JimMueller

iTrader: (9)

Did/do you have obnoxious odors and fumes coming from the exhaust even with the stock cam? If you later put in a bigger cam and kept the cats off, did the situation get worse?

2004tr

Jim
I have experienced exactly the same problem.
My engine is stock but my exhaust system uses S&P headers
with 3 in. stainless steel pipe to the silencers via flanged connectors
(either straight through,for track,or a high flow cat,for road test emmisions.)
I have had to fit the cats permanently as it was unpleasant to drive for any distance.
I would be interested to hear if there is anything that can be done with tuning to lean out the mixture as it does seem to be unburnt gasses from a rich mixture. Or is it something else ?

I also found little improvement in performance with the straight through pipes fitted. Hope someone who has overcome this problem can advise best course of action.

Trevor
Replica Cobra 2002 LS1/T56

orangeapeel

iTrader: (18)

I didn't get that bad smell off my first LS1, but the second one did it like crazy. Stock and aftermarket equipped.

BIG_MIKE2005

iTrader: (116)

Yea, if you remove the cats you will smell the spent & unspent fuel fumes. Just part of the modding game. You can really smell it with LT's & ORY.

Ericbigmac83

iTrader: (19)

Smells great doesn't it? yea, youre pretty much stuck with the smell if you dont want cats, so take it or leave it

CaMaRo67RS355

iTrader: (75)

screw go with true duals and bullets no cats and headers it will smell like gas not obnoxious unless ur at a red light

RedRallyeZ

iTrader: (20)

ive had mine off for like a year now and i dont even notice it at a red light anymore. Even passengers in the car dont say anything about it. if its sitting in the garage warming up then you may smell it, but even a catted car smells then.

litle88

iTrader: (20)

I smell it and LOVE IT!!!!!!!!!!!!!!!!

why would you take your cats off?
for better fuel economy?
Helping with global warming?

Come on man, they can't be that obnoxious!

JimMueller

iTrader: (9)

Nah, I've got a friend who I'm trying to help resolve this problem. He had the ORY with his stock cam and he said it smelled, but didn't smoke. Now he switched to a Vinci 060 cam...

DUR @ .004" 290*/ 294*
DUR @ .050" 228*/ 232*
LIFT .551 / .551
OVERLAP 68*
LSA 112*

... and it's smoking out the tips. Other threads seem to be indicating it's merely a result of the ORY. But since he says "It did smell, but not smoke" with the stock cam, we're still wondering if the tuning is off at idle, or if it's a mechanical issue.

jimmyblue

iTrader: (11)

I ran with gutted cats for a year or three, it had a smell
to it but not "obnoxious" or overly noxious. It smelled
like happy motor to me. But instead of soot at the tips
it became more like tar.

With the headers it's stankier because the mixture is
swinging wider (going by idle O2 volts).

litle88

iTrader: (20)

There is only one way to find out.
Has he gotten it dyno tuned?

I also get some soot on my tips.

JimMueller

iTrader: (9)

No dyno tuning yet. No in-car wideband, but I may be able to move mine temporarily to his car. O2's are basically flatlining around 2-300mv and peaking around 700mv once in a great while at idle.