how much timing at idle 
how much timing at idle
Originally Posted by SideStep
Be careful... Too much timing at idle can cause your cats to super heat and start a fire... Don't ask how I know.... 
superheat the cats, but didn't want to reach 'POOF' stage.
Hawk
I think mor etiming should give the charge more time to burn thus the cats not having to work to hard to consume any extra fuel it may see in the exhaust. I would like to know also how extra timing could cause cats to burn and blow?
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you either raise the rpms or the raise the timing, to help out with the idle. 850-950rpm and 28-32 idle timing takes care of most cams. of course the more extreme the cam, the more extreme the measures need to be taken. at 1050rpm, just about any cam's lope disappears.
How do your guys timing profiles look compared to RPM?
In other words, what is the shape of the graph? Does it decline with an increase of RPM? How much timing are you guys running in the upper RPM?
In other words, what is the shape of the graph? Does it decline with an increase of RPM? How much timing are you guys running in the upper RPM?
TECH Fanatic
Joined: Mar 2003
Posts: 1,946
Likes: 1
With a G5X3, and AFR205s (59cc), Kooks (w/cats), SVO #30s, Vararam, blah, blah, blah all the bolt-ons. Sitting in a bank parking lot logging idle, we noticed a funny smell, then we noticed a red glow from under the car. I opened the passenger door and looked under the car to see the cats glowing a bright white-red. We could smell plastic (C5) burning... 
Not my car but I a horrible sick feeling in my stomach.
The AFR was 14.6 and we had 30 of timing at idle... We backed timing down to 24 and the glowing went away
We were increasing the idle timing to get rid of some of the gas smell...
On my C5 I have LGs with cats all the way back next to the cat-back. If I use the factory idle timing (17*) the cats don't get hot enough to convert. When I set the idle timing to 26* I start getting that slow drip drip out of the exhaust tips, like you do with normal exhaust systems converting correctly. Also this ended the smell I had at idle.
Not my car but I a horrible sick feeling in my stomach.The AFR was 14.6 and we had 30 of timing at idle... We backed timing down to 24 and the glowing went away
We were increasing the idle timing to get rid of some of the gas smell...
On my C5 I have LGs with cats all the way back next to the cat-back. If I use the factory idle timing (17*) the cats don't get hot enough to convert. When I set the idle timing to 26* I start getting that slow drip drip out of the exhaust tips, like you do with normal exhaust systems converting correctly. Also this ended the smell I had at idle.
I'm at about 28 degrees of timing at idle right now.
But, I still get gas smell, and even some smoke at idle. I've leaned out my VE at idle by about 60%, 80% and 90% at 400, 800, and 1200, but I'm still rich.
Should I bump the timing more?
But, I still get gas smell, and even some smoke at idle. I've leaned out my VE at idle by about 60%, 80% and 90% at 400, 800, and 1200, but I'm still rich.
Should I bump the timing more?
Originally Posted by silverTA2002
I'm at about 28 degrees of timing at idle right now.
But, I still get gas smell, and even some smoke at idle. I've leaned out my VE at idle by about 60%, 80% and 90% at 400, 800, and 1200, but I'm still rich.
Should I bump the timing more?
But, I still get gas smell, and even some smoke at idle. I've leaned out my VE at idle by about 60%, 80% and 90% at 400, 800, and 1200, but I'm still rich.
Should I bump the timing more?
as for the idle, what's the VE number in the cells you idle in? more like 30 or more like 55? any more info on your setup? (injectors setup especially)
TECH Enthusiast
Joined: Mar 2004
Posts: 647
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From: Australia
Eliminate the gas smell by targetting a smooth idle and tuning your VE to within +/-4. Oh, and run cats. Good for the air we breathe.
A well tuned car shouldnt need band-aid fixes like 30* timing at idle.
A well tuned car shouldnt need band-aid fixes like 30* timing at idle.
Originally Posted by MNR-0
Eliminate the gas smell by targetting a smooth idle and tuning your VE to within +/-4. Oh, and run cats. Good for the air we breathe.
A well tuned car shouldnt need band-aid fixes like 30* timing at idle.
A well tuned car shouldnt need band-aid fixes like 30* timing at idle.
After Marcin suggested it to me. at idle its good to go a little lean. Im at about 5+ for my ltft's and thats helped with some of my gas consumption at idle. getting better...cant wait for the new o2's and wideband!!
