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  #61  
Old 04-15-2006, 09:04 AM
t walgamuth's Avatar
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now bobsterman, you have not insulted me or my profession, so i will respond to your story.

i have never heard that one, but i have heard similar stories about how the width of rail road tracks go all the way back to the roman times and is in fact the width of a two wheel ox cart. (that one i beleive)

i dont know about medieval england but i do know about what i have found in this country. in older structures with wooden lath and plaster, it is dicey business driving a nail in the wall because the stud spacing can be anything from 8" to 33" more or less. you really dont get into precise locations of wood framing until the introduction of standardized sheet goods such as 4 x 8 plywood and drywall. in order to avoid cutting each and every piece of material so that you can nail the ends to a board (and, structurally this is essential) you have to maintain precise spacing that works with the 8' dimension. so 6", 8", 12", 16" and 24" all will work. 16" is by far the most common for floors and walls. 16" and 24" are the most common for roofs.

in older buildigs also, you can find many examples of walls that are not plumb and rooms that are not square (in the corners). i have seen rooms that are nearly a foot longer one side than the other.

folks say "they don't build them like the used to" and in many cases that is a good thing.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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  #62  
Old 04-15-2006, 10:23 AM
t walgamuth's Avatar
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so i went back to my log, which i still have since the buyer of the car didn't care if he had it, and looked again at the info that was there before changing the rear end from 346 (stock for a 300 na) to a 307. my kids were driving the car and there is evidence of at least eight tanks but they were a little sloppy and didnt always record all the info so there were only three tanks that i could decifer. they worked out to 21, 26 and 22 mpg. i can tell that the one at 26 included a trip to colombus oh. so that was pretty much all highway.

so then we changed the rear to 307. i wont put a sharp pencil to it but that is about a 10% change in ratio.

the next twelve tanks i did. the mileage on them was 29.4, 20,26,28,28,25,30,20+,28,20-,22 and 20. the ones near between 28 and 30 were all highway. the others were mostly town driving.

so it is not a double blind test using computers and regisered engineers, but it is sufficient for me anyway, and i think i am more critical than most, to say that the mileage increase was pretty close to the same percentage as the gear change.

in any case it is enough to convince me that if i wanted a mileage increase i would spend good money doing it and expect this kind of results.

tom w
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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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  #63  
Old 04-15-2006, 10:54 AM
t walgamuth's Avatar
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and i found torque and hp max specs on the na engines.

max torque on all the 616 and 617 engines from 74 to 81 is 2,400 rpm.

max hp on the na 617 is always 4000 rpm.

max hp on the 616 is shown to be from 4000 to 4200 to 4400, depending on the year.

there could be some errors because i found that the 79 sd is listed as having 8.7 compression, 217 hp and 235 ft. lb or so of torque. this can't be right, can it?

so the max figures seem pretty close to the 617 turbo curves posted above.

tom w
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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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  #64  
Old 04-15-2006, 11:10 AM
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Quote:
Originally Posted by t walgamuth
they were a little sloppy and didnt always record all the info so there were only three tanks that i could decifer. they worked out to 21, 26 and 22 mpg. i can tell that the one at 26 included a trip to colombus oh. so that was pretty much all highway.
Average fuel economy with very poor data: 23.0 mpg

Quote:
Originally Posted by t walgamuth


so then we changed the rear to 307. i wont put a sharp pencil to it but that is about a 10% change in ratio.

Ratio change = 11.3%


Quote:
Originally Posted by t walgamuth

the next twelve tanks i did. the mileage on them was 29.4, 20,26,28,28,25,30,20+,28,20-,22 and 20. the ones near between 28 and 30 were all highway. the others were mostly town driving.
Average fuel economy: 24.7 mpg


So, the average fuel economy improvement is 7.4%


As I've told you, you'll never get the the same percentage fuel economy improvement as the axle ratio change.

Even with your widely varying driving conditions, your own data proves my previous statement.

It's time to get off your soapbox and agree that you're not correct.

Last edited by Brian Carlton; 04-15-2006 at 11:24 AM.
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  #65  
Old 04-15-2006, 11:40 AM
Larry Delor's Avatar
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Quote:
Originally Posted by t walgamuth
there could be some errors because i found that the 79 sd is listed as having 8.7 compression, 217 hp and 235 ft. lb or so of torque. this can't be right, can it?
No...that can't be right. Compression is in the neighborhood of 19:1. Those look like numbers for a 450.
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  #66  
Old 04-15-2006, 11:48 AM
t walgamuth's Avatar
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actually brian, werent you predicting 7% gain in fuel economy on a 20% gear ratio change?

7% gain on a 10% gear ratio change more nearly supports my position.

tom w
__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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  #67  
Old 04-15-2006, 12:06 PM
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Quote:
Originally Posted by t walgamuth
actually brian, werent you predicting 7% gain in fuel economy on a 20% gear ratio change?

