[BellasBmw]

I have absolutely no idea about performance parts . Now that i got a car that i can play with down the road- can someone give me a quick over view of intakes, exhausts (i know it makes a louder noise ), etc... And if in the future i wanted to add something to bump up the power just a bit, whats the best way to do this? Thanks guys!

[F32Fleet]

Sorry to bust your bubble, but you should've bought the 330. Aside from suspension you're out of luck. Unless you want to install a supercharger, the engine will NOT give u anymore than what it already has without spending lots of $$$ (as much if not more than what the 330i would've cost you).
Software, Injectors, CAI's, LW Flywheels, etc etc. are fun to install/relatively cheap but won't give you anything appreciable.

I wouldn't be surprised if Dinan just gave up on the E90.

[YYdoodle]

socom, I think you're jumping the gun just a little bit.. I agree with you that there's likely not much performance gain to be had from most mods, but who knows for sure yet.... maybe the tuners, but not us (at least not me). The people at bimmerworld.com seem to indicate that some power gains may be possible. I just saw this post yesterday from jamesc the founder, he seems to be saying that some power gains may be possible.

http://www.e90post.com/forums/showthread.php?t=1679

[F32Fleet]

But it's a question of how much HP : $ spent. Without serious engine/transmisison modifications I believe he's SOL. What can I say, I'm a bit of a pessimist and very bitter person in general.

It's like this, why spend $2-3k modding your car's engine/transmission when for just an add'l $3k more you can get the real deal, with full manufacturer warranty?

Some people say they couldn't afford it, but if you can't afford the payment for the 330 why do u think you can afford to put down a couple of extra thousand $'s cash on car mods?

[CC 330i]

Originally Posted by BellasBmw

I have absolutely no idea about performance parts . Now that i got a car that i can play with down the road- can someone give me a quick over view of intakes, exhausts (i know it makes a louder noise ), etc... And if in the future i wanted to add something to bump up the power just a bit, whats the best way to do this? Thanks guys!

Now I am one of the biggest critics of "making a 325 into a 330", but I think that modding the car via a mild intake or exhaust is fine, and a cool thing to do. You may not get a very good horsepower increase for your dollar, but a new exhaust can add a sportier exhaust note, and a new intake and exhaust could add a couple of horsepower. (less than 10 hp in most cases).

Most of the 40hp difference between the 325 and 330 is in the intake system, meaning the variable path intake. I think basically the 325s is just simpler, and probably tuned more toward economy. The 330i intake system is more complex, and is tied into the software of the car to optimize power at different RPMs. I think their are 3 different paths that the air can take depending on RPM. Traditional intakes just have one path, and you only get optimum power at a certain RPM range.

So aftermarket intakes for the 325 may take the form of a variable system like the 330 (maybe stock 330 parts for example) or just a better version of what the 325 already has. (single path I think). Assuming it is a single path intake, here are some things to think about.

Most aftermarket intakes and exhausts are about maximizing air flow through the engine. Pump in as much cold air as possible, and allow that air (and burnt fuel) to exit as quickly and efficiently as possible. So aftermarket intakes are usually freer flowing. A better air cleaner can do a little bit, but usually you have to change the shape of the intake and filter to improve flow. What the 330i intake does is basically change the shape of the intake as the engine speed increases. This optimizes power over a broader range of RPM.

Exhausts, if they have a lot of bends in them that are not efficient for airflow, can also be improved somewhat by a straighter, cleaner path. Aftermarket exhausts usually emphasize greater diameter as well. This can help peak horsepower by reducing backpressure, but this can also hurt torque at lower rpm, and may hurt fuel economy.

To really get the most out of the 325 intake/exhaust, you need install aftermarket downpipes, which are basically the "headers" or exhaust pipes that come right off the engine. You may hear about "cat back" exhausts a lot. These usually are easy to install and only go from the catalytic converter back. Installing new downpipes usually is much more time consuming and difficult. In some cases you have to take other things out to get to the engine to install them. You are probably looking at 4+ hours in a qualified shop to have this done. This may or may not void your engine warranty, since downpipes are bolted directly to the engine. Tuned downpipes allow the greater airflow of the intake to exit the engine more efficiently. BMW does a pretty good job of designing it's downpipes, but maybe there is some hp to be gained if you change the intake too.

You may also have to install different or bigger catalytic converters, which are smog reducing devices that are on the exhaust pipes. This can make your car non smog legal. It may not increase emissions, but technically, changing any factory smog equipment is illegal in CA.

Then, making the exhaust the least restrictive as possible from the cats back is important too. A freer flowing exhaust (true dual exhaust) is usually better for peak horsepower at high rpm, but may hurt torque at low RPM. I noticed that my 330i has a valve on the exhaust to shut one of the exhaust pipes, and I think this may be to help fuel economy while decelerating. So there is obviously some benefit to making an exhaust MORE restrictive, because BMW went out of their way to make a valve to plug one exhaust pipe in the 330i.

So depending on how much horsepower you are looking for, intake/exhaust may be a good way to go. If you just want a sportier sound and maybe a couple more horsepower, a cat-back exhaust is a good choice, along with a K&N air filter. You could get this done for about $1000-$1500 probably. There should be many out in the next few years.

