My V11 seemed to run perfectly on 87 Octanes (Regular) gas rating... strange?

[guzziart]

Well, after reading some of your responses maybe I should reconsider running a couple tanks of "premium" to confirm (in my mind) that there is definitely a difference in performance....short of putting bike on dyno.  My v11 doesn't have lambda sensors so there's no way the ecu would adjust for out of range combustion, detonation, preignition, etc.

Kevin_T said Just because you can't detonation doesn't it's not there. Might take microscope to bits of aluminum on your spark plug.  Yeah, maybe I'll pull the plugs & shove the borescope in there & take a look.  I have a clue what microscopic bits look like based on my experience with my '72 eldo flaking cylinders.  The fine metal shavings were on the plugs & in pooled oil on the top of the heads under the valve covers....it was very obvious, no fancy tools needed to detect that issue. 

[LowRyter]

12 hours ago, Lucky Phil said:

That's because the adaptive learning in the EFI system had adjusted the LTFT ( long term fuel trim) and ignition to adapt to the low octane fuel you run. It senses LAMBDA and knock and adjusts the ECU to cope with the fuel. If you pull the ECU fuse or disconnect the battery for 10 minutes and then reinstall preferably when the engine is at operating temp (so the idle relearn is faster) and null out all the learned 87 octane parameters and put some 91 octane in it you will feel it go MUCH better.

 

Phil 

I know that.  My old Camaro had all that too.  Computer + knock sensor.  

Where I'll disagree is that it won't go any better or faster.  No seat of the pants difference whatsoever.   I ran both cars for years running 91 premium.  I switch to cheap gas and it runs exactly the same.  So I've done a before and after.   The computer was already calibrated for premium.  I don't even pay for 100% gas, I get the cheaper 10% ethanol.  If I felt a difference, I'd pay for premium.  One advantage with cheap gas, it's fresher and gets pumped out sooner, less chance of old gas and contamination. 

If I was tracking the car or running down the strip, I'd follow your advice.  I'm a little skeptical it would make more than a few hundredths on the quarter mile but why leave it to chance? 

For my bikes, I buy premium.  I don't want to risk detonation, particularly those legacy big cylinder air cooled Guzzis with the clunky gearbox that makes me occasional lug the engine if I take out in 2nd.  But that's another story.  

And I will admit that I'm not totally convinced that what's pumped out of the 91 pump is any different than the 87.  Maybe it is, maybe it isn't

[guzziart]

Does anyone out there know of catastrophic MG engine failures as a result of using lower than OEM specified octane fuels?  

I follow OEM recommended specs (sae, api, jaso,etc) for oil but for some reason I have ignorantly departed from that logic for fuel.  I hope my quest for thriftiness doesn't bite me.

[Joe]

23 hours ago, LowRyter said:

I know that.  My old Camaro had all that too.  Computer + knock sensor.  

Where I'll disagree is that it won't go any better or faster.  No seat of the pants difference whatsoever.   I ran both cars for years running 91 premium.  I switch to cheap gas and it runs exactly the same.  So I've done a before and after.   The computer was already calibrated for premium.  I don't even pay for 100% gas, I get the cheaper 10% ethanol.  If I felt a difference, I'd pay for premium.  One advantage with cheap gas, it's fresher and gets pumped out sooner, less chance of old gas and contamination. 

If I was tracking the car or running down the strip, I'd follow your advice.  I'm a little skeptical it would make more than a few hundredths on the quarter mile but why leave it to chance? 

For my bikes, I buy premium.  I don't want to risk detonation, particularly those legacy big cylinder air cooled Guzzis with the clunky gearbox that makes me occasional lug the engine if I take out in 2nd.  But that's another story.  

And I will admit that I'm not totally convinced that what's pumped out of the 91 pump is any different than the 87.  Maybe it is, maybe it isn't

While on a ride during the New Cumberland WV MGNOC National Rally back in maybe 05-ish. We had to fill up in BFE at a little mom & pop store, another rider told me that it takes a few gallons of gas to transition from Premium to regular within the pump. So if true, you would only be getting very little premium gas filling a 5gal tank that previously just ran 87. Again, I can't verify if true, but clearly octane levels fluctuate regardless of what you select on the pump from area and vendor. 

[guzzler]

In true Guzzi thriftiness and suspender snapping....

I'm thinking of running 91 octane instead of 95 after it cost me $28.00 for 14 litres on Thursday morning.

Never really worried about it before but that's beginning to be on the nose!

Cheers

[audiomick]

1 hour ago, guzzler said:

I'm thinking of running 91 octane instead of 95

 

Can't do that here anymore. The lowest availabel is 95.

[Lucky Phil]

On 7/28/2023 at 1:21 AM, LowRyter said:

I know that.  My old Camaro had all that too.  Computer + knock sensor.  

Where I'll disagree is that it won't go any better or faster.  No seat of the pants difference whatsoever.   I ran both cars for years running 91 premium.  I switch to cheap gas and it runs exactly the same.  So I've done a before and after.   The computer was already calibrated for premium.  I don't even pay for 100% gas, I get the cheaper 10% ethanol.  If I felt a difference, I'd pay for premium.  One advantage with cheap gas, it's fresher and gets pumped out sooner, less chance of old gas and contamination. 

If I was tracking the car or running down the strip, I'd follow your advice.  I'm a little skeptical it would make more than a few hundredths on the quarter mile but why leave it to chance? 

