So does a backbox delete rob power?

Beetlegav said:
From what I recall 4th
Which on the e46 and 36 would be fine as they're 5speed.
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Why wouldn't your car produce full power in 4th gear? I thought the torque limiter only affected the bottom gears?
Regards
 
Which ever gear is closest to final ratio is usually used. When we next get a Z4 in I will try and do a before and after on the Rollers.

You can find an excellent exhaust guide by following the link below
http://www.ek9.org/index.php?threads/blinxs-official-intake-and-exhaust-thread.7868/
 
Ross - where are you located - I may be interested and able to help the b4 and after?

Pm me plse
 
I had the back box delete done by Infinity in the Summer.
I have not noticed any loss in power.
The exhaust sound is loud but probably not as loud as I thought it was going to be. You get lots of pops and bangs under deceleration and according to friends I have been on hoons with it sounds awesome under acceleration.
I don't find it too much of a drone when cruising. The secret is to keep the power on to maintain the speed without accelerating.
I've kept mine as it is and don't have any plans to change it back and for the record I'm well above boy racer age, having said that, most people who know me say I'm not wired up right
 
I suppose if you get better downpipes and an M-gruppe intake, you will even gain a few hp.
I ould never opt for a full delete though, that would be too loud for me.
 
Is there not a Db limit ?
As nice as it might sound, if there is a noise limit and aomebody wants to get awkward ??!!

I'm thinking neighbours being woken at night then reporting to the police etc.
 
Bad_Pritt said:
I suppose if you get better downpipes and an M-gruppe intake, you will even gain a few hp.
I ould never opt for a full delete though, that would be too loud for me.
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Got an afe intake fitted :thumbsup:
As for 'too loud' that's an age thing :poke:

ronk said:
Is there not a Db limit ?
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Passed the MOT without even a mention and I'm not even sure it's that loud unless I've just got used to it.
 
Noise limits on the road are down to the officer that pulls you over or the MOT testers choice. Obviously we build a lot of loud system and have never heard of anyone failing MOT. But we have heard of people being pulled over. As Dav says you would definitely notice a loss in power of 30bhp
 
ronk said:
What and where is the torque limiter?
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It's not unusual for full power to be limited in the lower gears on modern cars, it's written within the engine map-not sure if it can be over written with an ECU remap or not.
Regards
 
Dav the wheel nut said:
I had the back box delete done by Infinity in the Summer.
I have not noticed any loss in power.
The exhaust sound is loud but probably not as loud as I thought it was going to be. You get lots of pops and bangs under deceleration and according to friends I have been on hoons with it sounds awesome under acceleration.
I don't find it too much of a drone when cruising. The secret is to keep the power on to maintain the speed without accelerating.
I've kept mine as it is and don't have any plans to change it back and for the record I'm well above boy racer age, having said that, most people who know me say I'm not wired up right
Click to expand...
if you don't mind me asking, what all was deleted? Cat, res, and muffler? Or just muffler?
 
This may seem like a stupid question to some of you, but how come you guys on here go straight for deleting the backbox, rather than bypassing the centre silencer using straightpipes?

Any particular reason at all?
 
nfbr said:
This may seem like a stupid question to some of you, but how come you guys on here go straight for deleting the backbox, rather than bypassing the centre silencer using straightpipes?

Any particular reason at all?
Click to expand...
Most likely because it sounds better. Or maybe because the muffler is more restricted but I'm just assuming.
 
Smartbear said:
ronk said:
What and where is the torque limiter?
Click to expand...

It's not unusual for full power to be limited in the lower gears on modern cars, it's written within the engine map-not sure if it can be over written with an ECU remap or not.
Regards
Click to expand...

Thanks, I hadn't heard of that scenario.
 
I'm not that educated on automobiles and this may seem like a silly question. But...

how come when my ford fiesta (yep, fiesta, I once drove a heap of shi*e :oops: ) had a little hole in the back muffler box it lost so much power? I could feel it. It was more of a struggle to get it to accelerate quicker. The same was for a Mini Cooper S.

And when you chop the bloomin whole thing of on a Z4 the effect is negligible?

Why is this?

Hope someone can answer this.

Thanks. :thumbsup:
 
I think this one will run and run until there is conclusive proof with dyno results before and after.. and I'm not doing anything unless I see proof!
 
sharkman07 said:
I think this one will run and run until there is conclusive proof with dyno results before and after.. and I'm not doing anything unless I see proof!
Click to expand...
Why not just put a flange to make reversible? There's a couple members that have done that I believe..
 
Technically speaking a loss of backpressure should gain power at the top end, but lose torque at the bottom end and mid-range.
Hence my idea of removing the centre resonator (less of a backpressure loss) and a minor but noticable increase in sound.

I may take this on myself in a month or so. If it sounds sh** I'll just stick the centre silencer back on.
 
The reason for loosing the back box rather than mid box is due to the fact you will see a lot more resonation inside the cabin with centre box removal than you would back box removal
 
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