Running 93 programs with 87 octane Gas

[Shambo]

Any Experts out there that can explain if running lower octane on performance tunes hurt anything? I would be expected not to perform as well, but there are anti knock devices on the engine and does not knock? So would it damage anything?

 

[Pull Ya]

Yes!
Jay

 

[Graygoose]

Detonation!

If you want to tune it, you have to buy the better gas. Cant have performance without paying at the pump.

 

[Saltillo Express]

^^that

 

[Etroze86]

Pay to play, always number one thing I tell people when modding their vehicles.

 

[drittal]

To maybe touch a little bit on why it could hurt the motor. I believe one of the ways the tuner improves performance is by increasing the timing and turning down the sensitivity of knock sensors. To keep detonation from damaging engine components the tuner will specify an octane of gas that they know their tune will not experience detonation with.

 

[jwheeler]

If you are at a station that only has 87 for some reason, you are better off loading a different tune until you can get better gas.


Sent from my iPhone using Tapatalk

 

[MADDOG]

if you have to run a lower octane than your tune is rated for, DO NOT go full throttle and into high RPM.

The stock "factory tune" will allow the motor to adjust for different octanes of fuel. The aftermarket tunes are locked into an octane and if it isn't present, detonation will occur. One thing to understand here is whether or not the tuner re-writes the stock knock retard program parameters. If it does, the computer won't back off due to knock retard and some damage will occur.

One of the more prevalent engine failure issues is due to tuned engines running the wrong octane causing detonation... you don't want this!

Carry your tuner with you in case you can't get the octane the tune requires. You can switch back to stock (the computer will work out the proper tune for you) or throw in the 87 octane tune.

So if you don't have the octane the tune requires, change the tune. Or...don't push the engine to redline under WOT and back off a bit if you traditionally drive with a heavy foot.

 

[fordtech90]

Aren't our trucks recommended to run at least 89 octane anyways?

 

[MADDOG]

Aren't our trucks recommended to run at least 89 octane anyways?

It varies. A case in point is the 2014 to 2015 or 2016 6.4L equipped trucks.

My 2014 manual says use 87 and that there is no benefit to using a higher octane fuel.

Come 2015 or 2016 and now the manual states to use 89.

Not sure what changed but it is a bit confusing. I ran 87 up until recently and have switched to 89 to see how it runs and if there is any advantage in doing so with respects to mileage, performance, etc...

I'll run it past the winter blend fuel system and into the lower ethanol fuel season before I come to any conclusion.

But back to the point, you have to be careful running lower octane than is required by a tune. If stock it won't be a problem whichever you decide to run.

 

[Paluby]

Pay to play, always number one thing I tell people when modding their vehicles.

Resounding advice

 

[BlownGP]

I ran 87 with a 93 tune for a little while. It was when gas was expensive and I forget I had the 93 tune in. I wasn't tearing up the roads but I do have a heavy foot. Didn't have any problems.

Yeah I wouldn't do it again. I would say it's a not as big of a deal like it would be if I was boosted or something. Some knock is not going to blow your motor.

 

[Shambo]

Great! Info! Thanks!

 

[BigDogg795]

It varies. A case in point is the 2014 to 2015 or 2016 6.4L equipped trucks.

My 2014 manual says use 87 and that there is no benefit to using a higher octane fuel.

Come 2015 or 2016 and now the manual states to use 89.

Not sure what changed but it is a bit confusing. I ran 87 up until recently and have switched to 89 to see how it runs and if there is any advantage in doing so with respects to mileage, performance, etc...

I'll run it past the winter blend fuel system and into the lower ethanol fuel season before I come to any conclusion.

But back to the point, you have to be careful running lower octane than is required by a tune. If stock it won't be a problem whichever you decide to run.

I wonder if that's for the 6.4? I could have sworn my manual from online recommends 89 still for the 5.7... hmmm...

EDIT: I was right, the 3.6/6.4 does call only for 87...the 5.7 still uses 89 for "optimal performance".

 

[danam]

I'm curious I had the 93 cold air intake tune with my programmer installed but yesterday I had to unhook the battery for a bit when I hook the battery back up and started the car I went to get gas because I was on empty end up putting 89 and instead of 93 when the battery is unhooked does that mean you lose the tune I just assumed you did so that's why I went with 89 instead of 93

 

[BlownGP]

I'm curious I had the 93 cold air intake tune with my programmer installed but yesterday I had to unhook the battery for a bit when I hook the battery back up and started the car I went to get gas because I was on empty end up putting 89 and instead of 93 when the battery is unhooked does that mean you lose the tune I just assumed you did so that's why I went with 89 instead of 93

No, the tune in stored in the PCM. It's a computer so it loses power, everything will still be stored in it.

But like most of the newer PCM it learns, so it will lose all adaptive features and they will come back after driving a while.


and I was always told the 09+ HEMI's take 89..
You can run 87 and the computer will compensate you just won't get the most out of the motor.

 

[Numnutz]

I'm curious I had the 93 cold air intake tune with my programmer installed but yesterday I had to unhook the battery for a bit when I hook the battery back up and started the car I went to get gas because I was on empty end up putting 89 and instead of 93 when the battery is unhooked does that mean you lose the tune I just assumed you did so that's why I went with 89 instead of 93

I wouldn't think so, you don't lose the stock tune when you disconnect the battery. The only way to change a tune is ti rewrite the tune to your vehicle.

 

[MANual_puller]

I have an '11 2500 and I am running a DSP trinity and usually monitor the knock sensors and knock retard. DSP canned tunes do retard timing for knock. I'm on the 91 tune and normally run 91 octane as I can't find 93 anywhere around here. I had an episode a while back where I got in the truck and started driving and I noticed the knock sensors freaking out more than normal and it was retarding especially when I bogged it. I started freaking out a bit until I found the gas receipt in the door, wife put in 87 can of octane booster fixed the problem and as soon as it got below half tank I filled it up with the good stuff, ran it down to fumes and filled it back up with the good stuff. No problems since. Octane ratings really do make a big difference in performance and they need to be tuned accordingly.

 

[jasonw]

As others stated, custom tunes can curtail or turn off the anti-knock programming in the computer. In my area, I cannot run 89 octane with an 89 tune, 91 with a 91 tune, etc. as I still get engine knock at WOT or high RPMs, no matter what gas station I fill up at. Its even worse with 10% ethanol that most stations out here use. I now run an 89 octane tune with 91 gas from Costco on both my truck and my wife's 2014 Grand Cherokee (5.7L V8), and have not had any issues since.

 

[Ramit355]

The 2014 5.7 calls for mid-grade 89 at all times and discourages any thing over 10% ethanol. I never have ran ethanol in my Truck or 87 octane. never had any pings.Rattles or knocks!