JaySpec7

Since the RX-8 now uses a MAF, is there any limitation as far as bolt on mods?

I'm curious and have searched since an intake/downpipe/catback is basically the furthest you could go on a stock ecu on an RX-7, anything added after that (i.e. midpipe/IC etc..) result in lean conditions and greatly risk a blown motor.

TIA
Jay

epitrochoid

as far as bolt ons and ecu tuning is concerned, it's like comparing apples to oranges.

you can pick up 20hp with a mild retune, but some mods, particularly intake, can mess with the ecu resulting in a loss of power, since the ecu is tuned for a stock intake box. or you can bolt on all you've got and end up with about the same.

if you want both, go with CZ stage 2 and a full exhaust, cat and all. either way, most people shun the intake, but some still stand by it...

of course, like most things in the rx-8 world, there's no dyno to go by :P

rotarygod

The RX-8 can't be compared with the last RX-7. Hell, no other RX-7 can be compared with the last RX-7. The 3rd gen RX-7 was a speed/density system that used a map sensor. No maf sensor. The previous fuel injected RX-7s used an air flow meter. Not even close to comparable. The 3rd gen ecu did not know if it was getting more air or not. With more boost of course you'll run lean. If the car can't sense more air then how can it give more fuel? It can't. The RX-8 runs extremely rich. You will not blow up a naturally aspirated engine by running lean. You will just lose power. When tuned properly detonation is not an issue with a naturally aspirated car. The only reason a naturally aspirated rotary would detonate from a lean condition is if the leading/trailing spark plugs were timed to fire too close to each other. By increasing the timing split to at least 10 degrees, this will never happen. Power will fall off before detonation occurs. The only other way is to use really low octane gas, much lower than what is currently available. It is nonsense that you can not run 89 octane in the Renesis. It will do it easily. Every previous naturally aspirated rotary has run their best on low octane and the Renesis is not so different from the older ones that this shouldn't still apply. If it does it is an ecu issue not an engine issue.

At this time the car is far too new to know the limits of the stock ecu or the engine itself. People are still developing turbo kits, supercharger kits, nitrous kits, ecu upgrades, exhaust systems (legal and illegal), intakes, ignition systems, etc. If the model of car isn't at the very least a minimum of one year old from the time it was first released, you are not going to fully understand the true potential and even then there will still be development work. Ask this question again in a couple of years after people have had time to study the car. It is no where even similar to previous systems used. We are only just now starting February of the same model year of the very first RX-8! Be patient people!!!

JaySpec7

Thanks for the response... I just wanted to make sure

only reason I compared it to the RX-7 is coz I have one... LOL

I guess having an RX-7, I want to know everything... I had to worry about all the "what not to do's", reliablity mods, flooding, leaks and on and on.. paranoid? maybe... I have to say, NO one knows what maintenance is like til you've owned a 3rd gen... I hope it won't be the same for the 8...

As far as the CZ stage 2, yeah.. i'm looking at it.. that's when I sell my RX-7 and decide to go w/ the 8.. the CZ stage 1 is great, i'm just concerned with a NA rotary w/ no cat and a catback, in regards to sound... if you can only hear my FD w/ 3"- 4" piping

rotary-convert

posted by rotary god --------It is nonsense that you can not run 89 octane in the Renesis. It will do it easily. Every previous naturally aspirated rotary has run their best on low octane and the Renesis is not so different from the older ones that this shouldn't still apply. If it does it is an ecu issue not an engine issue.---------------




forgive my ignorance but why would the ecu in an 8 want to distinguish different octanes? which leads to my next question why in previous gen rotaries does low octane provide the best results?

also has anyone ran any octane less than premium?

still learnin here!!
d

zerobanger

I've run 87 many times and 91 many times. I cant tell the difference.

93rdcurrent

If you do a search you will find pros and cons coming from different people in regards to octane. I personally haven't tried a lower octane but this car does have a high compression without FI. More compression usually needs a higher octane but Rotary God has a good idea of what this engine is capable of as far as I can tell and I won't argue with him.

Jhouse

oh yea and as if leaning out the ever so richly tuned motor would do us any harm....

