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7thGear said:
id love to do it

but let me freakin finish my minime first!!



on a side note, you said that going back to pump gas after using the stuff requires retuning, what if you gradualy reduce the dosage mixed until your back to using 100% regular gasoline?? would that be okay

seems like a nice thing to do with an engine thats dirty... but then again seafoam is a tried and tested product.
TJ's case is particularly interesting but it is also unique because he did what everyone here -quite properly- harps about, he tunned his car. In the process, changes such as his A/F ratio create conditions that, were he to go instantly back to pump premium, would be uterly disastrous. It would also make girlieracer's blab about purposely blowing up a D seem trite because TJ's would be spectacular ( I think girlieracer missed a shift but TJ has a turbo that would be blowing into a lean engine.) Since I am not familiar with the range that the ecu can alter the mixture, I really can't comment on what would happen if he increased the spec grav slowly. I would speculate that it would work up to some point after which the computer could not compensate for but it may be instantly spectacular or it may not, I really can't say.
 

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its fine... its the same as old school racer putting moth balls in the gas tank ive dont it before... but dont mix the 100octain cool blue chevron race gas and it.. its kinda goor if its a racer only other than that it runs really hot.
 

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Actually, to set the record straight...
The Civic is supercharged, which explains why I have no intercooler & very hot boost, and subsequently the detonation problem.

Also, my car runs a Zdyne fully programmable Honda ECU. I've been dicking with it for nearly 3 years ironing out all the drivablity while maintaining lead foot power. That has been after the built motor. I've had the Zdyne for 6 years now.

Anyway, this year (the car is only driven seasonally due to CDOT's liberal application of snowmelter), I began experimenting with higher octane fuel to cure the detonation. I have a J&S Safeguard, for those not familier, it employs a knock sensor and retards individual cylinder timing based on the magnitude of knock. The J&S has a small display with 10 LED's...the LED's indicate timing retard activity & how much is being pulled out. My point is that I can see the detonation that one would normally not hear, especially with a 3" exhaust.

So, this season's fuel experimentation started with a gallon & 1/2 of avgas, just to prove or disprove that the motor wanted more octane. I blended that 50/50 with our "premium" gasoline. The result, no detonation. A standard test of mine is to drive the section of I-70 between Golden & the upper Genesee exit, AKA Buffalo Heard Overlook. It's about a 5 mile stretch with the steepest section at something like 7% grade. With the motor working in boost for that long, detonation always rears it's head. With the avgas blend, I drove that section entirely in 5th gear at no less than triple-digit-speed the whole way and saw only a whisper of detonation compared to what I normally would see.

So, it needs more octane. Knowing that the lead in avgas (even the low lead stuff) is bad for o2 sensors & cats, I began looking for something else, which is when I ran into the currently debated Toluene.

A 10% mix makes all the difference. Why I typed all that? I'm just watching the minutes tick towards 5:00pm...

Now, since it's only 4:50, DSS...would a better erosive study of toluene to fuel system components not be to rig up a benchtop fuel system made of junkyard parts - A pump, legitimate fuel lines, etc. Taking care not to light the bomb, of course. With all the infinate concoctions of synthetic materials created by man, I don't think I'd be convinced by some 7-11 straws. I'm no chemist though.

Oh, now that I remember what I was building up to say in the first place...
The tune in the ECU is unchanged since I began with the higher octane study. So, there would be no tune to go back to when detoxing from Toluene. The car runs most impressively on days like today...what is it? 60 degrees out?

FYI, getting away from Toluene and into some GT100, a friend of mine is doing some recon this evening. Apparently, there is a Sinclair in the Tech Center that sells it.
 

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i ned to go bak to skool for so edjumication after reding that.

