how to boost mpg and hp?

[Crewdude007]

I recently put a cat back exhaust on my 01 XJ. I use it mostly for on-road driving. I was thinking about getting a hi-flow throttle body and cold air intake also. What size throttle body would anyone suggest? I have seen 62-68 mm. Also gave some thought to putting headers on. What's the best mod for the price?

 

[90Xjay]

What's the best mod for the price?

IMO, the cold air intake is.

 

[TwistedCU]

mpg - manual locking hubs

 

[jeep_tsi]

one of the first things id do is upgrade the coil with a high performance one,also bigger spark plug wires to carry the extra juice for 42000 volts id recomend 8.0mm or larger also a capacitve discharge ignition system(ex.msd will cause probs. with computer if dont have this i found out the hard way),port polish intake and exhaust reflash the computer, headers,bore it a little, new fuel injectors,cam thats all i can think of for now

 

[OutOfStep]

exactly

Its like one big chain of events, as soon as you fix one bottle-neck you move to the next one.

I would go with the cold air intake first, the throttle body wont help if you dont get more air to it.

If you go with both the throttle body and the cold air intake you need to adjust (or at least check) your air/fuel ratio as you'll probably be running way lean when you give it hell (especially if you go with the headers as well)

 

[90Xjay]

mpg - manual locking hubs

good point TC

 

[bajaxj]

Before I installed my Cold air my 96 w/5spd was getting around 17mpg both city and highway now I average around 19. The one I purchased was an AEM

 

[jeep_tsi]

me i have a 97 gc (5.2 v8)with the works on it i was just tryin to think of some of the mods that i have that are dyno proven to work me as i was building mine my brother in law owns a performance shop with a chassis dyno last time on the dyno was puttin 400hp/350torque to the ground on pump gas thats supercharged too no nitrous planned my foots to heavy for that would most likely blow my self up needless to say its a gofast on pavement go anywhere ride lots of fun no lift yet still thinkin about that one take it off roadin quite often no problems yet better find some wood to knock on might have jinxed my self but if i do get stuck have a mile marker hydraulic winch to get my self out so no worries