Do 13B Motors Tolerate Detonation with Upgraded Seals?
06-23-15, 05:35 PM
#1
Do 13B Motors Tolerate Detonation with Upgraded Seals?
I've been away from FDs for quite a while but I know there were several types of more durable apex seals coming to the market, for instance the rotary aviation seals and the cryo treated seals.
Are people blowing less engines because of these new seals or will a good overboost still end your day? Is it anywhere similar to a forged piston engines durability or even a well built non forged motor?
Are people blowing less engines because of these new seals or will a good overboost still end your day? Is it anywhere similar to a forged piston engines durability or even a well built non forged motor?
06-23-15, 06:25 PM
#2
I tried several different seals and found they are more resistant to breaking than stock 2mm seals, but still break. So I went to using stock 3mm seals.
When the seals don't break with detonation you end up breaking the side housing dowel lands when the rotor housing flexes away from the extreme combustion pressure of detonation. You can stud the block or dowel it to decrease this flex.
If you don't break the dowel lands you sack out your apex seal springs and put huge wear on the apex seals leading edge from the extreme heat of detonation.
Seems impossible to "fix" that last one.
I do think the strengthening helps the rotary last longer under detonation, but it is still surprising how quickly a rotary can go to hell from just the combustion heat of detonation.
I wonder if it has to do with the apex seal lifting off the rotor housing when the spark plug boss area expands with heat of detonation causing combustion spitback into the compression stroke and so runaway pre-ignition.
When the seals don't break with detonation you end up breaking the side housing dowel lands when the rotor housing flexes away from the extreme combustion pressure of detonation. You can stud the block or dowel it to decrease this flex.
If you don't break the dowel lands you sack out your apex seal springs and put huge wear on the apex seals leading edge from the extreme heat of detonation.
Seems impossible to "fix" that last one.
I do think the strengthening helps the rotary last longer under detonation, but it is still surprising how quickly a rotary can go to hell from just the combustion heat of detonation.
I wonder if it has to do with the apex seal lifting off the rotor housing when the spark plug boss area expands with heat of detonation causing combustion spitback into the compression stroke and so runaway pre-ignition.
06-23-15, 06:30 PM
#3
RX-7 Bad Ass
iTrader: (55)
The new seals are FAR more forgiving of detonation, but nothing is detonation-proof. I've heard many stories of situations that would have grenaded a stock apex seal motor (wastegate line came off, etc.) that the new tech seals dealt with no problem.
3mm is an option but sometimes having the rotors machined causes its own problems. Shipping rotors is damn near like Russian roulette, I've seen MANY rotors damaged beyond repair through shipping. Also, I've seen rotors cut for 3mm seals that BARELY touched the oil passages inside the rotor, leading to an oil burning engine.
I will put it this way, I won't build a motor any more with stock apex seals. That's my opinion and my preference.
Dale
3mm is an option but sometimes having the rotors machined causes its own problems. Shipping rotors is damn near like Russian roulette, I've seen MANY rotors damaged beyond repair through shipping. Also, I've seen rotors cut for 3mm seals that BARELY touched the oil passages inside the rotor, leading to an oil burning engine.
I will put it this way, I won't build a motor any more with stock apex seals. That's my opinion and my preference.
Dale
06-23-15, 08:24 PM
#6
Original Gangster/Rotary!
iTrader: (213)
It's interesting that FC guys are posting in this section about cracked irons..... guys, with 13B-REWs that's not really an issue for any street car making sane power levels (i.e. not drag 800 rwhp plus).
Be very careful which aftermarket seals you choose to put in your engine.
We've had good success for years with RA Black seals and have been using RX Parts seals as well recently. I can't comment on the other brands out there, but again if you experiment with engine internals you can't complain in the event you need to pull the engine
Be very careful which aftermarket seals you choose to put in your engine.
We've had good success for years with RA Black seals and have been using RX Parts seals as well recently. I can't comment on the other brands out there, but again if you experiment with engine internals you can't complain in the event you need to pull the engine
06-24-15, 01:43 AM
#7
I am currently making my own seals from scratch, in my shop. If it works, great. If it does not, its a learning experience.
So far I've machined one prototype and machined the rotors to suit it. It will take many more months yet though.
So far I've machined one prototype and machined the rotors to suit it. It will take many more months yet though.
