You failed to mention that your Atkins seals are cryogenicly treated. Makes a huge difference.

 

Wow ! without knowing any conditions such as ignition advance or air/fuel you just about solved the cause of failure......so ~400hp is the magic number when pump gas becomes unstable and self ignites !!!!
Your above explanation makes as much sense as your "why our rotaries blow up and how to solve the problem" article!!!

-->What was Mazda thinking when they developed a Hydrogen-powered Renesis engine knowing the volatile nature of hydrogen gas !!!

Hmmmm..maybe because injection, compression, ignition and exhaust areas are separated from each other, therefore pre-ignition of the gas is non-existent.
Rotaries have been known to have the ability to run on very low octane without pre-ignition due to its design which kind of contradicts your theory.

Pre-ignition is when your air/fuel mixture ignites prior to spark plug firing. Most often caused by a "hot spot" or simply heat within the chamber, such an overheated spark plug, glowing carbon deposits or anoverheated motor(side irons). They all seem to be existing issues already from abnormal combustion pressures from previous cycles.
Possible causes of abnormal combustion pressures:
high compression, over advanced ignition, lean A/F condition, uncontrolled boost, wrong octane gas, failing cooling system, un-efficient turbo or intercooler system, restrictive exhaust, mis-firing from bad ECUs or ignition amplifiers, etc....

It's obvious pump gas is not the big culprit of almost all broken engines as BDC wants everyone to believe.
I feel safer running my 19-20psi on pump gas set up then his methanol auxiliary system @ 26psi which has had its own issues.


PBK7: I agree with you being near the limit of boost on pump gas.
To get 400rwh it should happen at much lower boost with your setup unless you have some restrictions.
what did other dyno runs look like before rear rotor letting go?
what does your ignition advance and A/F look like from peak torque to max rpm?

Looking forward to being corrected somewhere :-) typing on my sleep !!!

JD

 

Yep. I used the "super seals" in my street port, have had nothing but good results with the atkins as well. I suppose it doesnt matter what you use, if your tuner doesn't ping your motor!

 

I failed to mention it because they arn't! I've used them too, but they're not what Im using in the bridgeport.

 

Will try to post the Dyno sheet later today!

Boostn7, what possible restrictions could we have besides the intercooler&piping (xspower stockmount with 2.5inch piping?

Again, though i believe there is merit in what BDC has to say, my preference is to stay away from the A.I. and have an efficient and as reliable system as possible on pump!

 

lack of power I'd guess is a: small turbo and b: engine building

for a comparison, at 17-18 psi I made 427rwhp with a gt4082 (close to a t04s, smaller inducer) and a stock s5 engine

 

Aren't RA seals housing eaters and why not just run stock mazda seals? Aftermarket aren't that much cheaper.

 

2.5" piping sounds small, even factory piping is 2.75" min. Intercooler core could also be a restriction.
what are the specs on the turbo ?

As far BDC, he's probably the only person I know that limits his tuning to 13psi on pump gas, maybe he's had bad luck or something.

With so many 2 rotors running over 13 psi and making over 400rwh safely on pump gas there's no black magic involved, just plain good old tuning and understanding the limits of each application.

If pump gas was so bad we would not have motors running over 11:1 compression or boosted factory cars running over 18psi from factory.

JD

 

+1 for Atkins seals. I don't understand the idea behind why people think they don't "hold boost" or however it's characterized.

B

 

I'll probably get yelled at. Seems to be a fairly common response to my general arguing against the norm.

Crispeed, I need to chat w/ you. Going to send you a PM.

B

 

Considering it only makes 100 or so horsepower, that is a good question. The answer to why it makes so little power of course is because hydrogen is a crap fuel that burns to fast for an internal combustion engine when it comes to making power.

 

You are one of the most correct and smartest people on the forum. Let them yell. Believe me you aren't the one that looks bad. The difference between you and most others is that you aren't afraid to try things and then build and test them yourself. Then you share your results, experiences, and logic as you go not to mention you try to put as many disclaimers as you can as to why you tried a certain setup with what you had. Of course knowledge always expanding and evolving. Too many people don't understand that (this forum is proof!) but then again when all most people do is hand over the money for some second rate over the counter product with a famous name stamped on it, I wouldn't expect them to understand. Creativity is hard find anymore. Keep it up. In fact stop helping others learn. I have. It's a waste of time.

