What's the least expensive way to up the HP on a 325i and by how much?

[LABachlr]

I'm looking into getting my first bimmer, and can not pass up a 325i that is for sale that has both the extended warranty and extended maintenance plan. The thing is, I like fast cars. So, I was wondering how much it would cost to up the HP to that of at least a 330i, if possible. If not, then by how much can I increase the HP, how, and how much would it cost?

Please advise.

Thanks.

 

[535iracer]

that's 41HP you'd have to gain, it will probably cost quite a bit... I would reccomend the 330i... overextend yourself a little bit, thats what its all about LOL

 

[Kirby]

It will cost you more to build up a 325 than it would cost to buy a 330 instead. You just can't magically gain 25 - 40 hp. Remember, there is a reason for 500cc bigger engine!

A chip or Shark Injector might get you 10 - 20 hp. New exhaust 3 - 6 hp, air intake 3 - 6 hp. But don't add them all up and expect to get 32 hp, and it will not be an across the rpm range increase, just a peak or boost at a limited rpm band. It just doesn't work that way, law of diminishing returns applies here!

Or spend $5,000 - $10,000 for a turbo or supercharger and get 75 to 100hp.

 

[codex57]

Like the others said, you're not gonna be able to do too much. I'd just hold out until you can extend yourself to a 330. It's totally worth it. I kinda regret not doing it myself. Especially now that I'm working with a guy who has a 330 ZHP. Difference is huge and nothing short of forced induction is gonna get my car to his level or higher.

 

[rjp325i]

You cannot do much tuning on a BMW without spending big bucks if you want to get the hp up to the level of a 330. Supercharging or turbo charging is also expensive. Don't forget also that the 330 has 1 inch larger brake rotors all around for increased stopping power. The factory has done most of the easier hp improvements before you get the car. Reprograming the computer costs about $350 and gets you about 10 hp at the top end. Air intake kits and exhaust will get you a few more but still will not come close to equaling the hp or torque of a 330 and still not nearly as quick as a ZHP because of gearing differences. Save up and buy a 330 it will be worth it as I found out. You however have to make the decision. The 325 is still a nice handling car to be enjoyed just do not expect miracles from a 2.5 L engine without emptying your bank account especially if you have to pay someone to do the work.

 

[Section_8]

3.46 Differential swap - 3-400 dollars - This alone makes you as fast as a manual 328 once you get used to the quicker shifting. Poor man's turbo..

Slap on intake, exhaust, chip, maybe some other minor things like a underdrive pulley kit, and yes you are as fast or faster than a 330 (manual even) in a 323/325, for approx $2k or so.

You guys bashing what a 325 can do, must forget that a 330 is only a half second faster in the 0-60 than a 'poor' 325. As stands, I'm as fast as a manual 330 and I haven't even done a pulley change - just the 'common 3' and the diff swap. Consistantly pace or outdistance 330's now. (If it's auto I leave it like a 328)

The ZHP has 10hp on a 330, it's not like it's a leaps and bounds difference, 'maybe' 1 carlength in the 0-60.. The gearing difference is the single biggest 'advantage' to the ZHP, and this can be accomplished in the 323/325 to a greater degree with the simple diff swap I mentioned above. I've run with a stock ZHP (manual) and by the time we reach 100, he's only about 1-1/2 carlengths on me - nothing to go gaga about.

All that said if you've got the wad in your pocket and 'want' to build a fast BMW, start with the 330 platform, you 'might' get it as fast as a e36 M3 w/o going FI.

Go FI, and you'll eat 330's for lunch and cause E36 M3 owners to wonder if their car is falling apart..

 

[codex57]

That's for a stick. If it's auto, the 330 is a huge step up in speed. Can't do a differential swap cuz, well, it's already there stock.

 

[DrPierceMD]

Look into g-power. They are actually looking for U.S. distributor's. Right I believe they are only operating out of germany. They have some really good stuff. Although it can put a BIG hole in your pocket. For about $12,000 you can get a 325ci running at 415hp. You can start making e46 M3's look stupid. But it is a hell of a lot of money for that.