Home » Public Forums » GMCnet » [GMCnet] Jim Bounds interesting recent posts
| [GMCnet] Jim Bounds interesting recent posts [message #325912] |
Fri, 10 November 2017 09:58  |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
|
Senior Member |
|
|
I have followed with interest his comments about why carbs no longer work (todays gas won’t vaporize correctly for use in a carb) and now why our engines are blowing up mote frequently (they run too hot under some condition).
Take a look at the presentation I did on Fitech (http://www.bdub.net/FiTech_is_the_Real_Deal.pdf). Near the end are two important slides that I think help explain what he is saying. The slide with the two charts is very telling. Those charts are based on an engine running pure gasoline with a stoichiometric air/fuel ratio of 14.7:1. One chart shows peak power at an air fuel ratio of around 12.5:1 (quite rich) while peak economy is around 16:1 (way too lean for our engines to survive for very long). Those charts are based on UNADULTERATED gasoline. The curves for gasoline laced with alcohol would look much differently.
The slide on the next page shows stoichiometric A/F ratios for various chemical compounds. For octane it is 15:1, for ethanol it is 9:1. We not only have been adding ethanol, we have also added a number of other distillates and removed others. So, just as he has been saying, everything we learned about engines when we were all much younger is out the window given whatever it is we now pump into our fuel tanks. Just for giggles, see what happens to those curves if the only change was adding 10% alcohol. The stoichiometric would shift from 14.7 to 14.1. Now guess what happens if you go to lean, either because you reprogram your fuel injection to do that, or because your carb gets dirty inside and does it on its own without you even knowing it, or because you monkey around with the jets, air correctors, power valve springs, etc. in the hope of better mileage. On flat land you might get away with that if you drive at 50 to 60 mph where the air drag is low, but climb any kind of hill or load the engine up with head wind or by speeding up and you will quickly be running way too lean for the conditions and way to hot for any kind of engine longevity. Just what he has been saying.
I am not a petroleum engineer so don’t know for sure how those curves change shape for whatever is in our fuel today, but my guess is however those curves change the result is we should now be striving to burn MORE FUEL day in and day out if we want to keep these old engines healthy. I’m going to guess there is a direct correlation between fuel consumption and engine life. Likely 8mpg is around the BEST one should shoot for these days.
How many times have we heard people say that their coaches ran much better and got much better fuel economy driving in Canada on premium fuel with no alcohol. The only way that could happen is if that coach was set up way too lean for driving on gasoline laced with alcohol. My thoughts anyway.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
glwork@mac.com
http://jerrywork.com
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jerry & Sharon Work
78 Royale
Kerby, OR
|
|
|
|
| Re: [GMCnet] Jim Bounds interesting recent posts [message #325915 is a reply to message #325912] |
Fri, 10 November 2017 10:21  |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
|
Senior Member |
|
|
I'm still trying to figure out exactly what E10 looks like on a O2 Sensor, I have a wide band sensor I use with my carb.
From what I understand, an O2 sensor doesn't actually measure air fuel ratio directly but computes it from oxygen in the exhaust.
This measurement is called Lamda. A Lambda of 1 gives you a stoichiometric AFR no matter what the fuel mix
So if you add ethanol the indicated AFR is incorrect, but an AFR of 14.7 ( a Lambda of 1 ) is still stoichiometric.
I think that anyone tuning anything these days has no excuse to not be running a WB O2, theyre cheap and accurate.
The other question is where on the AFR curve should we be running.
I'm betting about stoichiometric or slightly richer. But no one seems to be publishing that info
________________________________
From: Gmclist on behalf of Gerald Work
Sent: Friday, November 10, 2017 9:58:58 AM
To: GMC Motor Home Post
Subject: [GMCnet] Jim Bounds interesting recent posts
I have followed with interest his comments about why carbs no longer work (todays gas won’t vaporize correctly for use in a carb) and now why our engines are blowing up mote frequently (they run too hot under some condition).
Take a look at the presentation I did on Fitech (http://www.bdub.net/FiTech_is_the_Real_Deal.pdf). Near the end are two important slides that I think help explain what he is saying. The slide with the two charts is very telling. Those charts are based on an engine running pure gasoline with a stoichiometric air/fuel ratio of 14.7:1. One chart shows peak power at an air fuel ratio of around 12.5:1 (quite rich) while peak economy is around 16:1 (way too lean for our engines to survive for very long). Those charts are based on UNADULTERATED gasoline. The curves for gasoline laced with alcohol would look much differently.
