Opinions needed. Should I run 91 octane in my S2 FZ6 after I install performance mods?

[teko89]

I plan on running a KandN air filter, NGK iridiums, Cat delete pipe, airbox mod, Delkevic midpipe and silencers with no baffles, and a juicebox. I run 87 octane now which I notice actually gives me a little more snap than 91 octane. But Im worried with much higher flowing intake, exhaust, and increasing fuel. Not sure if I should still run 87, or after the mods would 91 be more appropriate? What do you guys run that have performance modded FZ6s?

 

[beatle]

None of those mods sound like they would warrant a higher octane fuel. If the timing was advanced or compression was raised, I would run higher octane. You'll be fine with 87. If you happen to find the engine pings or knocks, you can always use higher octane fuel.

 

[FinalImpact]

None of those mods sound like they would warrant a higher octane fuel. If the timing was advanced or compression was raised, I would run higher octane. You'll be fine with 87. If you happen to find the engine pings or knocks, you can always use higher octane fuel.

Well said and spot on...
Hot dry days where the engine is heat soaked from lots idle time in traffic, etc, may warrant a bump.

As stated, if you advance the timing colder plugs and better fuel are required.

 

[Motogiro]

With the CAT delete and fuel management will you be doing any tests to see what your air to fuel ratio will be? I would be more concerned with A:F than I would octane with the effect the mod can have on the mix throughout the rpm range. Air to fuel mix alone will always effect where detonation occurs and so timing, compression ratios, plug temp range etc. all fall into the picture of a healthy performance modification. Is your bike going to be tested after these mods?

 

[patrickb37]

OP mentioned a Juicebox in the mod list, presumably that would be used to correct the A/F ratios after the rest of the mods are installed?

 

[FinalImpact]

I've mentioned this in other threads but please keep in mind the S2 Chassis has CATs in the header tubes, so getting a clean read of the AFR is not easy. Of concern here is the CATs likely lack the same efficiency of catalyzation for all flow volumes/engine output. Meaning applying an offset to compensate for them may not be a linear curve across the board.

It is why my S2 has an S1 header and a wideband O2 sniffer and data logger... FWIW most speed shops dont even notice the mini cats in the headers...

With the timing advanced and Free flowing exhaust + AFR at 13.1:1, she moves and has great throttle response. Yes, 91+ octane always for her!

 

[beatle]

A cat shouldn't make that much of a difference in the AFR reading. At least it didn't on my car. The pre-cat wideband on my car was within a couple tenths of the wideband at the tailpipe when I tuned my car on a dyno.

Good enough for government work.

 

[Love@FirstRide]

i run 91 always because i think it contains better additives for lubrication/ cleaning purposes. I think it has more torque in the low range with the high octane but that's just my butt telling me

 

[major tom]

I'd say no from my experience. I use to be a mechanic in Durango and our gas was regular grade for everything. We would get tourists from the low lands who continued to use premium and they'd come in with fouled plugs. "nothing but the best for old Betsy" LOL. They got away with it down low but it probably wasn't needed there too.

 

[Red Wazp]

i run 91 always because i think it contains better additives for lubrication/ cleaning purposes. I think it has more torque in the low range with the high octane but that's just my butt telling me

Waste of money. Higher octane is for anti knock, nothing more. If your motor isn't pinging or knocking under throttle at low rpm's you don't need it.

 

[Motogiro]

A cat shouldn't make that much of a difference in the AFR reading. At least it didn't on my car. The pre-cat wideband on my car was within a couple tenths of the wideband at the tailpipe when I tuned my car on a dyno.

Good enough for government work.

I'm thinking because it's a smaller displacement motor, you may see a difference when you get rid of back pressure, especially at lower rpm and idle. That makes a difference in A:F. I'm thinking this might be out of range of the OEM ECU and then you'd rely on the additional fuel management. I had an FZ6 with 2 Bros, K&N and a PClll. I rode it a while without having it tuned and then had it professionally dyno tuned. What a difference! Those numbers do translate to a strong running, healthy bike.

 

[rideslikean00b]

Hot dry days where the engine is heat soaked from lots idle time in traffic, etc, may warrant a bump.

Sat idle in traffic on a bike? Solution: Filter more. ;-)

 

[raja777m]

Sat idle in traffic on a bike? Solution: Filter more. ;-)

Ya, filtering in USA is still illegal, except for California(which is in books already) and soon to be in Texas.

 

[FinalImpact]

Sat idle in traffic on a bike? Solution: Filter more. ;-)

Copy that!
For future reference I'll use the sidewalk! Blah