nice post BTW
 
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Tj, I thought long and hard about what you are saying here and I came to some thoughts.
What I am refering to with my warning is that whatever else is true, the mix will have a lower specific gravity than the standard pump fuel. Therefore, the injectors will meter out a larger volume. Without that J&S safeguard gizmo, you would find yourself running very lean for a very short time. With it, it is almost certain that it would retard the timming so much as to make it appear that the mixture is indeed rocket fuel.
While your experimental method is interesting, it has some fatal flaws. First, even under extreme work conditions, increases in altitude result in decreases in ANI requirements. This means that as you climb you should see less, not more, detonation for a given air fuel ratio regardless of the timming. When combined to your previously stated A:F, I feel quite certain that a good percentage of your detonation is atributable to a lean condition even in the face of the altered flow in the injectors. Some other percentage of the detonation may be atributed to the relationship between cam timming and ignition timing. Just as it is not the case that more advance ignition produces more power, it is also not the case that less will automatically reduce detonation. Under lean conditions, the delay in ignition means that some of the time the compression alone will ignite the A:F mixture. Gasoline is a very poor compression ignition fuel and it will almost certainly result in knocking which then results in retarded timming which then.....
Now, once the car is moving at any given velocity, it will always take much less energy to keep it moving. what this means is that lack of preignition while climbing up to 11000 or so is no more an indicator of good performance at 50mph than it is at 110 mph. What you want is a condition of increased demand for output something like using engine braking to go from 100 to 25 or so. The reason is that if there is a preignition event while you are moving at 100mph you are almost certain to miss the power drop when the gismo corrects for it. However, when you do it slowing down, any loss in power is instantly visible because the rate at which you are slowing down decreases sharply and would be reflected on your stopwatch laps at each 10mph mark. When you graph this it will jump out at you as a sharp inflection followed by a soft inflection. If you used points, the line ploted by a line of best fit would encompass all but the points indicating the rate change.
Before you ask, there is certainly a rate of climb up. however, unlike the engine braking test, the intracylinder pressure is constantly being reduced -just by climbing- and the amount of energy required does not increase sharply and then drop gradually, it increases gradually to an asymptote. While Hondadog can probably calculate that easily, I find it easier to do the slow down test. Incidently, the engine braking test also reduces your chances of contact with a silver camaro.
So the fatal flaws result from the assumption that the test is both valid (test what it claims) and reliable (condition X will always yield result Y) since these assumptions are not supported by the hypothesis or the results, the experiment is fatally flawed. To make it valid, you would need to run a stoichiometric air fuel ratio which necesitates a barometer for each test and an adjustable A:F . To make it reliable you have to disconect the gizmo and get zero detonation under fast acceleration on a level grade and zero detonation on the engine braking test on a level grade. Then, with the gizmo on, you should see no activity under either condition. Then, given that baseline, one can move towards alterations in A:F for power output.
In reply to your suggestion of an entire fuel system, I would suggest that more information may be gleamed from the straws than you might think. When you first start, the straws are of length x. when you finish, the straws are of length X-y and this occured over a period of time T so that a rate can be calculated and thus the errosive or cleaning capability of a given mixture. In the case of the valves, you would need somewhat more sophisticated equipment. With a microscale balance you would weigh the valves before and after and note the diference over time. One might get a graduated cylinder big enough for the valves and some deionized water and at a standad time x one would wash of the chemical by dipping the valve in distilled water and then droping it in the graduated cylinder. Although it will take an eagle eye, it is posible to discern the change from a marked before to the after as a decrease in volume displaced. Given that information, one might then decide the extent of the risk and benefit that one is comfortable with.

oh, thanks for the info, I have a list of places but I dread the idea of going into the tech center and it seems that the other places in the list-short of going to bandimere- sell it out of 55gal drums.
 

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gezuz fkin christ

keep throwing shit out, all i can do is read, makes me wish i paid more attention in physics class

business for me!
 

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Curious George
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Discussion Starter #48
Mothball power where can I find a 5000 box ? more simple I think :p

Seriously, gaz pump will the best and the safest I think !
 
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Don't Give Up!!

Belette said:
Mothball power where can I find a 5000 box ? more simple I think :p
Seriously, gaz pump will the best and the safest I think !
First, only the right mothballs would work, they have to be naphthalene based. Further, the naphthalene disolves in the gasoline and I will look further into this but if memory serves phthalic anhydride (which interestingly is one of the starting reagents needed for the synthesis of indigo-the dye in blue jeans) is the solvation product that makes the difference (Makku? MikeD16?)
The wrong ones will clog your fuel system quite well.
That being said, the answer is not to be found in giving up!! Given that this is a sticky post, the discussion must continue because there are others in this forum with far more chemistry and physics knowledge than I and there is a solution out there. However, that solution can not be found by regret or by surrender; it must be found by the seemingly interminable separation of wheat from chaff.....Science and the creative application of what is known to thorny problems....engineering. The fact is that I have learned more physics -and understood it better- by messing with cars than I ever did in classes which, given my major, were major's courses and hence suffered from an overabundance of quantitative examples that only a physicist could love....the bird flying at N altitude and at N speed droping something (egg, feeces, discarded prey) on unsuspecting (and occationally even spaced beach goers) where one would then calculate all sorts of things when the real point was that any falling object has both a horizontal and a vertical velocity vector and that they fall in parabolic arcs....while trully important things like the carnot engine (google it or go to the library and get the 2 programs that deal with engines in The Mechanical Universe and Beyond it will be worth your effort,) specific heat, thermodynamics and temperature, and fluid dynamics, remained undiscussed or posponed. While spring harmonics is important (unsprung weight, rebound, energy disipation,) must it be reduced to what amounts to a math brain teaser? At least here, one can investigate, speculate, and learn, secure in the knowledge that the math is not the focus, the effect on the car is.