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06-24-15, 07:31 AM
#8
It's interesting that FC guys are posting in this section about cracked irons..... guys, with 13B-REWs that's not really an issue for any street car making sane power levels (i.e. not drag 800 rwhp plus).
Be very careful which aftermarket seals you choose to put in your engine.
We've had good success for years with RA Black seals and have been using RX Parts seals as well recently. I can't comment on the other brands out there, but again if you experiment with engine internals you can't complain in the event you need to pull the engine
Be very careful which aftermarket seals you choose to put in your engine.
We've had good success for years with RA Black seals and have been using RX Parts seals as well recently. I can't comment on the other brands out there, but again if you experiment with engine internals you can't complain in the event you need to pull the engine
I now have the later gen 2nd gen irons with the improved casting such as the 3rdgen's. To me getting the improved casting is just a bandaid for a problem that I have yet to find.Aftermarket apex seals always left a sour taste in my mouth. So much drama and inconsistent data. Love people quoting this motor has this or that seals for 5 or more years yet they have no kms put on the engine. Local tuner swears by REC seals. Just because a drag racer uses a set of seals and has success doesn't mean a daily driven car can use it.
Sad part is I could have bought a Porsche GT for what I have in this FC over the past 15 or 16 years. Or at least a nice FD.
06-24-15, 08:11 AM
#9
Does anybody have experience with Rice Racing seals?
Apex Seals The real facts with no hype
Claims....
* Highest fracture ~1000% increase in toughness & very high temperature tolerance
* Un-breakable in the engine, with NO CATASTROPHIC FAILURES
* ULTIMATE DURABILITY, with ZERO RAPE of rotor housings
* Each set certified hardness tested, with signed production certificate
* Hardness is through entire piece, NOT coated or nitride, or cheap OEM hardened tip only
* Bespoke alloy and heat conditioning treatment, engineering a premium APEX SEAL
* Bespoke springs, NOT designed around inferior OEM items like the pretenders
* ONLY seal complete twin springs that will not relax under high temperature or wear out prematurely
Apex Seals The real facts with no hype
Claims....
* Highest fracture ~1000% increase in toughness & very high temperature tolerance
* Un-breakable in the engine, with NO CATASTROPHIC FAILURES
* ULTIMATE DURABILITY, with ZERO RAPE of rotor housings
* Each set certified hardness tested, with signed production certificate
* Hardness is through entire piece, NOT coated or nitride, or cheap OEM hardened tip only
* Bespoke alloy and heat conditioning treatment, engineering a premium APEX SEAL
* Bespoke springs, NOT designed around inferior OEM items like the pretenders
* ONLY seal complete twin springs that will not relax under high temperature or wear out prematurely
06-24-15, 12:42 PM
#11
GoodfellaFD3S
It's interesting that FC guys are posting in this section about cracked irons..... guys, with 13B-REWs that's not really an issue for any street car making sane power levels (i.e. not drag 800 rwhp plus).
Well, I have both FC and FD and I do hope the REW irons are more resistant to cracking than the FC irons. I cracked the 1 front (upper dowel), 2 intermediate (down on pass side motor mount land) and 2 (newer reinfoced) rear irons (upper dowel) of the FC.
It's interesting that FC guys are posting in this section about cracked irons..... guys, with 13B-REWs that's not really an issue for any street car making sane power levels (i.e. not drag 800 rwhp plus).
Well, I have both FC and FD and I do hope the REW irons are more resistant to cracking than the FC irons. I cracked the 1 front (upper dowel), 2 intermediate (down on pass side motor mount land) and 2 (newer reinfoced) rear irons (upper dowel) of the FC.
06-24-15, 12:53 PM
#12
Moderator
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the FD ignition system is also less prone to ignition cross fires.
06-25-15, 11:09 PM
#14
Apex seal technology has come a long way over the past few years as well ad advances in tuning and the additional of additional safetys such as meth injection.
The stock Mazda seals are a decent balance of strength and longivity. However, one good knock and you will break a stock seal. For this reason I don't recommend them on anything but stock motors. For anything making power and especialyl single turbo cars, we exclusively use RX Parts seals. We have used them in everything from near stock, 700hp+ race cars, and everything in between. I have yet to hear anyone breaking one. The also do not trash the rotor housings like some of the other aftermarket seals out there. The nice thing about the RX Parts seals is if they do suffer enough abuse, they warp. This causes a loss of compression but no internal motor damage. A stock seal and some other aftermarket seals will have long broken, causing major damage and an expensive rebuild.
