cliffyk

You do not absolutely have to retune to switch from the 19s to the 21a (Ford didn't when they made the change), however the engine will run quite rich at higher loads and WOT with the 21s and that will cost some power.

With the 24 lb/h injectors you will definitely have to retune. I have no idea whether a DiabloSport handheld supports this--I suspect not...

FrostByte

U will need a custom tune.

jdmeaux1952

Ford designs the injectors to work at about 90% of their duty cycle. With a Naturally Aspired engine (NA), by changing one step up on injectors (19# to 21 #) the injectors do not work so hard to keep the fuel flowing. A tune will help to increase the efficiency of the injectors over the factory tune.

Do not forget that the factory tune is a compromise between power and emissions. An aftermarket tune will liven up the engine with a minor increase in timing and have the injectors working more efficient within their duty cycle.

When you start adding power adders (SC or turbo), you will need lots more fuel. That is when you get to go have your vehicle dyno-tuned for maximum horsepower (which is the mistake most people make). Power adders need lots more fuel to make their power, so it is not unusual to see a SC engine running 82Lb injectors.

If you are looking for a little more hp, sure change your injectors up one step and put a tune on the engine. You will like the results.

Dominasian

I asked because it was kinda unclearn to me in the original post, now its makes sense, i knew it, just wasn't sure on this duty cycle thingy. I had a turboed car, but its was different than a mustang. I was doing all tuning my self because the ECU let me do that. Fuel trims, Combined trims at closed and open loops, fuel graphs and many more, but i guess with ford its all much simplier, just go to a dyno, pay 500$ and tune it

cliffyk

Or buy a tuning system that lets you do that, SCT Advantage or Delta Force's Commando will let you do all that and more--with the Moates Quarterhorse you can do it on the fly while driving (someone else is) the car...

jdmeaux1952

Like Cliffyk said, buy a handheld that allows you to do all those things. Go check them out and contact the manufacturer to see to what point you can make the adjustments.

Most people are just happy enough with the pre-loaded tunes, while others will go to a dyno setup and get a custom tune. It all depends on what you want.

Dominasian

Handheld should be enough for me cause i am not gonna go crazy with my set up, maybe later on when ill have funds for now preloaded tune should do the job

highroller02

throw some basic suspension mods up on here and let the power be put to the pavement. Power is nothing without traction...

jdmeaux1952

You are right. If the suspension is too tight and unforgiving (like most), you never get the power down to the pavement. What good is a 650 rwhp engine if all you do is spin the tires? You need an active (for drag racing anyway in particular) suspension that allows weight transfer from the front to the rear. The vehicle will actually lift the front tires slightly as the weight goes back.

Www.allfords.com and forums.corral.net/forums both have excellent write-ups on how some people set up their own suspension.

cliffyk

That's fantastic...


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My mother told the story of three elderly women sitting in rockers at a nursing home. They were talking about their lives and the first stated she had been raised in a proper family, gone to the finest boarding schools, married a prominent doctor and lived a life of ease. The second woman said "Oh how wonderful!", the third said "That's fantastic!"

The second woman then said that she was the daughter of a tycoon, went to the finest schools in Europe, married a count and never wanted for anything. The first woman said "Oh you were so blessed!", the third woman said "That's fantastic!"

The first two turned to the third and asked about her life. She said that she lived with her grandmother after her father was killed and her mother ran off, that they were dirt poor and she only went as far as sixth grade in public school--and that her grandmother taught her to say "Fantastic!" instead of "bullshėt"...