It would appear I popped an Apex seal
 

I may have joined part of the club I didnt want to be in. The "I blew a motor club". I am so upset with myself lol, but I am not really sure how I messed up. To keep it simple I am not really sure what happened.
I just put a mid pipe on and ended up turning down the boost all the way on the manual controller because of creep. It was basically running off the waste gate. I assumed that if I dont boost over 14-15 psi I should be safe as all my AFRs were in the 10s and 11s. I got up to just under 14psi earlier from creep . I have a very rich and conservative map installed.
I did a wot 2nd gear pull, hit a large bump and almost got airborn, heard some chatter that almost sounded like 3 or 4 electrical discharges (which I would assume was the seal). I got off the gas, braked, and upon reaching a stop the idle was rough with a vac of -10 (-200s) on the commander. Drove about a mile home. When I got out of the car and let her idle and cool down I could hear what sounded like air coming from under the uim like psst psst . psttt. I assume that's the seal getting pushed around or scraping up my housing??
It was a cool night 71°f but I was a little heat soaked. 107 on the knock.
so wth?
96 octane fuel with premix
2200 secondaries with a rich map
I feel like throwing up. I will do a compression test in the next few days I guess to confirm, but really?? A big .89 just blew my motor on 96 octane?
here is a pic of the max commander readings. I know the air temp is hot, but it wasnt that hot when I did the pull
https://cimg3.ibsrv.net/gimg/www.rx7...c2d9aff510.jpg

Compression test before anything so you're not chasing your tail. But if you're lucky it could be the map line.

^This.
And if your lucky enough that's it's the MAP line that popped off.
Then put the cat back in until you can get it properly tuned.

Well I dont think it is the map line that popped off. You mean the map sensor I should have replaced with a 3bar? The line from that to the uim is still on tight.
The cat will go back on regardless, but so that still doesnt really answer wth happened. The midpipe may be creeping, but again the afr were safe. Wot is in the 10s. Maybe a millisecond spike occurred that wasn't compensated for? I dunno. I just know this is terrible lol.The map sensor according to some is good for 16psi and others till 14psi. .89 is only 12.9 psi.
earlier I ran .94 or 13.6psi. Was I just lucky it didnt blow before?
I've been running .85 all day all night before.
https://cimg6.ibsrv.net/gimg/www.rx7...321bfa5c95.jpg

With the air being that hot, it might had detonated with boost creep. Compression test it. Post what you find.
good luck,

Just to elaborate on Estevan said, you NEED a cat in the midpipe or some form of restriction. The only other option is to really port the wastegate, which would require removing and disassembling the turbos.

Without either of those things done, you will have boost creep. Especially if you've upgraded the intercooler or changed the stock airbox.

I'm not going to say that's what caused your issue, but it is a known problem. I'm assuming you got upgraded secondaries since you posted up about that fuel rail, so you should be safe from a fueling standpoint once you get boost under control and a tune.

Good luck!
Vince

Thx for the replies all. I am not sure if creep is some magical issue that the pfc or gauge doesnt see. I don't really understand the difference if the creep is putting it to 14psi or the controller. If I want to run off the spring yet the creep brings it to 12psi why is that a problem? Shouldn't it actually be less stressful on the motor as the boost is at the 12psi for a shorter duration of the spring? Anyway, that is me VENTING because I am pretty upset over this.

My gut told me to get rid of midpipe for the opposite of what everyone thinks. If I want to run my boost at 12 I want my 12 now and I want to hold it (like it was). The creep takes awhile to get there so I have less power. Of course creep is another reason as I would like to keep my eyes solely on the road from time to time. It would be nice to do some wot pulls and not be paranoid and always have to incorporate boost and afr into scan. (Which Inwill probably do anyway)

I should have more than enough fuel for 14+psi so it concerns me a bit for the future. My tune is verified by me watching the afr. I dont know how else to do it. If they are in the 10s they should be fine. Inj duty was what 76%?

The temps where high. Again, they were were a little lower than what's on the pfc. Scarey thing on the temp is I live in Miami. This will be a common issue so I dont drive my car in the summer and boost over 12? Water injection could help, but what about our boys in AZ or TX running higher boost? There are quite a few "pros" out there in hot climates that to this day say water is a waste.