As far as 3mm seals, these were a bandaid when the seal technology wasn't there. The seal is wider, therefore causing more wear to the rotor housings. The seal is also heavier and supported by a single spring, so it tends to chatter at high rpm. Machining of the rotors to accept the 3mm seal must be exact, and this opens up too much room for error.
One thing I will note is with any harder seal, you MUST premix if you want the motor to last. The factory oil metering system falls short in even stock cars. If you look at the RX8 motors, they have 2 oil injectors per rotor housing and then in later versions 3 to help lubricate the apex seals and rotor housings. It took Mazda a long time to learn.
No matter what seals you run, any detonation is bad and eventually it will break something. If the apex seal doesn't go, you will break a corner seal and eventually the iron. Have a solid setup. Deal with a competent tuner. We have had over 5 years with 20 something track events as well as 10,000+ street miles on our motor at the 500 wheel hp level without a single issue.
The stock Mazda seals are a decent balance of strength and longivity. However, one good knock and you will break a stock seal. For this reason I don't recommend them on anything but stock motors. For anything making power and especialyl single turbo cars, we exclusively use RX Parts seals. We have used them in everything from near stock, 700hp+ race cars, and everything in between. I have yet to hear anyone breaking one. The also do not trash the rotor housings like some of the other aftermarket seals out there. The nice thing about the RX Parts seals is if they do suffer enough abuse, they warp. This causes a loss of compression but no internal motor damage. A stock seal and some other aftermarket seals will have long broken, causing major damage and an expensive rebuild.
As far as 3mm seals, these were a bandaid when the seal technology wasn't there. The seal is wider, therefore causing more wear to the rotor housings. The seal is also heavier and supported by a single spring, so it tends to chatter at high rpm. Machining of the rotors to accept the 3mm seal must be exact, and this opens up too much room for error.
One thing I will note is with any harder seal, you MUST premix if you want the motor to last. The factory oil metering system falls short in even stock cars. If you look at the RX8 motors, they have 2 oil injectors per rotor housing and then in later versions 3 to help lubricate the apex seals and rotor housings. It took Mazda a long time to learn.
No matter what seals you run, any detonation is bad and eventually it will break something. If the apex seal doesn't go, you will break a corner seal and eventually the iron. Have a solid setup. Deal with a competent tuner. We have had over 5 years with 20 something track events as well as 10,000+ street miles on our motor at the 500 wheel hp level without a single issue.
Last edited by IRPerformance; 06-25-15 at 11:18 PM.
06-27-15, 01:29 AM
#15
I'm running 2mm cryo seals from Atkins in my FD and 13bre FC and you really cannot see or feel a difference. Compared to stock side seals, the seem much stronger and have taken far more abuse than what I did with OEM stuff. I pulled apart my FD engine for a fresh up and noticed that running premix is the way to go especially with harder seals like RA unbreakables which I had in my 13brew before pulling it apart for inspection.
Don't want to start a huge debate here, but unbreakables apparently wear housing or some say "Eat" housings. RA unbreakable seals as expected, wore my housings just a tad after 40,000km of daily driving with premix (OMP isn't to be depended on
) till I switched to Cryo seals for something different.
Will update on how Cryo seals wear, but I expect less wear on the housings for sure as they have more give that RA unbreakables imho
Don't want to start a huge debate here, but unbreakables apparently wear housing or some say "Eat" housings. RA unbreakable seals as expected, wore my housings just a tad after 40,000km of daily driving with premix (OMP isn't to be depended on
) till I switched to Cryo seals for something different. Will update on how Cryo seals wear, but I expect less wear on the housings for sure as they have more give that RA unbreakables imho
06-27-15, 09:10 AM
#16
"stronger" is generally proportional to harness. The harder it is, the stronger it is. Problem with hard seals is that if they are harder than the surface they rub against, the rubbed surface (i.e. the housings) will wear. Ideal would be to match the hardness of the housings with the seals.
That addresses wear, but the other problem is detonation. You really can't have it both ways (a seal that won't wear down your housings and also survive detonation). In a trade off world, i would design for wear and prevent the engine from detonating.
That addresses wear, but the other problem is detonation. You really can't have it both ways (a seal that won't wear down your housings and also survive detonation). In a trade off world, i would design for wear and prevent the engine from detonating.