JaySpec7

I thought those where only California RX-8s??

rotarygod

The only reason the Renesis would distinguish between high and low octane gas isn't actually an engine but rather an ecu issue. The factory ecu as we all know is tuned like crap. Some people have claimed to have detonation on low octane gas. Detonation shouldn't occur on a naturally aspirated car. It isn't fatal in about 99.99% of the cases. This doesn't apply to cars with forced induction. The issue is that the leading/ trailing split is too close at the point of detonation. Obviously when an engine detonates there are a couple of easy fixes. The easiest solution is to run higher octane gas. The other fix is to adjust the timing a little. Typical thinking is to retard the timing but on a rotary increasing the timing split will accomplish the same thing. The engine would much rather run on low octane gas since it combusts faster. The lowest octane, crappiest fuels out there have always worked good in naturally aspirated rotaries. There is no point to running higher octane unless you have forced induction or just like paying more for gas.

The Renesis is only unique and some people swear that low octane works fine and others say that their car runs better on high octane. I do know your wallet empties much faster on high octane so I guess there is a benefit to someone somewhere. The people retuning the ecu's need to keep at least a 10 degree timing split between leading and trailing so detonation will not occur. You could actually keep this split and advance the timing so far that power will begin to fall off and there still won't be detonation. The splits have been too aggressive. There is no reason why you couldn't have a 260+ hp Renesis (when properly tuned) that couldn't run on low octane. You can. Someone just needs to work on the ignition side of tuning.

If there in fact really are issues with the RX-8 not liking low octane, this will get corrected with tuning. However I suspect that there aren't any issues and that it is just an illusion. The factory service manual may say to use only premium fuels but Mazda also says not to replace any parts (air filters, exhausts, etc) with anything other than genuine Mazda original parts. We all know that everyone listens to them on that!

Tony Orlando

Boy, I think I'm going to regret this, but here goes......

The statement shows a total lack of knowlege regarding the events inside a combustion chamber.

My words are not as eloquent as his, so I quote Corky Bell, one of the most respected tuners in the business:

Detonation, spark knock, pre-ignition or ping, whatever you want to call it, is death to a motor. It is caused by heat in the combustion area, and it does NOT require the presence of Forced Induction to kill a motor. It can be caused by running plugs that are of too high a heat range, a cooling system that is insufficient, drawing extremely hot air into the motor, or using fuel that burns too easily. (This is especially important in an engine that uses a high ratio of compression)

So to recap, to tell people is not only incorrect, it is irresponsible. Running RICH does no harm to an engine. It will eventually shorten the life of o2 sensors, spark plugs, and catalytic converters, but the excess fuel acts as a coolant in the combustion area, therefore lowering temperatures. Running lean to the point of pinging is the absolute fastest way to destroy an engine, bar none.

zerobanger

Corky is probably the most controversial also.

MazdaManiac

iTrader: (3)

While I enjoy much of what Corky Bell has written, I can tell you that there many that have some reservations about many of the thinkgs that he asserts.
I certainly have experiences that counter some of the more fundamental assertions that he has made.
However, it is also important to note that the bit that Tony Orlando quotes above is applied to turbocharged motors and is quoted out of Corky's book "Maximum Boost" which is about turbocharging and its pitfalls and requirements.
While it is true that detonation is not a good thing, the fact is that on a naturaly aspirated motor it is of little consequence.

With regard to timing split between the leading and trailing plugs - if I advance the leading plug and not the trailing plug, isn't the split increased by default?
That means, according to what rotarygod has said, I could screw the leading timing out as far as I like without a worry.
Right now I am playing with ignition timing on my E-Manage and I havn't gone past 5° of advance, but I think I will start to get more bold in that realm now that the fuel is right.

Omicron

I feel a looooong response coming from Rotarygod... :D

canzoomer

On a rotary ping/knock/detonation can do two types of damage:
cracked seals, mainly apex seals
flat spots on rotor bearings.

As a general rule, knock can be more likely to cause damage to a rotary than a piston engine.

The RX-8 has a pretty decent knock sensor, and the ECU responds by cutting timing drastically when it detects knock.