This post must continue because gasoline is a very complex mixture and there is power to be had. However, such power can not come from ignoring the science, it must come from asking "what if" more, not less. If you do not understand what someone says, ask!! others might then jump in and open a whole new avenue of discussion that might lead to a solution. You dont have to know, you only have to want to know.

And to open such speculation, there is some evidence that increased Methyl tertbutyl ether (MTBE) can be added in excess in the winter without danger of vapor lock and that the increased oxygen content will translate into increased output. anyone? is there an equivalent chemical for the summer that will not result in vapor lock?
 
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oh and 7thgear, do you supose I have any idea what points in a mortgage mean or do? why is it interest and this points thing? you can probably buy a car and get a real deal, most of us end up taken to the cleaners in some way or another. Heck, that may well be a great idea for a new main thread. As more and more civics and CRXes are sold by second tier dealers who may be out to scam the unweary, it might useful for a main thread to discuss how not to get taken to the cleaners.
 

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i think the general hinderence to automotive design is the fact that the gearheads that never went to school discover stuff through trail and error, and therefore cannot elaborate on complex theorems. While the techs that spend 10 years in university often do not have the lust for automotive design and a need for speed.

the ones that do however combine both traits are very rare, and most often will be hoarded up by the top companies for their own RnD. To have a gear head with a degree in physics/chem, loose on the world wide web, sharing their knowledge, is very very rare.

most of the time they are experienced racers themselves, and often simply do not want to share the hidden knowledge that they have discovered simply to have that edge.

DSS you are one of those few people, i'm suprised you look down onyourself in terms of knowledge, i'm pretty sure anyone in here applauds you in your contribution to this site!!

but yeah, we need to get more engineers aware of the fact that sites such as these exists, meh, time will tell.
 

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ohh and the only way anyone will get a deal on a car such as a CRX, or a hatchi roku for that matter, is if they buy it off of somebody that has no clue whats its worth is

price is a general product of supply and demand, if supply is high but demand is low, producers will generaly be inclined to sell at a lower price to get rid of stock, if demand is high and the supply is low, suppliers have the "freedom" to charge whatever the fuck they want ( case in point, gasoline), thats where the hatchi roku's and crx's fall into, everybody finaly figured out that people want these old heaps of metal, the supply of which is dwinlding, therefore those that know that people in reality will be willing to pay almost anything, they feel free to jack the prices.

a crx in my opinion is not worth more than 500 dollars net, chances are the shell is rusted in atleast some places, the general life of the car has put stress on the metal all around, if the car did not have a strut brace during its life, the front of the car is all wacked out probably by now from all the turns n shit, general fatigue all around. The interior is all shot/ripped/smells/broken and what not, your gonna need a new seat atleast cuz the dude/dudete that sat in there before you probably destroyed the seat. Engine wise as well, you basicaly need to rebuild the engine if you expect any sort of "sports car", i dont care how good a D is, a D after 200 000 miles is a slow D, you will also need a new battery, hoses, radiator, brakes, tires, fix all the electrical problems

etc
etc
etc
etc

but nooooooo, because everyone is so gung ho to buy the damn thing, they still pay 3000 ++ bones for because its a "cult classic", i say bull shit.

but what are u gonna do, thats the free market economy for you. Speculation is everything, thats how people really make money in north america, you generate hype, and then you sell, thats all there is to it.
 

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I have to admit at first I was sceptical about you DSS but after reading your posts I can see you arent just some poser. Props for all the information you have posted. Keep it up bro. I think its great that you elaborate on the subject you are speaking about.
 

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Curious George
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Discussion Starter #54 (Edited)
There IS a difference in fuels - aside from the octane rating.

Different fuel blends burn at different rates under the same temperatures and pressures. Absolute fact.

