rxspeed7

iTrader: (5)

+1 no matter what paper says, real world experience will always trump theories. Most tuners have their set ways they tune, no matter what any document says they will always tune an engine to what they want.

That's like me trying to tell my boss he needs to change how he's been tuning rotaries for the past 20yrs+, not going to happen. It's obvious that some people take what they read online to heart and run with it. If you are serious about wanting to tune vehicles and build high quality motors that are going to last you gotta find reputable sources that have many strong running motors under their belt(doesn't have to be high powered). You also have to be smart enough to be able to differentiate internet bs and hype from actual real world knowledge.

j9fd3s

iTrader: (3)

generally, sponsors like their logo on the car somewhere....

arghx

iTrader: (3)

I don't want rxspeed7, Karack, or anyone else to misunderstand where I am coming from. It may seem like I am just repeating some crap I read in a book somewhere, being some armchair tuner. But I actually do deal with this kind of stuff in my day job. In this thread I am simply engaging in discussion for discussions sake. I'm bringing up stuff in response to the topic Howard has prompted, just to break the monotony of the "should I buy a GT35R" threads. Since the rotary is in limbo while we wait for a new one from Mazda, it's kind of cool to talk about newer theories and technologies. To quote myself:

I'm not actually advocating that anyone here start leaning their engine out in an unusual way to pick up power except in the most unusual of circumstances. I tune rotaries too, remember? I don't see how anyone here could put such interesting theory into practice with normal street tuning procedures, regular equipment, and the budget of a hobbyist. Again, it's discussion for discussion's sake.

rxspeed7

iTrader: (5)

I in no way doubt you at all, you know what way is up but I just fear for others to take this info and run with it like it's gospel. Seems to happen way too much on this forum, way too many people get misled with bs.

Liborek

I hear you, but to really understand tuning, one has to examine why certain approach works and why certain doesn't.

For example, everyone according to the internet wisdom knows that conventional port injected turbo engines run rich, but how many people can say why is it done? Fuel antiknock index remains the same no matter mixture, so why? EGT control? As absolute number, EGT is important only for turbine life. Mixture strength is important in determining how much power can given fuel support, but most won't know why and others will just tell keep it this and that rich...

Or another example, methanol fueled engine with its huge antiknock rating should have no problem in running with lambda 1 at full power, evaporative cooling of huge fuel mass should cover it. And still, it is not done, it would preignite in PFI engine.

These research papers hold information from which conclusion can be drawn to understand why the things are done in the way they are, even though the paper itself doesn't discuss rotary platform.

Thread title is clear, are we tuning too rich? Answer is no, additional fuel keeps whole charge temperature lower and this is determining factor if the engine will or won't knock on given fuel. Otherwise it wouldn't matter if the engine is run at lambda 1 or 0.7... Of course, if the liquid fuel pours from the exhaust, its little too much

rotarygod

iTrader: (1)

The very unfortunate thing you fail to mention is that some people completely discount any theory at all. Usually because they have absolutely no clue what it even says. I'd venture to say the only people that are against theory are the completely ignorant ones, of which there is an overwhelming abundance of in the world. Theory works. It's up to people to verify it. If what works in the real world is different than your chosen theory, you had the wrong theory or at least errors in it. Everything is explainable. You just have to know how to. That's what makes it difficult and why often times people get it wrong. It wasn't the fact that all theory can be wrong. It's that THEIR theory was. The important thing to remember is that sometimes trial and error and existing guidelines are quicker and easier which makes going into theory a relative waste of time unless it's for the fun of it or personal knowledge. The big thing many people forget though is that some people will do something their entire lives but will have done it wrong the entire time so be careful about blindly believing what others do no matter who they are.

j9fd3s

iTrader: (3)

exactly. i bring up the ancient example because, its cool, and because they were doing 190mph for 500km's at a time 75 years ago. or maybe 160hp/liter is a better measure.

we should be able to do it today, as physics is physics.

Liborek

Exactly. If someone is not comfortable with test result, not theories but test results from modern advanced piston engines, lets use test results from the work of pioneers of the internal combustion engines. Physics didn't change and trend from these tests can be transfered and does work for rotary platform.

Anyone who went through RE by Kenichi Yamamoto and for that matter any paper regarding rotary engines knows that rotary is treated exactly same as piston engine and basic knowledge about tuning parameters correlates nicely between two platforms.

BTW that part with refueling is sick. I heard that they were using some really toxic compounds is compressor engines. Those guys were just mad

j9fd3s

iTrader: (3)

which refueling part? there is one clip where the fuel tank overflows on the driver, and they just tell him to keep racing... he's not in fire, but chemical burns!

from wikipedia "Fuel used was a custom mix of 40% methyl alcohol, 32% benzene, 24% ethyl alcohol and 4% gasoline light."

there is another clip where it catches fire in the pits, and its on fire, but you can't see the flames!

