i chose Goopy because of the cost factor, the fact that they have almost 1100WHP out of a 13B engine and they have versatility with oversized seals in worn rotor seal slots.

 

ALS was my original choice. I've read some good things abou them. Ra handle detonation but they seem to be their own problem with that leak issue. I just found abou a brand frm Canada called rec. Rotary engineering. It's a two piece and they supposedly can handle a ton of boost. Www.rotaryengine.com I Think is the website. I know oem is good but I'd rather margins on the safe side.

 

I saw a set of housings grooved like a 78 lp after a high boost application....

 

Haha. On what seals?

 

There's no reason why the stock seals cannot handle numbers over 500whp in a properly tuned engine. Even 700whp isn't that big of a stretch for them as long as detonation doesn't occur. If you need a "bandaid" seal to keep the motor together then the setup and method of tuning need to be addressed.

 

RA super seals

 

I know oem can handle good power/boost. but they shatter when detonation occcurrs. Im gonna run new rotor housings and id rather not have to buy new ones again. Its cheaper to replace a bent set of seals than rotor housings. I know its all about tuning but should something go wrong for some reson...

 

See. there it is again. super seals eating housings. My builder said they used to do that but not anymore. Im not sure about the RA. I think im gonna go with ALS. Sure you get what you pay for but ive heard more bad things about RA and oem than als. Both cost more than ALS. i wish i knew more about the REC seals. All i know is what they have on their website.

 

FRom what i have heard between some members in this community the only problem with the RA supers is warpage. But one could also argue that is due to an aggressive tune i suppose.

 

Thats the first time ive heard of warpage on an ra. I guess no seal truely is bulletproof.

 

Has anyone heard of ALS having a leak problem like the Ra? Its a single piece. How does that expand when hot vs. the 2 piece seals?

 

It's going to depend on the particular material's thermal expansion rate. They will all expand, though ceramics probably to a lesser extent, as will the rotors, housings, irons and so forth. If you really want a one piece seal then ask the manufacturer what clearance they recommend for your application, anyone worth their salt who's making apex seals should be able to give you a reliable figure.

 

thanks. This sounds very smart but what do i do with that figure? Lol I dont know anything about clearance.

 

i used to say and think that until i realized that it just isn't possible to tune up and retune the car once a year for every customer out there. having band-aids to cover for issues that WILL arise is not a bad thing. the 450RWHP daily driver i last built lasted a good few years and 30k miles before it popped, which isn't bad but still not up to my standard.

use the base width of your rotor housings minus the apex seal width for a clearance measurement.