use factory recommended plugs only. do not use any platinum plugs or any other sorts of plugs with strange/performance alloys in them. they negate performance rather than support it...at least when it comes to our 4.0's. it's simply an engine character.

however my bosch platinums in my 86 MJ with 96 buick 3800 in it KICK ***

indianaman...you should be running 4.88's if you want it to remain streetable on the highway. IIRC this is the deepest gearset you can go with a dana 30 front axle. otherwise 5.13's are great for wheeling/tootin around town

I really don't advise wasting $$$ on a K&N. they're an oiled filter, and a basic parts store brand replacement paper element filter filters more than they do. I only have an OEM K&N because it was still a good filter, and it came with the entire motor/trans etc. that I'm running.

 

no i have no title for it just trailer hauled rig

 

thats alot of rpm..Im doing around 2100-2200 at 70mph (this is a onroad rig) i have the AW4 i heard with 33's/4.56 and the aw4 they put you right back to stock RPM. any truth?

 

i have 33 with d30 front d44 rear limited slip rear end automatic i think 3.55 already

 

he's talking a rig mildly driven highway/interstate (or not at all)

using 4.88's at his speeds will net him the best off-road performance (with stock axles), and higher low-speed mpg, by keeping it in the powerband.

indanaman...do 4.88's if you're gonna spend the money to upgrade. don't forget to consider lockers

 

i got locked rear stock
and im goin to get air lockers for front

 

just to give you a little idea...

my 87 comanche is a 4.0/auto high output (converted) with a dana 44/dana 30 combination, 4.10 gears and 33x10.50 bfg a/t's (they're worn to approx. 32.75") and I cruise 70mph at 1900-2000rpm on the highway. were I to go to 4.56's that would take me up approximinately 250(ish) rpm and put me in the maximum efficiency range for the motor's powerband (were it a stock 4.0...as it is, the power band is probably changed by performance mods such as bore, cam, 2001 intake, 62mm tb, and the 19lb injectors I have on it plus mopar performance cap, rotor, wires). however, if I want to upgrade to 4.88's I will be running around 2450 to 2600 rpm depending on terrain at 70mph. that's absolutely perfect...I don't drive it that fast unless I'm going wheeling, and I want the lower gears when I'm going wheeling.

 

you go 70mph when your wheelin? damn

 

haha, I mean hilly/flat etc.

indianajeepman...you don't have it locked from factory. you may have limited slip, but otherwise it's installed not OEM

 

I've down that in previous XJ's and my dakota I owned. Also gone up to 60mph in 4Wheel Low in my dakota.

 

it never sliped on me hahaha
I MEAN IT IS NOT LOCKED I KNOW THAT BUT I MENT IT IS LI9MITED SLIP
sry for caps too lazy to erase and retype
but i typed that and this and still doing this instead of goin and fixing it anyhow i do want to get a arb air locker for front so i should get 4.88 or for 4.10

 

you'd want to choose between 4.56 and 4.88, 4.10 is out of the picture when talking about new gears with your tire size.

you will have to buy a new carrier for your rear gearset anyways, so you won't be able to use your trac-loc limited slip anymore.

 

WRONG...and illegal in all states, regardless if they do emission tests or not!!

 

cosxjfan,

I was wondering when that would be brought up.



I completely agree and anyone not running a cat is doing our "sport" a world of harm every time they get caught.

 

yea so what performance air filter should i get?