BMW 540i on Dyno with Resonator and Silencer Removed

[qcdstick]

Since this video has been getting popular again all of a sudden, here is the information from the day of the dyno.

ht tp://picasaweb.google.com/nbur­ress/­ExhaustModSpring2008

It has the dyno charts, A/F ratios, raw data etc... Pretty much everything I have on it. Some of you more technically minded people can mull it over if you like.

[qcdstick]

@qcdstick Just a head's up, you'll aparently have to type the link into your address bar... Youtube inexplicably is adding a couple "-" to the link so you can't simply remove the space and copy paste.

[540i6E39]

i actually gained hp by going to a 3" catback with a magnaflow no chamber so in reality it sounds to me like your car hadnt adapted yet. i would almost bet that if u dynoed your car today even with your miles u would have a gain not loss.

[540i6E39]

well removing the resonator and silancer wont make u lose back pressure or if it does wouldnt be enough for u to have a 10hp loss... removing the muffler or changing to say a magnaflow muffler would make u lose some back pressure which is the whole point of changing it..

[540i6E39]

It could also be that the car hadnt adapted itself yet to the change in back pressure. wonder if you dynoed it after resetting the computer and driving for the 3 cycles if the numbers would be higher?

[qcdstick]

@540i6E39 It is possible, I'm not really sure on the finer points of how all that works. I don't think a re-test after adaptation would be meaningful since the atmospheric conditions would be a lot different by then. That, and it has been a few years since I did this so the car has many more miles than it had then also.

I will say that I like the change, and don't notice or miss any power loss that may be there. To my butt-dyno the thing still hauls some ass and sounds good too.

[IPGAuto]

@qcdstick - Removing them caused less power? I'd throw on a catback and get rid of the resonators. Just to have that back pressure. I noticed a torque drop after doing a muffler delete.

[theapeman1989]

wow! so you lost 3hp and almost 20 torques? something doesnt sound right

[qcdstick]

@theapeman1989 It is an engineered tuned exhaust system... The results are not all that surprising when you take that into consideration. There is nothing else to explain it; same car, same dyno, same day. The only thing that changed was the exhaust setup. Pretty cut and dry results.

[cconant13]

Electric fan conversion... I'm assuming this was a custom job? I am so sick of my car sounding like a semi driving around town and I'd like to do a conversion as well.

[qcdstick]

@cconant13 At the time of this video it was a custom job. I was utilizing a off the shelf electric fan situated inside the stock shroud. However I was never able to implement a good way to seal the gap between the outside of the electric fan and the inside of the shroud. As a result some of the air could pull around the fan rather than through the radiator and cooling was insufficient in harsher conditions. I solved the problem with a Zionsville shroud and fan and have had 0 problems since.

[cconant13]

@qcdstick Thanks for the info. I live in Phoenix, so there are "harsh conditions" quite often. I'll look into it.

[qcdstick]

@cconant13 Also, if your car sounds like a truck all the time, check your fan clutch ASAP. Last thing you want is that blowing up... Not pretty.

[cconant13]

@qcdstick Well it's not ALL the time, just when it's 110+ out and I'm sitting in traffic. The clutch is fine - I can stop the fan with my hand at idle, spin it backwards, etc... unless it's locked up because of the immense heat, of course. And it always disengages above 3000-ish rpm.

[SupraTompan]

The stock resonator has more duties that to make the car being more silent. It also levels out the pulses of the exhaust, and also absorbs lots of vibrations, so removing it makes in all cases a power loss.

[G10350]

Oh no. Please tell me the numbers skyrocketed when you added a performance muffler! I have a Hooker Aero chamber and all else removed...

[GhostFaceKillu]

what was the power gain???? I really would like to know i have a 2000 540i m-sport and want to run a similar exhaust setup. I see you had it dyno'd before and after so could you tell me the results?

[Madmaxuke]

Mate click on the "more info" text in the top right of the screen under the video owners details. Apparently losing the reistance and back pressure by dropping the resinator and silencer caused a power loss of nearly 10 horses and a bit of torque.

[thechosenone453]

aint no thang for the solid 540