 

John.
It's hopeless to try and argue this point with Brian because this is what he's has acheived and it's based on his experience. Now both you and I know that's not complety true because we both and many others have experienced different results. Basing horsepower level on fuel octane is Bs from my experience. If I believed that I would be still running 12psi on 93 octane like I did when I first started 20yrs ago. Fifteen years ago I made 350hp on 93 octane. Today I make just over 500hp on 93 octane and will guarantee 450hp all day and night on 93octane without any form of auxillary injection that everyone has jumped on the wagon as of late.

The original thread starter is proof of what not to do and that's not based on the use of 93 octane. I've always said the key to a successfull rotary is dependant on the entire combination. Why run high boost with a very in-efficent setup. You're asking for trouble. Some you people think race gas is the answer to all your troubles when the fact is that motors still blow up on any kind of fuel. Again it's the entire combination that matters. HOT AIR no matter how high an octane fuel, no matter how rich an A/F ratio or ignition retard use will DETONATE plain and simple. Making your combination as effiecnt as you can will result in the best and most reliable performance. As an example I have ran up to and just above 40psi with high octane race fuel and have seen the limits as far as knock with those fuels. Guess what at that level knock is not based on horsepower but based on the ability to keep the charge air cool enough as to not self ignite with a set combination. The same combination let's say with an air-to-water I/C would lower charge temps enough to maintain a safer boost level. Why run 40 ppsi and above with high octane when there's methanol fuel. With the cooling properities of methanol you can remove the I/C and run lot's of igniton advance and the sky is the limit with the boost as no one has found that limit as of yet at least not tuning wise. Mechanically wise yes that limit have been found and measures are always been taken to take it to the next level.

 

Still wrenching my posts out of context I see.

When did I say that "400 is the magic number" or make any definitive statement as such? I didn't. Think of it like this: It seems to be that around that area is where things start to happen. The guys at 350hp and below don't seem to have issue, but once we get to and cross this 400 area, that's where all the sudden we see the street-driven, pump gas running cars that have or have had blown motors. It's an issue of load and not some "magic power number" as I certainly don't believe, John. Good grief.

Really... then let's approach this argument through the back door: Why run race fuel at all? After all, if "pre-ignition of the gas is non-existent", as you say, why waste $5 to $10/gal on race fuels for higher octane?

"wrong octane gas" -- Alright, then. Besides there being more causes for pre-ignition than what you've listed (auto-ignition of the charge motivated by heat exacerbated by compression ratio, high IAT, or both prior to timed spark, firing spark too early due to poor tuning, etc.), I'd like to focus on the "wrong octane gas" comment. You haven't given an argument here about octane and how it relates to what we do with the RE. What gives?

It's obvious that you're mistaken and pump gas is the culprit. Answer my question above as to why anyone would run race gas and then argue to the contrary if you wish to show that I'm mistaken.

Feel safe all you want. I beat the hell out of my car at 24-26psi for 4 months, over-spinning a dinky TO4B compressor with a stock top mounted IC, and never had an issue with it until I did something foolish myself on the dyno. But, of course, I'm not the only one here who's cracked a front plate before.

Funny you bring this up even though everyone who reads my blog will know that my system has zero reliability issues and never has, not withstanding the change of sealing washer I had to use due to my putting the nozzle in a thicker-cast spot. FYI John, it turns out that everything I did to troubleshoot what was going on had nothing to do with the system whatsoever. Turns out it was where I was placing the IAT sensor and the lack of air temp/fuel correction that was throwing everything off. +1 for the bulletproof Alkycontrol system.

The obvious question: What in the hell is the limit of pump gas?!

You spend time arguing against my theory on the general limits of pump gas, you argue against how I said it seems to occur around the 400hp and above area generally speaking (even though you attempted to paint it as if I gave some magical, solid power figure as being "the limit"), you make the assertion about "pre-ignition being non-existant" yet provide no further explanation nor any argument to counter my point about the culprit being pre-ignition, and yet in the next breath you say that the original poster was "near the limit of boost on pump gas"?

Are you ever going to explain your point or are you just going to throw empty assertions out w/o any substantiation? If you have an idea, atleast share why you think you're right! Contrary to popular Internet belief, it's not enough to just toss something out there; the argument needs merit.

B

 

Rather than me started another thread, I thought just to ask the question here. As been speaking to few Rotary engine rebuilders in the past 2 days and trying to decide who to use for the rebuild and single turbo conversion. They all seem to stress that rotary engines were meant to work around 0.8 bar (11.60 PSI) but with the intended GT4088 turbo that I got will not get full spool till around 15-18psi (1.0342 - 1.241 bar).