This is a dyno sheet showing a torque curve from an RX-8 that was run too lean at around 4,400rpm to 5,500rpm. It survived, BTW..
The dip in the brown line is where the ECU retarded ignition to stop the knock.

rotarygod

Here's your long response now! I got to warn you, we get 20,000 characters max and I'm going to try damn hard to hit that right now!:D

Tony: Since you directed yours at me, I'll direct mine at you.

I know more about the rotary engine and how it works than most people and will easily challenge my knowledge against them any time any day at any place. Most of these forum members will vouch for that as well.

I find my statement far from irresponsible. You stated that detonation "does NOT require the presence of forced induction". In this respect just as you have stated it you are correct. Detonation can in fact occur in a naturally aspirated engine. What is irresponsible is to use a book based soley on forced induction as an argument against non forced induction tuning. If you would like to know what Corky Bell really thinks PM atsturbo here on the forum. His is a very knowledgable forum member who has known Corky personally for many years. You'd probably be very interested to know what Corky really thinks about water injection. He actually doesn't object to it as his book suggests!

I understand your statements and will admit that it is in fact possible to hurt a naturally aspirated engine with detonation. But it is very unlikely. In order to damage an n/a engine you really need some very crappy and irresponsble tuning. Then you need to just ignore all of the warning signs of bad running, low power, etc and keep pushing the car past where it wants to go. Before I hit some technicalities I must in fact address one of your statements and I'll just quote it below.

"Detonation, spark knock, pre-ignition or ping, whatever you want to call it, is death to a motor."

First of all before you go tearing apart my post, please learn about what you yourself are talking about. Detonation is NOT pre-ignition although it is known as knock and ping due to the sounds it makes. Detonation is a spontaneous combustion within the engine that is caused soley by the pressures and heat of the engine. At this point the air/fuel mixture would ignite even if there wasn't a spark plug to light it off. This is essentially what a diesel engine is except that it uses a glow plug which is constantly lit to insure that everything gets burned. The glow plug itself is only there to raise the internal combustion temperature. Detonation is typically confused with pre-ignition since it is usually associated with advanced timing. However you can run really high boost pressures, low octane, and a very retarded timing and still get detonation. Retarding the timing reduces the pressures of combustion within the engine leaving a less desirable condition for detonation to occur in. Lowering the pressures lowers the chances of detonation. Remember with added pressures comes added temperatures. There are only a few ways to combat this; using a higher octane fuel which burns slower, retarding the timing to reduce pressures, or to cool the intake charge. Cooler air is denser air. Denser air takes up less space. Smaller molecules means more air fits into that space. The same amount of air in less space leaves more extra space which leaves less overall pressure.

Pre-ignition is almost just like is sounds. If a mixture is lighted too early (timing WAY off!) the mixture will ignite at a point where the gasses try to expand before the chamber has reached it's minimum size. More about this 2 paragraphs down.

Detonation does result as you said due to high pressures and temperatures in the combustion chamber. However since you quoted Mr. Bell may I remind you that forced induction in itself IS higher temperatures and pressures. It takes energy to compress air. This added energy has to go somewhere and it is given off in the form of heat, hence the greater air temperatures. Obviously an intercooler is used to make up for the big downside of forced induction. Yes detonation can kill a naturally aspirated engine and in fact has at times in the past. However what are the compression ratios of these engines? Very high compression ratios create higher combustion temperatues and pressures. Adding forced induction is in itself changing the "effective compression ratio". Look that term up. It is in Mr. Bell's book. Yes I own it too! Also look up his 1075 degree max temperature number as well. It is the theoretical number we are trying not to hit.

Why does advanced timing cause more pressure than a lesser timing? Remember that when the timing is advanced by a certain amount, it is this amount before the combustion chamber reaches
is smallest point that the plug(s) fire. Remember that since the flame front travels outward at a certain speed not everything is ignited at the exact same time. This means that the timing can be advanced as long as the gasses effectively start to expand after the engine has reached maximum compression. Just because we fired the plug there doesn't mean that the chamber has enough pressure to warrant an expansion yet. This leads us to Maniac's statement about running the timing out as far as he wants without worry. Not true. If you fire it too early the flame front will try to expand before the chamber is at it's smallest point. Now all of a sudden you have some very high pressures in the chamber as well as extremely high temperatures. We've just discovered pre-ignition. Pre-ignition will lead to detonation but detonation will not necessarily be caused by pre-igniton hence the confusion of the terms.

