Guerilla Exhaust Bypass - BRUTAL!

bojan said:
Just do the sound generator thing. I did it on my 2.5 and the car is just perfect. Proper sportscar when I want it and quiet when I'm not in the mood. As you have a 2.2 it will cost you around 150€ you need 8 original parts from BMW and you can install it yourself. You can check it on how to on this forum, but if you want the parts, just google BMW z4 sound generator and some American has posted the numbers of all parts.

Yes, I know about that mod, but it also disrupts the air flow and it only increases the sound of the inflow... I also already have a sports filter. Maybe I should hear it for real first :-)
 
Bad_Pritt said:
bojan said:
Just do the sound generator thing. I did it on my 2.5 and the car is just perfect. Proper sportscar when I want it and quiet when I'm not in the mood. As you have a 2.2 it will cost you around 150€ you need 8 original parts from BMW and you can install it yourself. You can check it on how to on this forum, but if you want the parts, just google BMW z4 sound generator and some American has posted the numbers of all parts.

Yes, I know about that mod, but it also disrupts the air flow and it only increases the sound of the inflow... I also already have a sports filter. Maybe I should hear it for real first :-)

I don't think that it disrupts the air flow. It's originally fitted to 3.0, it's a closed system and the original airbox stays on. It has a membrane so I don't think that it does anything other than increase the intake sound to the cabin. Maybe somebody with more technical knowledge can give us better answer.
 
Anyone concerned about performance don't worry! As mentioned it will allow the engine to breath easier (assuming the pipe diameter isn't smaller than stock) but we run MAF sensors so the ECU will see the extra air flow and supply the correct amount of fuel and spark angle.
It's only engine's running carb's or MAP sensor based system's that would run lean :thumbsup:
 
Taz x said:
Bad_Pritt said:
Just got an offer from Guerilla systems... tempting, tempting...

is it a secret?

lol, no no. There is a temporary action now to have 1 bypass with remote controlled valve installed for 500 euros all-in (ideal for all the 2.0i Zeds out there). Next week, there will be an action for a double valve system (which better suits the strait six).

But as I already had a double bypass on my 911, I can profit of the "customer appreciation program", meaning I can get a discount on my next remote controlled bypass system... So far, we are not yet talking prices as we are first trying to figure out what a good set-up would be. Obviously, a double bypass would make the most sense, but that's 1.000 euros, which I find somewhat expensive for just extra sound. Performance-wise there is little difference except for a difference in back pressure.

Anyway, an idea would be to mount a single bypass on the resonator. This way it is cheaper and you still have some kind of backpressure so that the difference in air flow is not too great. It is true that the MAF will cope, but the question is: how fast? The bigger the difference, the more time the ECU might need to adapt to the changed settings? So if you open/close the valve at high speed for example, what will be the effect during the time the ECU needs to adapt? So this is why I proposed a single bypass to ensure a minimal backpressure in order not to put to much strain on the ECU (in the long run). The idea on the resonator was the Stealer's idea as he already did this on an Infinity.

But I do not know how much space there is under the car to mount the bypass on the resonator... Looking at some pics found online, it seems that the undercarriage set-up is really really tight. Furthermore, I would prefer to control the valve with a "fake" sport button which you can find on the 2.5 and higher.

IMO, this bypass system really makes more sense for the smaller engines out there, like mine. OK, I had it on my 911 and I must admit, opening the valves on the highway really made it sound like a proper race car... But it also attracted the attention of the French police during a trip to the French coast :roll:
 
Anyone who thinks BMW straight sixes don't sound good with loud exhausts should come for a tunnel run with me! :driving: I dare you to heel-toe a loud Z4M in a tunnel and not giggle like a moron afterwards. :lol:

[youtube]sHMXkYFUh9o[/youtube]

Now being able to be really loud one moment and stock volume the next is just icing on the cake! :P
 
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