Fuel Octane Requirements

[ponch]

Originally Posted by blowndodge

Ray, my Nomad has 4 plugs...

So does my beemer.

[cactusjack]

Originally Posted by blowndodge

Ray, my Nomad has 4 plugs...

So does my wife's Hyundai.

[ponch]

Originally Posted by R_W_B

Ray that is an excellent summation and I don't disagree since you have far more knowledge of such that a backyard mechanic like me. Additionally most everything you said in your post is spot on.

Only thing that puzzles me is Harleys also have a 9.x to 1 CR and they "will" ping on just about anything less than 93 Octane, which is what the HD manual recommends. They also have one plug per cylinder.

I think also the ECU timing of the ignition influences the ping scenario. And and the cam characteristics also plays into it, in that how well an engine breaths can increase or decrease it's CR also, regards of the stroke length and cc of the head area. Additionally water cooled engines (for the most part) tend to run cooler overall than air cooled. The engine temp can influence the ping so that could also play into why the air cooled harleys will predetonate more.

Maybe you could elaborate on that, since I don't have the specs of cam duration and lift for either handy. I must say though I kinda like being able to run regular gas in my Nomad. I've have not tried that yet for fear of the ping.

What plays into this is if the engine has true closed loop management. My beemer has 12:1 compression ratio, is air/oil cooled, has run on 87 (I had no choice once in BFE on the way to Crescent City), and BMW says 89 or better (93-94 is recommended for best performance). The computer detects ping and retards the ignition timing accordingly. Power is lower, but it will run. My guess is that the computer management on the Kawasaki 1700 isn't the same as it is on the ZX14 and some of the other ninjas. Considering what the bike cost, I would think it would be standard as it is on the C14, which is less expensive, yet has more technology. Sometimes I have to wonder who makes these decisions and why.

[R_W_B]

Originally Posted by Vulcan Hammer

Just to clarify...

The compression ratio (CR) based on Swept Volume vs Combustion Chamber volume is determined by design and it's fixed, but the mass of air+fuel getting into the cylinder does change as a function of camshaft parameters (lift, duration, overlap) and how open the throttle is. So you could say that the camshaft + throttle changes the effective Compression Ratio to some degree.

Yea that's what I meant but didn't say it exactly right, but I'm still kinda leaning to thinking my old Harley pinged under 93 octane due to being air cooled and just ran hotter than a water cooled bike.

Originally Posted by ponch

What plays into this is if the engine has true closed loop management. My beemer has 12:1 compression ratio, is air/oil cooled, has run on 87 (I had no choice once in BFE on the way to Crescent City), and BMW says 89 or better (93-94 is recommended for best performance). The computer detects ping and retards the ignition timing accordingly. Power is lower, but it will run. My guess is that the computer management on the Kawasaki 1700 isn't the same as it is on the ZX14 and some of the other ninjas. Considering what the bike cost, I would think it would be standard as it is on the C14, which is less expensive, yet has more technology. Sometimes I have to wonder who makes these decisions and why.

Exactly, but (at least my) Vulcan is Open loop all the time, well that is unless Kawa has implemented a dyno count tuning system like what Cobra seems to have done. In any case mine has no 02 sensors.

I'm not familar with your Beemers anti knock adjustment logistics, Harley does this with the ION sensor circuit on the primary side of the coil and matches it to pre-determined data in the ECU.

But even most narrow band closed loop systems on idle and cruise, but open loop on acceleration and loads can still adjust as you say to the extent of their lookup table diversity (and the limitations of the open loop range).

In other words take any EFI Harley, which would be the just said scenario, and put pipes on it and you can run without a tuner and most likely never burn a valve from running too lean, because it can adjust a certain amount. But add big air to the scenario and the maps just ain't equipped for that and you are probably gonna run lean and over time burn a valve.

Actually open loop is better for piggyback tuners like the PCV. Cage racers will tell you that a wide band closed loop system will evenutally re-adjust a piggyback tuner solution and that a USB cell reflash is the only effective tuner in that scenario.

A true wide band total closed loop system will in fact readjust to any piggyback solution. Most cages nowdays also have a MAAP sensor with allows building the VE tables on the fly. I don't think I ever heard of bike with a MAAP. Many of them do have a MAP sensor but that is density only and not volume.

[Peg]

Originally Posted by RACNRAY

Engines produce power via volumetric and thermal efficiency. How well the cylinders are
filled and how well they can be evacuated is the volume aspect;more in and more out makes more power. How well the engine converts that volume of air and fuel into heat and thus work is the thermal part.

Back to the volume part. An engines' "STATIC" compression ratio is fixed. The engine will have varying levels of "effective cylinder pressure" during operation. Low cylinder pressure at idle and low rpm/part throttle operation, more cylinder pressure at higher rpm/large throttle openings.