A lower octane fuel burns faster which is what gives us a greater likelyhood of detonation. Remember that timing and pressure are directly related to flame front speed and where it is expelling its greatest energy in relation to combustion chamber size. A faster burning fuel may actually cause all of the usable fuel to burn before the chamber has hit it's smallest point. Bad idea. However, using a higher octane, slower burning fuel can cause the flame front travel to be just slow enough that the chamber is past the minumum mark as the gsses are reaching their maximum energy. That's how octanes make a difference.

So now that is out of the way here's why the timing of the rotary is so unique. There are many proponents of low to no split plug firing on the rotary. In other words many feel that the most power to be has is by firing both the leading and the trailing plugs at the same time. This is both true and false. It is more beneficial at higher rpms but not disastrous at low rpms. What is harmful is to fire the trailing plugs first. Guess how the Renesis fires at startup and idle!!! This all goes back to flame front travel speed. At such low rpms, the engine isn't really advanced as far as timing goes. You can fire either plug first and have the flame front still exert its force in the proper direction. However, when the engine revs up, the timing advances and suddenly that few degress may make all the difference due to the plug's physical location as compared to the leading plug. It is called a trailing plug because it fires 2nd after the leading. However, when we reverse its firing with the leading, suddenly due to its location, it is firing 15-20 degrees earlier than the leading would have, had the firing order been correct! You guys will need to really put some thought into that one to fully understand what I am referring to but it's true. Just draw a picture. It's faster. Based on this firing 15-20 degrees earlier in effective location than the leading you can now see why the timing at idle allows the Renesis to work in this fashion. Timing isn't advanced at idle but based on which plug fires first it effectively is. Again, just think hard! Once the ecu advances the timing then figure out how advanced it effectively is! Pre-ignition! As a solution to the Renesis starting issues remember this, race cars that have "locked" timing typically have it fixed at maximum advance. While great for power it is also much harder to start than timing retard. This is why we have it. See a Renesis correlation to how the leading/trailing split works!!!

OK so now back on track since that got so confusing my own IQ dropped from typing it. Since we have 2 different plugs firing at 2 different times within the rotary combustion chamber we have some unique timing issues. First of all we know that we can't advance the timing too far since we don't want preignition. This is rpm sensitive as well so we can theoretically advance the timing farther as rpms rise. In reality this is determined by combustion pressures and temperatures at that point. The engine torque peak is the point of maximum combustion pressures. It doesn't matter if our torque peak is at 3500 rpm. We can advance the timing before and after this point but this is the spot of lowest usable advance.

We can actually retard the timing so far that we get preignition on the next incoming cycle. This is so far gone though that it is not even considered an option and the engine wouldn't run anywhere near this point anyways. Retarding the timing just creates a flame front expansion later in the cycle. The farther we get the gas expansion after the chamber expansion, the less pressures we'll have. This is why retarding the timing is the norm. Now back to the timing split in the rotary.

By firing both plugs simultaneously, we create 2 flame fronts that are pushing towards each other. This creates uneven chamber pressures by raising them. Remember that more pressure is more temperature and we have twice the energy being released at the same time. By having a decent timing split as Mazda intended, we are relying on the leading plug to ignite the mixture while the rotation of the rotor as well as the rotor recess shape maintains correct flame front travel. The trailing plug just merely fires to clean up any residuals that didn't get burned the first time. There isn't much energy left in this waste so power isn't really effected. Yes there is more energy with firing the plugs together but we need to keep the internal temperatures down below the detonation threshold. An engine makes it's most power right up before it detonates. This is why race engines run on the ragged edge of tuning with no margin for error. This is where the most power is made. If we retard the timing too much, we will fire the trailing plug on the other side of the apex seal pre-igniting the next incoming mixture. This is why the timing split is so crucial to detonation and how just adjusting it can reduce the chances.

