| Re: [GMCnet] EFI Question [message #349763 is a reply to message #349761] |
Tue, 29 October 2019 18:09   |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
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Senior Member |
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Asperaton, when moving air has lower pressure than stagnant air.
I see it in our air filter side all the time.
On Tue, Oct 29, 2019 at 1:36 PM James Hupy via Gmclist <
gmclist@list.gmcnet.org> wrote:
> I agree. Even reversion of gasses or reverberations in sonic pulses in the
> gas stream can affect the O2 sensor. Placement of it upstream or downstream
> is also critical, but nowhere near as critical as an exhaust leak.
> 2 stroke exhaust design is almost as critical, particularly on
> expansion chamber type exhausts. Pipe shapes, twists and turns, even
> welding slag, pipe diameter and length also have an effect.
> Jim Hupy
> Salem, Oregon
>
> On Tue, Oct 29, 2019, 1:14 PM Matt Colie via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> Tom Lins wrote on Tue, 29 October 2019 13:07
>>> Could someone explain to me why an exhaust leak could affect the
> reading
>> of a O2 sensor?
>>> I cannot picture how a leak out of a pressurized pipe could make a
>> difference in the AFR reading inside the pipe.
>>> Or am I not understanding something here.
>>
>> ljdavick wrote on Tue, 29 October 2019 13:34
>>> I'm no expert but I expect that the pressurized pipe is really filled
>> with pulses of exhaust gas pressure interspersed with pulses of vacuum.
> The
>>> vacuum (less than ambient pressure) draws in outside air.
>>
>> This is exactly the correct answer and it is why when running a closed
>> loop engine in a laboratory setting, we still needed an absolutely tight
>> exhaust system.
>> Yes, even a little leak can matter.
>>
>> Matt - the refugee from DynoLand
>> --
>> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
>> Electronically Controlled Quiet Engine Cooling Fan
>> OE Rear Drum Brakes with Applied Control Arms
>> SE Michigan - Twixt A2 and Detroit
>>
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmcrvparts.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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