Low end torque

[reardriven]

Re: Low end torque

I believed the reason is to 'de-tune' it to have lower hp for marketing purposes with the same capacity engine.

Marketing drives product differentiation even within the same model. Engineering has to execute this at the lowest possible cost and what better way then just to tweak the engine to detune it.

So presumably E60 523 owners can recover this "lost ponies" relatively easily?

 

[Shaun]

Re: Low end torque

I've read somewhere in Bimmerfest that there is this vacuum actuated valve that closes/opens one of the twin pipes before the tail muffler which serves as some sort of a noise-control mechanism and some Americans have gone to disconnect the vacuum tube and plugged it with golf-tees so that the valve remains open all the time.

Does this apply to our Euro spec cars?

I dunno.. you should check the factory service manual or ETKA or something..

I think shawn or alan knows though..

cheers

 

[Racebred]

Re: Low end torque

for e46, only applies to the 330

 

[stevenwu]

Re: Low end torque

Hi,

I believed the answer is YES BUT for the new 6pot valvetronic engine, I have not really look into it if there is a resonance valve in them. If they are still using the dual runner length intake manifold, then there is one.

Thx

 

[stevenwu]

Re: Low end torque

and my 323 M52TU setup la.................

 

[reardriven]

Re: Low end torque

I've just checked my 325. There is none; Racebred is probably right.

 

[stevenwu]

Re: Low end torque

Hi,

Summaried:

318i val - Do not have
320 2.2 - do not have
323 2.5 - Have
325 2.5 - do not have
330 3.0 - have

hope this help.

 

[mwtang]

Re: Low end torque

Thanks Shaun.

I just noticed something that is very interesting and wish to share with all of us.

M52TU engine and M54 engine both having 2.5L but M52TU has poor throttle response, lower torque values on both low (5000rpm) have the following reasons.

a) Restricted intake filter box, smaller CSA at the intake.
b) Restricted exhaust box, excluding middle piping which do not contribute much on high end after switching between single and twin piping.

I think most of us already knew about the 2 points above. However, very sad to say that 'they' further detuned it at the intake runner side, programmed it to be exactly opposite.

In other word, when it suppose to be long runner at low rpm, it switched it to short runner. Switched to short runner length at high rpm (>4000rpm). The switching of the resonance valve is 180 deg out of phase when comparing to M54 profile. This way, it will cause it to react poorer torque values at both ends and maintain same torque values at mid range, 245Nm@3500rpm.

Just wish to share so for those who wish to 'tune up' all the 323, 523 etc engine, just re-programmed this valve to M54 setting will probably help a lot.

Thanks.

Hi guys, am driving a M52TU, 320i e46. been browsing through through the forum and i find it really informative. My ride unfortunately comes with the valve at one of the tail pipe, was told not to remove it as it will lose back pressure. Some of my mates installed the ACS Muffler hence losing low torque. Been getting different opinion on changing the rear muffler.
May i know what's the results like if i change my muffler to ACS, would i lose back pressure due to the removal of this valve? am also planning to drop-in a K&N filter or even BMC CAI.

would appreciate all recommendation

thanks in advance.

 

[stevenwu]

Re: Low end torque

Hi,

To see if you will lose low-end torque, just unplug a vacuum tube that connected to the exhaust valve. This will make the valve 'open' all the time.

drive a few day and see if you like the sound and torque.

To be honest, this is how it sound and feel when you put on the 'tuner' exhaust.

hope this help.

 

[mwtang]

Re: Low end torque

thanks mate for the info....will give it a try