I have my idea of what happened, but will wait for the teardown. Or It could have just been not getting my 3 bar map sensor, but according to what everyone says the stock should be good till a minimum of 14psi.
I will do a "listening" test today and will do a compression test soon to verify and post it.

Hope I dont come across as rude to anyone as I appreciate all comments. I am upset as I know I just cost myself 6k+. , but I am concerned or nervous for the future of what to run.
on a positive note I guess if I have to rebuild I will know 100% what I am dealing with on the motor and the turbos.

Using a pfc without any engine protection feature is inherently risky, also bearing in mind its s rotary, and they often just let go.

Thx for the reply Skeese. Could you elaborate a bit on the no protection? Are you speaking about knock/retard? From what I gather there really isnt any protection out there that truely works. If this thing is blown I need to do some serious research to figure out how I am going to handle this in the future. The " just let go" isnt an option for me. I understand it can happen, but if there are steps to prevent I would love to be pointed in the right direction. I thought I had a pretty decent idea, but apparently not. 96 octane obviously didnt help much in this case and it is expensive.

What boost was the car tuned for?

I dont want to say until I hook up the datalogit and look at it myself. It should have been safe to 14psi for sure. Of course I should have looked at it before, but so am learning all this so I have to trust in others in the mean time.
At .94 (13.6 psi) she was at low 10s on the afr. I know someone that ran 14psi on 11.3 afr for years supposedly. .89 isnt even 13psi.
I will let you know when I look at it.

It sucks, but it happens to all of us. As stated, do a compression test to be sure then start making a plan.

How old was the motor? Old stock motors with thin apex seals don't put up with much for long, even if it's tuned right and everything.

The good thing is it looks like you are wanting to get the most out of your car. This is an opportunity to build a solid foundation for your car, not just a quality motor but making sure everything attached to it (gaskets, hoses, wiring) is all in top shape.

Figure out if it blew then start making a plan. See what your budget is and look at options - you can build it yourself, buy a used short block, buy a new short block, send it to a shop and have them do everything, there's a range of options depending on budget and your mechanical ability.

You won't find a good answer as to "why" it let go. I do IT for a living and I always joke "I gave up asking why it broke ages ago". Going with a mid pipe opens up the breathing of the engine tremendously, it really needs to be properly tuned for it. Also if your timing map hasn't been touched in the PowerFC the stock map can be more aggressive than is good.

You'll be fine, we've all been there!

Dale

Just saw your post about boost and AFR. Remember, the AFR is as good as the gauge which aren't perfect and that's the combined AFR at the downpipe - you could have one rotor running lean and one rich and not know it.

Dale

Are you absolutely SURE it was 96 [Anti-Knock Index (AKI) or (R+M)/2] octane? If not, it wouldn't be the 1st time someone got off-spec gas and had detonation. I've had that happen several times - luckily not in my FD.

Dale thanks,

I am trying to look at this in a positive way. That is true about the afr. I was going to put it on a dyno today actually with the cat back on to verify afr. Well, not happening I guess. Could have been timing also.
It sounds blown with the noise test while cranking. I will try to verify soon with the compression tester.

That is whats advertised.

The PFC is a great ECU but it has absolutely no engine protection features. It only takes one lean condition under boost for a rotary engine to detonate and blow a seal, so anything from a fuel pump failing, pump sock clogging, fuel filter clogging, injector sticking, regulator going bad, pump hitting relief pressure, map sensor shitting, etc can cause a detonation inducing lean condition and the PFC will just keep on spraying the same fuel and firing the ignition like nothing was wrong, because it has no way of knowing something is wrong or any actions to take if something was detected. On a long enough time frame, these parts will fail in any automotive application and most of these cars are all 25+ years old at this point...its only a matter of time.

Modern ECUs allow you to set up engine protection to help prevent the engine from ever seeing a lean condition capable of blowing the motor. If fuel pressure drops outside of the allowable threshold, bang, ignition cuts fuel keeps flowing, car shoots flame and you never risk firing a lean mixture. Same thing can be setup to protect against high intake air temps, lean AFRs outside of fuel pressure, overboost, sensor faults or literally any function of the car the tuner decides can be a hazard. Using a knock/retard function is outdated and bad practice as you have to be knocking to sense the issue and react. If engine protection is set up properly, you'll never get to that point.

