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[GMCnet] Exhaust Size [message #300899] Fri, 20 May 2016 21:38 Go to next message
Dolph Santorine is currently offline  Dolph Santorine   United States
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Registered: April 2011
Location: Wheeling, WV
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Senior Member
I found this very informative (and confirmation of the 3” exhaust system the PO installed)

Enjoy.

Dolph

DE N8JPC

Wheeling, West Virginia

1977 26’ ex-PalmBeach
1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010

“The Aluminum and Fiberglass Mistress"





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Re: [GMCnet] Exhaust Size [message #300900 is a reply to message #300899] Fri, 20 May 2016 21:55 Go to previous messageGo to next message
Dennis S is currently offline  Dennis S   United States
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Registered: November 2005
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Dolph

I suspect you intended to include a link.

Dennis

Dolph Santorine wrote on Fri, 20 May 2016 21:38
I found this very informative (and confirmation of the 3" exhaust system the PO installed)

Enjoy.

Dolph

DE N8JPC

Wheeling, West Virginia

1977 26' ex-PalmBeach
1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010

"The Aluminum and Fiberglass Mistress"





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Dennis S
73 Painted Desert 230
Memphis TN Metro
Re: [GMCnet] Exhaust Size [message #300901 is a reply to message #300900] Fri, 20 May 2016 22:08 Go to previous messageGo to next message
Dolph Santorine is currently offline  Dolph Santorine   United States
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
Senior Member
Yep.

10 Fingers. All thumbs.

Here!

https://www.youtube.com/watch?v=_PVXvHkr-Vs&list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE




> On May 20, 2016, at 10:55 PM, Dennis Sexton wrote:
>
> Dolph
>
> I suspect you intended to include a link.
>
> Dennis
>
> Dolph Santorine wrote on Fri, 20 May 2016 21:38
>> I found this very informative (and confirmation of the 3" exhaust system the PO installed)
>>
>> Enjoy.
>>
>> Dolph
>>
>> DE N8JPC
>>
>> Wheeling, West Virginia
>>
>> 1977 26' ex-PalmBeach
>> 1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010
>>
>> "The Aluminum and Fiberglass Mistress"
>>
>>
>>
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> --
> Dennis S
> 73 Painted Desert 230
> Memphis TN Metro
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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Re: [GMCnet] Exhaust Size [message #300902 is a reply to message #300901] Fri, 20 May 2016 22:48 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
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This on the same site was sorta interesting too:

https://www.youtube.com/watch?v=2sQJPZYSoUI&list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE&index=8

Ken EFIAddicted H.


On Fri, May 20, 2016 at 11:08 PM, Dolph Santorine
wrote:

> Yep.
>
> 10 Fingers. All thumbs.
>
> Here!
>
>
> https://www.youtube.com/watch?v=_PVXvHkr-Vs&list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE
>
>
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] Exhaust Size [message #300903 is a reply to message #300901] Sat, 21 May 2016 01:02 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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Registered: July 2006
Location: Belmont, CA
Karma: 9
Senior Member
The video applies to high performance.
Our Headers are small tube ad Y design to aid in low end rpm( 2200-3200
RPM) and goes into a 2.5" muffler and Y into a 3".
All the bends are Mandrel bent so the diameter is not compromised.
Jerry Jarden designed the original system and did a Dyno test.

On Fri, May 20, 2016 at 8:08 PM, Dolph Santorine
wrote:

> Yep.
>
> 10 Fingers. All thumbs.
>
> Here!
>
>
> https://www.youtube.com/watch?v=_PVXvHkr-Vs&list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE
>
>
>
>
>> On May 20, 2016, at 10:55 PM, Dennis Sexton wrote:
>>
>> Dolph
>>
>> I suspect you intended to include a link.
>>
>> Dennis
>>
>> Dolph Santorine wrote on Fri, 20 May 2016 21:38
>>> I found this very informative (and confirmation of the 3" exhaust
> system the PO installed)
>>>
>>> Enjoy.
>>>
>>> Dolph
>>>
>>> DE N8JPC
>>>
>>> Wheeling, West Virginia
>>>
>>> 1977 26' ex-PalmBeach
>>> 1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission,
> EV-6010
>>>
>>> "The Aluminum and Fiberglass Mistress"
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>>
>> --
>> Dennis S
>> 73 Painted Desert 230
>> Memphis TN Metro
>>
>> _______________________________________________
>> 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:
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>



--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: [GMCnet] Exhaust Size [message #300912 is a reply to message #300901] Sat, 21 May 2016 09:51 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Registered: March 2007
Location: S.E. Michigan
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Senior Member
Dolph Santorine wrote on Fri, 20 May 2016 23:08
Yep.

