Kawasaki Ninja 1000 Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
456 Posts
Discussion Starter #1
It's obvious we have some engineers on this forum, and I have a question that's bugging me. So, Ivan says of his reflash, use regular gas, high octane is just a waste. I have always associated high compression ratio with high performance. Also it is my understanding than engine knock or ping is caused by pre-ignition, and that higher octane fuel means that it doesn't ignite -prematurely from the heat of compression. Presumably you can avoid this by advancing the spark, but at the cost of maximum power and efficiency.

Now I understand that by optimizing other parameters, Ivan could increase power (say a richer fuel mixture), but it your goal is performance, why tune for regular gas?
 

·
Registered
Joined
·
5,756 Posts
Thats a very good question geld i would like to know that myself, it looks to me you would optimize the spark for higher compresion and higher octane to produce more power. We always run jet fuel in our stock cars. And we converted our racing carts to burn on alky and changed the coil for hotter spark,
 

·
Registered
Joined
·
5,756 Posts
What dont make since is higher compression engines produce more hp for a given engine weight, by altering the spark for detonation it looks like you would be given up something, none of my engine builders ever said anything about building a race engine and tunning it to run on low octane fuel. Im going to have to bring out the BS flag on that one. Or i pissed away alot of money over the years
 

·
Registered
Joined
·
291 Posts
It's obvious we have some engineers on this forum, and I have a question that's bugging me. So, Ivan says of his reflash, use regular gas, high octane is just a waste. I have always associated high compression ratio with high performance. Also it is my understanding than engine knock or ping is caused by pre-ignition, and that higher octane fuel means that it doesn't ignite -prematurely from the heat of compression. Presumably you can avoid this by advancing the spark, but at the cost of maximum power and efficiency.

Now I understand that by optimizing other parameters, Ivan could increase power (say a richer fuel mixture), but it your goal is performance, why tune for regular gas?
This is a good and common question. It has a fairly simple answer :)

Just to note, I am no engineer. I am an avid motorcyclists, and currently work as a motorcycle mechanic as I have on and off for my life. I have built more motorcycle engines than i can count, and entered into the high octane vs low octane debate on the inter webs more times than makes sense.

Simply put Octane is simply a measurement of how much heat and pressure a fuel can take before it will auto ignite. Auto ignite means combustion before the spark plug event occurs, often called pre ignition or detonation.

That's pretty easy. Our bikes are relatively low compression for a motorcycle, and simply are not generating enough heat or pressure to need higher octane fuels.

The confusion comes in because people equate high octane with high power, and typically incorrectly believe that high octane means more power, cleaner burning, and SAFER.

How much power a fuel makes is dependent on it's chemical makeup and how well it is matched to it's intended use. Higher octane is just not always higher power.

VP makes a good race fuel that is 87 octane for motorcycles. It will make more power than 87 pump gas (or 91-93) in an average stock motorcycle engine. But the average guy wants to put 105 or 110 in his street bike, and then by placebo effect thinks his bike is faster, when it is clearly not.

Simply put if your engine does not knock or ping on 87 octane then there is no need for higher octane. If you want more power then use a higher quality fuel. (Fuel that "Makes power" starts at $20 a gallon)

The other big problem is people and the US Government...lol People in large numbers can be knuckleheads, and the government has some mandates for fuel that makes this subject more difficult to nail down. There are seasonal fuel "recipes" mandated by the Fed, and they are not only seasonal by also regional. This makes fuel cost more BTW, but whatever.

Then you get the people on the inter web that say my bike pings on 87, when the truth is they just had a dry chain that had not seem lube in 5k miles. When engine knock becomes a real concern for motorcycles you will see knock sensors built into them by the OEM's as that will be cheaper than warrantying a bunch of engines.

And when you get knock, you retard the timing not advance it. Advancing it will make it worse.

Hope that helps....
 

·
Registered
Joined
·
604 Posts
This is a good and common question. It has a fairly simple answer :)

Just to note, I am no engineer. I am an avid motorcyclists, and currently work as a motorcycle mechanic as I have on and off for my life. I have built more motorcycle engines than i can count, and entered into the high octane vs low octane debate on the inter webs more times than makes sense.

Simply put Octane is simply a measurement of how much heat and pressure a fuel can take before it will auto ignite. Auto ignite means combustion before the spark plug event occurs, often called pre ignition or detonation.

That's pretty easy. Our bikes are relatively low compression for a motorcycle, and simply are not generating enough heat or pressure to need higher octane fuels.

The confusion comes in because people equate high octane with high power, and typically incorrectly believe that high octane means more power, cleaner burning, and SAFER.