As normal the talk continues that I can get away with 0.9 bar or even 1.0 bar, but how true that is? Considering new rebuild, running on 93 or 95 Oct fuel, large FMIC, Apexi FC + Commander, uprated secondary fuel rail, 1600cc secondary injectors, aluminum radiator, 60mm wastegate, Apexi AVCR boost controller, Apexi SAFC II, uprated fuel pump. At a later stage I will upgrade the ignition and consider water injection as well.

Also I received my Apexi FC + Commander on Monday from Japan and being it a used unit it came with no manuals which I know I can download of Apexi website but can't find anything on the manuals about using boost controller kit with the FC. In other words, Im considering to remove the Apexi AVCR and just use the FC + commander it self. There is another connector plug near where the commander connects, is that what used to connect the boost controller kit?

 

Brian Brian turn on yo PHONE!!!!!!!!!

 

Yep, not a big performer but shows the flexibilty of the wankel by running either gasoline or hydrogen for super clean emissions.

Yep gain, hydrogen is highly volatile and flammable.
We use it in rocket engines and bombs and when used in piston motors pre-ignition is a major concern. Since the rotary's intake and combustion chambers are separate then it makes it ideal for a highly volatile fuel.......including pump gas:-).

JD

 

Yes, very hopeless.
Still remember years ago when I boosted past 14psi on the dyno and I yelled at the guy for not lifting off the gas..... also lived in that bubble where 14psi was the max:-)
JD

 

On my T04S at 15 PSI and pump (93 octane), I find that 9s in the leadings and BR10EIX in the trailing give good results for me. You may wish to consider moving to a 10 or 11 trailing as some others have suggested.

Brian

 

I think I just lost an engine from multiple dyno pulls with 9's in the trailing.

 

please get the dyno site back up... I miss looking at it.

 

Here it is ------>"The first weak-link is the fuel. It almost always is, without exception, on these street-driven cars that aim for and exceed 400hp when sticking to using pump gas."
That's exactly what I'm saying....there's no magic number but many have reached similar numbers safely and are able to duplicate them over and over given they have an efficient combination.

That was about hydrogen use in a renesis where unlike a piston motor pre-ignition is avoided thanks to the rotary's separate intake and combustion chamber.
Its a known fact that the shape/movement of the wankel combustion chamber prevents pre-ignition and allows it to run lower octane.
I feel that pre-ignition it's usually brought about as a result of abnormal combustion pressures or persistent detonation which increases heat flow within the combustion chamber.

Wrong octane has more to do with common sense such as someone tuning a setup with race gas and then attempting to run 89 octane.

You could resist detonation with higher octane fuels which slow down the combustion process and keep everything normal. The higher the octane the higher the performance potential.
All fuels also have a knock limit. The point when the temperature of the remaining air/fuel reach autoignition. Increasing boost, timing, compression, or higher inlet or coolant temps will increase chamber pressure, which in turn will bring you closer to autoignition.

Sorry, but I would consider those Atkin seals the culprit before anything else.
Crispeed said it best......its all about the overall package running at its peak efficiency and you will have the best results regardless of fuel used.
I know my limits on pump gas and if I need more, race gas is the answer.

Sorry, but broken front plate= detonation.

On pump gas I've seen similar #'s as Crispeed....~500rwh @ 20psi (dynoed 484rwh @ ~18psi). I've run full throttle up to 170mph @ 18psi many times.....and it's been together for 2 years+.
I've tried running 3/4 tank of pump gas with 1/4 C16 race gas up to 24psi and knock levels on the PFC were less then 5.

Original poster was running 19psi which for me is near the limit for 9:1 rotors but considering he was using std Atkins seals I would have run less. He also made 417rwh which is low but then again it was @ 6500 rpms.
I'm sure he will make his reliable 400rwh at less boost once he takes care of any obvious issues.

BDC: How much boost do you think you could run safely on your 70/30% Alky system with your bigger turbo ?

JD

 

Boostn....Atkins seals the culprit? I thought these things were sent from GOD! Please correct or inform me, thanks.

 

I already told you no. Atkins seals are fine.

 

PBK7 , sorry about your engine loss, we all know that sinking feeling!
What ignition amplifier are you running?
What were the IAT's that you were seeing on the dyno?
What type of ducting do you have on the XS intercooler? How well is it sealed?
Barry