Omega Owners Forum

Chat Area => General Car Chat => Topic started by: tigers_gonads on 21 May 2013, 13:51:56

Title: engine / exhaust question
Post by: tigers_gonads on 21 May 2013, 13:51:56

Why does a engine lose power / torque and the emissions rise when you have a leaking exhaust ?

Title: Re: engine / exhaust question
Post by: henryd on 21 May 2013, 14:46:30

The exhaust system is tuned to the vehicle to get flow/back pressure correct hence a big leak will lose performance,leaking exhaust (after cat) shouldn't affect emisions as such but will affect air/fuel ratio as air is drawn in thereby messing with the lambda reading at the tailpipe :y

Title: Re: engine / exhaust question
Post by: Marks DTM Calib on 21 May 2013, 15:15:48

It will only impact emissions if there is a leak pre lambda sensor, what happens is that as the exhaust pulse passes (as its a pulse, not a continuous flow), a vaccum is created (as the exhaust gas has mass and inertia) and draws air in....this is detected by the O2 sensor and impacts the mixture.

What is more important is what were the emissions values?

I ahev to say that exhaust leaks are not the usual cause of emission issues on the Omega......

Title: Re: engine / exhaust question
Post by: slowboy on 21 May 2013, 15:56:37

ditto to last 2 lineshttp://images.omegaowners.com/forum/smf2000/Smileys/oofstd/thumbsup.gif

Title: Re: engine / exhaust question
Post by: tigers_gonads on 21 May 2013, 16:11:25

No problem with emissions as far I can tell.
The car has had a very slight blow for a few weeks but I was going to leave it until I replace the cats.
Over the last couple of days, the blow has got a lot louder and the grunt seems to have tailed off and its using more fuel   :(

Just had a brain wave and thought i'd ask the question  ;)

Thanks