Peak cylinder pressure, for best power output, MUST be timed to occur just after the top of the stroke.

To tune for maximum power, you would like to use a fuel that burns at the quickest possible rate - without "knock" (there - that covers pre-ignition and detonation) so you can initiate burning at the latest possible time and still produce peak cylinder pressure at around TDC. That way, the rising cylinder pressure pushes back down on the top of the rising piston for the shortest period of time - decreasing power lost there.
A more specific location for peak cylinder pressure would be ~15 degrees after TDC. There is some variance from that figure - but not more than a degree or so in an engine using gasoline. When the ignition timing is correct, power output will be highest for that rpm and throttle position.


Octane?
If you look at the octane rating as only an indicator of what the fuel was designed for, you'd guess that a 120 octane fuel was probably designed for an engine that was prone to "knock" - like an older American V8 with relatively poor cooling and high compression. That fuel will be blended to burn at controllable rate that matches the high pressures and temperatures present AND resist "knock". A good match for those V8 engine conditions.

Burn Rates- That's the ticket!!
If you take that same fuel that worked well in the above V8, and run it in an engine, like a cbr900, with it's lower cranking compression and lower combustion chamber temps, it will, without a doubt, burn much too slowly at those lower temps and pressures and reach maximum cylinder pressure too far after TDC for best power.
Things generally burn slower when they are cooler and vice versa. Peak cylinder pressure will occur much past TDC - decreasing the power produced if you keep the same ignition timing.

You can advance ignition timing to try to recover power, but that will cause the air/fuel mixture to burn earlier in the crank stroke and spend, percentage wise, more of the energy produced by the expanding, burning mixture, pushing back down, trying to prevent the piston from rising up to the power stroke - robbing power.
 

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Curious George
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Discussion Starter #55
If you MUST use a slow burning fuel, which USUALLY has a high octane rating, advancing the ignition timing will lessen the power loss, but the best results are usually obtained with the quickest burning fuel obtainable, that, of course, doesn't "knock".

All other factors being the same, except for burn rate - use the quickest burning fuel that doesn't "knock", light the spark in the middle of the combustion chamber, adjust ignition timing to reach peak cylinder pressure ~TDC and keep your mixture correct. When the ignition timing is correct, the engine will make best power for that fuel.

There is a difference in the burn rates of different brands of fuels that are available. Some compliment one engine and some compliment the existing tuning of a different type of engine. Our Supersport YZF750 was really responsive to different pump fuels and liked a different type of race fuel (same brand of fuel) than our gsxr750 Supersport bike. Something on the order of 1%-2% power difference.

Generally, the cbr900's are extremely power sensitive to different fuels. It has to do with the basic combustion design.

Does using a fuel with higher octane numbers automatically make more power?
Not unless they are preventing "knock".

My vehicle runs fine and doesn't "ping" on "regular" fuel, but, it's a little "peppier" with "premium" fuel. What should I use?
If you are wanting the extra power - use "premium" fuel - if you are saving money? Use "regular" fuel.
As long as it doesn't "ping" all is well, as far as generally accepted......

Is there a difference in standard street pump premiums?
Yes. ~1%-2% power output. Try a few and use the brand that works best in your bike. Or, you can bring your bike in and I can charge you a lot of money to test fuels for you.

Is there a difference in additive packages between different brands of fuel - even if they have the same "octane" rating?
Yep! There actually is. Some of the detergent packages are patented. I know for a fact that Chevron's Techron (techroline?) was patented. Years ago, when they first released it, they really loaded up the fuel with it. If your 4 stroke motorcycle jetting was too rich - it would actually, as an "oily solvent" with a flashpoint of ~1500f, build up on the insulator of the spark plug, unless you cleared it out every once in a while - it would actually foul!
That was many years ago and all is well now!
Oh - it really would remove minor fuel injector deposits, too!

Energy content?
There is a really SMALL difference in different pump premiums - depending on the fuel recipe - I'd suspect a insignificant difference - like .01% power difference. Relative importance between different standard fuels? Much less than being off by 1/4 main jet.
 

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Curious George
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Discussion Starter #56
Octane boosters?
If they prevent "knock" in you vehicle, they WILL help produce more power, but if the engine is NOT knocking? No significant / cost effective, happy results. "Not a "buy" at this time." There ARE compounds that will improve power, yes, but they weren't down at Pep Boys and Grand Auto when we bought all of them in 1999.
If you make a compound that works, we are available to do confidential testing. (As far as testing, I dearly wish that there was an available, cost effective fuel compound that did work!)