How much power a fuel makes is dependent on it's chemical makeup and how well it is matched to it's intended use. Higher octane is just not always higher power.

VP makes a good race fuel that is 87 octane for motorcycles. It will make more power than 87 pump gas (or 91-93) in an average stock motorcycle engine. But the average guy wants to put 105 or 110 in his street bike, and then by placebo effect thinks his bike is faster, when it is clearly not.

Simply put if your engine does not knock or ping on 87 octane then there is no need for higher octane. If you want more power then use a higher quality fuel. (Fuel that "Makes power" starts at $20 a gallon)

The other big problem is people and the US Government...lol People in large numbers can be knuckleheads, and the government has some mandates for fuel that makes this subject more difficult to nail down. There are seasonal fuel "recipes" mandated by the Fed, and they are not only seasonal by also regional. This makes fuel cost more BTW, but whatever.

Then you get the people on the inter web that say my bike pings on 87, when the truth is they just had a dry chain that had not seem lube in 5k miles. When engine knock becomes a real concern for motorcycles you will see knock sensors built into them by the OEM's as that will be cheaper than warrantying a bunch of engines.

And when you get knock, you retard the timing not advance it. Advancing it will make it worse.

Hope that helps....
Have to agree with this.
 

·
Registered
Joined
·
5,756 Posts
I thought an engine with over 10:5:1 compression ratio is considered a high compression engine
 

·
Registered
Joined
·
291 Posts
What dont make since is higher compression engines produce more hp for a given engine weight, by altering the spark for detonation it looks like you would be given up something, none of my engine builders ever said anything about building a race engine and tunning it to run on low octane fuel. Im going to have to bring out the BS flag on that one. Or i pissed away alot of money over the years
I think you may be mentally inter correlating several things that have no real world correlation.

Compression ratio and engine weight are not inter related. Diesels have much higher compression than our bike do, and they are HEAVY...lol

All engines and engine tunes are a compromise. Nothing is perfect. With our little ninja 1000 that can Kawasaki was never after absolute power. They wanted an engine that was very strong on the low end that would work in a Sport Touring bike while being fun to ride, reliable, and meeting all the involved regulations. I think they won.

Whenever you set ignition timing Detonation is always a concern. There is a very small window where the expansion of the fuel and air mixture needs to start happening. And it's a real balancing act as you are lighting off the spark plug while the piston is still on the way up the cylinder.

With any engine combination you want to run the least octane possible. Octane is not like money where more is always better...lol Octane is like medication, you need just what the doctor ordered, no more and no less.

And generally speaking using aviation fuels in automobiles and motorcycles is not the best idea. Aviation fuels are typically designed for engines that see the same rpm for long periods of time with very little variation. This is much different than a Motor cross bike doping laps, or a stock car where the rpm's vary constantly. One good thing about Aviation fuels is they typically store very well...lol

My 2011 N1K has a full system, reflashed ECU, pcv with Ivans map, tighter squish and slightly higher than stock compression from a missing head gasket layer and a decked cylinder head, as well as being professionally ported and larger intake and exhaust valves. I like in Moore Ok so we typically have good pump gas and decent weather conditions. I always run 87 octane.

Kawasaki and the other OEM's have to stay on the safe side because they have no idea what people are going to do with these things, or put these things through. I mean what if a guy wants to ride through Death Valley with his G/F? He packs up and gets everything ready. He hops his 300 lb self on the bike, lets his 350 lb G/F get on the bike, and runs on down the road to death valley. He manages to stop at the least busy and crappiest gas station right before he rolls through the Valley of Death. He is riding in 6th gear at 38mph and just lugging it up every scenic pull out possible.... Kawasaki needs to bike to work for that guy too...lol
 

·
Registered
Joined
·
291 Posts
In any instance I can possibly think of yes....

But there is a really simple test to find out. Next time you fill up, use 87. Don't listen for anything you didn't listen for before, and don't ride any differently. If you cannot tell any difference, then you don't need 93.

Truthfully the knock resistance between 87 octane and 91-93 octane is not that amazing. For cars it makes a difference, but for motorcycles it's not huge.

The real problem is when someone try's 87 they listen and fell for stuff they have never listened for or tried to feel before. If I stole your motorcycle out of your garage, rode all the fuel out of it and filled it up with 87 you would never know the difference 99 times out of 100.

Ivan is the guy who actually tuned your bike, he wrote the fuel maps and the ignition maps. He has not one thing to gain from steering you wrong. I trust Ivan completely.

93 octane most times will make less power than 87 is a stock engine street bike. It has been dyno'ed time and time again.

