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Discussion Starter · #1 ·
I just bought a 2003 325iT. I already have a 2003 330xi, and i can tell the difference in power.

I'd like to pep up the 325i a bit without going crazy, are there noticeable gains in intake and exhaust (catback) on these cars. Also, what about a chip?
 

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TheMalibuMafia
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I just bought a 2003 325iT. I already have a 2003 330xi, and i can tell the difference in power.

I'd like to pep up the 325i a bit without going crazy, are there noticeable gains in intake and exhaust (catback) on these cars. Also, what about a chip?
Put a different differential in to get more torque if you wana "feel" the power.
exhaust really doesn't give noticable power at all. And if were talking you want to feel a diffeence in power... your going to have to go the forced induction route.
A chip won't do anything other then make it feel like more jolty throttle response. Unless if your car was supercharged or turboed then a tuned chip would be noticable.
 

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Keeping it surreal
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I just bought a 2003 325iT. I already have a 2003 330xi, and i can tell the difference in power.

I'd like to pep up the 325i a bit without going crazy, are there noticeable gains in intake and exhaust (catback) on these cars. Also, what about a chip?
*Realistically*, no....there`s nothing (worthwhile) that will help...."What you see is what you get" with these engines. If you`re *determined* to throw your money away, be aware that power increases come at a steep price....$100 per horsepower is pretty much the norm....
 

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Ich bin ein Bimmerer
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Yep, replace the VANOS seals and keep the tires properly inflated. Might want to make sure the plugs are good, air filter is clean, oil is healthy (1500 is long IMO) with good filter, and realize you bought a quality, "near-luxury" sporty vehicle that is comfortable, exceptionally ergonomic, and honestly does very well for the power it has. For reference, my 2004 ZHP at stock 235 hp had almost identical 0-60 and 1/4 mile published numbers to the 300 hp Rustang GT of the same year. And the braking distance matched the Porsche 911 of that year, as I recall. Not too shabby! It won't win anything, but it wins on the "everything".
 

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Discussion Starter · #5 ·
About what I thought. I'm not new to BMWs, just never had one of these. I work for a dealership and had our head tech and fellow enthusiast go through it with a fine tooth comb. Still might do an intake and exhaust but not in any hurry. I'm buying wheels for it tomorrow
 

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About what I thought. I'm not new to BMWs, just never had one of these. I work for a dealership and had our head tech and fellow enthusiast go through it with a fine tooth comb. Still might do an intake and exhaust but not in any hurry. I'm buying wheels for it tomorrow
There's another thread on here about the Active AutoWerke re-flash/map of the ECU for our cars. I posted their dyno results that show an increase of 12.4 HP and an 11.4 ft lbs of torque on the 330. Cost = $399.

They claim the same kind of results for the 325i (+15hp and +12 torque).

Take a look under the ECU reflash thread. EDIT - Found the dyno results
 

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Keeping it surreal
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About what I thought. I'm not new to BMWs, just never had one of these. I work for a dealership and had our head tech and fellow enthusiast go through it with a fine tooth comb. Still might do an intake and exhaust but not in any hurry. I'm buying wheels for it tomorrow
Intake & exhaust will change the sound of your engine, but that`s about all....it`s been discussed here thousands of times.

There's another thread on here about the Active AutoWerke re-flash/map of the ECU for our cars. I posted their dyno results that show an increase of 12.4 HP and an 11.4 ft lbs of torque on the 330. Cost = $399.

They claim the same kind of results for the 325i (+15hp and +12 torque).

Take a look under the ECU reflash thread. EDIT - Found the dyno results
Until we witness similar results *on a fester`s car*, I would still take these figures with a grain of salt....manufacturers often come up with results that for some reason are unobtainable by the rest of us....
 

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Until we witness similar results *on a fester`s car*, I would still take these figures with a grain of salt....manufacturers often come up with results that for some reason are unobtainable by the rest of us....[/QUOTE]

Bob...if you're not careful, folks will start to think you're a cynic!!
 

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Tilted, Brim low Brim low
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"Well, It***8217;s Better To Look On The Negative Side Then Positive (Through My Assumption). . That Way When You Expect It, It Won***8217;t Have Such An Emotional Impact On You Once It Actually Happens....Ex. Disappointment -Back On Subject- So BMW.Nick Don***8217;t be surprised If you don***8217;t get the Full Horsepower And Torque With The Mods. ."
 

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Discussion Starter · #11 ·
Trust me, Im used to disappointment, Im a Cubs fan!

Again, Im not looking for a race car, just a wee little extra pull. I like the sound of the Active Auto chip. I may go that route as well. Then I can report back to the 'fest
 

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ROLL TIDE!
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I just put a set of headers on a 330ci. The car had a lightened flywheel, CAI, and AC Schnitzer muffler with the second resonator removed. It was pretty peppy before the headers. Post header it is a little faster, but the guy paid $200 for the headers, $200 for jet hot coating, and paid me $400 to install them (not enough BTW). So he had $800 in it for probably 10 peak HP and maybe a little more in the mid range. Worth it? Not in my mind.

Th AA tuning may work on a car like the above, but not on an otherwise stock E46. I have the Shark Injector on my 323i, and while I did notice a tiny bit more torque in mid range, it isn't an appreciable difference. And the only reason I went with Shark is because it was given to me.
 

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Smolck,

what did your guy do about the post cat sensors? I am a little disappointed to head about headers, thought about doin that once the car is "mine" not the family car.
If you were willing to invest the dough to remove the head, do some port & polish work, and switch to more agressive cams, THEN the headers would have a much greater effect on performance.
 

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ROLL TIDE!
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Smolck,

what did your guy do about the post cat sensors? I am a little disappointed to head about headers, thought about doin that once the car is "mine" not the family car.
Right now the post cat 02's are in the drug bin hanging loose (literally). Keep in mind it isn't my car, the guy who owns it might think it is a lot faster. But the most I have ever seen on a dyno for headers was 11 peak hp. That said, if you buy ebay ones for $100 and do the install yourself, it might be worthwhile.
 
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