Is there a difference in 100-105 octane race fuels as compared to street pump premium when used in a motorcycle engine?
Yes. Some of the best WILL ADD, without a doubt, repeatably, no question about it, 3%-4% power improvement (under 2.6% oxygen content and without nitrobenzene or related compounds). Some of the 100-105 octane race fuels that were not designed for high revving, low compression engines don't work very well at all - making roughly the same power as pump premium.
Now.... that was 2002 info -
2004? Even more power from fuels - and still at the ever popular USA $17 to $22 a gallon range!

Have a doubt? Get some Nutec or Elf race fuel. You will feel it.

And yes, there are some odd compounds in race fuels. One of the above fuels left a brown carb deposit. Wouldn't wash out with gasoline, solvent, carb cleaner, 409, Simple Green, Fantastic or soap and water. Weird. Weirdest - it DID dissolve and drip away in liquid form after being doused with an aerosol can of "Off" mosquito repellant that we had left over from the Brainerd AMA National. It was a waxy deposit.......

Factory Pro in one of the only motorcycle Fuel Injection AND Injector matching facilities in the US - We do both and more design dynamometers that deliver .2 hp meaningful resolution and repeatability.

We can supply matched sets of injectors for better fuel control and increased power. We can supply up to 1% tolerance injector sets when available.

As far as what GJ and KC write, I've grew up reading and rereading everything that they both wrote. I ported an SR500 cylinder head just like GJ did in a magazine project. As I was doing it, I just knew I could spend more time and be more careful and end up with a small port that flowed more than his did. But, that's another "experience" (experience is what you get when you don't get what you want.) Actually, it did work OK. Ask some day. I think that it's still in my home garage, next to the Suzuki Rotary engine oil.....
 

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Curious George
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Discussion Starter #57
What is an Octane Number?

The amount of resistance that a fuel has to detonation. The higher the number, the less likely it is that a particular fuel will detonate in a particular engine. The number is as compared to a standard fuel (not necessarily gasoline)

Octane? Resistance to knock? Compared to what?
Isooctane ( C8C18 ) is the high value reference fuel. It has a knock resistance value of 100 RON.

N-heptane ( C7C16 ) is the low value reference fuel. It is very prone to knock and has a value for 0 RON (zero/naught).

For values above 100 RON, a mixture of isooctane and tetraethyl lead mixed according to DIN 51756 (DIN in at least in most of the world) is used.

How do they raise the knock resistance of a fuel?

In the old days, TetraEthyl Lead (TEL) or TetraMethyl Lead (MEL) was added, with TEL being the most common in the United States. Now, as leaded fuels are not allowed to be sold in many areas, other, generally more expensive and less effective as compared to cost, fuel additives are added. Lead was an extremely effective knock suppressant.

How much lead was in "leaded" fuel?

By law, fuels intended for on road use have been limited in maximum lead content for some time. Maximum lead content was limited to .15 to .33 grams/Liter in the late 1970's.

Lead poisoning causes brain damage like mine. Most fuel has been unleaded for quite some time. People born after the late 70's must be much smarter than the older people like me again :p
 

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Curious George
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...wow, lets just say i'm gonna read this over twice, print it, and put it in a folder :)


ahem.

sorry if i'm hijacking this thread

but other than: compression, piston design, igintion timing and octane ratings,

what are some of the ways to reduce an engines tendancy to knock? You mentioned in your first post that a cooler engine is less prone to knock, would a do it yourself improvement of engine cooling help with knock? just some ideas to throw around.
 

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Curious George
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Discussion Starter #60
Fuel, fuel mix, all around you have flash point, boiling point and freezing point, If you can your engine with non-knocking ignition by cooler combustion chamber area to prevent predetonation due to over temp vs ignition temp vs fuel carateristic, you don't have to run higher octane rate ! octane doesn't make much more power, only anti-detonation help ! But it's little more than that, in simpliest way to explain, that's it !

Others ways to prevent knocking that you haven't mentionned:

- Run your car when it's cold and frozen outside :p
- colder park plugs :p
- colder air at the intake
- combustion chamber design
- better cooling system
- running little bit richer to cool combustion area
- Ecu reprogramming to run well with cooler engine
- wrapped exhaust to do not overheat engine bay
- cam design may too help but I don't know very much about that
- Maybe more, I think no more for now :)

:)
 
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