For my bikes, I buy premium.  I don't want to risk detonation, particularly those legacy big cylinder air cooled Guzzis with the clunky gearbox that makes me occasional lug the engine if I take out in 2nd.  But that's another story.  

And I will admit that I'm not totally convinced that what's pumped out of the 91 pump is any different than the 87.  Maybe it is, maybe it isn't

You mean the "Crossfire system " ?

 

Phil

[guzzler]

43 minutes ago, audiomick said:

Can't do that here anymore. The lowest availabel is 95.

I keep hearing rumours of 95 being phased out here too...

So may have go to 91 at some stage.

Cheers

Ps Brad Black warned me about using 98 here as per LP's post. 

[LowRyter]

10 hours ago, Joe said:

While on a ride during the New Cumberland WV MGNOC National Rally back in maybe 05-ish. We had to fill up in BFE at a little mom & pop store, another rider told me that it takes a few gallons of gas to transition from Premium to regular within the pump. So if true, you would only be getting very little premium gas filling a 5gal tank that previously just ran 87. Again, I can't verify if true, but clearly octane levels fluctuate regardless of what you select on the pump from area and vendor. 

I've wondered that as well.  No doubt there is cheap gas in the hose or whatever the last person filled with.  Running a bike getting 4 gallons, how much is high test?  I'm guessing more that 3 1/2 but I haven't a clue.  I've wondered about that just about every time I fill up.  

[LowRyter]

2 hours ago, Lucky Phil said:

You mean the "Crossfire system " ?

 

Phil

No, it's a '94 LT-1 engine.  Has sequential fuel injection.  It was good engine, reverse cooling (aluminum heads first) but that optispark distributor (running with the water pump) and getting to the sparkplugs and wires was awful.  The main seal leaking at 160k miles finally did for me.  Would I spend a ton of cash to bring this up to spec or spend a little more and find an a nice LS3 'vette?   If I was a mechanical wiz like you I might have resto mod'd it but it's easier to sell it and write a check.  I love the 'vette BTW..it has 150 more HP but the torque is more an equalizer between the two than one might think.  The Z/28 was a nice ride, the 'vette goes to another level and thank goodness it has traction control. 

Both cars ran the same on 87 ...at least by the seat of my pants.  Never a knock, faster than I can go.

 

Note: when I had the Camaro at 18 years old (140k miles), one of my buddies got a new Hemi Challenger (6 SPM like mine).  We did a street run, like at 10 mph and hit it on cue, he didn't pull away.  He sold the car thereafter. I just thought he was playing with me, I only know he sold it.  The bullet Camaro was a head of it's time.  easy car to drive with my right toe.  The 'vette takes a little more experience to play with.  And you can change the plugs and wires in an LS engine in about 45 minutes.

 

who wouldn't like this? 

 

[p6x]

 

[LowRyter]

@p6x

 

I'm not suggesting anyone run cheap gas unless they have no choice.  But it would make sense for Guzzi to make that a spec just for warranty and liability purposes.  I'm guessing that air cooled big bore bikes don't have a lot of tolerance in heat and traffic.  Perhaps better on the open road with lots of wind and not lugging?

[p6x]

1 hour ago, LowRyter said:

@p6x

 

I'm not suggesting anyone run cheap gas unless they have no choice.  But it would make sense for Guzzi to make that a spec just for warranty and liability purposes.  I'm guessing that air cooled big bore bikes don't have a lot of tolerance in heat and traffic.  Perhaps better on the open road with lots of wind and not lugging?

Did not imply that you were suggesting anything either.

I have ran the V11 with ethanol free gas, and now with 87 Octanes. I did not notice any difference with either.

I was merely showing that Guzzi does recommend 91 minimum according to the USA way of computing.

In France, the regular is named E-95, and is 95 Octanes using the European way of computing. What does Guzzi recommend there?

In the 70's I did put regular in cars that required premium. I could run them smoothly, providing I would not be harsh on the gas pedal, and gear down before any climb. The engine would often keep running after I switched the ignition off, so you had to stall the car to shut it down. Gas in France always was a major source of indirect taxes. Still is.

This time, with regular gas in the tank, the V11 did not feel any bit different than with premium, driving it my usual way.

In 2004, Ethanol was not compulsory in the US, but was available as E10. In the US Ethanol mixed Gas became compulsory in 2005.

Whatever Guzzi recommended at the time is based on data available then.

Maybe E15 87 (R+M)/2) is good enough. I am not going to try E85 though...

[MartyNZ]

1 hour ago, p6x said:

I was merely showing that Guzzi does recommend 91 minimum according to the USA way of computing.

That sticker you posted says "91 RON".

That equates to 87 (RON+MON)/2, which is the rating system used in USA & Canada.

[docc]

My 2000 V11 Sport Owner's Manual has this awkward jumble:

Recommended [fuel]:           Supergrade petrol (97 NO-RM/min.)

                                            Unleaded Petrol (95 NO-RM/min.)

> First of all, I have no idea what "Supergrade" refers to except that it is contrasted with "Unleaded." Is "Supergrade" leaded gasoline?

> No mention of ethanol.

> It "seems" 95 RON is the manufacturer's recommendation and that converts to ~91 AKI (RON + MON / 2). I found one source that stated  90.25 AKI.

I would/ have run 87 AKI "regular" US fuel in a pinch, but would not put heavy loads on the motor (eg: aggressive passing) especially in high ambient/engine temperatures.

In "a pinch", I suppose a 2-stroke mix would be okay, but I tried diesel fuel once and didn't get much past pulling away from the pump . . .