The slide on the next page shows stoichiometric A/F ratios for various chemical compounds. For octane it is 15:1, for ethanol it is 9:1. We not only have been adding ethanol, we have also added a number of other distillates and removed others. So, just as he has been saying, everything we learned about engines when we were all much younger is out the window given whatever it is we now pump into our fuel tanks. Just for giggles, see what happens to those curves if the only change was adding 10% alcohol. The stoichiometric would shift from 14.7 to 14.1. Now guess what happens if you go to lean, either because you reprogram your fuel injection to do that, or because your carb gets dirty inside and does it on its own without you even knowing it, or because you monkey around with the jets, air correctors, power valve springs, etc. in the hope of better mileage. On flat land you might get away with that if you drive at 50 to 60 mph where the air drag is low, but climb any kind of hill or load the engine up with head wind or by speeding up and you will quickly be running way too lean for the conditions and way to hot for any kind of engine longevity. Just what he has been saying.
I am not a petroleum engineer so don’t know for sure how those curves change shape for whatever is in our fuel today, but my guess is however those curves change the result is we should now be striving to burn MORE FUEL day in and day out if we want to keep these old engines healthy. I’m going to guess there is a direct correlation between fuel consumption and engine life. Likely 8mpg is around the BEST one should shoot for these days.
How many times have we heard people say that their coaches ran much better and got much better fuel economy driving in Canada on premium fuel with no alcohol. The only way that could happen is if that coach was set up way too lean for driving on gasoline laced with alcohol. My thoughts anyway.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
glwork@mac.com
http://jerrywork.com
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
|
|
|
|
| Re: [GMCnet] Jim Bounds interesting recent posts [message #325916 is a reply to message #325915] |
Fri, 10 November 2017 10:54 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
|
Senior Member |
|
|
Keith,
We acquired a Lambda meter back in 1994 to help program the Hal Tech ECM
that I was running. Back then it was a $ 2,200 instrument.
We used that to help us with EFI as well as carb units.
Until then, I had no idea of how the ratio was based.
Since graduation from engineering, I just don't have the mind to get into
details like I should.
Glad to see that you understand. Thanks.
On Fri, Nov 10, 2017 at 8:21 AM, Keith V wrote:
> I'm still trying to figure out exactly what E10 looks like on a O2 Sensor,
> I have a wide band sensor I use with my carb.
>
> From what I understand, an O2 sensor doesn't actually measure air fuel
> ratio directly but computes it from oxygen in the exhaust.
>
> This measurement is called Lamda. A Lambda of 1 gives you a stoichiometric
> AFR no matter what the fuel mix
>
> So if you add ethanol the indicated AFR is incorrect, but an AFR of 14.7 (
> a Lambda of 1 ) is still stoichiometric.
>
>
> I think that anyone tuning anything these days has no excuse to not be
> running a WB O2, theyre cheap and accurate.
>
>
> The other question is where on the AFR curve should we be running.
>
> I'm betting about stoichiometric or slightly richer. But no one seems to
> be publishing that info
>
>
>
> ________________________________
> From: Gmclist on behalf of Gerald Work glwork@mac.com>
> Sent: Friday, November 10, 2017 9:58:58 AM
> To: GMC Motor Home Post
> Subject: [GMCnet] Jim Bounds interesting recent posts
>
> I have followed with interest his comments about why carbs no longer work
> (todays gas won’t vaporize correctly for use in a carb) and now why our
> engines are blowing up mote frequently (they run too hot under some
> condition).
>
> Take a look at the presentation I did on Fitech (
> http://www.bdub.net/FiTech_is_the_Real_Deal.pdf). Near the end are two
> important slides that I think help explain what he is saying. The slide
> with the two charts is very telling. Those charts are based on an engine
> running pure gasoline with a stoichiometric air/fuel ratio of 14.7:1. One
> chart shows peak power at an air fuel ratio of around 12.5:1 (quite rich)
> while peak economy is around 16:1 (way too lean for our engines to survive
> for very long). Those charts are based on UNADULTERATED gasoline. The
> curves for gasoline laced with alcohol would look much differently.