Doesn't matter how well a PFC is tuned. If something in the mechanical/fluid system has an issue, whether it be an random failure or wear failure, the PFC is just going to keep on spraying and firing which can, will, and has historically been the cause of many a blown rotary.

By "just let go" I'm referring to the fact that these engines are inherently wear parts. On a long enough time frame they'll all wear out and require the replacement of housing and apex seals at the very minimum as these parts experience significant levels of frictional contact regardless of proper lubrication. The centrifugal force of the seal face on the housing increases as rpm increases which drives up housing wear (a counterweighted apex seal solution was actually patented by aerospace manufacturer Curtiss Wright through a co-op program with NASA in 1969 that resolves this issue, but that is a different conversation). Not to mention that the factory balance on these engine from mazda sucks. I've seen a stamp balanced stock port come off balance at 6000 rpms at only 18-20 psi where the rotorface ran into the front iron and blew a golfball sized chunk out. They are sensitive engines, and it doesn't take much for one to trash itself...its just fact.

Honestly, upgrading to a modern ECU and running a well thought out set of engine protection functions is the absolute best thing you can do to aid the longevity of the rotary engine.

Skeese

This is true as well. This type of condition is most easily kept in check by monitoring the EGT on each runner. If you ever start to see a significant split, you know you need to start digging and find out why the one isn't fueling the same before you continue to push it.

Skeese

Thanks, I appreciate the thorough explanation. I will start looking into other ECUs, but I really have to keep a budget in mind (haha as I start building a 8k plan for a new motor and turbos).
What I can think of so far is
1. I have a new fuel pump ( I may add a dual setup incase one fails?)
2. My 2200 secondaries supposedly had 5k miles on them. I sent them to RC for clean and test. All was excellent. Not sure what I can to here. Maybe larger primaries would help compensate for a failed secondaries? Not sure how programmable that is on a pfc.
3. Intake air temp. I am going to get a KS style hood. The vents are right on the IC.
4. I had a new FPD. Maybe eliminate it?

I could go on and on.

I dunno. I will start putting together a plan to help eliminate a lot of bad possibilities. I will balance the rotors and shaft for sure. Obviously the map needs to be looked at. Maybe this motor was never rebuilt and at 56kish miles she just had enough. It is odd that I was running just fine at a higher boost level and all the sudden just got 107 on the knock on a lower level. Really sucks. Especially considering I was very happy at my 12.5psi with the cat.

You don't really want to be adding a second fuel pump to be a backup to a primary in case of failure, but rather only do so when you find that the first pump is cant keep up with the engine's fuel demand and as a result the fuel pressure is dropping off. Running more pump than you need all the time makes for a much higher flow rate and will effectively cause higher fuel temps. As the combustion mixture is made up of fuel + air, fuel temp is still a huge factor in the overall temperature of the combustion charge and as a whole a hotter charge is much more susceptible to pre-ignition or detonation. If you do need to run twin pumps to hold fuel pressure up top, its best to stage them so that only 1 is running until you need the second. If under 500hp, you really shouldn't need anything more than 1 pump.

If you have 2200 secondaries, even with factory primaries, this should be PLENTY for anything you will be doing with the twin turbos. If you change injectors on the PFC, you'll have to retune the entire fuel map basically from scratch as its an injector pulse width tune and not a VE tune where you would simply change the injector sizes in the tune settings and only have to make a few tweaks at staging if necessary. It won't matter if you go to bigger primaries in a secondary fails while under boost, you'd still shoot lean without any engine protection...and its likely game over.

Vented hood is good for intake air temp, but there are alot of other factors that contribute to the air temp that can still drive it up. With the right ECU setup, you'd have it go into limp mode and kill power/boost if you ever exceeded a set high air temp range.

I don't know about the FPD, but I dont think it would be the source of any of the issue, I'd leave it unless you have some actual specific reason to suspect it had anything to do with it.

