So does a backbox delete rob power?

lol , I removed the secondary cats the resonator and did a 1inch bypass on back box . Bypass was first gave a little more of a growl and no drone . Next I did a Afe intake that made it note at the front ... At this point power still same feeling (all in the head) . Next I took the secondary cats of and the resonator box and fitted straight through pipes . Throttle response feels slightly sharper but nothing major . Exhaust note changed considerably more deeper tone with a little poping on the over run . Over the moon with it and no DRONE !
 
lotus791 said:
lol , I removed the secondary cats the resonator and did a 1inch bypass on back box . Bypass was first gave a little more of a growl and no drone . Next I did a Afe intake that made it note at the front ... At this point power still same feeling (all in the head) . Next I took the secondary cats of and the resonator box and fitted straight through pipes . Throttle response feels slightly sharper but nothing major . Exhaust note changed considerably more deeper tone with a little poping on the over run . Over the moon with it and no DRONE !

Sounds good without being excessive :P
Any chance you could post a recording of it for us to hear?
Regards
 
ronk said:
Beetlegav said:
mr wilks said:
I could hear it before i could see it [emoji14] it did sound beefy tho , was quite impressed 8) unlike my neighbours [emoji14]


Haha I piss my neighbours off actually, one on a completely different street tracked me down n threatened to call the police on me :lol:
All because I woke her poorly son at 4 in the afternoon! Could understand if it was at midnight! (I stick my car in 5th at night and idle down my street)
I just told her to ask politely or I'll purposely drop a cog everytime I go past her house :D

They hated my beetle too and that was standard :lol:


I've been in that situation in my 20's with a full race set up 1293 cooper s (late 60's) I suppose now I'm old I can understand why it got up their noses! I probably woke the whole neighbourhood up. :D

Good fun at the time tho! [emoji106]
Same set up on my mini, minus straight cut gears. Oh the noise.

Need to look into my zed for more noise
 
Ross0604 said:
The reason for loosing the back box rather than mid box is due to the fact you will see a lot more resonance inside the cabin with centre box removal than you would back box removal

Not true in the slightest. Working in the tuning industry (all be it the VW/Audi side of that industry) I've driven a fair few S4's with the 4.2 V8 that have had the centre silencers removed - Absolutely no drone, where others I've driven with the rear silencers (that are much larger and do much more silencing) were absolutely awful for drone levels at cruising speeds.

I think I'll experiment myself and base my final thoughts on what I experience.
Having said that - We have a customer with a Mk5 R32 using a stock exhaust with the centre silencer chopped and straight piped - It has no resonance issues but sounds awful. Just too harsh a sound.
The result could be bad, but I'd rather find out the proper way rather than just opinion.

We'll see :)
 
This one is bypass

http://youtu.be/Nrs2kbwNc-Q


And this one secondary cats removed .

http://youtu.be/7ulsN1ebqo4


Can Rev it too hard next door has wee kiddys sleepin lol

Link fixed
 
I've got a spare exhaust system now so might finally put this to bed and get on a rolling road
 
First one sounds good! A subtle increase above the stock volume but nothing too loud or boisterous.
I take it that's with the small centre silencer removed.

The second one won't load. Says its a private video (ooh err...)
 
That actually sounds real nice! Good work and thanks so much for the video clips!
 
Cheers for the sound clips lotus!
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Just had the back box delete done to my Z... Had it done by Silver Systems in Leek, Staffordshire for £80 - he did a great job and it's reversible too. It sounds awesome - the youtube clips out there don't do this mod justice, especially if you like the old straight six sports car soundtrack! As for the power... My butt dyno originally said that it feels a little slower... but then I thought "does it just feel slower because I'm used to going faster for the same level of noise in the cabin?" Same noise level pre-delete would require higher RPM... I recalibrated my butt dyno by turning up the radio real loud :D , and tried again... This time I didn't really notice any power loss :thumbsup: It was difficult to resist the urge to pop into a McDonalds car park with the radio up loud and the noises out the back, though :rofl: Radio now back in it's usual position (off) and I'm very happy with the results :driving:
 
Just to confirm some other stuff:

My engine is an M54B30 I think (my Z is an early 3.0, not a later si)... On the pops / bangs / crackles: yep, especially when you release the throttle, or use engine breaking! To be fair, mine did a bit of this before the mod, just VERY quietly.

I'll post a video up when I get a chance, probably over the weekend :thumbsup:
 
It has crossed my mind that my butt dyno might be misinterpreting the slight feeling of power loss because of the noise. Seems really odd to say but it almost feels like the loss of power is being sucked out by the noise the exhaust produces. Or it could be as some people have suggested because of a lack of back pressure. Im going to be getting the exhaust changed over in coming months to another non standard system so ill report back if I notice any difference.
 
Has anybody noticed any change in how long the engine takes to warm up after having this done? Not sure if it's just a coincidence but my engine seems to be taking longer than it used to, to warm up. Mainly the heating.
Any suggestions?
 
Beetlegav said:
Yeah just backbox delete on the 3.0i m54 b30 engine.
It's so much more brutal than It sounds in the video :lol:


Do you find that you get that fart sound at low revs that most backbox deletes get on Z4s?
 
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