>
> The slide on the next page shows stoichiometric A/F ratios for various
> chemical compounds. For octane it is 15:1, for ethanol it is 9:1. We not
> only have been adding ethanol, we have also added a number of other
> distillates and removed others. So, just as he has been saying, everything
> we learned about engines when we were all much younger is out the window
> given whatever it is we now pump into our fuel tanks. Just for giggles,
> see what happens to those curves if the only change was adding 10%
> alcohol. The stoichiometric would shift from 14.7 to 14.1. Now guess what
> happens if you go to lean, either because you reprogram your fuel injection
> to do that, or because your carb gets dirty inside and does it on its own
> without you even knowing it, or because you monkey around with the jets,
> air correctors, power valve springs, etc. in the hope of better mileage.
> On flat land you might get away with that if you drive at 50 to 60 mph
> where the air drag is low, but climb any kind of hill or load the engine up
> with head wind or by speeding up and you will quickly be running way too
> lean for the conditions and way to hot for any kind of engine longevity.
> Just what he has been saying.
>
> I am not a petroleum engineer so don’t know for sure how those curves
> change shape for whatever is in our fuel today, but my guess is however
> those curves change the result is we should now be striving to burn MORE
> FUEL day in and day out if we want to keep these old engines healthy. I’m
> going to guess there is a direct correlation between fuel consumption and
> engine life. Likely 8mpg is around the BEST one should shoot for these
> days.
>
> How many times have we heard people say that their coaches ran much better
> and got much better fuel economy driving in Canada on premium fuel with no
> alcohol. The only way that could happen is if that coach was set up way
> too lean for driving on gasoline laced with alcohol. My thoughts anyway.
>
> Jerry
>
> Jerry Work
> The Dovetail Joint
> Fine furniture designed and hand crafted in the 1907 former Masonic Temple
> building in historic Kerby, OR
>
> glwork@mac.com
> http://jerrywork.com
>
>
>
>
>
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
|
|
|
|
|
|
| Re: [GMCnet] Jim Bounds interesting recent posts [message #325920 is a reply to message #325916] |
Fri, 10 November 2017 11:20 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
When burning long chain hydrocarbons, so many by products are created that
it is hard to sort it all out. Today's motor fuels "ain't your fathers
motor fuels". Using a voltage of less than 2 volts to tell you what your
air fuel ratio is, is an exercise in futility, in my opinion. Lamda is only
the tip of the iceberg. Lean means one thing with leaded fuels, something
else entirely with alcohol blended fuels. The refrigeration effect of
various fuels is all over the map as well. It is not likely to improve any
time soon.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Nov 10, 2017 8:55 AM, "Jim Kanomata" wrote:
> Keith,
> We acquired a Lambda meter back in 1994 to help program the Hal Tech ECM
> that I was running. Back then it was a $ 2,200 instrument.
> We used that to help us with EFI as well as carb units.
> Until then, I had no idea of how the ratio was based.
> Since graduation from engineering, I just don't have the mind to get into
> details like I should.
> Glad to see that you understand. Thanks.
>
> On Fri, Nov 10, 2017 at 8:21 AM, Keith V wrote:
>
>> I'm still trying to figure out exactly what E10 looks like on a O2
> Sensor,
>> I have a wide band sensor I use with my carb.
>>
>> From what I understand, an O2 sensor doesn't actually measure air fuel
>> ratio directly but computes it from oxygen in the exhaust.
>>
>> This measurement is called Lamda. A Lambda of 1 gives you a
> stoichiometric
>> AFR no matter what the fuel mix
>>
>> So if you add ethanol the indicated AFR is incorrect, but an AFR of 14.7
> (
>> a Lambda of 1 ) is still stoichiometric.
>>
>>
>> I think that anyone tuning anything these days has no excuse to not be
>> running a WB O2, theyre cheap and accurate.
>>
>>
>> The other question is where on the AFR curve should we be running.
>>
>> I'm betting about stoichiometric or slightly richer. But no one seems to
>> be publishing that info
>>
>>
>>
>> ________________________________
>> From: Gmclist on behalf of Gerald
> Work > glwork@mac.com>
>> Sent: Friday, November 10, 2017 9:58:58 AM
>> To: GMC Motor Home Post
>> Subject: [GMCnet] Jim Bounds interesting recent posts
>>
>> I have followed with interest his comments about why carbs no longer work
>> (todays gas won’t vaporize correctly for use in a carb) and now why our
>> engines are blowing up mote frequently (they run too hot under some
>> condition).