I wish you the best regardless of what you decide to do. It's not going to hurt the engine to use 93, but it is in this instance a waste of money and you will make less power doing it.
 

·
Registered
Joined
·
291 Posts
I thought an engine with over 10:5:1 compression ratio is considered a high compression engine
Well everything is subjective. 10.5 to one is pretty high for a SBC (though now with Fuel injection and digital ignition maps it's more common all the time)

But 10.5 won't make diesel work I don't think.

My factory service manual lists the 2011-2013 Ninja 1000 at 11.8 to one. That is just not very high by motorcycle standards.

There is a lot that goes into it, and I am not the formost expert for sure, but basically the larger the bore the more likely you are to have pre ignition.

These motorcycles have very small bores compared to cars (except the big V-Twin bikes), they have all alloy engines that dissipate heat better than the average car, they have typically good cooling systems, and they use very little of their overall power to move the vehicle compared to a car. Also the combustion chambers and ports on these motorcycles likes like Formula 1 technology compared to the average car engine...lol

The motorcycle engines have everything going in their favor to avoid pre ignition. That's why they don't yet need knock sensors, which every automobile and truck has.

Automobiles are heavier, use more of their total power to just move the vehicle, typically have cast iron engine block and cylinder heads (though to be faiir many cars do have alloy heads and some alloy blocks), have no where near as nice ports and combustion chambers...etc

Cars are starting to use direct injection so that they can use higher compression ratios. I hope eventually that tech comes to Motorcycles :) We could see 15 to 1 factory engines in super bikes...lol

The advancement of electronics in the last ten to fifteen years has made it possible to make crazy power with gasoline engines. Lots of 1,000+ HP street engines in high dollar cars rolling down the street now a days.

Getting rid of carburetors and distributors has increased power potential dramatically:)

I have built several 13.5 to one engines here in OKC and they all live on 87 octane.
 

·
Registered
Joined
·
828 Posts
I don't have much time to go into this. I've written about this somewhat in another thread about Ivan's reflash. Most of you are looking at the STATIC compression ratio (CR). The one you really need to be focused on is DYNAMIC CR (DCR). It is also why a little knowledge about a topic can be dangerous. It is like understand the difference between cause & correlation.

Here is the Cliff's notes version. I don't have time to go into a real technical discussion on this.his is a simple concept and represents the ratio of the swept volume of the cylinder (displacement) to the volume above the piston at top dead center (TDC). For example, if our demo cylinder had a displacement of 450cc and a 50cc combustion chamber (plus volume over the piston crown to the head) the CR would be 500 divided by 50, or 10:1. If we were to mill the head so that the volume above the piston crown was decreased to 40cc, the CR would now be 490/40, or 12.25:1. Conversely, if we enlarged the chamber out to 60cc, the CR would now be 510/60, or 8.5:1.

Most you know that higher CRs result in better performance but increase the risk of uncontrolled combustion in the cylinder (pre-ignition, detonation, etc.). A lot of things affect this as well, not just CR. Such as cylinder head material, combustion chamber design, cylinder head coating, # of valve and location in the head, etc.

So how high should your CR be? We typically want the highest we can, based on the fuel available and our intended usage. Static CR is VIRTUALLY MEANINGLESS! It is a measurement that has almost no VALUE without CONTEXT!

So what puts it in context? You need the camshaft specs! No significant pressure will start to develop in the head (on a 4 cylinder otto cycle type motor) UNTIL the intake valve CLOSES! At that point the cylinder pressure will start to rise. The DCR is what the air fuel mixture actually “sees” and is what “matters”, not the static CR. Because DCR is dependent upon intake valve closure, cam specs have as much effect on DCR as does the mechanical specifications of the motor.

DCR is MUCH lower than static CR. The more aggressive the cams you have, the more static CR you'll likely need. Milder cams will require less static CR. Ultimately the DCR of a street/track motor will be in the 8-9:1. This is usually a static CR of 10-12:1. If you use race fuel of course you can go higher.

So there are a lot of factors but DCR is very significant with respect to the tuning of the N1k motor. Any extra octane more than you need is a waste.

Please keep in mind that Kawi seemed to have played with the cam timing over the years. These subtle differences can have a significant effect on the DCR and its impact on detonation/pre-ignition, etc. When Kawi was trying to boost the low end, the most likely went with milder cam timing to trade off higher rpm HP for low end TQ. I never looked at the specs for each year so I am not certain, highly likely but not validated. Theoretically this means Ivans tune should be different for EACH different "config" of the N1k if there is more than a minor variation in specs.

Sorry I don't have time to go into more detail but this should help out quite a bit.
 

