Ive got a 2004 4.2L V6 manual and was wondering what suggestion anyone had for Air intakes, chips, gears, and exhaust sys. I just put rims and some BFG ATs on it and needs a boost. Ive looked at Mac and K&N intakes and it seems as Mac offers more Hp gains. Also if anyone knows what gears come stock with it would be helpful. My driving is all highway so take that into consideration.

 

You can get the gear ratio by reading the axle code off the door sticker.

 

a Magnaflow SI/DO set-up seems to be the favorite among 4.2 owners. Either a 14" or 18" would do justice. I love my exhaust note, especially paired with my K&N '77 series CAI. Also a xCal 2/3 with custom tunes would help out ALOT with mileage.

here are the axle codes:
19 — 3.55 non-limited slip — F-150
25 — 4.10 non-limited slip — F-150
26 — 3.73 non-limited slip — F-150/Mark LT
27 — 3.31 non-limited slip — F-150
B5 — 4.10 limited slip — F-150
B6 — 3.73 limited slip — F-150/Mark LT
H9 — 3.55 limited slip — F-150
18 = 3.08 non-limited slip — F-150

 

dirty88, what is alot with mileage? How much increase are we talking about?

 

it depends on your driving style, and whether its highway or city. just ask around, and you will get a bunch of different answers...

 

I wouldn't expect much more than 20 mpg on the highway, no matter what mods you do. Yes, I've heard of people getting as high as 25, but that's rare and you would probably have to drive at 55 mph on cruise control to do it - and it won't happen with oversize tires or aggressive tread tires.

My 03 is stock except for a low restriction muffler, I'm assuming it's similar to yours, and the BEST I ever got on a tank was 23.2, the worst was 12.8. My normal highway driving gets between 18 and 19 on E10 gas, cruising in the 65 to 75 mph range. If I can get pure gas, I can knock down 20 mpg if I keep it down to under 70 mph.

 

yeah I just looked and I have a 19 axle code. Ive been looking at JET programmers. Seems to be the best bang for your buck ie up to 130 hp and 205 ft/lbs of torque. Which I wouldn't expect to get out of my V6 but Im sure it'll give more gains for the price than a air intake sys or exhaust sys. What do yall think about programmers?

 

Those claims are usually made on higer end cars, not our trucks. Best bet would be to stick with either an Edge Evo or an Xcal 2/3, with tunes from PHP (Power Hungry Performance), Troyer, or VMP.

The best mileage I've seen so far in my truck was 20.3, crusing @ 70-75, with AC on, and doing I-10 through lower Texas hill country....Still waiting on better results.

For now I say go with an exhaust, then add a CAI and/or programmer later.

 

Start by putting racing decals on your windows.......it will make it look faster anyway!

 

No, even better. Do like elivista, and paint your throttle cover red, and put sticker on the side of the truck!! and you will have 260 RWHP!!!!

 

If you get a Scan Gauge II, you'll go right up to 232 HP.

 

stay away from throttle body spacers...
check out mac mufflers too.. their cold air intakes are definitly worth it. but i really really like the way MAC's mufflers sound.

ive heard them on lightnings, 4.6l mustangs, 3.8l mustangs and i have one on my truck.

oh i had 300rwhp but removed my sport stickers (xl sport) and immediately lost like 25rwhp...

 

yeah those gains are for the diesels.


get a custom tune, 4.10 gears, a larger throttle body, a "GOTTS INTAKE", e-fans and a shift kit.

 

Have yall ever heard of someone blowing their engine do to a programmer?

 

yeah. pretty simple actually. you flash your engine with a programmer and love it so much you drive the dog ot of it 24/7. sooner or later its going to die

i think the only thing that will actually degrade the life of a stock 4.2L is a turbo setup. if you had the money and could afford new internals for the 4.2L AND a turbo, i think ur fine. but directly, ive never heard of a perfectly fine engine go out due to a tune