Altering intake and exhaust systems can improve volumetric efficiency thus raising the "effective cylinder pressure". Free-flowing intakes and exhausts, cams, cylinder port flow rates and don't forget turbos/blowers/nitrous oxide/ram air intakes all will increase the effective cylinder pressure.

RACNRAY

<Whoosh>......</Whoosh>

[ponch]

Originally Posted by R_W_B

Yea that's what I meant but didn't say it exactly right, but I'm still kinda leaning to thinking my old Harley pinged under 93 octane due to being air cooled and just ran hotter than a water cooled bike.



Exactly, but (at least my) Vulcan is Open loop all the time, well that is unless Kawa has implemented a dyno count tuning system like what Cobra seems to have done. In any case mine has no 02 sensors.

I'm not familar with your Beemers anti knock adjustment logistics, Harley does this with the ION sensor circuit on the primary side of the coil and matches it to pre-determined data in the ECU.

But even most narrow band closed loop systems on idle and cruise, but open loop on acceleration and loads can still adjust as you say to the extent of their lookup table diversity (and the limitations of the open loop range).

In other words take any EFI Harley, which would be the just said scenario, and put pipes on it and you can run without a tuner and most likely never burn a valve from running too lean, because it can adjust a certain amount. But add big air to the scenario and the maps just ain't equipped for that and you are probably gonna run lean and over time burn a valve.

Actually open loop is better for piggyback tuners like the PCV. Cage racers will tell you that a wide band closed loop system will evenutally re-adjust a piggyback tuner solution and that a USB cell reflash is the only effective tuner in that scenario.

A true wide band total closed loop system will in fact readjust to any piggyback solution. Most cages nowdays also have a MAAP sensor with allows building the VE tables on the fly. I don't think I ever heard of bike with a MAAP. Many of them do have a MAP sensor but that is density only and not volume.

Most beemer riders don't bother with tuning their bikes and leave them stock. There isn't much to be gained and probably a lot to be lost, like gas mileage and power unless you really know what you are doing. I haven't looked up all the sensors, but it has at least two o2 sensors and has more electronics than some cars. It doesn't even have fuses. It has a controller that shutdown circuits if they get overloaded. It also has CANbus. You might get a few riders install a power plug, which spoofs the temp sensor at low rpms as it runs a little lean, but that's about it. The germans usually try to get things to work together pretty well and all their bikes are 50 state too.

[Kevinhyland]

Thank you for your wealth of knowledge, I appreciate it, sounds like you really know your stuff. I just wanted to make sure I would not harm my motor by running 87. Ride safe.

[Kevinhyland]

Thanks, is this just a characteristic of the Tri Ovals? The bike does sound bad ass and power increase is amazing.

[carsixten]

My Nomad 1500FI is picky when it comes to which gas it likes. It will ping badly if I use certain brands, even if the octane is 89+. I use BP brand premium 93 whenever I can get it. SuperAmerica and Holiday premium gas is OK. Cenex or Caseys gas is ping, ping, ping all the way.
Here in the corn belt states, ALL our gas is E-10, (10% ethanol) as mandated by state laws. IA, MN, WI, SD, IL, IN, NE, and many other states.
One time in Montana, I had to run a tank of 85.5 octane, because that was all they had in a one pump town. The gas was alcohol free though. The bike ran much better than expected, with just a little ping under hard acceleration. It ran better on 85.5 than it does on 87 or 89 octane E-10.
I wish I could get ethanol free gas here. It's much better in motors that sit a lot like chain saws, weed wackers, snow blowers. The ethanol gives less power too - lower gas mileage. We're stuck with E-10 for now because the ethanol lobby is very powerful around here.

[R_W_B]

Originally Posted by carsixten

. . . . . . . . . .
I wish I could get ethanol free gas here. It's much better in motors that sit a lot like chain saws, weed wackers, snow blowers. The ethanol gives less power too - lower gas mileage. We're stuck with E-10 for now because the ethanol lobby is very powerful around here.

I wish I could get ethanol free gas too (in Florida). The 10% Egas ruins small engine plastic gas lines. It's a poor fuel additive and benefits only the grain farmers. It's tax payer (you and I) subsidized and is not cost efficient. In other words gas would be cheaper without it. It's done under the guise of "being greener" as is much stuff shoved in our faces and out of our wallets now days.

[dshelly]

Most of the stations here have 10% ethanol in regular (85.5) and the plus (87). The Premium (91) doesn't have ethanol in it.

Here is the confusing part about gas here. In most of Eastern MT regular gas is 85.5 plus is 87 and premium is 91. However, once you get west of Butte the octane rating changes. Regular goes to 87 plus goes to 89 and premium goes to 93. The shitty part is that the higher octane gas sold in the western part is the same price as the lower octane stuff they sell here. I always run the premium stuff here, since it's ethanol free.
My bike will run on the plus, but why buy plus and use an ethanol treatment? just use the premium and be done with it. I do however add seafoam in the winter when I store it to keep the fuel fresh.