I just put 20's with 285/50/20 tires on my 2003 F-150 SCAB with a 4.6. They didn't really slow my truck down but acceleration is down slightly probably because of the added weight and increase in tire size. What would be the best mod to help this, should I buy new gears or would a Superchip Reprogrammer help by changing the shift points?


2003 SCAB 2wd. 4.6
Helix power tower throttle body spacer
K&N Air Filter
Gibson Sweptside Cat-Back Exhaust
Edelbrock Performer IAS Shocks
20x9 Ultra Hotschott Wheels w\t
285/50/20 Goodyear Eagle GTII

 

Quicker gears and a chip/tuner will help a stock truck or your modified truck. The chip/tuner can recalibrate your speedometer, correct shift points, and increase power. I installed 4.10s on my 2000 F-150 with stock tire height and couldn't have been happier with the results.

 

I am quite confused. Either it is slower or it isn't.

Anyway, what was the stock tire size? I am not familiar with 2wd stock sizes. Your new setup is 31.2" in diameter whcih i have a feeling is a fair amount larger than stock. However, most 20" rims and tires are a noticably heavier than stock sized rims. More rotational weight menas more inertia which take more power to turn.

If you have these things without the stocm PCM, you are really missing out. A Superchip/Tuner will make the most of these other mods. I would get that next, then decide if you want the gears.

 

Thank's for the help, I have ordered a set of 3.73 gears and a Superchip 1715. Getting gears installed Monday.

 

good choice... I just recently installed 4:10's on my 01 f150 4.6L and im on 24's...my accelaration seems to be back...next project magnacharger...

24" Katana Azzad's/ 305/35 kumho
Flowmaster 40 original w/ dual outlet
pro comp 9000 shocks (fr)
pro comp 3000 shocks (rear)
Hellwig rear anti-sway bar
Front A- arm and front sway bar-
polyurethane energy suspension bushings
BBK 75mm TB
BBK pulley set
Summitt racing shorty headers
custom track bar
K&N Kit GEN II
Power programmer III
HD lower valance
HD speed tubes