Dinan is a really good tuner, and their stuff is covered by BMW warranty. I may install some of their stuff when it comes out for the E90, but I read that it will be at least a year. They probably need at least that long to engineer something better than what BMW spent years developing. Think about that when tuners come out with parts a couple of months after a car's launch. How much time and money likely went into developing that part?

[ogrady]

Great post as always CC330i.. thanks for the info and insight.

[BellasBmw]

It seems as if everytime i ask a simple question about upgrading or atleast modifying my 325, SOMEONE always comes along and tells me that i should have bought the 330 and to basically quit asking. Ive posted a couple times regarding this issue and no one responded with a legitmate answer (except for CC330i, thanks btw). Ok i agree, why spend the extra $ when in the end i should have just sprang for the 330- BUT this is something i can do in the future, when i have extra money to play with. I could not afford to finance a nearly $50K automobile right then and there. It seems as if 330 is the only way to go so DONT even try with the 325.. No offense, im sure everyone is out to help and offer their suggestions- but last time i posted about upgrading to xenons, i got numerous posts telling me, "should have bought the 330", or when i posted the issue regarding 325 v 330- i got more responses telling me that in the end i was better off with a 330. Im sorry but this is my 1st car that i actually give a sh*t about, and im looking for any means possible to make this car everything i wanted it to be. I just need some assistance along the way (not critcism or regretfulness), and what better way to accomplish this, than ask the people who would know.

[CC 330i]

Like I said, I am probably the worst offender when people say they want to take their 325 to 330i performance. I will tell them it is not worth the cost. I will say "BMW can make a better 330 than an aftermarket shop.

But you didn't ask that. You asked if you could add a few horsepower with an exhaust, and "what is an intake, etc", which are legitmate questions.

For a relatively small amount of money, there are definitely things you can do to personalize your car and add a little performance.

Some other things you can think about:

Handling:

1. Maybe add bigger/wider wheels and stickier tires down the road.
2. Maybe add adjustable shocks or more expensive gas shocks down the road.
3. Maybe consider an entire suspension system. Just BE CAREFUL because your 325 was tuned by BMW for RUN FLATS, and they finally got it right with the E90, so I doubt aftermarket suspensions would ride very well. They might be very rough and may actually hurt handling.

Engine Performance.

1. Get a K&N (or equivalent) air filter for your existing intake system. Sooner or later, your air filter will need replacement, and get something like a K&N in the stock size and shape to replace it. You will probably see some air flow increase. Your car's computer will adjust fuel delivery and maybe will give you more power. Very cheap (less than $100).
2. Think about getting a cat back exhaust if you don't mind a louder more agressive exhaust note. You will likely gain a few horsepower, but this is mainly about sound. You might lose some fuel economy too.

That's about all I would advise. None of these things shoud hurt reliability (except maybe a full suspension). Save all your stock parts (except the air filter of course) so that when you go to sell the car, you can put it back to stock. No one likes buying someone else's science project. Talk about poor resale. You would be lucky to get the same price for a modifed car as a stock one.

[F32Fleet]

Originally Posted by BellasBmw

It seems as if everytime i ask a simple question about upgrading or atleast modifying my 325, SOMEONE always comes along and tells me that i should have bought the 330 and to basically quit asking. Ive posted a couple times regarding this issue and no one responded with a legitmate answer (except for CC330i, thanks btw). Ok i agree, why spend the extra $ when in the end i should have just sprang for the 330- BUT this is something i can do in the future, when i have extra money to play with. I could not afford to finance a nearly $50K automobile right then and there. It seems as if 330 is the only way to go so DONT even try with the 325.. No offense, im sure everyone is out to help and offer their suggestions- but last time i posted about upgrading to xenons, i got numerous posts telling me, "should have bought the 330", or when i posted the issue regarding 325 v 330- i got more responses telling me that in the end i was better off with a 330. Im sorry but this is my 1st car that i actually give a sh*t about, and im looking for any means possible to make this car everything i wanted it to be. I just need some assistance along the way (not critcism or regretfulness), and what better way to accomplish this, than ask the people who would know.

Yea..I'm sorry. I just don't want BMW's too turn into some cheezy tricked out honda civic looking car with asian writing on the window.

[BellasBmw]

Thanks for the response, i will def look into all of this for the future. And when the time is needed for a new air filter, ill def go with the K&N, as i heard this is a great one as well.

[CC 330i]

Originally Posted by Socom

Yea..I'm sorry. I just don't want BMW's too turn into some cheezy tricked out honda civic looking car with asian writing on the window.

Tell me about it. Gotta love driving next to a slammed Civic and the guy's head is bouncing up and down violently because he's just chopped the springs in half. He's got what looks like a Dyson vacuum cleaner for an exhaust and it sounds like my lawnmower when I take the muffler off. Oh, I miss Irvine...

It was getting pretty bad in Carlsbad when I moved away too!

[BellasBmw]

Originally Posted by Socom

Yea..I'm sorry. I just don't want BMW's too turn into some cheezy tricked out honda civic looking car with asian writing on the window.

Haha Trust me, if that ever happens to my E90, I give you all permission to come to Ca and offically slap some sense into me.