Weber 32/36DGV verses the Weber 38DGES

(pooh bah)
Tue Nov 01 2005
10:09 PM
Sarge
(carpal tunnel)
Wed Nov 02 2005
01:33 AM
yodta
(pooh bah)
Wed Nov 02 2005
10:35 AM
yodta
(pooh bah)
Wed Nov 02 2005
12:27 PM
I know, man, I know. I couldn't believe Randy (the Honda mechanic brother in-law) wasn't backing me up on it. instead, he said,
and I quote, "Any car will ping under the right conditions." what the hell's that supposed to mean?
I couldn't think straight at the time with them all ganging up on me. what the heck's a knock sensor even there for in EFI setups if
pinging is okay?
Re: Weber 32/36DGV verses the Weber 38DGES
Here's Auto Meter's version of the narrow band:
http://store.summitracing.com/default.asp?target=/egnsearch.asp&N=400442
Sarge
Re: Weber 32/36DGV verses the Weber 38DGES
yeah, I looked at a few of those when I was shopping for mine. I don't know, I don't think there's anything wrong with the one I
have. an A/F meter is a simple device -- the display on them is simply based on the output voltage from the O2 sensor. the more
important thing, I think, is the sensor placement. my understanding is that if it's not a 3-wire heated one, then it's supposed to be
as far up the exhaust system as possible to ensure it heats up properly to give a correct reading. mine's in the pipe off my #3.
Re: Weber 32/36DGV verses the Weber 38DGES
interesting information on pinging...
found here http://www.msgroup.org/Contrary/NEG037.html
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>Pinging is the sound of damage being done to your engine.
That is not true. In a normal non-pinging engine, the spark plug fires at the desired time and initiates a spherical flame that moves
across the combustion chamber consuming the air/fuel mixture as it goes. This flame increases the temperature and pressure in
the cylinder and creates your power. When the combustion chamber temperatures get high enough, it is possible for the air/fuel
mixture to spontaneously combust (pre-ignition). This is what happens when a car "diesels" on runs on after the ignition is turned
off. Commonly the source of the ignition is from carbon deposits or simply a sharp edge on the piston or head surface.
When both pre-ignition and regular ignition occur simultaneously, you get two flame fronts moving towards each other. When
they meet, they extinguish each other with a loud pop. That pop is the ping. This effect is similar to turning off the acetylene on an
oxy/acetelene torch. The ping is not harmful. But it is an indication that there is something amiss, something that may be silently
damaging you engine.
One source is excessive carbon buildup. That means nothing is wrong and the engine simply needs a good cleaning, ON THE
INSIDE. The reason for the excessive carbon could be due to an oil consumption problem, either leaky valve seals or worn piston
rings. Either way, the head needs to be removed to solve the root cause, the can be decarboned at the same time. An engine is
normally good at burning away carbon on it's own. The problem could also be due to mal-adjusted carbs or a dirty air filter
causing the engine to run way to rich. Again, that is a problem that needs correcting and a 1/2 bottle of Techron engine deposit
cleaner will quiet it right up. In no case does the pinging from carbon cause engine damage.
The other cause of pinging is excessive cylinder temps. As the temps rise, the sharp edges of the piston will ignite the mixture.
The excessive temperature will also start to melt the piston. Again this could be due to a number of situations. One case would
be a dirty air cooled engine or a water cooled engine with some problem with the cooling system. The other possibly is that
engine was designed to run that hot (like a race engine) and simply needs higher octane. This will in time cause engine damage,
but it is again and indication of a problem. If the engine is dirty, higher octane will cause the pinging to go away, but it is still
running too hot.
Contrary to what the gasoline companies advertise, engines never need to change octane. If a new engine is happy with 87 and
at 40,000 miles starting pinging, that means is time for some maintenance, not higher octane. Many european cars and bikes
need higher octane because of their better fuels. The US has the "worst" fuel in the world. Germany starts the fuel grades at 96
octane, the their engines are designed to need it. Now, many foreign manufacturers "de-tune" their engines to run on our 87
octane gas. If your engine needed 89 or 92 octane new, then that is what you must run. If it didn't need 92 new, and does now,
look for a problem.
Your comment, however, about altitude was right on track.
Now on the subject of a properly tuned engine pinging. Yes, they should ping, a little under certain conditions. Engineering is a
field of compromise. You want the most power, the best fuel economy, the cleanest emissions, and the longest longevity out of
any engine. But each of these conditions requires different tuning, generally opposite from each other.
An engine needs to be tuned to operate at a sweet spot that is the compromise of all requirements.
As I said earlier, pinging can be the result of high combustion temps, and this is the type you would expect to occur. High temps
are caused by a combination of lean fuel and advanced timing. Lean fuel produces higher combustion temps and hence more
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