>>
>> Take a look at the presentation I did on Fitech (
>> http://www.bdub.net/FiTech_is_the_Real_Deal.pdf). Near the end are two
>> important slides that I think help explain what he is saying. The slide
>> with the two charts is very telling. Those charts are based on an engine
>> running pure gasoline with a stoichiometric air/fuel ratio of 14.7:1.
> One
>> chart shows peak power at an air fuel ratio of around 12.5:1 (quite rich)
>> while peak economy is around 16:1 (way too lean for our engines to
> survive
>> for very long). Those charts are based on UNADULTERATED gasoline. The
>> curves for gasoline laced with alcohol would look much differently.
>>
>> The slide on the next page shows stoichiometric A/F ratios for various
>> chemical compounds. For octane it is 15:1, for ethanol it is 9:1. We
> not
>> only have been adding ethanol, we have also added a number of other
>> distillates and removed others. So, just as he has been saying,
> everything
>> we learned about engines when we were all much younger is out the window
>> given whatever it is we now pump into our fuel tanks. Just for giggles,
>> see what happens to those curves if the only change was adding 10%
>> alcohol. The stoichiometric would shift from 14.7 to 14.1. Now guess
> what
>> happens if you go to lean, either because you reprogram your fuel
> injection
>> to do that, or because your carb gets dirty inside and does it on its own
>> without you even knowing it, or because you monkey around with the jets,
>> air correctors, power valve springs, etc. in the hope of better mileage.
>> On flat land you might get away with that if you drive at 50 to 60 mph
>> where the air drag is low, but climb any kind of hill or load the engine
> up
>> with head wind or by speeding up and you will quickly be running way too
>> lean for the conditions and way to hot for any kind of engine longevity.
>> Just what he has been saying.
>>
>> I am not a petroleum engineer so don’t know for sure how those curves
>> change shape for whatever is in our fuel today, but my guess is however
>> those curves change the result is we should now be striving to burn MORE
>> FUEL day in and day out if we want to keep these old engines healthy.
> I’m
>> going to guess there is a direct correlation between fuel consumption and
>> engine life. Likely 8mpg is around the BEST one should shoot for these
>> days.
>>
>> How many times have we heard people say that their coaches ran much
> better
>> and got much better fuel economy driving in Canada on premium fuel with
> no
>> alcohol. The only way that could happen is if that coach was set up way
>> too lean for driving on gasoline laced with alcohol. My thoughts anyway.
>>
>> Jerry
>>
>> Jerry Work
>> The Dovetail Joint
>> Fine furniture designed and hand crafted in the 1907 former Masonic
> Temple
>> building in historic Kerby, OR
>>
>> glwork@mac.com
>> http://jerrywork.com
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] Jim Bounds interesting recent posts [message #325921 is a reply to message #325912] |
Fri, 10 November 2017 11:50 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
I did read JimB's blog, and there is a little I disagree with but there is also very little hard information there.
As an auto-lab rat from the early 70's (on and off), I can tell you for a fact that at lot of both Jim's and your premise is correct, but some is not.
Since the early 70's (at Chrysler Proving Grounds) is has been a stated fact that the carburetors we all know are not a vaporizing or gasifying device. In actual fact, the industry has referred to them as "solid fuel" carburetors for years. While the droplet size does matter for emissions (back when a carburetor could even meet those standards), there was a running game (with a large number of really strange plays) between large and small. Small droplets cold burn faster and the larger more slowly. Not too different than gun powder grain size. Which you wanted depended on just what you were trying to accomplish at that moment. The capability to maintain a stoichiometric over a wide band did not arrive until the EGO sensors got reliable. Even then, the "closed loop" carburetors were not that good at much of anything.
Other running issue is: What is gasoline?
Even before "reformulating" this was an open question. When we were getting non-indolene test fuels, we always got a report with the carbon/hydrogen ratio. even if this number was in target, we still could only use indolene (a specific chemical hydrocarbon that can be used as motor fuel) because it was the only thing stable enough to give stable emissions values.
