Good points I talked to a car nut at work and when I told him about this mod he laughed at me and said he didn't think it was worth it. I like to get a lot of opinions on different mods and then based on the information I gather come to my own conclusions. And so far I feel this mod ain't worth it.

 

we are uping the timing so the higher octane does help against pinging. why do you think all the manufaturers of all the programmers suggest a higher octain fuel? to reduce pinging. its not only for higher compression vehicles.

 

also, about the fouling of the plugs, if that is so do the jet chips require the same increased plug changes? because im pretty sure they up fuel and timing

 

if you advance timing you will need a higher octane because of its slower burn rate.. you don't want it to predetonate (ping) because a lower octane has a faster burn rate
by advancing timing and using a low octane fuel, the mixture will burn too fast before the cylinder reaches TDC because you advanced the timing, started to burn the mixture sooner than normal. so by switching to a higher octane fuel you slow the burn rate down, allowing the mixture to complete its burn through the cycle.

so to whoever said you don't need a higher octane fuel for advancing timing, you're an idiot. if you advance it more than what stock calibration calls for you need a higher octane fuel. otherwise the computer will just retard the timing until the spark knock is gone. thus defeating the purpose of advancing the timing

 

also. no it doesn't keep the truck in 'warm up' mode. if you had any idea on how the computer calculates how much fuel to dump into the engine you'd know this.

but the computer takes ECT temp into consideration as well. so regardless if its 9,000ºF outside or -9000ºF outside, as long as the ECT reads ~190º truck is no longer in 'warm up' mode. and stops dumping a load of fuel into the combustion chambers to WARM UP THE CATS. otherwise running rich makes the engine run COOLER, running lean makes it run HOTTER. your engine would warm up much faster if it didn't have to warm up the cats first.

now this sensor what it does it tells the computer how dense the air coming into the engine is . now depending on how cold it is, depends on how much fuel it delivers. colder air is usually denser. so it dumps more fuel.

The IAT sensor provides an input voltage to the Powertrain Control Module (PCM) indicating the density of the air entering the intake manifold based upon intake manifold temperature. At key-on, a 5–volt power circuit is supplied to the sensor from the PCM. The sensor is grounded at the PCM through a low-noise, sensor-return circuit. The PCM uses this input to calculate the following: [ul][*]Injector pulse-width[*]Adjustment of spark timing (to help prevent spark knock with high intake manifold air-charge temperatures) [/ul] The resistance values of the IAT sensor is the same as for the Engine Coolant Temperature (ECT) sensor

School DISMISSED

 

So Zack, do you think this mod is worth it then? I mean, I definitely noticed a difference, running on 87 octane alone... I am gonna switch to 89 or 93 after this tank is gone... but what do you think regarding the mod?

 

i think it def. works. but i think it'd be safer to wire it up to a switch so you can toggle between it being on and 'normal'. so that you're not dumping more fuel than you need to at cruising speeds. that's just wasting fuel and making carbon deposits in your head and on your piston (you can just run a can of decarb through your TB every 15,000 miles or so to get rid of these). but otherwise at WOT i think its a fairly safe mod.

 

fuel system cleaner would also work wouldnt it?

 

Well honestly, here's the thing....

I drive to and from my college about twice a month, to visit friends and what have you.. I drive the same roads each time... and same speeds each time (58mph) same weather conditions..... and I went there three days apart.. two weeks ago, I went on a Friday and then on a Tuesday... so I guess 4 days apart.. anyways....

Both times it was about 85 - 90 degrees, and no wind.... same trip, same speed... and before the "mod" I got 21.9 hand calculated mpgs... 86 miles on 3.926 gallons of gas... (I filled up before I left, and I write how many miles I go, on each gas receipt I get... I fill up always at a little Citgo station just inside town)

Then after the "mod" I did the same trip, this time having to completely stop for construction, sitting for at least a minute, getting back UP TO SPEED, and then continuing my trip.... I went the same 86 miles, but this time.. I went on 3.665 gallons of gas.... or... 23.46mpg...

 

it does, but decarb works much better. with fuel system cleaner i can get a car to white smoke for about 30 seconds.. with decarb about 3-4 minutes.. hahahaha