Since I still have some space left I'll explain how to tune a rotary for timing. This assumes someone actually reads this far. I'm going to repost much of this in another thread later anyways. Start with fixed timing of 10 degrees on a naturally aspirated engine. If you have to advance the timing past 30 degrees you've probably gone a little too far. 25 advanced is about the max but this is rpm dependent. Advance the timing to the point that timing starts to fall off and then retard it back a degree or 2. Once this is set, start to adjust the trailing split to less. If the car loses power increase the split again. Try it both directions. This step is actually a pain in the *** since this is all rpm AND load sensitive. The timing split will be the greatest at the torque peak. After this point you can advance it. Be very careful with running no split, especially on a forced induction engine. I'd start with 15 degrees split and then adjust from there. A greater split a low rpms seems best for low end power and fuel economy. Play around with it a little and record your results. They are different for every porting configuration as well. Based on the fact that we have leading and trailing plugs which fire at different times, my above statement about the most power at the edge of detonation isn't always true in regards to the rotary. At least not on a naturally aspirated one. If you;ve hit detonation on an n/a rotary you;ve got more power to get out of it yet. If we had a fixed firing split or only one plug per rotor, then the ragged edge statement would apply.

If I rambled sorry about that. I'm good at it and I've had some alcohol in me tonight (yes on a Sunday!). I may come back later and see if I can make any of it more coherent.

Damn only 12342 characters out of a possible 20,000.

Japan8

And we bow down before the might of the rotarygod...


That was some great info. While my mind feel a bit like mush , explanations like this have so greatly enriched my automotive knowledge and especially rotary engine knowledge.

MazdaManiac

iTrader: (3)

Slacker!

When I meant about timing was that I can adjust it out to the edge of detonation and see what happens without the worry of a catastrophic meltdown that might occur in a FI application.

Now, if you could just tell me how much I wouldn't have to think so hard!:p

JaySpec7

my head hurts!!!

but GREAT INFO!!

rotarygod,

what about running too rich? I was told the reason for blowing my motor in my FD was do to running too rich. Chucks of carbon deposits was what killed my side seals...

rotarygod

Running rich isn't dangerous. An air/fuel ratio actually only burns within a relatively narrow a/f range. Outside of this range it doesn't burn. If you were to light a pool of oil on fire (don't try this!), it would not just explode. The top of the pool would burn but the lower levels have no air to react with so they can not combust. This is why it takes oil fires so long to burn out. You have to wait for it to burn from top to bottom.

Now back on track. When you run a really rich a/f ratio in an engine, most of it will still burn. Only the amount in proper proportion to the available air will combust effectively. The rest of the fuel will serve as a cooling medium and pass right through the engine. Since not all of it burns, not all of the available energy within the engine was utilized. Also remember that fuel takes up space that you could have used for more air. Remember that since the remaining fuel somewhat cools down the combustion temperatures we are also left with less pressure internally and therefore less likely to detonate. This fuel going out the exhaust can get ignitied though through sheer heat from the pipes though. This is what causes backfires between shifting or on deceleration in race cars. They are just rich at this point.

Any carbon additives or other additives in fuel that break down into carbon can leave some deposits in your engine. We've all seen the gasoline commercials about carbon deposits and their gas. The rotary has one other very unique problem which is the cause of most of its carbon buildup issues. We need to inject a small amount of oil into the combustion chamber to help lubricate the seals. This oil is not designed to mix with the gas nor is it designed to burn cleanly. It is the burning of the injected oil which is leading to most of our carbon buildup issues. Luckily the solution is very easy and many are doing it. The key is to find an oil that is designed to lubricate seals, mix effectively with gasoline and burn cleanly. The answer is in your weedeater! 2 stroke oil. This oil mixes very well and burns very cleanly.

Mazda fell on their asses in this area. They need to do a seperate oil reservoir that is fed from 2 stroke oil rather than sucking up our lubricating and cooling engine oil. This oil is very dirty anyways. Why do we want to run it through the combustion chambers? We don't. At this time I am unaware of a fix for the RX-8 however every previous rotary can get the adapter for this use from Rotary Aviation for less than $100. Install a small reservoir and then just wire in a sensor with a gauge so you'll never run out. Simple and logical. That's probably why Mazda didn't do it.

