I have a 2000 F-150 4X4 with 3.55 gear ratio. So far I have a superchip, a K&N filter, and Flowmaster 40 series cat-back system. I am looking for more low end grunt. I can floor my truck now and the tires barely spin. You would think that with a V-8 I would be able to do crazy burnouts. I also have the sport package with the 17" wheels and the wide all-terrain tires. I think that may have something to do with it. I was think of the JBA headers but the price is a little steep. Any suggestions would help. Thanks!

 

If you want more low end power, take off your flowmasters. They provide a less restrictive exhaust which takes away low end power. Headers will do the same. The chip and air filter give more low end power. Your tires are also wide, which equals more traction, which equals less tire spin. If the tires are taller than stock, it takes away low end power.

 

I'll trade tires with you.
You won't have any problem spinning them.
Damn Goodyears

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Truck Pictures

99 XLT 5.4L Regular Cab 4x2 120" Wheelbase 4 wheel disc brakes/ABS 5 star larait style wheels Toreador Red/Silver 3.55 gears 255/70/16 OWL Delta toolbox, Ford Running Boards, Ventshades, Bugflector, Bullrings, Donnelly compass mirror, 2" Rear drop.
Eclipse 5340 cd player
Memphis ARCS50 component speakers w/tweeters mounted flush in the door panels (excellent sound)powered by a Sherwood 35x2 RMS amp
Kicker ZR360 for the 2 Audiobahn AWC10 subs
regcab54@sc.rr.com

 

Thanks for the reply y'all. I think I'll just have to deal with no low end power. I have to remember a 4500lb truck is no race car.

 

Get your wallet out, 'cause the word on this site is this is gonna cost some good bucks, and install some new rear end gears. Try a set of 4.11's. The ratio will DEFINATELY wake your truck up outta the hole. If you do lots of hiway miles, your gas mileage will suffer a little. You can figure out your new RPM's at 60 miles an hour by determining the circumference of your tire, and dividing it into 5280 feet( a mile). You travel one mile per minute at 60mph, so RPM is easy to figure out.

Let's use my truck as an example:
My tire (a little tall) is 94.5 inches in circumference = 7.875 feet
You can get your circumference by measuring the tire's diameter and multiplying by "PI"(3.1415927)
Therefore, 5280 ft divide by 7.875 = 670.47619 tire revolutions per minute.
Now, multiply that by your gear ratio:
(mine's 3.08)2065 RPM
a 4.11 = 2756 RPM
a 3.73 = 2500 RPM
a 3.55 = 2380 RPM
Don't forget, your overdrive actually drives less than one to one.. (4R100 O/D is 1:1 in third, and .71:1 in fourth) I'm not sure what the slushbox automatic is, but it's probably close to this.I just don't have that number off hand.

(3.08)2065 x .71 = 1466 RPM
(4.11)2756 x .71 = 1957 RPM
(3.73)2500 x .71 = 1775 RPM
(3.55)2380 x .71 = 1690 RPM

The numbers will show higher RPM's for stock tires or lower profile rubber.
The next trouble you'll have is the speedo will be outta whack, but look that up on the message board as well, lotsa guys have overcome this problem, too. I think ya just gotta send your chip back to Mike, & tell him your new ratio. They reprogram the chip.
So, with the overdrive, and 17" tires, the 4.11 rear end is not so bad, and you'll LOVE the difference. I have 4.11's for my '66 Mustang coupe, and have driven long distance trips up north, and got used to it. Car tires are much smaller, and at 60mph, I spin 3500 RPM.
Glance at Neal's(the freak) comments and see how HE likes his new gears!

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'97 S/C XLS black/silver 157" WB, 4.6/auto, 3:08, home made custom stainless tube grille, terminator muffler, phantom sweep wiper switch(factory installed), a few billet aluminum goodies (the list grows), airbox mods, TPS tuned
email: bazils@hotmail.com
http://content.communities.msn.com/bazilspix/PhotoAlbum

 

Thanks for the advice I am not sure I want to switch the gears I figure that would cost about $1500 and I don't have the money right now. I also do about 60 miles of highway driving everyday at about 80mph so I thin the 4.11's would kill my gas mileage. I tend to drive with a lead foot right now I am getting about 13mpg highway and about 5 or 6 mpg city. I think I am just going to save my money for a while and later on maybe drop in a 351. I think that should wake up the torque!! Anyway thanks!!