Lastly, knock isn't directly tied to boost but rather detonation. The car may have been running perfectly and healthy at 12.5 PSI with no knock at all, then something in the fuel system either hiccuped or shit and you ended up lean and even at that lower boost level it detonated and kicked a seal.

As for a rebuild and new turbos, you should be able to get by with much less than $8k. Call Zachariah Richardson at Eccentric Performance and he can get you sorted for MUCH less than that and he only puts out 10/10 work.

Skeese

Well that sucks.

For safety, i inject water/meth, ported my wastegate (even though i still have a cat) and professionally tuned to 12 psi (there's more to a tune than just fuel).

And FWIW, IRP is selling new kegs for $4,600

Yes it does suck. I am very interested in how it happened, but I guess we wont have a clue until it is cracked open.

easy for me to say, but obviously I am short on some info somewhere. Control your boost/turn it down or restrict exhaust. Or get more fuel and make sure it is tuned. Even then I guess no 100% guarantee. I am definitely the wrong person to ask right now lol. New just about everything, plenty of fuel, 96 octane and still pop. Lol

Do you know how old the motor is in your car?

Dale

Diagnosis all starts with a compression test, everything up to that point is speculation at best. Original 3 piece apex seals chip tips(speculation), it is a common occurrence

to be honest I do not know for sure. Car had 53k on and supposedly 3k on the motor. Did it have 3k? No idea. That is going off trust. Anyone could make a receipt or "proof" of.

Yes I need to do the compression test for sure. The audible test doesnt have good results though. You can definitely here the speeding up of the cranking over certain points.
Would be a wonderful start to the New Years if I am crying over nothing...., I hope that's the case. Unfortunately 98% sure it probably isn't.

You are right in being pessimistic - uneven cranking is a definitive sign of VERY uneven compression. Ask me how I know...broken compression ring in my F2000. :(

As noted by Skeese, timing is important. If timing is bad, an engine can easily be blown.

$10K wont get you a new engine "and" new turbos unless you do the R&R. Do the compression test and let us know.

Good luck :)

Where you go from here is an ECU upgrade and a tune that involves some engine protection. Otherwise you'll continue to have these scares indefinitely and ultimately something will happen that causes it to let to, and there will be no failsafe there to catch it. ALL of this is easily prevented with a modern ecu and quality engine protection setup. The PFC was designed around the same time as the Motorola bag-phone, but you don't see people trying to use bag-phone GPS in 2019 to navigate.

$10k will for certain get you that if you aren't shooting for huge power. Buy a brand NEW MAZDA complete keg from IRP for $4800 here as mentioned and then strap a set of used 99 spec or BNR twins to it for another couple grand max, then buy a haltech and a tune and your're out at max for $8k with a quality ECU, brand new motor with all new parts, and better turbos than you started with. Not to mention that you can sell all the parts of your old keg that are still good for probably $1800 and that PFC for probably $500.

Just sayin, its very doable. Just can't get sucked into things like turblown quotes or overbuilding an engine for what you need, those are where you get burnt.

Skeese

I will look into the Haltech. So there isn't a thing with the pfc that can be done in your opinion? I hate the fact I just spent 1k on that. What's the Haltech running? Or which model. I guess I will start to research it as I know nothing about it. Protection would be nice.

The PFC has no engine protection, nor any way to add it. The best you can do is tune extremely conservative, maintain every aspect of the car religiously, and monitor both wideband readings, fuel pressure, and EGT in both runners constantly like a hawk to try and spot anything indicative of an upcoming failure but even then you can't respond quick enough should something crap.

I've tuned PFC's, adapronics, haltechs, and a few AEMs and prefer the haltech platform by far. For single turbo or parallel twin 2 rotor you'd want to run the elite 1500, but if you have a sequential twin turbo car you need the 2500 to run all the required I/O's for the twin stuff. I personally have the 2500 on a single turbo car, but I run a ton of additional stuff with it. I can't tell you how many times I've hit engine protection in my car while street tuning it myself and had the cut save my ass. Haltech makes a patch harness for the S6-S8 Rx7's that allows you to plug the ECU into the factory harness should you not want to go the custom harness route.