·
Registered
Joined
·
828 Posts
Well theory and reality don't always agree since nobody but you knows exactly how you'll use your bike. Now if we took those conditions we could see what the load looks like, density altitude, any mods you have, etc.

So to the extent possible, let your ear by the guide. If you hear it pinging/knocking, etc. let off the throttle to be safe. It should pull timing but why risk it. If you are running 87, and this happens frequently from a top tier supplier, then go up to 89. If you are running crappy gas, like Pemex was, then try a better brand first.
 

·
Registered
Joined
·
456 Posts
Discussion Starter #14
Well theory and reality don't always agree since nobody but you knows exactly how you'll use your bike. Now if we took those conditions we could see what the load looks like, density altitude, any mods you have, etc.

So to the extent possible, let your ear by the guide. If you hear it pinging/knocking, etc. let off the throttle to be safe. It should pull timing but why risk it. If you are running 87, and this happens frequently from a top tier supplier, then go up to 89. If you are running crappy gas, like Pemex was, then try a better brand first.
So I guess FIRST I need to take out my earplugs to try this experiment.
 

·
Registered
Joined
·
456 Posts
Discussion Starter #15
Just wanted to thank folks for their thoughtful and informative posts. I learned a lot about compression ratio and octane that I never knew.
 

·
Registered
Joined
·
291 Posts
I don't have much time to go into this. I've written about this somewhat in another thread about Ivan's reflash. Most of you are looking at the STATIC compression ratio (CR). The one you really need to be focused on is DYNAMIC CR (DCR). It is also why a little knowledge about a topic can be dangerous. It is like understand the difference between cause & correlation.

Here is the Cliff's notes version. I don't have time to go into a real technical discussion on this.his is a simple concept and represents the ratio of the swept volume of the cylinder (displacement) to the volume above the piston at top dead center (TDC). For example, if our demo cylinder had a displacement of 450cc and a 50cc combustion chamber (plus volume over the piston crown to the head) the CR would be 500 divided by 50, or 10:1. If we were to mill the head so that the volume above the piston crown was decreased to 40cc, the CR would now be 490/40, or 12.25:1. Conversely, if we enlarged the chamber out to 60cc, the CR would now be 510/60, or 8.5:1.

Most you know that higher CRs result in better performance but increase the risk of uncontrolled combustion in the cylinder (pre-ignition, detonation, etc.). A lot of things affect this as well, not just CR. Such as cylinder head material, combustion chamber design, cylinder head coating, # of valve and location in the head, etc.

So how high should your CR be? We typically want the highest we can, based on the fuel available and our intended usage. Static CR is VIRTUALLY MEANINGLESS! It is a measurement that has almost no VALUE without CONTEXT!

So what puts it in context? You need the camshaft specs! No significant pressure will start to develop in the head (on a 4 cylinder otto cycle type motor) UNTIL the intake valve CLOSES! At that point the cylinder pressure will start to rise. The DCR is what the air fuel mixture actually “sees” and is what “matters”, not the static CR. Because DCR is dependent upon intake valve closure, cam specs have as much effect on DCR as does the mechanical specifications of the motor.

DCR is MUCH lower than static CR. The more aggressive the cams you have, the more static CR you'll likely need. Milder cams will require less static CR. Ultimately the DCR of a street/track motor will be in the 8-9:1. This is usually a static CR of 10-12:1. If you use race fuel of course you can go higher.

So there are a lot of factors but DCR is very significant with respect to the tuning of the N1k motor. Any extra octane more than you need is a waste.

Please keep in mind that Kawi seemed to have played with the cam timing over the years. These subtle differences can have a significant effect on the DCR and its impact on detonation/pre-ignition, etc. When Kawi was trying to boost the low end, the most likely went with milder cam timing to trade off higher rpm HP for low end TQ. I never looked at the specs for each year so I am not certain, highly likely but not validated. Theoretically this means Ivans tune should be different for EACH different "config" of the N1k if there is more than a minor variation in specs.

Sorry I don't have time to go into more detail but this should help out quite a bit.
It's neat to say Dynamic running compression. makes a person feel smart :)

The compression ratio and the DRC are of course interlinked. There are limits to engine efficiency. When you go by race gas for your street bike they don't ask the DRC, because the average guy has no idea what it is, and it's too difficult to measure properly for most people.

So now you have told him to worry about something he cannot measure...

Typically when you buy race gas they will ask the compression ratio, the engine size and configuration, the rpm limit, and the intended use.

Are you one of those guys who always has to show he is smarter? That's no good, I am the same way... Gonna be some head butting for sure.

