Home » Public Forums » GMCnet » [GMCnet] Max torque/max RPM
| Re: [GMCnet] Max torque/max RPM [message #157420 is a reply to message #157277] |
Fri, 20 January 2012 15:27   |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Thanks Jim,
So with 3.70 gears we need 3300RPM for 65mph.
That must mean the torque converter is slipping a few hundred RPM's.
I just got back from a trip driving it real easy to see how it affected my MPG. I stayed below 60MPH and only got 9.5MPG.
Regards,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: [GMCnet] Max torque/max RPM [message #157421 is a reply to message #157277] |
Fri, 20 January 2012 15:28 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Senior Member |
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Sorry, I misread. You have 3300 RPM at 70MPH.
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: [GMCnet] Max torque/max RPM [message #157429 is a reply to message #157277] |
Fri, 20 January 2012 17:36 |
Gary Casey
Messages: 448
Registered: September 2009
Karma: 0
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Senior Member |
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Bill, I think, despite what you may hear, that the standard engine will have torque peak somewhere below 2,000 rpm. More like 1800 or even less. Yes, any dual plane manifold will produce a bump at about 2800, but I think in practice that bump is just delaying the downward plunge of torque above 2,000. Contradicting what I just wrote, I have a number from a GM stock engine test that says it(a non-toro 455 with the tall intake manifold) can produce 234 hp and 341 ft lb at 3600, which is the peak hp. At 1600 rpm it makes 388 ft-lb and at 2000 it is good for 396. 2400 give 398 and 2800 is 397. So from 1600 up through 2800 the maximum torque is just about flat, with a rated torque peak of 2400. Then it starts to dive. At 3200 it is down to 377 (not bad), but by 3600 it has dropped to 341. Then at 4,000, past the power peak it's down to 302. I have no data beyond 4000. And this is for the raised-manifold version. As any hot rodder
knows, raising the runners always gives more torque at higher rpm. I'll bet that the standard Toro engine won't produce much more than 220 hp at 3600 and the power peak might even drop to 3200 rpm. So a cam that peaks the torque at 2200-2300 rpm? The standard cam pretty much does that. Generally, the more torque the engine is able to produce at cruise rpm, the poorer the fuel economy - not better. But that depends on the details of the cam profile. I think I could make a cam that would produce less torque at 2800 and better fuel economy - mostly done by just retarding the cam timing. That would produce more reversion (back flow) during the compression stroke, reducing the available torque - and pumping losses. And a retarded exhaust opening increases the expansion ratio, improving engine efficiency. I could name the technique after myself - the "Casey Cycle", but a guy named Miller beat me to it.
Gary Casey
OK, so max torque occurs at 2800 rpm in the stock motor.
And with 3.70 gears that will get you ~65mph.
Has anyone tried to cam the motor for max torque at 2200-2300 RPM?
And did they get better fuel economy?
Thanks,
Bill
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| [GMCnet] Three images of Folkmann paint design [message #157434 is a reply to message #157429] |
Fri, 20 January 2012 18:34 |
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I just uploaded three images showing the paint design (and colors) for Frank
and Marcella Folkmann's 1978 Royale. They'll take it to Topeka Graphics
where Larry and crew will do a fine job.
Frank has worked to modernize the coach and added several things (noted in
the descriptions). He and Marcella have a Chevy SUV in Cardinal Red and
wanted that to be one of the primary colors in the design. The design
started as a photo he took of a coach and then worked with me on
modifications and color choices. You'll note the colors used in the side
view. Both 2010 Chevy colors are shown and referenced to PPG color numbers.
As with other images, the shading and highlights are to simulate coloring in
the real world.
This was my first visor to do from the front so I hope it's pretty close to
reality.
The license on the rear tells a bit of a story. It is based on the Indiana
auto tags used ten or so years ago. The motto says "The Crossroads of
America". The red square has the date I did the rendering (JAN) and the blue
tag has the year code (12). The 26 is the county code for Gibson County. The
"F" is for Folkmann, of course. The 1978 is for the year of the coach. In
the background is the outline of Indiana, stars and torch -- these symbols
are on the state flag.
If you click on the images you'll get a better view of things and can begin
to make out the detail I put into the image. I sent Frank images that can
scale up larger than the MH Photos site will accommodate. I do believe you
can make out his name on the lighted entry handle, however. I'm particularly
proud of the rear LEDs (Frank has replaced the original lights) and the
tread on the tires. Lots of care is represented here. I went to the extra
trouble because Frank lives on the highway I used to travel at least twice
weekly going to and from college in Oakland City from 1965 to 1969.
--
Byron Songer
Louisville, KY
http://www.gmceast.com
Sights to see and places to stay
Find or submit a
GMCer recommendation
http://www.gmceast.com/travel
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--
Byron Songer
Full-timing to enjoy the USA
Former owner but still an admirer
GMC paint schemes at -
http://www.songerconsulting.net
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| Re: [GMCnet] Three images of Folkmann paint design [message #157436 is a reply to message #157434] |
Fri, 20 January 2012 18:49 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Byron,
Yet ANOTHER nice job from Songer Studios! ;-)
I was surprised to see that the rear low profile A/C unit was as far forward of the red roof maker lights and luggage rail.
I thought the only units that would clear them were the OEM high style.
Would you please ask Frank what brand / model they are.
Thanks,
Rob M.