Basically running rich may have had an effect on your carbon buildup especially if you were using low grade fuels but I suspect it is also a combination of this as well as the oil metering system.

rotary-convert

[QUOTE]Originally posted by rotarygod

- The key is to find an oil that is designed to lubricate seals, mix effectively with gasoline and burn cleanly. The answer is in your weedeater! 2 stroke oil. This oil mixes very well and burns very cleanly. -


just like in my old school kawasaki two stroke!!!
how many parts oil per gas are we talking about for the 8? (that is if anyone does it already)

btw
cheers to rotarygod for all the good gouge

Tony Orlando

I knew you'd take that way too personally. But don't attack me and claim I don't know what I'm talking about when you contradict yourself repeatedly in your own posts. Let's have a gander, shall we?

You said: Yet in your first post, you claim the following: Huh? Doesn't running overly lean create a hotter combustion area? (less fuel vaporizing to absorb heat.) Wouldn't that eventually lead to detonation? So how would that not hurt the engine?

You then go on to tell us in your latest post that it has nothing to do with spark: Even though back in your first post, you claim that detonation is the result of poor spark plug timing. See?


See what I mean?

I never called your spark timing theory into question, just the way you shrug off detonation and running lean as if they are impossible in a NA motor, and only minor annoyances. Try running 87 in a 2002 Miata and see if you get detonation. I'm new to this little forum, but I get the impression that everyone around here respects "Canzoomer", and it would seem that he agrees regarding the catastrophic effect of detonation on an engine. That's my only point. My ONLY POINT!! Make sure you read this sentence before you reply. I don't question your timing theory. I'm simply saying the following:

Detonation = Bad news. And to tell people that running lower octane can't cause it is WRONG. Telling people you will not blow up a natrually aspirated engine by running lean is WRONG.

Bloviate all you want about my lack of knowlege, but make sure you aren't disagreeing with yourself every other post before you attack me.

rotarygod

Actually I didn't attack you personally and have nothing against you personally. Doesn't it make sense though that if you tear apart my posts that I will do the same in return?

The point about detonation is that a naturally aspirated engine doesn't have the pressures associated with forced induction. Remember that Corky Bell in his book states that at 1075 degrees absolute is the internal temperature that we want to stay below to avoid detonation. One way to increase temperature is with increased pressure. Just because a naturally aspirated engine and a turbo engine can both internally reach this temperature threshold doesn't mean that the combustion pressures are the same. You have alot more pressure built up in a forced induction engine and this is alot more energy waiting to be released. When detonation happens in a forced induction engine, you have many times more pressure and stress being exerted on the seals. This is what kills the engine not the detonation in itself.

If you want a very cryptic example lets look at what brought the World Trade Center down. The jet fuel burned so hot that the steel started to melt. However the 2nd tower to get hit fell first. It also was hit lower. The same temperature extremes were present in both buildings. The difference was that being lower, the weight exerted more stress on the structure and the 2nd tower to get hit fell first. Treat Corky's number as this temperature extreme for detonation threshold and then treat the amount of boost as the weight of the floors. If we'd have hit the very top floor would the building have fallen? Maybe, but the liklihood is far less since stresses are lower. It doesn't mean that it can't happen. It just means that it far less likely to.

I'll go back and more clealy explain my own statements since you felt they were a contradiction. The fact is that without going into laymans terms every scenario has more than one possible outcome. I'd have figured out the you would know how and when to apply them but apparetly that was a misjudgement on my part.

I'll go back and state the quote again with a little emphasis where necessary.

"I understand your statements and will admit that it is in fact POSSIBLE to hurt a naturally aspirated engine with detonation. " This doesn't make it probable. On a turbocharged engine, damage from detonation is so probable that it is almost a pure fact. On an (n/a) engine designed relatively mildly (street use) this just isn't an issue. As with what I said above, even if it does occur, the stress levels on the engine are not that great. This leads me to the other quote. "You will not blow up a naturally aspirated engine by running lean. " On a street engine this is true. If you build a very high compression race engine you do have the possibility. Remember that boost is a rise in "effective" compression ratio and this in itself will contain more pressure. I shouldn't have to explain this. It is the absolute small details that everyone gets so edgy about but you need to realize that I am writing from a purely functional standpoint with how it applies to our streetdriven cars.

