E46 325i Headers Installed - Dyno Graphs included

Ok guys, if you remember my last thread of my B25 stock dyno at 155whp, I got the car dyno'd after headers to show my 11whp gain. Not too bad for a 325i.
The installation was a breeze, the bolts on the head came off like butter without breaking any studs or such! I did not take of the motor mount, and it is definitely not needed, plenty of room to take off headers.
Disconnecting headers from cat-back was a pain in the @ss. 4 of 4 bolts snapped and then I had to punch the fvck out of it with a pneumatic impact gun, and the damn thing wouldn't budge. I ended up taking a pry bar and pry-ed it off.
I was able to install 15 out of the 16 bolts, the middle bolt on the back header was impossible. I had all sorts of extensions and such available, just not possible at all.
I went back and checked the system for any leaks and such, and it is all ok. No leaks were found.
Connecting the header to cat-back was a b1tch. We used a hydraulic jack also to move the cat-back around, to try to align them up perfectly, it just wouldn't happen. We were MM off for the bolt to catch on to threads, and then I pushed my foot down on the foot hydraulic jack to get more leverage and the whole car got up and moved literally 4 inches to the left off the lift. Now we have to get all the stuff out of the way, lower car, re align, etc. Then after hour and a half of messing around with that last bolt we just used a nut and bolt and it did the trick. Hasn't snapped yet, and no leaks were found.
Make sure you use OEM gaskets and nuts.
Here are some pictures and such below.

Ceramic Coated Header from Anthony @ BimmerBrakes




To anyone that wants to purchase headers, I definitely recommend these, I had no issues what so ever. Everything was a perfect fit, oxygen sensor bungs are actually functional. The sensors screwed right in, and they were perfectly placed.


OEM Catalytic Converters


Notice the difference


M54B25 Engine Block



And on to the dyno graphs

NET GAIN = 11 WHP/ 3TQ SAE CORRECTED

Stock Dyno




Dyno with headers


-Kind of pissed off the guy needed 12 pulls to get 3 clean ones, where as the first guy got 3 good pulls each time...My tires are pretty worn out now.


Overall I'm very happy with results. Love the new exhaust tone. Love the new smell.
No service engine soon light due to o2 sims that work perfectly which were also bought from BimmerBrakes. I got the header install done in approximately 8 hours, BUT I did have the car on the lift ft high, and a professional toolbox with all extensions, pieces, etc.
Very fun install. Not hard at all, but never again.

Sorry for delay.

great job. Believe me, you say never again and you will end up having to do it a couple more times, happened to me. I am glad to see some real numbers, guess my butt dyno hadnt lied to me. the torque curve also looks a lot better. enjoy the mod. I am really curious though as to how you did it w/o pulling the mount. Also i amsure if you go in from above you should be able to get the top nut, but what I did was full torque down the shorty header and then do the long one.


all in all glad it worked out for you.

I loosened them both first. Pulled rear out, pulled front out. Connected front. Connected rear.
Them went in and out without any force/probems.

Do you have run files? I'd love to see an overlay of them vs stock.

nice write up, and very good to see dyno numbers

want headersssssss!

I just checked bimmerbrakes' website and could not find any mention of ceramic coating...only that they're stainless steel. Your pic doesn't look ceramic coated either. Are you sure they're not just SS?

Originally Posted by Iceman00

Do you have run files? I'd love to see an overlay of them vs stock.

Unfortunanely no.

Originally Posted by jamex

I just checked bimmerbrakes' website and could not find any mention of ceramic coating...only that they're stainless steel. Your pic doesn't look ceramic coated either. Are you sure they're not just SS?

The ceramic coating was during the group buy. I'm sure he can get them coated for you.
They are ceramic metallic coated, and they are most def coated. I could smell it when I first started up the car.

Nicely done!

this is my favorite mod so far on my 325i

awesome pics/charts man. after seeing this i'm really interested in getting the headers. the results are amazing!

quick question for you or anyone else who did this mod: is the smell really THAT bad and unbearable? i was talking to a guy at the euro shop i go to and he said that the smell is completely unbearable and smells like rotten eggs. is that true?

also how is the sound with the stock exhaust?

thanks guys

You have the stock exhaust right? How does it sound?

Great write-up, getting my SS headers installed tommorrow so hoping everything goes well...

Will be purchasing in about a month!!!! Im super excited.
If i opt just for the SS headers, will I see any negative outcomes? I guess a better way to put it is, do you really need to get coated headers?

Originally Posted by ///Mine

awesome pics/charts man. after seeing this i'm really interested in getting the headers. the results are amazing!

quick question for you or anyone else who did this mod: is the smell really THAT bad and unbearable? i was talking to a guy at the euro shop i go to and he said that the smell is completely unbearable and smells like rotten eggs. is that true?

also how is the sound with the stock exhaust?

thanks guys

Originally Posted by RogueStatus37

You have the stock exhaust right? How does it sound?

http://forum.e46fanatics.com/showpos...15&postcount=2

Originally Posted by xi325xi02

Will be purchasing in about a month!!!! Im super excited.
If i opt just for the SS headers, will I see any negative outcomes? I guess a better way to put it is, do you really need to get coated headers?

Just do it. It helps keep heat in, and helps with sound.

Originally Posted by TrickTizzle

http://forum.e46fanatics.com/showpos...15&postcount=2



Just do it. It helps keep heat in, and helps with sound.

nice vids!

how's the smell once you installed the headers? is it unbearable?

Originally Posted by ///Mine

nice vids!

how's the smell once you installed the headers? is it unbearable?

Nope. It doesnt smelll that much. Only time you will smell it if you get out of the car right after you drive it hard, otherwise in the smell is very faint in the morning, and when I get out of the car once it has warmed up. As far as the rotten egg smell, I haven't noticed anything.

Originally Posted by TrickTizzle

Nope. It doesnt smelll that much. Only time you will smell it if you get out of the car right after you drive it hard, otherwise in the smell is very faint in the morning, and when I get out of the car once it has warmed up. As far as the rotten egg smell, I haven't noticed anything.

thanks a lot for the answers man. 10/10 thread

i'll definitely be getting the headers sometime soon

Holy shit. It sounds fucking awesome with stock exhaust. Im impressed. Cant wait to install them on my car

again great job.

@ the guy whotalked about rotten egg smell. your mechanic must be off his rocker. if you let the car idle in one place you will get a slight smell of gasoline cause there are not cats. but you should never smell rotting eggs.... at least not from the headers.

Great Thread!