2000 Silver reg cab F-150XLT 4.6L 4X4 Sport
Automatic, Superchip, K&N
Flowmaster 40 series Cat-back
Manik brushguard with 2 150 watt offroad lights
OE Cab steps
Midland CB with dual whip ant
The list keeps growing!!!

 

Are you serious??????? 5 or 6 mpg in the city?????

Have you considered adding a supercharger?

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1998 F-150 XLT 4x4 SC/SB 4.6L, Auto., 3.55LS, TTP, etc.
More info at http://www.fordf150.net

 

Superchargers are too expensive and they kill engine life!!

 

Why is it that a less restrictive exhaust causes you to loose your low-end torque??
According to Gibson exhaust reps - there cat-back system reduces backpressure but INCREASES hp and Torque throughout the whole RPM band???

 

Headers gave me more low end power than the superchip. Bite the bullet and get the JBA jet-hot coated headers. Thay are worth every penny.


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97 F150 SC 4X4 4.6
Gibson Catback
JBA Headers
Ford Motorsport 9MM wires
Superchip
JLL Stealthbox
Rockford Fosgate punch 45 to drive stealthbox

 

I looked at the JBA headers $460 is a lot of money but I guess if you compare it with a supercharger that cheap. I think I just might order the headers!! Do you know how long it takes to install them and how hard it is? If I am going to spend that kind of money they better be fairly easy to install. I don't want to have to pay someone another $200 to have them installed!! Thanks for the pointers!!

 

Headers are not that hard to install. It does take at least six hours to install a set, but it is fun to do. Took me six hours
two beers, four crown and cokes, one vicodin and one xanax. Had to get up the next morning and check my work because I did not remember putting them on.. LOL .. I do recall that putting back on the header bolts was kind of a pain. Make sure you use anti seize when putting the bolts on. Plus run your engine for 30 minutes and retighten the bolts.

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97 F150 SC 4X4 4.6
Gibson Catback
JBA Headers
Ford Motorsport 9MM wires
Superchip
JLL Stealthbox
Rockford Fosgate punch 45 to drive stealthbox

 

Gorp, did you have to pull the dip stick and fendor liners to get at the exhaust manifolds. What kind of low end gains are we talking quicker pick up or tire spin ?

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99' F-150 XLT 4.6L SC 4X4 ORP LS

- K&N Air Filter
- Custom air intake from fender to TB
- Superchip
- PowerAid TB Spacer
- ASP Underdrive Pulleys
- Accel Coil Packs
- Rapidflow 3" single CatBack exhaust
- Fluidyne Trany cooler
- A.R.E. Hard Tonue Cover
- Duraliner bed liner
- Mobil1 5W-30

 

Yes I had to pull the dipstick. That is ease to do.... Very easy.. The headers made my truck very quick off the line with a little tire spin. If you get headers make sure you buy the JBA Jet Hot Coated headers.
Thay make the most power of any headers you can buy. you also will not get that tinny underhood leaking sound from them. I am sold on them.. And in my eyes thay are worth far more than any chip, I can still run 87 octain gas... wahoo

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97 XLT 4.6L SC 4X4 ORP Gibson Catback
JBA Headers.. Hot Coated
Ford Motorsport 9MM wires
Superchip. Not is use
EX supercharged. For Sale
JLL Stealthbox
Rockford Fosgate punch 45 to drive stealthbox

 

highroller: See the many posts explaining HP vs Torque, what makes torque, what makes HP, some explain it much better than I ever could..

Exhaust backpressure has some affect on what RPM the peak torque will occur.. In the 5.4L, the peak torque is at a nice low 2500 rpm when stock..

So, its possible that some exhausts can produce more torque and more HP, but these peaks are at higher RPM's.

My recommendation would be to get the 5.4L instead of the 4.6 if you want to be drag racing.. (No replacement for displacement)


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Y2K F250 XLT SC 4x2 5.4L 5sp 4.10LS