06-27-15, 12:57 PM
#17
TomU
"stronger" is generally proportional to harness. The harder it is, the stronger it is. Problem with hard seals is that if they are harder than the surface they rub against, the rubbed surface (i.e. the housings) will wear. Ideal would be to match the hardness of the housings with the seals.
You have that backwards.
The stock seals are as hard as you can get steel- well they aren't even steel anymore on the wear surface. The steel is converted to a ceramic like crystal structure.
Aftermarket seals are softer and tougher. They can generally take more abuse without cracking because they do not fracture. However, because they are soft they are incompatible with the chrome wear surface and cause galling.
I have also found the aftermarket seals can't take high temperature abuse, if they don't bend or wear the leading edge off they get micro cracks along the wear surface which then crack the seal in half with shock.
"stronger" is generally proportional to harness. The harder it is, the stronger it is. Problem with hard seals is that if they are harder than the surface they rub against, the rubbed surface (i.e. the housings) will wear. Ideal would be to match the hardness of the housings with the seals.
You have that backwards.
The stock seals are as hard as you can get steel- well they aren't even steel anymore on the wear surface. The steel is converted to a ceramic like crystal structure.
Aftermarket seals are softer and tougher. They can generally take more abuse without cracking because they do not fracture. However, because they are soft they are incompatible with the chrome wear surface and cause galling.
I have also found the aftermarket seals can't take high temperature abuse, if they don't bend or wear the leading edge off they get micro cracks along the wear surface which then crack the seal in half with shock.
07-03-15, 06:33 PM
#21
blue, steel can be extremely soft under the right circumstances so that's hardly a definitive criteria for "this is harder". Also, steel has a crystalline structure in general and changes in it also cause changes to its hardness and other properties.
07-03-15, 07:14 PM
#22
Rotor or no motor
iTrader: (24)
TomU
"stronger" is generally proportional to harness. The harder it is, the stronger it is. Problem with hard seals is that if they are harder than the surface they rub against, the rubbed surface (i.e. the housings) will wear. Ideal would be to match the hardness of the housings with the seals.
You have that backwards.
The stock seals are as hard as you can get steel- well they aren't even steel anymore on the wear surface. The steel is converted to a ceramic like crystal structure.
Aftermarket seals are softer and tougher. They can generally take more abuse without cracking because they do not fracture. However, because they are soft they are incompatible with the chrome wear surface and cause galling.
I have also found the aftermarket seals can't take high temperature abuse, if they don't bend or wear the leading edge off they get micro cracks along the wear surface which then crack the seal in half with shock.
"stronger" is generally proportional to harness. The harder it is, the stronger it is. Problem with hard seals is that if they are harder than the surface they rub against, the rubbed surface (i.e. the housings) will wear. Ideal would be to match the hardness of the housings with the seals.
You have that backwards.
The stock seals are as hard as you can get steel- well they aren't even steel anymore on the wear surface. The steel is converted to a ceramic like crystal structure.
Aftermarket seals are softer and tougher. They can generally take more abuse without cracking because they do not fracture. However, because they are soft they are incompatible with the chrome wear surface and cause galling.
I have also found the aftermarket seals can't take high temperature abuse, if they don't bend or wear the leading edge off they get micro cracks along the wear surface which then crack the seal in half with shock.
I have done several microstructure and hardness testing on a variety of apex seals.. the technology that goes in the oem apex is fantastic. No aftermarket seal have the variation in heat treatment along the length and height like OEM. When the strength/hardness is increased the material becomes brittle (vs ductile). This is why the others warp instead of break.
The hardest one is the RX8 OEM with more than twice the HV than the OEM FD (2 or 3 piece) and 3 times of other aftermarket ones with very apparent results in the microscope .. who ever says otherwise is just full of **** !
Rice contacted me a few days ago to promote his seals after a "dispute" he and someone else had on fb... I highly doubt that the information he has are backed up in any sort of scientific/engineering way.
Last edited by R-R-Rx7; 07-03-15 at 08:09 PM.
07-03-15, 07:27 PM
#23
Does anybody have experience with Rice Racing seals?
Apex Seals The real facts with no hype
Claims....
* Highest fracture ~1000% increase in toughness & very high temperature tolerance
* Un-breakable in the engine, with NO CATASTROPHIC FAILURES
* ULTIMATE DURABILITY, with ZERO RAPE of rotor housings
* Each set certified hardness tested, with signed production certificate
* Hardness is through entire piece, NOT coated or nitride, or cheap OEM hardened tip only
* Bespoke alloy and heat conditioning treatment, engineering a premium APEX SEAL
* Bespoke springs, NOT designed around inferior OEM items like the pretenders
* ONLY seal complete twin springs that will not relax under high temperature or wear out prematurely
Apex Seals The real facts with no hype
Claims....