So, the fact that reformulated motorfuel may have a stoich number that is other than 14.68 is just not an issue. From an SI engine's point of view, there is little change over a significantly wide range. Again, this is just one of the problems that new engine controls manage. Just about all of the engines that have a EGO per bank and a modern ECU, are actually doing a cylinder by cylinder mixture control. This has to happen for current standards. It was not desired in the mid-70s cat cars, because they counted on the rich/lean pulses to keep the cat lit and still provide enough O2 for the desired reactions to complete.
Then there is the issue that not all the cylinders see the same mixture (the end cylinders often get lean) with any central fuel feed system. The initial charge pressure (present in the cylinder when the intake valve closes) has a lot to do with what is going to happen when the fire gets started. No, all the cylinders of an engine are never the same and less than a wide open manifold only exacerbates that issue by steering the charge mixture in different directions.
We live east of the Mississippi and rarely encounter altitudes above 6KMSL, but the coach rolled over the Big Horn on the way to Yellowstone and the coach did not complain. We even had to go around a couple of little four-wheels that could not keep speed up at 9200MSL (according to my GPS). They were all too new to be open loop. And, we still did our regular 9.2 for that journey.
So, before you get all fired up to change to a tack-on "fuel injection", decide if it is something you really want to do.
As Dick Paterson has been known to say, most carburetor problems start with the ignition. I am not fond of HEI, but it can be serviceable, you just have to be sure you have the spares along. But, you should carry ignition spares in any case.
Matt - I'll get down off the milk crate now, I have some passcar work to do today still.
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
| Re: [GMCnet] Jim Bounds interesting recent posts [message #325922 is a reply to message #325912] |
Fri, 10 November 2017 12:03 |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
|
Senior Member |
|
|
Jerry, I don't want to open a can of worms, but the longevity of the FITech
unit, with its electronics in a sometimes very hot throttle body, has been
questioned. One of the coaches you sold had a FITech system and suffered a
sudden fuel delivery failure for the new owners on their trip home. What
was the final diagnosis of that failure? There was speculation at the time
about effect of heat on the electronics.
I'm attracted to the FITech for that inevitable time when I lose faith in
my carb and have to send it off for rebuilding. I like the relatively
simple installation, which fits with my sharp limitations on tinkering
time. Until then, I have a good mechanical temperature gauge and if my
engine ever runs hot, it's keeping that fact a tight secret. I did not see
any evidence of overly lean running when I pulled the plugs during my
recent (preventative maintenance) engine replacement.
I recall (probably inaccurately) comments from Dick Balsley from years ago
that lean running and even detonation are not problems at part throttle.
The question is how much we are opening the throttle for given conditions,
and is the power enrichment feature kicking in early enough? That led to a
discussion of power valve springs at the time. He said Rochester designed
for richness to overcome the manufacturing tolerance in the carbs and to
overcome the variation in mixture caused by intake manifold passages. The
number 15% comes to my mind as being the target (6% for the carb itself),
which means a design AFR of no more than 12.7 during power enrichment (when
it is critical), to ensure that all air has fuel to burn instead of metal,
even with pure gasoline.
Does an O2 sensor average the reading across all cylinders? (And it only
reads one bank.) If so, I would want it 10% rich just to keep one cylinder
from leaning out at WOT as a result of intake mixture variability.
Rick "may be remembering this wrong" Denney
On Fri, Nov 10, 2017 at 10:59 AM Gerald Work wrote:
> I have followed with interest his comments about why carbs no longer work
> (todays gas won’t vaporize correctly for use in a carb) and now why our
> engines are blowing up mote frequently (they run too hot under some
> condition).
>
> Take a look at the presentation I did on Fitech (
> http://www.bdub.net/FiTech_is_the_Real_Deal.pdf). Near the end are two
> important slides that I think help explain what he is saying. The slide
> with the two charts is very telling. Those charts are based on an engine
> running pure gasoline with a stoichiometric air/fuel ratio of 14.7:1. One
> chart shows peak power at an air fuel ratio of around 12.5:1 (quite rich)
> while peak economy is around 16:1 (way too lean for our engines to survive
> for very long). Those charts are based on UNADULTERATED gasoline. The
> curves for gasoline laced with alcohol would look much differently.
>
> ...
