Quench vs engine emissions
Thread Starter
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Quench vs engine emissions
Trying to figure this one out but not having any luck.
I'm hoping to build another motor for the 78 next year, and right now NOx is a potential enemy.
I would like to increase CR (currently ~8:1) to about 9.5 - 10:1.
Running aluminum heads, 216/216 110 hydraulic flat cam. Would probably up to like a 218/224 112 hydraulic roller cam for the next motor.
Heads are AFR 195, pre-eliminator. May up to eliminators.
Could do 350 or 383, might do the latter to keep the Rs down.
So I know that by increasing the CR I run the risk of increasing NOx. My quench right now is probably garbage. I have no idea what it is, but it's likely BIG. (74cc heads, 0.039 gasket, flat top pistons some level below the deck).
How would tightening the quench up affect smog levels?
I'm hoping to build another motor for the 78 next year, and right now NOx is a potential enemy.
I would like to increase CR (currently ~8:1) to about 9.5 - 10:1.
Running aluminum heads, 216/216 110 hydraulic flat cam. Would probably up to like a 218/224 112 hydraulic roller cam for the next motor.
Heads are AFR 195, pre-eliminator. May up to eliminators.
Could do 350 or 383, might do the latter to keep the Rs down.
So I know that by increasing the CR I run the risk of increasing NOx. My quench right now is probably garbage. I have no idea what it is, but it's likely BIG. (74cc heads, 0.039 gasket, flat top pistons some level below the deck).
How would tightening the quench up affect smog levels?
Thread Starter
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Thread Starter
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
I guess the more efficient combustion chambers helps as well.
@TSW - going to have to get myself some more Vizard books.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Sorry, after scanning thru several titles I haven't been able to put my finger on it yet. Maybe it was Voegelin, Staffel, or someone else, but I do recall it being fairly clear and by a reputable source. Based on whatever was the text, I've actually looked into this matter for my own purposes, and the sims I've run with this in mind have certainly been favorable. Figure if a build isn't a max-effort one anyway, why not try to clean it up a bit where practical?
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We are true environmentalists. Even with a complete lack of emissions requirements, I'd still try to make my car run decently clean.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
We have a WINNER! Thats the reason Chevy gave up the good style Fuel Injected combustion chamber in the 71 model year, same for the big block excepting the LS-6 but the lowered the compression to eliminate NOX emissions.
Safety Car
Joined: Nov 2008
Posts: 3,717
Likes: 551
From: Seattle Washington
With out really knowing the answer to your question I would say that a more modern head like the AFR's would be more efficient, and therefore more carbon frendly. I do know on a Diesel we used to use Starting Valves, a small Valve in the Cly Head that opened to allow Compressed Air in to start the Engine. It worked well and there wasn't any starter motor. But Emissions have put an end to them, as the extra Valve made a dead spot in the Quench killed emissions. I would assume polishing the Combustion Chamber would do just the opposite and Help Emissions.