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Old 05-25-2011, 09:12 PM   #1
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Join Date: Aug 2009
Location: Ontario Canada
Posts: 966
My Ride: 1999 328i (M54b30)
M52TU - DIY: (gains on a budget)

Hi everyone,

I have officially started the quest to extract more power from the M52TU in my 328i. I hope that this thread can serve as a useful resource for others looking to get power out of the older geneneration of e46. There is lots about the difficulty in getting more power from the 325/330s, but not much that is specific to the 323/328s.

Let me preface this by saying, that at this point, my goal is to have a daily driver that I can run hard at weekend road course track events and get as much power as possible out of it safely and affordably. I don't have big dollars to throw at gaining little bits of power. My money has to count for more than its worth. If this describes you, then this is just what you have been looking for. I grew up working on muscle cars (drag cars), I own a 1967 Buick Skylark with a Big block 430 making close to 400 horsepower and I know what power feels like. I was missing the rush that real horsepower gives while simultaneously relishing the superb driving dynamics that are BMW. I currently work as a service advisor at the local Toyota dealership, so I have access to vehicle repair amenities that others may not have, however, in keeping with the spirit of this thread, I will be doing all of these mods at home with common hand tools and nothing higher than floor jacks.

I have done extensive research on what is out there for our cars and have started off this quest with 2 mods that looked cheap and effective.

330i (M54) Intake manifold swap


Ebay Headers.

To do both mods cost me a total of 243 bucks!!!
I got the intake for $150 from a scrapyard with the Disa Valve attached and the headers were $53 plus $43 shipping to Canada from Ebstores on Ebay.

We had a long weekend up here in Canada this past weekend and so I used the few days off to get this work done. On the Saturday I started with the Intake. Pulled my old intake off which was pretty straight forward, however, I had one hiccup for about 20 minutes while I wrestled with getting it to budge more than an inch or two after I thought I had removed every bolt. A quick google search revealed an annoyingly buried bolt up under the throttle body. Its easiest to get to from under the car by reaching your hand up past the transmission on the drivers side and feeling for it. It clamps a bracket to the block from under the intake. (You will need the car in the air to do this mod, if you are using ramps like I did, make sure you drive it up while you can.) Also, ensure you label everything. I'm a classic example of what not to do. Once I get started on a project I get in a rush and push hard to get it done, often this results in more delays then necessary. When reassembly time came, it was stressful getting all the connections right and hoping I wouldn't have to tear it down again to fix a missed vacuum line or connector.

The only thing preventing this from being a straight bolt on job is the fact that our throttle body is smaller than the 330s. This means that in order to bolt our throttle body onto the m54 intake we need to either purchase or fabricate an adapter plate. I have no money, therefore I chose the later option. TMS sells an aluminum adapter for 60 something bucks, so that is your first option, people online also have plans to get an adapter machined which would likely cost 50 bucks (option 2). Option 3 is to give me money and I'll sell you my design I'm kind of kidding. I'm not going to horde, after all, I want to get this out there. I will sell the adaptor I made if you want, but its even easier If I tell you what I did and you can make it yourself. I got the basic design concept from looking at the other adapters and designs out there. However, I thought to myself, why restrict this to the skills of a machinist. The intake is made out of plastic after all, why cant the spacer be as well. Hell, it will probably transfer less heat too. I went to my local commercial plastics supplier (for signage and displays and whatnot). I asked him for a plastic that could withstand 170F (the hottest I figure it could get that far from the block) and would be easy to work with. He gave me a sheet of 1 inch thick plastic for 10 bucks. I will update you all with the exact specs soon.

I used table saw, a drill, and a hole saw to cut it to my measurements for the bolt holes/throttle hole. The only snag I ran into with my preliminary design was that the throttle hole was centered to my bolt holes and slightly overlapped the edge of the manifold when looking through it so that there would be a ridge the air would hit when traveling into the manifold. A dremel used to widen the manifold hole quickly solved this. (I didn't really want to go back to the drawing board on the spacer just for this little ridge) However, this could be solved with future renditions. Also, due to the thickness of the spacer, the electronics box under the throttle body could not be bolted back up, it sits very nicely and does not rattle without its bolts anyhow. I used a thin layer of rtv sealer to seal the spacer and throttle body to the intake manifold.

So how did it work? ....

in one word, awesome. After the car adapted to the mod it just pulls like a new animal above 4k RPM. I swear I must have gained 15 horses maybe even 20 in some spots. (I will be getting dynoed when this is all finished). The torque felt untouched and the car is generally the same below 3k. I read a thread about a guy hitting the limiter because of missed shifts after this mod and I can say I totally empathize. I had to relearn my shift points once it adapted because my first few forays into the redzone happened so suddenly that I shifted too late after I already bounced of the limiter. It just flies through peak rpms now.

I took a day off on Sunday to drive it. On Monday it was game on again. The headers were actually an easier job than the manifold, but definitely tedious and frustrating in their own way. There are enough DIY's that I don't really need to elaborate on how this was accomplished. (speaking of which, if you need DIY's for these jobs you really should reconsider whether you are ready.) While it isn't required you be a mechanics wizard to complete them, you really need to be adept at working on cars before embarking on these jobs.

How did the increased exhaust flow work in conjunction with the increased Intake flow?

Once again, awesome. Gains all over. The car just pulls like a freight train now and It does not feel like any 200ish hp car I've ever driven. Of course its probably only making a bit more than 200, but the way the power comes on and the lack of loss in the BMWs drivetrain make it such a quick little car.
My friends 2002 Subaru WRX which I was working on simultaneously this weekend(doing turbo up-pipe and exhaust upgrades) does not feel as fast as my car now. It used to be just a tiny bit faster.

I am elated with the performance gains. It just feels like I must have gained a solid 30 horses in some spots due to these mods.

Stay tuned for future upgrades. I am thinking the next item on the list will be an Active Autowerke tune. After the tune I will take it to get a dyno test. (Unfortunately I do not have a dyno of a before from my car, but the local tester is very reputable and gets accurate and reasonable results)

Regardless, the car feels completely different. It just hauls now.

BTW, for those with experience, how much would I stand to lose in power by adding a set of high flow cats into the mix? (This is something I'm going to do anyway, I'm just curious)

Also, with saving money in mind, I reused both the exhaust and intake manifold gaskets as both looked to be in good shape. I have no leaks.

Who says you can't make cheap, decent power with a BMW. People need to open their minds and get out there and do some leg work and thinking on their own. If I will fault this community for one thing, it is expecting things to be handed to you. Bolt ons don't come from no-where. People have to fabricate and take risks. That is the R&D for future bolt ons. If you wait for some company to do it for you, you pay the premium. I'm sick of the only answers being FI,M3 or go home. While I agree that if you want super-car performance, those are the routes to go, you can get a fast car with much less money if you are willing to do the work yourself and look for the deals. FI might be something I'll be interested in when I have spare cash, but thats not the case right now.

I spent only $243 for a significantly faster car, thats it, thats all.

Last edited by jared_wiesner; 05-26-2011 at 09:07 AM.
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