Spark Plug Examination and FUEL

[christopher]

In the course of installing PyschoSleds new Bridge Controller, I pulled my OEM plugs this evening.

What can we learn from these plugs that have been running in a Supercharged Nytro....

 

[christopher]

Here is a better photo.
Plugs are in sequence as they came out of the engine.
Rider's left, center, rider's right.

Plugs have 2,207 miles on them.
Perhaps 400 of those are under MPI GEMs controlled boost?

 

[slash]

Center cyl looks a little lean lft shows some DET and just crappy fuel on all 3

 

[christopher]

Hmm

So what is to be done about Center Lean and Left Detonation?


As for the crappy fuel.
All this sled has ever seen is 91 Octane or 110 Race fuel.??

 

[judger101]

Im no plug expert but those look much different than my plugs that i changed the other day. Mine looked cleaner and more evenly burned

 

[slash]

well start with 1/3 can of 44K IN 3 tanks then add 2 gallons 110 per tank from now on the 44K will clean your injectors and the mix will stop DET

 

[MotoPsycho]

Some carbon build up as would be expected with a Nytro due to it's fat bottom... among other excessive fuel contributors you may have just removed...

Most interesting is more prevalent in the 1st pic - It looks as though there is a fair amount of "high speed glazing" of the insulators.

This can indicate that cylinder temps are rising quickly during hard acceleration, and plug temps are exceeding optimal temps.

During this condition, normal and abnormal deposits (like those introduced by an overly rich fuel mixture) may melt to form a "yellowish" and conductive coating. This condition can cause misfiring at high RPM...

Misfire's in the Nytro can cause the sled to die at moment of misfire...

Use your prior riding experiences to do the math on this one.

The best way to circumvent high speed glazing is to run a cooler plug... and those same plugs also help prevent detonation for the same reason - they dissipate heat better.

 

[slash]

Yes a colder plug will help Better fuel always helps

 

[christopher]

Some carbon build up as would be expected with a Nytro due to it's fat bottom... among other excessive fuel contributors you may have just removed...
Would that be Code language for MPI's GEMS Controller?


Most interesting is more prevalent in the 1st pic - It looks as though there is a fair amount of "high speed glazing" of the insulators.

This can indicate that cylinder temps are rising quickly during hard acceleration, and plug temps are exceeding optimal temps.

During this condition, normal and abnormal deposits (like those introduced by an overly rich fuel mixture) may melt to form a "yellowish" and conductive coating. This condition can cause misfiring at high RPM... Misfire's in the Nytro can cause the sled to die at moment of misfire...
Well Well Well.
Now doesn't that sound ALL TOO FAMILIAR?

Use your prior riding experiences to do the math on this one.
Yup, not too hard to put 2 and 2 together now.

The best way to circumvent high speed glazing is to run a cooler plug... and those same plugs also help prevent detonation for the same reason - they dissipate heat better.

Sweet.
Maybe things will get MUCH better rather than just Better!

 

[slash]

race gas will also drop combustion temp

 

[christopher]

well start with 1/3 can of 44K IN 3 tanks then add 2 gallons 110 per tank from now on the 44K will clean your injectors and the mix will stop DET

OK
Will go get 1 can of BG 44K and run 1/3rd of it through the next 3 tank fulls of gas.

Guess its time to buy some good fuel as well.
And here I thought the 91 octane was good enough.

Should I just BITE THE BULLET and stock up on some Ethanol Free gas while I am at it??

So you want me to run 20% 110 Octane with Good 91 Octane, Ethanol Free gas.
And your telling me that the Ethanol mixture is leaning out the gas by 10%, which is adding to my detonation problems, as evidenced from Plug #1.

 

[MotoPsycho]

There really is no question... if you can find non-ethanol, use it.

 

[christopher]

Was just on the phone with Slash.
He was telling me the very same thing.
We have one gas station in Idaho Falls that sells NON Ethanol fuel and 110 octane as well.

So I guess I will head over there tomorrow and stock up on some of both for my winter inventory.

Slash made an interesting comment about pumping 91 octane at the gas station.

He said that the average pump will hold appx. 3 gallons of fuel from the Tank control Valve to the nozzle. So the guy who just filled up his car with 85 left the hose filled with the lower grade fuel.

Never considered that.
3 Gallons is a LOT for one of our sleds.
So chances are GOOD that I was NOT always seeing 91 octane in reality.

Running 20% 110 will be a good safety precaution to make sure that doesn't happen again in the future.

And buying bulk Ethanol Free with absolutely Ensure that I have a higher overall octane rating for the super charger.

 

[MotoPsycho]

...oh yeah

proper fueling throughout the map will also decrease the likelihood of det.

Race fuel will eventually kill your o2 sensor.

 

[christopher]

...oh yeah

proper fueling throughout the map will also decrease the likelihood of det.

Race fuel will eventually kill your o2 sensor.

Ya.
So I was told.

There really is nothing simple/cheap about a boosted sled is there?

 

[MotoPsycho]

Much of this goes along with the recommendations we make concerning the additive to use in the fuel...

If you do buy fuel in bulk, do not store it from one season to the next...

 

[christopher]

Much of this goes along with the recommendations we make concerning the additive to use in the fuel...

OK, I am game.
Read your whole installation pamphlet and see NO mention of any Fuel Additive??

 

[judger101]

Hmm never thought of the gas staying in the hose from the last guy. Ill have to remember to use the station with the dedicated 91 pump

 

[towerrigger]

Hmm never thought of the gas staying in the hose from the last guy. Ill have to remember to use the station with the dedicated 91 pump

Or just throw a couple bucks in the truck first. Realized this a few years back running crotch rockets. Would fill up the bike and it ran like trash. The tanks on those bikes are so small. Dedicated 91 hoses are getting harder and harder to find now.

 

[judger101]

the only bad part is if you just have your sled with you. i guess you could have a spare can on the sled empty and just pop it in there until you can get to the truck.