I really need to write a thread on here about the proper use of engine protection, how to set it up, and why. Anytime I post stuff like that though it gets like 4 views and 2 comments, but still....it blows my mind that we are still talking about why rotary engines blow all the time with a PFC driving it.

Skeese

Skeese I like the sound of all this, but I was and ... I dunno maybe a little sceptical because I haven't really heard much about it. If it truely has protection that works it makes no sense not to go that route. Plug and play is always cool of course. If it is something I could get into for a couple grand and it saves me heartache and a lot of $ in the future it is a no brainer. If it is a "maybe it could help" prevent detonation in some odd circumstances I am not interested In spending. I would rather stick with the pfc, pay extra for tune, water/meth, extra cooling, extra lubrication, extra whatever. I think a write up would be awesome.

Also I will give you a page of comments!!! LOL
I actually have a tuner here in south Florida possibly they dont do pfc anymore

Power FC is a great basic ecu but it lacks any significant engine protection options. You can set it up to pull timing if coolant temps get too hot or fuel cut if it overboosts (bad) but it cannot do things like monitor fuel pressure or afr and shut down if there is an issue before it hurts something. That being said, we have maid close to 600whp with a properly setup power fc car and I've heard of even more. If you want to upgrade I'm a big fan of the new Haltech elite series ecus. They even have plug in models now.

Only issue I see is I cant see it saving me for a fuel injector failure. Fuel pressure sure. I could go dual fuel pump and help eliminate a little there, but injectors?
Does it have a knock sensor reader and cut accordingly?
The AFR option is awesome if it is a millisecond response (if that is even fast enough??).
Octane? What if I buy 96 and got 89 and pull 14psi on a hot day? Will it react fast enough?
Sounds like an awesome route to go, but. I find it hard to believe if it is so good why are we even having this conversation? I would think we would all be on it no? Like it should have been all over the forums a long time ago? I BLAME SKEESE FOR NOT PUTTING A THREAD UP!!! Just kidding, but I never would have went pfc route. I just want to know what I would be truely getting myself into as to justify swapping.
would it have saved me?? I dunno as we dont k k what happened yet of course.
Maybe a cost thing with all the options? If it is looking like 5k or something to set up with all options I will have to do some serious soul and pocket searching. I dunno. I am starting my research pretty much now as I type this.. I like modern. I think these FDs can hang with modern cars, why not have modern thi gs maki g them work.

No offense, but if you haven't heard about the pros and successes of modern engine protection then you either A) aren't a tuner or B) don't talk to a very good one. I'll try and get a write up started. I'll have some spare time away from work in the next few weeks for some surgery so I'll have some bored bed-ridden time I can dedicate to it. I'll try and pull some logs showing the engine protection going live and how the ECU responds with the cut.

This isn't new...the haltech PS series has been around for like 10+ years now and while its not advanced as the elite, it offers a level of engine protection that FAR surpasses what is available on the PFC.

And IR is right on all points...the PFC will trim fuel based on coolant temp, but that isn't really engine protection so much as a standard tuning operation. It does have an overboost fuel cut, which should really be an ignition cut. Cutting fuel due to excessive boost pressure on an engine that is extremely susceptible to failure due to detonation caused by a lean mixture...is a bad idea.

Skeese

skeese I am far from a tuner, but I learn quick.
I wish you the best on your surgery. Speedy recovery to ya.... well, as long as you have enough time to write all this up lol.... j/k
I am open to swapping. Just has to be worth it

I assure you, it is.

Skeese

Also while modern ECU's do have some great protection strategies they are not foolproof. Blown motors happen, they aren't the end of the world. The good thing is it doesn't happen anywhere near as often as they used to - before the PowerFC was out, people were trying voodoo and Oujia boards trying to keep motors together.

A good tune is the first part of the battle, the next part is knowing your mechanical system is in good shape and set up right - no hacked fuel pump wiring, ghetto hoses, ancient components, etc.

Focus on getting the car up and running again, you probably don't need to buy a $2000 ECU right now, put that where the car needs it most.

Dale

In the end, shit does still happen.

Throtl youtube channel just blew up their FD on the last dyno vid. Its running a halltech elite and it lost signal on the dyno at the top of the RPM band. Abel was behind the wheel tuning as well.