I don't even need to address the other quotes since you didn't read my post very thoroughly but rather tried to find something to pick apart. If you haven't figured out by now what circumstances can lead to detonation then my reposting won't help you. It is a temperature issue. You neglect that fact that pressure is also an issue. I never said that detonation is the direct result of spark plug timing. You said that. What I did say is that improper leading/trailing timing split can lead to it and then I very thoroughly expained why this is so. If you haven't figured out by now there are many circustances that can lead to detonation. Go back and read it again. I'm not retyping it.

You are corret detonation is bad news. It does exert SOME stress on the engine but without high boost pressures it USUALLY isn't catastrophic. I have never seen a street built naturally aspirated engine have a failure because of detonation. I really don't want to get into the circumstances as to how it could possibly happen. I'm being practical. But just to satisfy you, yes it is possible. Probability is different though.

Canzoomer did show you a graph of an engine that had detonation. On the dyno is a really bad spot to have it since the engine is already under stress. He also said it lived. He admits that the rotary is less tolerant of detonation than a piston engine but this again doesn't say anything about it destroying a naturally aspirated engine vs a turbo engine. When his detonated it was the result of very bad tuning. He'll admit this since it was developmental work. I also stated that very poor tuning would cause it. It did. Why would anyone drive like this? When this circumstance arises don't keep doing it.

I have never once disagreed with myself. You have just failed to interpret it properly. I'll attribute some responsibility to not being totally clear to the fact that I was also half drunk when I wrote that but I still consider that an excuse for improper interpretation.

You are trying to make it sound like a person running lower octane gas on their engines is automatically going to detonate and blow up. On a naturally aspirated car they are just going to lose power and hate it. Is it possible? Sure, anything is possible but probability states that it won't happen. Before you say it isn't worth the risk just consider that probability states that you are far more likely to get in a car wreck every time you go out and drive than you are likely to hurt your naturally aspirated engine from detonation. In contrast if you try this on a turbo engine you are almost guaranteed to hurt something. A turbo engine may die after only 1 ping and you didn't necessarily have to be able to hear it.

I still can't figure out how I am the one who's wrong?

I'm not trying to make this personal so don't take it that way. The last thing anyone wants is enemies on the forum. We can go to the RX-7 forum for that.

canzoomer

a small suggestion:

WOULD EVERYONE STOP TAKING EVERYTHING SO DARNED PERSONALLY??

Now , both of you, go to opposite corners of the room and stand facing the corner for 5 minutes.

A quote:
"Having an argument on the Internet is like running in the Special Olympics. In the end you may win, but you will still be retarded".

pp13bnos

Ok, I've expereinced detination over several vehicles. All where due to the wrong temp spark plugs, poor tuning, or a failure of somesort.

We all can agree that carbon apex seals are much more likely to break under det. than steel apex seals. Correct? Ok, here's the short story. I was running a 150shot of nitrous on one of my old 13B peipheral port motors, with 3mm carbon apex seals. The magnets inside of my fuel pump for my nitrous system (Motor/nitrous sytem each had a seperate fuel system.) for some reason came loose of the housing. Causing the gph to fall through the floor. I ended up pinging the motor realy badly. So badly, it cracked the rear steel, under the oil filter pedelstool. Apon tear down, and clean up, every apex seal came away fine. Some may call it lucky....but I think that det. on a n/a engine is'nt going to harm it nearly as much as a forced induction motor. I personally am not going to worry about det. in my 8.

About the octane on the 8. This last weekend, I had a chance to dyno my 8, and a friends 8. I was running 5 gallons of 110 octane and 5 gallons of 92 oct. He was running super unleaded. I put down 7rwhp more than him. Bolth cars have around 2,500 miles. Bolth 6spds....but I do have the appereance package....maybe the wing added some more ponies? :D

CJ