My experience with crap gas and octane booster

[ManBearPig]

2016 GT, almost completely stock. Lund 93 tune is the only real performance mod.


The car used to be a weekend toy for me so when I drove it, I usually drove it pretty hard. A few months ago it became my daily and I've felt lately that it just doesn’t seem to be running as strong as it used to. For a while I've attributed that to just being used to the power now that I drive it every day, but on the rare occasion that I really stand on it I've noticed the occasional knock activity at WOT near 6k-7k RPM. This is not consistent and it usually doesn’t pull much….typically a degree or less. Total timing advance (SAFTOT) near redline (6k-7k RPM) is usually only 24-25*, which seems low from what I recall. I thought I used to see 26-27* but it's been a while since I really paid attention.


I dumped a few ounces of VP Octanium in the quarter tank of fuel remaining in the car last night. I did a few WOT pulls and in both second and third gear I'm now seeing minimum 28-29* SAFTOT at 6k-7k RPM, I even saw as much as 31* once. Of course no knock, the car was adding a few degrees even up at 7k. I also notice that the car seems to pull noticeably stronger down low. It seems to ramp up timing much quicker.


Apparently, I've been getting crap gas lately. The strange thing is I get gas at the same few stations I always have. Usually at one of two Shell stations by the house, and occasionally at Walmart. Back when the car was a weekend driver I never had issues with any of these stations.


My question is this….Once I can find a new, better source for gas, should the car run about the same on good 93 as it does on the boosted crap 93 in the tank now? Or will it not run quite that good? What can I expect for total spark at redline on a good tank of 93? I'm guessing 26-27* is a good target and I won't see the 28+ that I'm seeing now on the boosted crap 93 in the car? Hopefully it will still "feel" as strong down low, or at least close to it, but I'm not sure what to expect since the fuel in the car now is probably at least 95-98 octane, maybe higher.


Thanks

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[Joe 5.0]

2016 GT, almost completely stock. Lund 93 tune is the only real performance mod.


The car used to be a weekend toy for me so when I drove it, I usually drove it pretty hard. A few months ago it became my daily and I've felt lately that it just doesn’t seem to be running as strong as it used to. For a while I've attributed that to just being used to the power now that I drive it every day, but on the rare occasion that I really stand on it I've noticed the occasional knock activity at WOT near 6k-7k RPM. This is not consistent and it usually doesn’t pull much….typically a degree or less. Total timing advance (SAFTOT) near redline (6k-7k RPM) is usually only 24-25*, which seems low from what I recall. I thought I used to see 26-27* but it's been a while since I really paid attention.


I dumped a few ounces of VP Octanium in the quarter tank of fuel remaining in the car last night. I did a few WOT pulls and in both second and third gear I'm now seeing minimum 28-29* SAFTOT at 6k-7k RPM, I even saw as much as 31* once. Of course no knock, the car was adding a few degrees even up at 7k. I also notice that the car seems to pull noticeably stronger down low. It seems to ramp up timing much quicker.


Apparently, I've been getting crap gas lately. The strange thing is I get gas at the same few stations I always have. Usually at one of two Shell stations by the house, and occasionally at Walmart. Back when the car was a weekend driver I never had issues with any of these stations.


My question is this….Once I can find a new, better source for gas, should the car run about the same on good 93 as it does on the boosted crap 93 in the tank now? Or will it not run quite that good? What can I expect for total spark at redline on a good tank of 93? I'm guessing 26-27* is a good target and I won't see the 28+ that I'm seeing now on the boosted crap 93 in the car? Hopefully it will still "feel" as strong down low, or at least close to it, but I'm not sure what to expect since the fuel in the car now is probably at least 95-98 octane, maybe higher.


Thanks

That would be really tough to tell. Just find a different busy gas station and try out some new gas when you run this tank down.

Instead of using an octane booster all of the time, ask your tuner if it would be okay to run a couple gallons of E85 in your tank for that extra boost.

 

[SVT-DADDY]

Can you do a log? The car is only going to add so much timing, so if you log your current mix and then good 93 you'll have your answer. I define good 93 as fuel that achieves -4 KR values.

When I was N/A I want to say my max timing under WOT was about the same as your seeing now on the Lund tune.

 

[TnWHTMARE]

I know this doesn't answer your question but I just want to say I feel your "crap gas" pain. If you drive 3 hours to the east to Knoxville where I am at, apparently it just gets worse. I too have a 93 Lund tune on mine and wont see more than 22.5. I've tried several different Shell stations and a brand new Exxon. I just gave up on the pump gas. Im now using E85 as much as possible and so far, to the opposite of our gasoline, the E85 has been very good. 86-88% is what Ive tested so far. If it wasn't for the E85, I simply would be up a creek. There may be better gas around here but I haven't found it.

 

[Joe 5.0]

I know this doesn't answer your question but I just want to say I feel your "crap gas" pain. If you drive 3 hours to the east to Knoxville where I am at, apparently it just gets worse. I too have a 93 Lund tune on mine and wont see more than 22.5. I've tried several different Shell stations and a brand new Exxon. I just gave up on the pump gas. Im now using E85 as much as possible and so far, to the opposite of our gasoline, the E85 has been very good. 86-88% is what Ive tested so far. If it wasn't for the E85, I simply would be up a creek. There may be better gas around here but I haven't found it.

If by "test[ing]" you mean the nGuage readout, that's pretty good! The highest number I've seen was E91 on my nGuage.

 

[TnWHTMARE]

If by "test[ing]" you mean the nGuage readout, that's pretty good! The highest number I've seen was E91 on my nGuage.

Nope, not via nGuage. I use one of the glass tube testers.

 

[erikkire18]

I'm also having trouble with good gas here n CA. We only have 91 and am currently data logging the car with lund. 91 pulls there was knocking at 7k rpms so we mixed in about 2.5 gallons of 100 octane and than data logged. that log came back with the fuel being good but still some knocking at about 7k rpm and at the shift. i am currently installing a meth kit but not sure if this will help with that knocking. the tuner said it might be false knock but everything is clamped correctly and the piping is on correctly to. any idea if my gas is crap still and might be causing the false knocking or any suggestions on why the false knocking is occurring. its been a 6 week project so far.

thanks

 

[SVT-DADDY]

Keep in mind with octane booster it takes some time to mix up completely and to get in your lines on these return-less systems. Usually about 10 miles of driving before it's consistent for me.

Even longer if you don't put the booster in before the gas.

 

[DavidHuff]

Nope, not via nGuage. I use one of the glass tube testers.

How does this work?

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