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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
Damn....! Sorry to hear that brotha.. I would start looking at the most obvious, physical damage like crake manifold leaks, then compression test.
Others with more experience will give you better guidance on what to check.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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
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.
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 **** 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.
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).
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.
Hmm. That sucks man. I test drove my car last night after doing brakes and pillow *****. Quick 2nd gear pull and the warning lights lit up in my cluster (jdm car with power fc). I hit .89 and injector duty was 94%, yikes. Stock twins and fuel system (afaik). Not sure where to go from here, I dont want to pop a motor.
Hmm. That sucks man. I test drove my car last night after doing brakes and pillow *****. Quick 2nd gear pull and the warning lights lit up in my cluster (jdm car with power fc). I hit .89 and injector duty was 94%, yikes. Stock twins and fuel system (afaik). Not sure where to go from here, I dont want to pop a motor.
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
01-15-19, 08:33 PM
