5.4 3v gas
11-04-2011, 11:13 PM
#21
Certified Ford Technician
it would help to get on the gas every so often also, city traffic or short trips can cause ridiculous amounts of deposits, I just did a tune up on a truck with 50k and 7/8 broken, I sent a bore scope in to check for any chunks of ceramic that may have fallen in the holes during extraction and there was carbon all over the valves and piston tops, the customer had told me that he "babies" his truck. and I know in MT regular is 85, and plus is 88 so I generally opt for mid-grade.
11-04-2011, 11:28 PM
#22
Certified Ford Technician
as far as running higher octanes in engines designed for a specific fuel there are expensive long term effects, high octane fuel in the 5.4 will get you lots of carbon buildup on the injectors, intake system, egr system, it can plug your cats, bad news, since a higher octane burns slower at a lower temp in a relatively low compression setting as the 5.4L all the fuel is not consumed which produces excess hydrocarbons, short term you'll get more power and better gas mileage, long term all that unburned "spent" fuel will become deposits in the exhaust which feeds the egr which feeds the intake so it gets everywhere.
11-05-2011, 05:00 PM
#23
12 Second Truck
I can't help but laugh at some of the post in this thread. Folks thinking the PCM will self adjust or just convinced that 93 is better regardless of logic or reason. I'm not out to step on anyones toes but again if the motor isn't tuned for it there will be no benefit. It will be the opposite. The PCM can not make an adjustment for this. There are vehicles out there with octance sensors but the f-150 isn't one of them. The PCM does have some room for adjustment in timing and fuel but again these are limited and based upon 87oct, air flow, barometric pressure, temps, and load on the motor. We have all seen the threads on lean conditions after the install of a CAI. If the pcm could simply adjust it would. And the fact is that it does but again within the parameters set at the factory. It can only add or take away so much fuel and timing. And a good flowing CAI will present the motor with more air then it has the ability to add fuel for and remove timing for to allow for a proper burn. Thats why you get a custom tune or a box tune that has parameters set higher and lower to allow the pcm more adjustment and hence the reason some of you have various tunes for various octances. Yes you can get more power and more efficiency from 93 but you have to have the tuning changes to reap those benefits. Otherwise your wasting your money and for those who said 'it runs better no matter what you say' you're offering an opinion based upon no fact or proof. It's a shame people won't read or study or strive to understand the way things work.
11-05-2011, 05:40 PM
#24
I Like Tires
Originally Posted by Blown Ford
I can't help but laugh at some of the post in this thread. Folks thinking the PCM will self adjust or just convinced that 93 is better regardless of logic or reason. I'm not out to step on anyones toes but again if the motor isn't tuned for it there will be no benefit. It will be the opposite. The PCM can not make an adjustment for this. There are vehicles out there with octance sensors but the f-150 isn't one of them. The PCM does have some room for adjustment in timing and fuel but again these are limited and based upon 87oct, air flow, barometric pressure, temps, and load on the motor. We have all seen the threads on lean conditions after the install of a CAI. If the pcm could simply adjust it would. And the fact is that it does but again within the parameters set at the factory. It can only add or take away so much fuel and timing. And a good flowing CAI will present the motor with more air then it has the ability to add fuel for and remove timing for to allow for a proper burn. Thats why you get a custom tune or a box tune that has parameters set higher and lower to allow the pcm more adjustment and hence the reason some of you have various tunes for various octances. Yes you can get more power and more efficiency from 93 but you have to have the tuning changes to reap those benefits. Otherwise your wasting your money and for those who said 'it runs better no matter what you say' you're offering an opinion based upon no fact or proof. It's a shame people won't read or study or strive to understand the way things work.
If what you other guys are saying were true, then Blown Ford here wouldn't need a custom tune and 93 fuel to run his SC'd 5.4 right? The computer would just "adjust" for the extra fuel and the 87 octane fuel to make it run. I'm sure 87 would run great right? Lol
Last edited by BassAckwards; 11-05-2011 at 05:45 PM.
11-05-2011, 09:39 PM
#25
Certified Ford Technician
custom tuning is available from ford for a ford racing supercharger and the pcm is reflashed specifically for the add-on, however the 5.4L does not require a reflash for the additions of a CAI or duel exhuast, the reason i know this is becuase i did a pcm update through the PTS website and IDS and it had the option for a custom ford tune all i had to do was enter the voucher # on the laptop. so i called and talked to an engineer to see what was available for the f150, and that was his answer. as far as stock tunes go, so the MAF injectors, and 02's can compensate within programmed parameters for CAI or Duel exhaust but not a SC
11-05-2011, 09:42 PM
#26
'08f150stx
Everyone has a different situation. Supercharged, aftermarket pcm tune, bone stock. I put in 93 octane thinking/believing my truck drove different and got just a tiny bit better gas mileage. In my case, I was wrong. 87 worked best for me and my factory stock engine.
Last edited by '08f150stx; 11-05-2011 at 09:52 PM.
11-05-2011, 11:12 PM
#27
I Like Tires
Originally Posted by bleufox99
custom tuning is available from ford for a ford racing supercharger and the pcm is reflashed specifically for the add-on, however the 5.4L does not require a reflash for the additions of a CAI or duel exhuast, the reason i know this is becuase i did a pcm update through the PTS website and IDS and it had the option for a custom ford tune all i had to do was enter the voucher # on the laptop. so i called and talked to an engineer to see what was available for the f150, and that was his answer. as far as stock tunes go, so the MAF injectors, and 02's can compensate within programmed parameters for CAI or Duel exhaust but not a SC
Last edited by BassAckwards; 11-05-2011 at 11:14 PM.
11-06-2011, 12:19 AM
#28
Certified Ford Technician
it definately can't adjust but i would say if your going to adjust compression ratio with a SC on a stock tune then adjust the octane to match since (and correct me if i'm wrong) higher octane fuels are made to burn more efficiently at higher compression because they have a longer burn time and lower flash point
11-06-2011, 08:48 AM
#29
12 Second Truck
it definately can't adjust but i would say if your going to adjust compression ratio with a SC on a stock tune then adjust the octane to match since (and correct me if i'm wrong) higher octane fuels are made to burn more efficiently at higher compression because they have a longer burn time and lower flash point
11-06-2011, 09:16 AM
#30
Senior Member
Compression ratio changes by shaving heads or changing pistons. Adding an sc does not change the compression ratio. It simply adds more air. More air needs more fuel. More air and fuel adds power and with power comes heat. Heat hot enough to ignite 87 octance before the plug fires. This is pre-detonation. To counter this you run a higher octane. Higher octane has more anti-knock products added thus slowing its ignition rate and raising its flash point. As for the CAI and exhaust causing lean conditions. Not every truck will have this issue. Some do and some do not. Ford has nearly 300 different pcm setups for these trucks from 04-08. Some have issues that others don't and as mentioned atmosphere plays a role. But getting back to the main point. The pcm does not have enough leway in adjustments from the factory to benefit from running 93. That is fully exploiting timing and a/f's for maximum effeciency and power.
Bubbabud