RotaryEvolution

iTrader: (30)

i wasn't trying to beat down anyone's sake of argument. it likely would help with power and turbo spool reaction times but in these engines it is more dangerous to lean out fuel trims than most other engines.

my point was, don't take this thread to heart as a tuning rule because it isn't a safe direction to take when tuning a rotary engine.

ignition timing is the best place to scale things back. the factory was a bit aggressive with it's timing and with rotaries you don't need to be on the edge with timing to still have very decent results. but with air fuel ratios on the other hand, you have to be in the middle of the field, if you tune for power leaning it out too far then you sacrifice that the fuel system will always be healthy, gambling on the reliability of the engine.

reasoning has already been explained in this thread.

rxspeed7

iTrader: (5)

lets face it, none of the personal cars we tune are race cars. If you do tune race cars and need every last oz of power by all means tune your car on the ragged edge. Hopefully it'll last for the race. But all my exp has been gained from people who have had record holding cars in both road racing and drag racing.

Now for the average smuck's street car there is absolutely no need to tune and set the car up where in everyday driving there could be a potential for detonation because its been set up soo lean in order to "optimize" power. anyhting over 400whp is useless on the street anyways.

seandizzie

iTrader: (1)

and our rotary engines should be covered in swastika's and rising suns...

http://en.wikipedia.org/wiki/Felix_Wankel

RotaryEvolution

iTrader: (30)

i like that!

i am half german after all.

Hail Hitl....


what?!

seandizzie

iTrader: (1)

Don't let one man's Mass murdering ideaology ruin the reputation of a hard working nation. Hitler was a Nut, Alot of great minds come from them there regions...

RotaryEvolution

iTrader: (30)

i'm surprised mercedes wasn't able to make it a viable engine, considering their engineering abilities.

Boxer2rotary

iTrader: (8)

[QUOTE=arghx;11023033]It's fuel economy and CO emissions. CO emissions are directly related to whether the mixture entering the converter is richer than stoichiometry. What happens is that even if the engine passes emissions during certification, it has to be retested after a year and after 4 years. If it fails enough testing you get a government-forced recall. So there is an incentive to leave a "safety margin" in terms of the CO emissions output, but then you have potential issues with high exhaust temperatures.

Some Subaru tuners/owners are kind of paranoid/hardcore. Totally eliminating the delay timer just hurts fuel economy on a typical moderately modded street car, but yes it is standard practice. The issues is that in 2008 Subaru doubled the delay timer, meaning the engine runs at 14.7:1 for a longer period of time before entering enrichment than earlier models. At the same time, manufacturing quality IMO decreased and those engines became more prone to losing piston ring lands. I usually cut the delay timer in half of what you'd find on an older model. The delay timer has different logic controlling it depending on the engine; some have an actual exhaust temperature sensor output that contributes to the logic.

I disagree with a lot of Subaru tuners. There's a lot of groupthink and paranoia among them, and I guess after messing with rotaries for so long I don't find myself too worried about blowing up piston engines. The stock ECU is about a gazillion times more powerful and safer (in terms of knock and boost control) than anything available for an Rx-7 so it's not a big deal.[QUOTE]

I actually have a DD 04 sti and have owned a wrx or sti since 2002. I also know a lot of buddys with DD 35r sti's running 500whp plus on pump. They all have the delay removed as two of them hit knock cause the delay is inconsistant at its crossover point (so I am told by some reputable tuners around here) and broke a ringland. Most of us with Rx7's don't run nearly the same amount of boost on a daily basis that people with EVOs and STi do so a knock from a MS of leaness can be fatal to the motor.

As for emissions owning an STi is like a godsend. As I am sure Arghx is aware, you can disable all CELs with an open source tune on stock ecu and pass emissions with no exhaust. (Minus physical inspection but you get the point).

BTW..I am not in desagreement with Arghx, its just that this subject is discussed all the time over on NASIOC.

arghx

iTrader: (3)

500whp STi's running 30 pounds of boost are a different animal than ones with bolt ons...

RiceFx306

iTrader: (7)

I definitely agree. I was terrified of my car for many years thanks to certain members of the forums and my shopping list for parts for the car got incredibly long. I finally went to visit with a local tuner and he laughed and put things back into perspective for me. I like him because he's blown up a lot of his own cars trying to figure out what works what doesn't and the limits. Now I look to the forums for guidance but try to stay skeptical on certain theory crafting. It's been a very monkey-see monkey-do community.

It's still interesting to have these discussions and whatnot as long as the info is taken in the context of what it actually is. We have some very intelligent people in our community and to watch the banter and just trying to keep up is quite a challenge. I've read some threads on here several times over the years and each time I go back I find the Martian text to be more and more comprehensible. So thank you all for sharing ideas, theories and most importantly knowledge.

Sorry...was searching for something else and resurrected an ancient thread.