How detramental is an exhaust leak after the O2 housing?

[my_gst95]

I was putting on a 3" turbo back on my 1G and after I was complete, I noticed I had a tiny tiny leak puffing out of section where the DP meets the hiflow Cat...and also a small leak where the O2 housing meets the DP due to a stripped bolt. The whole exhaust system is tight enough to not notice any performance loss or hear any odd sounds coming from the exhaust system and I intend to eventually fix it...but it did make me think, how bad is an exhaust leak after the turbo since some people have cutouts before the cat (I had that myself) or have removed their exhaust system after the DP. If exhaust gases after the turbo are trying to escape as quickly as possible anyway, does it hurt performance to have an exhaust leak as much as it hurts to have a boost leak? Just wondering...

my_gst95

 

[Stanford]

As long as it's after your O2 sensors you shouldn't be affected at all. If it was before the velocity of the air running through the pipes could cause a vacumm at higher RPM's. Your O2 sensor would see the fresh air coming in and think your car is running leaner than it really is. However you have a 1g and only have 1 O2 sensor right in the O2 sensor housing, so you should be fine.

 

[TurboGeoff]

it causes pk.

 

[dmtunc99]

it causes pk.

Can someone confirm this?

 

[marcmsj]

my car is exactly the same way right now. after putting in the new turbo and 02 housing, the bolt that goes from the 02 housing to the downpipe was completely stripped. it's on their firmly but it's leaking a little bit. so far i haven't noticed any performance lost but i do intend on fixing it asap.

 

[EclipseTrbo420A]

so wait....what are we saying this will do for vaccume? at idle mostly.

 

[my_gst95]

it causes pk.

It "could" be a reason for phantom knock, but an exahust leak doesn't guarantee 100% it will produce it. I haven't had an issue with PK at partial throttle with the exahust leak.

my_gst95

 

[my_gst95]

what are we saying this will do for vaccume? at idle mostly.

We aren't saying it will do anything with Vaccum, since an exhaust leak shouldn't effect vaccum at idle or any way.

my_gst95