But still engine protections should give you peace of mind and will probably save your butt numerous times. squeezing power out of these cars is a delicate balance, no matter 300hp or 1000hp, one thing goes wrong and its rebuild time.

Nowhere did I suggest he buy a $2000 ECU before getting the motor fixed or determining where the issue came from. I didn't think I had to specify that as doing so would be retarded...

One should obviously figure out what caused the failure first. I suspect if the OP was logging at the time of the failure on the PFC, all the logs would show a lean condition and high knock values at the point of failure in the log. All that pulling the engine apart may tell you is whether or not the apex seal failed due to detonation or not. Assuming the answer is yes, and you don't have a log with more than PFC data to show why it went lean and detonated and point to the failed part of the system, then you need to physically check fuel pumps, filters, lines, injectors and all wiring to find the source of the fuel failure. Strapping a new motor into the same system that failed obviously doesn't fix anything as the engine didn't blow itself up, something external to it failed and the PFC did nothing about it.

This is why I have my haltech setup to ALWAYS be logging the critical data when in boost. For tuning I'll plug into the PC and record all data to the computer hard drive, but for general day to day driving the ECU is setup to record only a handful of critical factors so in the unlikely event something fails I'll be able to know why. The ECU's built in hard drive can hold quite a bit of data when only recording the critical factors and only recording when in boost.

Sure, no level of engine protection is a 100% fix for the inherent design factors that make the rotary engine subject to failure, however aside from swapping in an engine with large metal pistons and big metal rods to absorb the force of detonation instead of the little 2-3mm seals the rotary has the best thing we can do is setup as many barriers as possible to avoid ever ending up in a detonation scenario, all of which begin with engine protection functions within the ECU. Which the PFC does not have.

It isn't rocket science. Prevent detonation by stopping the engine when you sense things that lead to detonation. If we can't do that we may as well just tune for 9.0 AFR's for reliability margin.

Skeese

I can't watch that video as I'm at work, but I'm wondering if that car was using the factory mag trigger sensors combined combined with an elite ECU and a patch harness over to the factory wiring? There have been several accounts that when pushed past 8,000 rpms, the factory mag sensors have been known to miss a signal causing the motor to blow with the haltech elite but in every condition I've seen they have been using the factory wiring and the older style patch harness (since patch harnesses are all compatible with the elite all the way back to the E8 ecus). Now I'm not entirely sure, but there's a chance the trigger wire shielding is lost somewhere in the patch as I haven't seen nor heard of this happening with an aftermarket hardness with proper shielding of the trigger wires all the way to the ECU.

The issue has successfully been mitigated when using the patch harness by altering the home and trigger voltage thresholds in the software and extrapolating the values out to 10,000 rpms instead of the ECU looking for the same signal at 8,000 as 10,000 (haltech basemap only comes with voltage threshold values to 8k). If someone wanted to take the initiative to setup a test rig and spin the factory trigger wheel on a drill end to 10k and dead nuts these values using a scope, that would be something worth talking about.

Skeese

^Rywire made him a harness for his Haltech Elite.

Also... they said it made like 530 @16-17psi.. on 91 pump.
All through a T3 footprint, GT35 style garrett turbo or something like that.

Testrun, sorry to hear about the engine.

500+ hp on 91 pump gas is asking for it, not to mention you're likely running on the ragged edge of lean with some real advanced timing to pull those numbers off of a turbo that small...

yes it gets blamed on a sensor skipping a signal instead of having proper tuning and engine protection? We could start with realistic expectations and tuning within known parameters...

Skeese

I am pretty sure I am doing this right. I just held the pressure relief of the compression tester while it was being cranked. Using the bottom (leading) plugs of course. Rear rotor got up to a little over 90 and had 3 hits or bumps on 90 and progressively got higher. The Front rotor is screwed. I get one 60 bump and nothing else the other 2 bumps seem like almost one continuous at 30.
if anyone wants email vid just let me know. I cant put a mp4 up on here and can't link it.

Damn this sucks

Tiny FPR, No FPD, and Retard Shit Fuel Pump setup on CA 91 Octane.

Dumb ownership is real easy to spot. Like PFC "tuned" cars. Sometimes they are one in the same.