>
> Jerry
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] Jim Bounds interesting recent posts [message #325924 is a reply to message #325921] |
Fri, 10 November 2017 12:40 |
Sammy Williams
Messages: 522
Registered: August 2010
Karma: -2
|
Senior Member |
|
|
I'd imagine both of the "Jims" have well engineered EFI systems that will
work for us in a GMC. (Yes I know I don't have one yet. Shhhh. lol) :)
Holley also has a bolt on EFI as does others. The OP makes a lot of sense.
Carburetors and today's "gas" are NOT meant for each other. Make sure your
engine
bay has a way to stay cool, make sure you have the proper thermostat in
your engine to help with cooling. Use a "water-wetter" it will help with
keeping the engine cooler.
A hot engine is never good. A proper EFI with todays fuel and a proper
operating cooling system will help engines to stay alive longer.
Sammy
GMCless (shhh! lol) :D
On Fri, Nov 10, 2017 at 11:50 AM, Matt Colie wrote:
> I did read JimB's blog, and there is a little I disagree with but there is
> also very little hard information there.
>
> As an auto-lab rat from the early 70's (on and off), I can tell you for a
> fact that at lot of both Jim's and your premise is correct, but some is not.
>
>
> Since the early 70's (at Chrysler Proving Grounds) is has been a stated
> fact that the carburetors we all know are not a vaporizing or gasifying
> device. In actual fact, the industry has referred to them as "solid fuel"
> carburetors for years. While the droplet size does matter for emissions
> (back when a carburetor could even meet those standards), there was a
> running game (with a large number of really strange plays) between large and
> small. Small droplets cold burn faster and the larger more slowly. Not
> too different than gun powder grain size. Which you wanted depended on just
> what you were trying to accomplish at that moment. The capability to
> maintain a stoichiometric over a wide band did not arrive until the EGO
> sensors
> got reliable. Even then, the "closed loop" carburetors were not that good
> at much of anything.
>
> Other running issue is: What is gasoline?
> Even before "reformulating" this was an open question. When we were
> getting non-indolene test fuels, we always got a report with the
> carbon/hydrogen
> ratio. even if this number was in target, we still could only use
> indolene (a specific chemical hydrocarbon that can be used as motor fuel)
> because
> it was the only thing stable enough to give stable emissions values.
>
> So, the fact that reformulated motorfuel may have a stoich number that is
> other than 14.68 is just not an issue. From an SI engine's point of view,
> there is little change over a significantly wide range. Again, this is
> just one of the problems that new engine controls manage. Just about all of
> the engines that have a EGO per bank and a modern ECU, are actually doing
> a cylinder by cylinder mixture control. This has to happen for current
> standards. It was not desired in the mid-70s cat cars, because they
> counted on the rich/lean pulses to keep the cat lit and still provide
> enough O2
> for the desired reactions to complete.
>
> Then there is the issue that not all the cylinders see the same mixture
> (the end cylinders often get lean) with any central fuel feed system. The
> initial charge pressure (present in the cylinder when the intake valve
> closes) has a lot to do with what is going to happen when the fire gets
> started. No, all the cylinders of an engine are never the same and less
> than a wide open manifold only exacerbates that issue by steering the charge
> mixture in different directions.
>
> We live east of the Mississippi and rarely encounter altitudes above
> 6KMSL, but the coach rolled over the Big Horn on the way to Yellowstone and
> the
> coach did not complain. We even had to go around a couple of little
> four-wheels that could not keep speed up at 9200MSL (according to my GPS).
> They
> were all too new to be open loop. And, we still did our regular 9.2 for
> that journey.
>
> So, before you get all fired up to change to a tack-on "fuel injection",
> decide if it is something you really want to do.
>
> As Dick Paterson has been known to say, most carburetor problems start
> with the ignition. I am not fond of HEI, but it can be serviceable, you
> just
> have to be sure you have the spares along. But, you should carry ignition
> spares in any case.
>
> Matt - I'll get down off the milk crate now, I have some passcar work to
> do today still.
>
>
> --
> 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
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] Jim Bounds interesting recent posts [message #325925 is a reply to message #325924] |
Fri, 10 November 2017 13:15 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
|
Senior Member |
|
|
I chuckle when I hear about water wetters. Do you know what is in them or are you acting on blind faith on their advertising or on what you read on the label?
They contain glycols which should not do any harm to your engine but will do nothing good more than a well formulated antifreeze solution will.