* Highest fracture ~1000% increase in toughness & very high temperature tolerance
* Un-breakable in the engine, with NO CATASTROPHIC FAILURES
* ULTIMATE DURABILITY, with ZERO RAPE of rotor housings
* Each set certified hardness tested, with signed production certificate
* Hardness is through entire piece, NOT coated or nitride, or cheap OEM hardened tip only
* Bespoke alloy and heat conditioning treatment, engineering a premium APEX SEAL
* Bespoke springs, NOT designed around inferior OEM items like the pretenders
* ONLY seal complete twin springs that will not relax under high temperature or wear out prematurely
Peter is always changing his tune but whatever he currently uses is always "THE BEST BITCHES!!!!"
a few years ago it was ceramic seals in boosted engines, now it's metallic.
a few years ago it was methanol, now it's pure water.
i'm sure there is other examples but you get the idea. a shiny box doesn't make an apex seal bulletproof, it will look the same as any seal after 100 miles inside the engine.
you can only learn through trial and error and so far the indestructable seals all have issues with wear in the housings, it's just the nature of compromise. personally i wouldn't go back to OEM cast iron, it causes more damage than good with it's wear resistance vs fragility. i'd rather tear apart and refresh an engine that has MOSTLY usable parts than an engine that is half trashed with metal debris, not to mention some of the VERY expensive turbos some of you guys are running.
add in that we now have rotor housing resurfacing shops in most corners of the world then even gouged housings usually are salvagable.
by the way, even the most cutting edge tough as nails ceramics we have today are still more fragile than the OEM cast iron treated seals and they cause more damage when they break than the OEM cast iron's do so how could anyone ever really give that their seal of approval? i've been saying they were bad in turbo engines long before he gave them his thumbs up. with water versus methanol, anyone who has tested boost>knock resistance in the real world can tell you which is better.
ceramics in a naturally aspirated engine however, good luck finding a more perfect match made in heaven.
anyways, it's just food for thought, maybe he has come up with something finally...
btw, you guys are reversing the term "hardness", the unbreakable seals are in fact softer than the OEM seals are. a softer material bends before breaking, it also digs into harder surfaces and creates more friction than an OEM seal will. so in effect if you detonate with an unbreakable seal the structure is weakened more easily and it softens further, allowing it to dig into the housings and gall both surfaces.
i'd bet that if you took a torch to an unbreakable seal it will begin to liquify sooner than cast iron will, the friction of the excessively heated chromium rotor housing may be causing the tips of the seals to break down easier. that is the easiest way i can describe what my theory is on unbreakables and why some engines come out looking like someone drug a rake across the housings.
OEM is best for mild detonation
aftermarket is best for salvaging expensive parts
ceramic is best for heat deflection and anti wear properties, but neither of the above 2
course i will admit when i'm just pulling **** outta my ***..
Last edited by RotaryEvolution; 07-03-15 at 08:06 PM.
07-03-15, 07:31 PM
#24
Rotor or no motor
iTrader: (24)
Peter is always changing his tune but whatever he currently uses is always "THE BEST BITCHES!!!!"
a few years ago it was ceramic seals in boosted engines, now it's metallic.
a few years ago it was methanol, now it's pure water.
i'm sure there is other examples but you get the idea.
you can only learn through trial and error and so far the indestructable seals all have issues with wear in the housings, it's just the nature of compromise. personally i wouldn't go back to OEM cast iron, it causes more damage than good with it's wear resistance. i'd rather tear apart and refresh an engine that has MOSTLY usable parts than an engine that is half trashed with metal debris.
a few years ago it was ceramic seals in boosted engines, now it's metallic.
a few years ago it was methanol, now it's pure water.
i'm sure there is other examples but you get the idea.
you can only learn through trial and error and so far the indestructable seals all have issues with wear in the housings, it's just the nature of compromise. personally i wouldn't go back to OEM cast iron, it causes more damage than good with it's wear resistance. i'd rather tear apart and refresh an engine that has MOSTLY usable parts than an engine that is half trashed with metal debris.
i have nothing against the guy nor that i know him. but his approach ALWAYS cracks me up .
