I have a 2003 F150 with a 4.6 V8 and a M90 Eaton Supercharger with 9 pounds of boost. My truck came with 3:55 gears and I'm wondering if I should go with 4:10 gears or add a water/methanol kit? Any thoughts?

Bixbystx

 

My initial response would be yes.. but what tire size are you running?

Under 32".. get some 4.10's

over 32-35... get 4.56.. anything higher.. 4.88-5.13's

 

I'm just have 285/60r/17's on my truck.

 

Forget the water/meth injection.

Get some 4.10's unless you plan on going bigger than the tire you have now.

2wd or 4wd? 4wd will be much more expensive.

Ether way.. gears will be more expensive.

 

get gears. if your 4x4, you could just gear the back and convert to 2x4 and loose about 500lbs, plus a lot of rotating mass

 

You will feel the 4.10s more then the meth but it would be nice to have both,,,,,,I did!

Phil

 

+1
Installed 4:10's a month ago...Definitely fun for the street...If your going from 3.73 to 4:10 it'll change your rpm range up to 300rpms extra.
I havent taken it to the track since the addition but, I cant really cant see it hurting my times like many people will say. Track times are 12.53 108 mph without gears. I'll have to post up new track times with new grears.

2003 Lightning | Ported Eaton, SCT Xcal2, 6lb, E-Fan, Lfp-exchanger, Lfp Idlers, JLP CAI, TR-6, 2/6 drop,
Bassani BX catback, SCT 2400 Maf, T-Bars,Chromies,Hoosier stickys', LC-1 Wideband, Boost gauge

 

How can I find out what gears my truck came with? (05 FX4 screw)

 

I know the 4.10s will give you a better 60' time as long as your trucks hooking up well!

Phil

 

Fosho!!!! Went to the track one time on street tires..It was the last time. It was an embarrasment... All my mods, hp, and tq., and barely ran 13.59. I use the claim of "the track wasn't prepped right", but these L's have too much tq for the street tires. Threw on a set of sticky's and it dropped my et's by a full second.

 

If you look inside your door panel on driver side there will be a gear description... Write it down because it will be like interperting hyroglifics. Also there is also a metal tag that hangs on your pumpkin. It sometimes too has the number. Call the parts department at Ford and they can tell you the what the code represents.

2003 Lightning | Ported Eaton, SCT Xcal2, 6lb, E-Fan, Lfp-exchanger, Lfp Idlers, JLP CAI, TR-6, 2/6 drop,
Bassani BX catback, SCT 2400 Maf, T-Bars,Chromies,Hoosier stickys', LC-1 Wideband, Boost gauge

 

Or just look on the rear end for this tag.


L55 means limited slip 3.55 in the 9.75" rear end.

 

x2
I've seen several posts where people "say" your ET's & track speeds well suffer.

Then others post actual timeslips and, lo and behold, things didn't suffer after all, and in fact improved a bit.

Another vote for gears versus water/meth injection

 

mine is L73.. so I figure that`s 3.73 .. thanx!!