-----Original Message-----
From: Byron Songer
I just uploaded three images showing the paint design (and colors) for Frank
and Marcella Folkmann's 1978 Royale. They'll take it to Topeka Graphics
where Larry and crew will do a fine job.
Frank has worked to modernize the coach and added several things (noted in
the descriptions). He and Marcella have a Chevy SUV in Cardinal Red and
wanted that to be one of the primary colors in the design. The design
started as a photo he took of a coach and then worked with me on
modifications and color choices. You'll note the colors used in the side
view. Both 2010 Chevy colors are shown and referenced to PPG color numbers.
As with other images, the shading and highlights are to simulate coloring in
the real world.
This was my first visor to do from the front so I hope it's pretty close to
reality.
The license on the rear tells a bit of a story. It is based on the Indiana
auto tags used ten or so years ago. The motto says "The Crossroads of
America". The red square has the date I did the rendering (JAN) and the blue
tag has the year code (12). The 26 is the county code for Gibson County. The
"F" is for Folkmann, of course. The 1978 is for the year of the coach. In
the background is the outline of Indiana, stars and torch -- these symbols
are on the state flag.
If you click on the images you'll get a better view of things and can begin
to make out the detail I put into the image. I sent Frank images that can
scale up larger than the MH Photos site will accommodate. I do believe you
can make out his name on the lighted entry handle, however. I'm particularly
proud of the rear LEDs (Frank has replaced the original lights) and the
tread on the tires. Lots of care is represented here. I went to the extra
trouble because Frank lives on the highway I used to travel at least twice
weekly going to and from college in Oakland City from 1965 to 1969.
Byron
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Three images of Folkmann paint design [message #157437 is a reply to message #157436] |
Fri, 20 January 2012 19:04 |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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Byron,
These are beautiful renderings of our beautiful rigs.
<http://www.gmcmhphotos.com/photos/showgallery.php?cat=5777>
Larry Davick
Fremont, California
The Mystery Machine
'76 (ish) Palm Beach
----- Original Message -----
From: "Rob Mueller" <robmueller@iinet.net.au>
To: gmclist@temp.gmcnet.org
Sent: Friday, January 20, 2012 4:49:24 PM
Subject: Re: [GMCnet] Three images of Folkmann paint design
Byron,
Yet ANOTHER nice job from Songer Studios! ;-)
I was surprised to see that the rear low profile A/C unit was as far forward of the red roof maker lights and luggage rail.
I thought the only units that would clear them were the OEM high style.
Would you please ask Frank what brand / model they are.
Thanks,
Rob M.
-----Original Message-----
From: Byron Songer
I just uploaded three images showing the paint design (and colors) for Frank
and Marcella Folkmann's 1978 Royale. They'll take it to Topeka Graphics
where Larry and crew will do a fine job.
Frank has worked to modernize the coach and added several things (noted in
the descriptions). He and Marcella have a Chevy SUV in Cardinal Red and
wanted that to be one of the primary colors in the design. The design
started as a photo he took of a coach and then worked with me on
modifications and color choices. You'll note the colors used in the side
view. Both 2010 Chevy colors are shown and referenced to PPG color numbers.
As with other images, the shading and highlights are to simulate coloring in
the real world.
This was my first visor to do from the front so I hope it's pretty close to
reality.
The license on the rear tells a bit of a story. It is based on the Indiana
auto tags used ten or so years ago. The motto says "The Crossroads of
America". The red square has the date I did the rendering (JAN) and the blue
tag has the year code (12). The 26 is the county code for Gibson County. The
"F" is for Folkmann, of course. The 1978 is for the year of the coach. In
the background is the outline of Indiana, stars and torch -- these symbols
are on the state flag.
If you click on the images you'll get a better view of things and can begin
to make out the detail I put into the image. I sent Frank images that can
scale up larger than the MH Photos site will accommodate. I do believe you
can make out his name on the lighted entry handle, however. I'm particularly
proud of the rear LEDs (Frank has replaced the original lights) and the
tread on the tires. Lots of care is represented here. I went to the extra
trouble because Frank lives on the highway I used to travel at least twice
weekly going to and from college in Oakland City from 1965 to 1969.
Byron
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: [GMCnet] Three images of Folkmann paint design [message #157443 is a reply to message #157437] |
Fri, 20 January 2012 20:40 |
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Oh, jeepers. I forgot the link. Thanks, Larry, for picking up on that.
In looking back at the front end I was reminded of how long it took to
satisfy myself with the look of the fiberglass grill, which is very
different from the original. I don't use CAD software for these
illustrations so getting the effect of light requires some smarts and some
slight of hand. I did have fun putting in the radiator, however. In honor of
Gene I should have made it aluminum.
Byron
Larry Davick wrote:
> Byron,
>
> These are beautiful renderings of our beautiful rigs.
>
> <http://www.gmcmhphotos.com/photos/showgallery.php?cat=5777>
>
>
> Larry Davick
> Fremont, California
> The Mystery Machine
> '76 (ish) Palm Beach
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
--
Byron Songer
Full-timing to enjoy the USA
Former owner but still an admirer
GMC paint schemes at -
http://www.songerconsulting.net
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| Re: [GMCnet] Max torque/max RPM [message #157710 is a reply to message #157429] |
Mon, 23 January 2012 01:17 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
|
Senior Member |
|
|
Gary,
I didn't realize the 455 had such a flat torque curve from 1600 to 2400 RPM. My coach must need a tune-up because it seems slugish at lower RPMs.
Regards,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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