which should i get first?

an underdrive pulley or CAI

i know im going to kick myself when ya tell me but what is CAI

CAI is cold air induction. It replaces the stock air cleaner box with a conical filter.

I would suggest the under drives first. You will see very little to no gains with the CAI and surely will not feel the gains. If you wanted to see the gains you would have to dyno the car before and after. Personally I think CAI is just a rip off.

I would go with the CAI first. The underdrives are good if you plan on getting lower gears to slow down the accessories up front. UDP's only give another 5hp and CAI can give 10-20 depending on the vehicle. I have both on my 2000 and noticed a bigger jump from the CAI.

well they both will add about the same hp at least thats what they are advertised i just think the cold air is more for looks though .by the way i knew id kick myself.

I would go with the CAI first. The underdrives are good if you plan on getting lower gears to slow down the accessories up front. UDP's only give another 5hp and CAI can give 10-20 depending on the vehicle. I have both on my 2000 and noticed a bigger jump from the CAI.

How the hell does lower gears slow accessories?

:rofl: well it ... yeah theres the...wait a minute yeah what 351Stang said

I think what he's getting at is that if you put lower gears in the rear with stock pulleys, your accessories turn faster due to increased engine RPM at a given speed, with underdrives they'll slow back down.

My .02 cents: CAI gives you the same gain as a K&N replacement filter, just looks better. UDP's are nice but can cause some quirks. Look to your exhaust for gains.

I'd go UDP over CAI neither one gives you real large gains but I think the UDP actually give you someting where I feel CAI is mostly looks. Plus UDP for 5.0 and 4.6 don't cause any issues that happened in there earlier days so no drawbacks to them.

Oops, yeah, I always forget that my UDP's are ancient March ones....They do cause me some charging issues...

It's a toss up. BTW my earlier post was in favor of UDP's "if" lower gears are put in the rear. The higher rpm's increase wear on the accesories, the UDP's will help them last longer. CAI is easy to install, UDP's require pulling the balancer off which is no big deal it just takes longer. Most stock air boxes are very restricted. More air in and more air out = increased HP. Pesonally I'd go in this order: cat back, x-pipe, cai, throttle body, gears, UDP's.

well being the mustangs intake is pretty good i'll say pullies would be better

how much are udp's? and what do they do?

cold air induction

how much are udp's? and what do they do?
Underdrive Pulleys range between $80 and a $130. Depending on application and metal chosen (steel, aluminum). Underdrive pulley kits basically free up excess power from crankshaft, water pump, and alternator pulleys giving you a little horsepower.

i'd go for underdrives. neither will get you that noticable difference when driving, but they help a lot down the line when you've done some more extensive intake mods and full exhaust.

i just put underdrives on my car, and it seems to pull just a hair harder. it would be better if it were a 5spd... but that's my next mod.

SO would i feel a difference with a catback n cai?

The catback and CAI work together well to make your engine breath better. This will add around 20 hp, which you'll feel (it's not huge but noticeable). You'll also get about 2-3 MPG increase which is a fringe benefit. While you are doing the catback throw on a performance X or H pipe with high flow cats. You are looking at around $1000 for all 3 mods.

UDP's require pulling the balancer off which is no big deal it just takes longer.

Now since the balancer is pressed onto the crank, and has holes drilled and tapped for the crank pulley to be bolted to it, plus the large saftey bolt....why exactly is it that you would have to pull the damper?
Really, have you ever changed a spark plug??? How about trying to learn a little so you know what your talking about when you say it. Seems to me you are almost blowing shit out your ass.

thats one of those new one piece pulley/balancer/crank/flywheel kits they are awesome

Now since the balancer is pressed onto the crank, and has holes drilled and tapped for the crank pulley to be bolted to it, plus the large saftey bolt....why exactly is it that you would have to pull the damper?
Really, have you ever changed a spark plug??? How about trying to learn a little so you know what your talking about when you say it. Seems to me you are almost blowing shit out your ass.

Sorry bud, but some newer Fords do require pulling the balancer to remove the pulley. I think 4.6's are this way (I may be wrong, I've never really worked on one) and I don't know about the 3.8 in question here....

I never seen one yet that the balancer had to come of maybe the crank bolt that holds the balancer on but never the whole balancer but , hey i could be wrong.

I would go with underdrive pulleys!

Really, have you ever changed a spark plug??? How about trying to learn a little so you know what your talking about when you say it. Seems to me you are almost blowing shit out your ass.[/QUOTE]

Dude maybe you should just look under the hood of a 4.6L before sounding like such an ass. BTW I just installed my UDP's 3 weeks ago, the balancer / pulley are a combo unit. Before you go off on being such a dick you should really get your damn facts straight. For others that are reading this I don't normally get into little spats but this pissed me off.