Emery Stora
77 Kingsley
Frederick, CO
> On Nov 10, 2017, at 11:40 AM, Sammy Williams wrote:
>
> I'd imagine both of the "Jims" have well engineered EFI systems that will
> work for us in a GMC. (Yes I know I don't have one yet. Shhhh. lol) :)
> Holley also has a bolt on EFI as does others. The OP makes a lot of sense.
> Carburetors and today's "gas" are NOT meant for each other. Make sure your
> engine
> bay has a way to stay cool, make sure you have the proper thermostat in
> your engine to help with cooling. Use a "water-wetter" it will help with
> keeping the engine cooler.
> A hot engine is never good. A proper EFI with todays fuel and a proper
> operating cooling system will help engines to stay alive longer.
>
> Sammy
> GMCless (shhh! lol) :D
>
>> On Fri, Nov 10, 2017 at 11:50 AM, Matt Colie wrote:
>>
>> I did read JimB's blog, and there is a little I disagree with but there is
>> also very little hard information there.
>>
>> As an auto-lab rat from the early 70's (on and off), I can tell you for a
>> fact that at lot of both Jim's and your premise is correct, but some is not.
>>
>>
>> Since the early 70's (at Chrysler Proving Grounds) is has been a stated
>> fact that the carburetors we all know are not a vaporizing or gasifying
>> device. In actual fact, the industry has referred to them as "solid fuel"
>> carburetors for years. While the droplet size does matter for emissions
>> (back when a carburetor could even meet those standards), there was a
>> running game (with a large number of really strange plays) between large and
>> small. Small droplets cold burn faster and the larger more slowly. Not
>> too different than gun powder grain size. Which you wanted depended on just
>> what you were trying to accomplish at that moment. The capability to
>> maintain a stoichiometric over a wide band did not arrive until the EGO
>> sensors
>> got reliable. Even then, the "closed loop" carburetors were not that good
>> at much of anything.
>>
>> Other running issue is: What is gasoline?
>> Even before "reformulating" this was an open question. When we were
>> getting non-indolene test fuels, we always got a report with the
>> carbon/hydrogen
>> ratio. even if this number was in target, we still could only use
>> indolene (a specific chemical hydrocarbon that can be used as motor fuel)
>> because
>> it was the only thing stable enough to give stable emissions values.
>>
>> So, the fact that reformulated motorfuel may have a stoich number that is
>> other than 14.68 is just not an issue. From an SI engine's point of view,
>> there is little change over a significantly wide range. Again, this is
>> just one of the problems that new engine controls manage. Just about all of
>> the engines that have a EGO per bank and a modern ECU, are actually doing
>> a cylinder by cylinder mixture control. This has to happen for current
>> standards. It was not desired in the mid-70s cat cars, because they
>> counted on the rich/lean pulses to keep the cat lit and still provide
>> enough O2
>> for the desired reactions to complete.
>>
>> Then there is the issue that not all the cylinders see the same mixture
>> (the end cylinders often get lean) with any central fuel feed system. The
>> initial charge pressure (present in the cylinder when the intake valve
>> closes) has a lot to do with what is going to happen when the fire gets
>> started. No, all the cylinders of an engine are never the same and less
>> than a wide open manifold only exacerbates that issue by steering the charge
>> mixture in different directions.
>>
>> We live east of the Mississippi and rarely encounter altitudes above
>> 6KMSL, but the coach rolled over the Big Horn on the way to Yellowstone and
>> the
>> coach did not complain. We even had to go around a couple of little
>> four-wheels that could not keep speed up at 9200MSL (according to my GPS).
>> They
>> were all too new to be open loop. And, we still did our regular 9.2 for
>> that journey.
>>
>> So, before you get all fired up to change to a tack-on "fuel injection",
>> decide if it is something you really want to do.
>>
>> As Dick Paterson has been known to say, most carburetor problems start
>> with the ignition. I am not fond of HEI, but it can be serviceable, you
>> just
>> have to be sure you have the spares along. But, you should carry ignition
>> spares in any case.
>>
>> Matt - I'll get down off the milk crate now, I have some passcar work to
>> do today still.
>>
>>
>> --
>> 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
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
Goto Forum:
Current Time: Fri Apr 26 07:01:25 CDT 2024
Total time taken to generate the page: 0.01238 seconds
|
GMCforum
Search
Help
Register
Login
Home
