Reducing exhaust fumes from cammed L77.

[Jeda]

Hi all, just thought I'd ask if anyone has been able to reduce the fuel smell from a cammed LS by going with larger cell count cats.

It has 100 cell cats which are useless, so I'm thinking of going with 400 cell cats and a retune.

Has anyone managed to eliminate or at least significantly reduce the fuel/exhaust smell on a cammed LS?

Cam specs are: 225/236 .629"/615" 114 LSA, 109 ICL

Current exhaust is a 3" crapforce cat back, 100 cell cats, and GM Motorsport triple stepped headers.

 

[dassaur]

Am I reading that right? Cam has +5 advance!?

 

[07GTS]

some tuning that not many shops do or understand can help with the smell, but at the end of the day if the cats arnt burning the emission it will smell, but tune wise should be able to clean up alot of it

 

[daves8]

Unrelated but does it drone?

 

[Jeda]

Unrelated but does it drone?

Less drone after the cam was done, but still there around the 1600-1900 range.

Prior to getting the cam done, the drone was horrible, and that's with afm turned off in the tune. With the cam swap, all the afm hardware is gone, maybe that helps with reduced drone too.

 

[Jeda]

some tuning that not many shops do or understand can help with the smell, but at the end of the day if the cats arnt burning the emission it will smell, but tune wise should be able to clean up alot of it

Do you know any tuners that have the talent to do this here in Melbourne?
The 100 cell cats may as well be gutted standard cats. They do the same job. The only difference is after market cats are easy to spot by anyone wanting to issue a defect notice.

 

[07GTS]

Do you know any tuners that have the talent to do this here in Melbourne?
The 100 cell cats may as well be gutted standard cats. They do the same job. The only difference is after market cats are easy to spot by anyone wanting to issue a defect notice.

not sure on any tuners as i havnt seen much of there work to see there style, the better shops i would expect to make these adjustments as any change from stock cam should be adjusted to suit but im not sure how many change it, yours has 2 deg of overlap at .005 which isnt too bad my old cam had 5 deg, if u have access to your tune file in hptuners u can send it to me and i can adjust to to suit your cam then send back and u can flash it in see how it goes

 

[Jeda]

not sure on any tuners as i havnt seen much of there work to see there style, the better shops i would expect to make these adjustments as any change from stock cam should be adjusted to suit but im not sure how many change it, yours has 2 deg of overlap at .005 which isnt too bad my old cam had 5 deg, if u have access to your tune file in hptuners u can send it to me and i can adjust to to suit your cam then send back and u can flash it in see how it goes

Thanks mate, unfortunately I don't have access to it. Really appreciate the offer though.

I'm considering taking it to Dale Paterson Motorsport for a retune. Might get the exhaust modified before I do though, getting rid of the xforce catback and useless cats.

 

[07GTS]

Thanks mate, unfortunately I don't have access to it. Really appreciate the offer though.

I'm considering taking it to Dale Paterson Motorsport for a retune. Might get the exhaust modified before I do though, getting rid of the xforce catback and useless cats.

if u get it tuned again then i can show u some settings to help out get them to adjust it will at least get your idle better and it helps with low end torque also and drivability also

 

[EYY]

APS, twin city dyno tuning (Brett is one of the best in the country to my understanding - worked at G&D and HPF when their reputations were at the top of the game), LS1pwr among others.

Just make sure you do your research before committing to a tuner.

With a cam they will often smell, and there’s not always much you can do about it. If the engine is happiest at 12:1 idle afr and that gives best off idle transition, thats where you want it. All engines will be different.

Of course have some 200 or 400 cell cats fitted first prior to retuning if it’s a real concern to you.