7% gain on a 10% gear ratio change more nearly supports my position.
Wrong again.

If you bothered to read what others write, you'd see that I predicted a 9% gain in fuel economy for a 20% ratio change. The percentage would be 45%.

Your own data shows an increase of 65%.

Your claim is 100%.

So, who is closer to the mark?

Trust me when I tell you........in all honesty.......physics and engineering are not your strong points.
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  #68  
Old 04-15-2006, 12:39 PM
t walgamuth's Avatar
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well, i dont think that it makes any sense to compare a gross average. and i prefer to compare highway to highway, which if done will be right at 10% which is the gear ratio change.

and i guess that we can let folks decide for themselves what my strong points are.

just like arguing about passages in the bible, different folks can look at data and see what they want to see.

lets put this one to bed and try to enjoy the shopforum.

have a nice easter.

tom w
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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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  #69  
Old 04-15-2006, 12:44 PM
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Quote:
Originally Posted by t walgamuth
well, i dont think that it makes any sense to compare a gross average.
Agreed.


Quote:
Originally Posted by t walgamuth

..............which if done will be right at 10% which is the gear ratio change.
Do not agree.

Quote:
Originally Posted by t walgamuth

and i guess that we can let folks decide for themselves what my strong points are.

lets put this one to bed and try to enjoy the shopforum.
Agreed.
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  #70  
Old 04-15-2006, 02:19 PM
Craig
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Happy Easter guys, I was wondering how long this would go on.
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  #71  
Old 04-16-2006, 11:07 AM
t walgamuth's Avatar
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til easter break!

tom w
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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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  #72  
Old 06-07-2006, 10:46 AM
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Posts: 36
Quote:
Originally Posted by t walgamuth
... but i have heard similar stories about how the width of rail road tracks go all the way back to the roman times and is in fact the width of a two wheel ox cart. (that one i beleive)

i dont know about medieval england but i do know about what i have found in this country. in older structures with wooden lath and plaster, it is dicey business driving a nail in the wall because the stud spacing can be anything from 8" to 33" more or less. you really dont get into precise locations of wood framing until the introduction of standardized sheet goods such as 4 x 8 plywood and drywall. in order to avoid cutting each and every piece of material so that you can nail the ends to a board (and, structurally this is essential) you have to maintain precise spacing that works with the 8' dimension. so 6", 8", 12", 16" and 24" all will work. 16" is by far the most common for floors and walls. 16" and 24" are the most common for roofs.

in older buildigs also, you can find many examples of walls that are not plumb and rooms that are not square (in the corners). i have seen rooms that are nearly a foot longer one side than the other.

folks say "they don't build them like the used to" and in many cases that is a good thing.

tom w
Tom... much belated answer, but I can't resist...

Railroad track width goes back to the standardized width of Roman chariots, based on the standardized width of two horses arses.

I understand the lathe and plaster thing, as for the past 18 years I have been renovating my great grandfather's farmhouse, built variously in 1908 and 1920. I get lots of leftover drywall. I rebuilt the windows by looking for the most square and plumb corner, and going from there.

Up here (North of North Dakota) a lot more 2x6 in the wall is used to make room for more insulation.

I'm not afraid of used lumber because by the time I'm done, the new stuff looks used anyway. Hooray for screws (Robertson head of course).
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  #73  
Old 06-07-2006, 11:46 AM
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But to, at risk, return to the topic, I'm gonna conclude that I better get offa the pot and hustle up that 280C I've been longing for, or put a 700 OD tranny in my 80 Cutlass, because the 373 IROC rear end is being too demanding of the 403 transplant, what with 3000 RPM at 60 MPH. Does anyone disagree with this conclusion.

BTW, if you are a degreed engineer with experience on the Edsel, or the Pinto gas tank design, or CJ or Corvair roll-over, try to hold your comments. My last job?? Engineering Management at Lockheed Martin in Air Force, Navy, and Army programs. And not having a BEng held the advantage of not being too enraptured by the Physics, though my school-boy experience was one of 90% competence.
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  #74  
Old 06-07-2006, 07:44 PM
t walgamuth's Avatar
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sorry bman, what is 90% competence. is this a quiz and i just lost?

tom w
__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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  #75  
Old 06-07-2006, 10:33 PM
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Quote:
Originally Posted by BobsterMan
My last job?? Engineering Management at Lockheed Martin in Air Force, Navy, and Army programs. And not having a BEng held the advantage of not being too enraptured by the Physics, though my school-boy experience was one of 90% competence.
I really like that. I cannot wait to get to the perfect company. 100% engineer managers and no engineers. That way they can make their decisions "not being too enraptured by the Physics" ... who needs the laws of nature, anyway?

Jl

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