Interesting to note, you will get knock or ping in the midrange when under load, and nearly never in the upper RPM's.

And the only motorcycle engine I ever built that actually knocked was an 04 G1K motor I built for a friends street bike. Originally I ported the head and had the head milled .025 (that's A LOT!). It was just going to be a mild perk up. The engine already had web cams. But then we went with a +2mm J&E piston package and the only head gasket I could get my hands on at the time was a bit thinner than stock.

That bike pinged on 87 or 91 just the same. Octane booster did not help. So I called Lee's and asked Lee what I needed to do, as I did not want to blow my buddies engine up. He said adjust the cam timing for more top end power and that will bleed off the cylinder pressure (what Dynamic Compression Ratio really is all about) in the mid range. So I did that and used an Ignition module to retard the spark a bit in the Middle. No more ping, and the bike made 176 RW HP. Same dyno had it at 140 stock.
 

·
Registered
Joined
·
5,756 Posts
What if your running a boosted engine with a turbo or sc where you can actually get more air in the engine, do you think you can get more power or tune more power with higher octane like 100 plus or higher, on a side note if you tune the engine to run on methanol it will definately make more torque than gas and run lot cooler, ive seen that on a dyno with my own eyes and have bought many gallons of the alky, unfortunately its a complete flush of oil and fuel systems after every race.
 

·
Registered
Joined
·
828 Posts
Sure, higher octane helps. Most high boost turbo/sc motors drop the CR to allow it to run more boost. The downside is even less HP/TQ off boost and then more when on. So the transition is more noticeable and a bit harder to manage with the turbo motors. You can run sequential turbos of different size though to help mask that a bit. The small one will spin up more quickly and then the large takes over or you can run too smaller ones that spool up more quickly as well.

If you don't have enough octane for your boost you can destroy a motor in milliseconds. The turbo/sc motors have to deal with the additional thermal loading the force feeding place on the motor. Look at the ideal gas law; PV=nRT. We'll focus on the P and the T; Pressure and Temp. As P increases so does T to keep a balanced equation.

So more boost (pressure) = more temps. You can use an intercooler which helps. But that tends to increase the intake length which can make the motor less responsive. I used an intercooler on my cars/bikes that was air to air. I think set up a jet spray of ice cold water on it. Then I also ran a small hit nitrous as well. The nitrous boosts power but I did it more for cooling the intake charge as well. I used a 2 stage kit, both very low output. I used a Hobbs pressure switch to control. The first stage had more nitrous which helped put a load on the motor, causing boost to come up more quickly. Once I had 3psi boost it shut off and the other would take over at 6psi up to max but at a very low level of spray.

Only a few times though I would go to this level of complexity (using the nitrous). Most of the time it was just the air to air intercooler with icewater spray. If I didn't have room for a big enough air to air cooler than I'd go air to water and build a small closed loop system using ice water. Not the way to go on the street if long time.
 

·
Registered
Joined
·
291 Posts
Turbo, SC, or nitrous just work to increase the cylinder pressure.

The more air you can get into the cylinder, and the more you can squeeze it, the more power you can make..... all things being equal.

But even then there are limits, and too much octane will lower the power output.

Octane DOES NOT MAKE power, the fuel makes the power, you just need the correct octane for the application.

Look at Top Fuel...lol That spark plugs stop working half way down the track and they are running on heat and pressure. Crazy.

Octane has nothing to do with power, it only has to do with heat an pressure. Fuel quality makes power, octane lets it work in the intended application.
 

·
Registered
Joined
·
291 Posts
What if your running a boosted engine with a turbo or sc where you can actually get more air in the engine, do you think you can get more power or tune more power with higher octane like 100 plus or higher, on a side note if you tune the engine to run on methanol it will definately make more torque than gas and run lot cooler, ive seen that on a dyno with my own eyes and have bought many gallons of the alky, unfortunately its a complete flush of oil and fuel systems after every race.
In these instances you build the engine first, and then find the fuel that works with your combination.

I mean when you build the motor you have a CR in mind, a set up in mind. Then you just have to use the fuel that works with that, but to be honest the fuel is part of the combination.

It's never like you are just going to add a higher octane fuel and it will make more power. That never happens. It could happen in a series with a standard fuel, but that's called cheating.

It is a combination. The difference between 87 and 91 pump fuel is just a little knock resistance, it's no power gain. The power is nearly the same. The fuel is crap to be honest...lol It's junk. This is the mistake people make,"but if I run higher octane I can have more power"... Not true in an of it's self.

Octane is not linked to power, nor is it linked to clean burning combustion chambers.
 
1 - 20 of 21 Posts
Top