10 Fingers. All thumbs.

Here!

https://www.youtube.com/watch?v=_PVXvHkr-Vs&list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE

I thought it was interesting that the 2-1/2 and 3 inch curves crossed at 3500.
Too bad that their dyno wouldn't hold it below 3000.
But then, I did spend a lifetime looking at curves like that.

Matt - The refugee from Dynoland


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] Exhaust Size [message #300920 is a reply to message #300899] Sat, 21 May 2016 13:13 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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Registered: October 2006
Location: Woodstock, IL
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Senior Member
At WOT yes the 3" better. At our cruise range the conclusion I come to is the opposite. Yes wish the graph started at 1500 legibly to get data that pertains to GMC.

John Lebetski
Woodstock, IL
77 Eleganza II
Re: [GMCnet] Exhaust Size [message #300935 is a reply to message #300920] Sat, 21 May 2016 17:09 Go to previous messageGo to next message
hal kading is currently offline  hal kading   United States
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Registered: February 2004
Location: Las Cruces NM
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Senior Member
Their test was with dual exhaust so (if my math is right) our single 2.5" exhaust @ 4.91 sq. in. is half of their dual 2.5". Our single 3" exhaust @ 7.07 sq. in. is less than their dual 2.5" @ 9.82 sq. in. and their dual 3" @ 14.14 sq. in.

Hal Kading 78 Buskirk Las Cruces NM
Re: [GMCnet] Exhaust Size [message #300947 is a reply to message #300899] Sat, 21 May 2016 21:20 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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Location: Woodstock, IL
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And they had a long truck system. But ours is even longer. At our RPM range we just are not moving that volume.

John Lebetski
Woodstock, IL
77 Eleganza II
Re: [GMCnet] Exhaust Size [message #300949 is a reply to message #300947] Sat, 21 May 2016 21:40 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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Senior Member
I have studied exhaust systems in single cylinder engines as well as multi
cylinder engines for too many years to recall. Conclusions are very
difficult to draw in them. There are some general guidelines to follow. Low
rpms (under 3000 rpms) benefit from smaller diameter header tubes. But
there are so many variables to consider all the way from the air cleaner
inlet to the exhaust tip that there are very few HARD AND FAST RULES. High
rpm engines nearly always have flat spots and reversion issues with large
diameter tubes at slow engine speeds, but benefit greatly from them at
higher engine speeds. Always a compromise or tradeoff when setting up power
trains. Matt Colie can give hours of data on dyno testing. More noise does
not equate with more power.
Jim Hupy
Salem, Or
78 GMC ROYALE 403 w/Doug Thorley small tube headers w/ dual flow masters
and 2 -1/2" single exhaust.
On May 21, 2016 7:21 PM, "John R. Lebetski" wrote:

> And they had a long truck system. But ours is even longer. At our RPM
> range we just are not moving that volume.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
> Source America First
>
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Re: [GMCnet] Exhaust Size [message #300955 is a reply to message #300902] Sat, 21 May 2016 23:05 Go to previous messageGo to next message
Dolph Santorine is currently offline  Dolph Santorine   United States
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
Senior Member
Great video find.

Hot Rods don't have to deal with changing altitudes.

I don't listen to Cassettes anymore. I kind of feel the same about how I atomize my fuel.

Dolph Santorine

DE N8JPC

Wheeling, West Virginia

1977 ex-Palm Beach TZE167V100820
1-ton, Sullybuilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010,


> On May 20, 2016, at 11:48 PM, Ken Henderson wrote:
>
> This on the same site was sorta interesting too:
>
> https://www.youtube.com/watch?v=2sQJPZYSoUI&list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE&index=8
>
> Ken EFIAddicted H.
>
>
> On Fri, May 20, 2016 at 11:08 PM, Dolph Santorine
> wrote:
>
>> Yep.
>>
>> 10 Fingers. All thumbs.
>>
>> Here!
>>
>>
>> https://www.youtube.com/watch?v=_PVXvHkr-Vs&list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org


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Re: [GMCnet] Exhaust Size [message #300976 is a reply to message #300899] Sun, 22 May 2016 13:22 Go to previous messageGo to next message
BobDunahugh is currently offline  BobDunahugh   United States
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Location: Cedar Rapids, IA
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Senior Member
Engines are made up of components that are sized to do a task. Operate in certain RPM ranges. Move something that is in a particular load range. Engines are really just an air pump. In our case. GM sized, and designed components such the exhaust, carburetor, distributor, cam, and even the water pump. To do the job of moving these GMC's down the road in an efficient manner. Yes. We put EFI systems on. But their just a more controlled carburetor that wasn't available back then. So to make any changes. You need to keep in mind it's a total package. These GMC's aren't high revving units. There just isn't that much exhaust coming out the tailpipe. If you're looking for better mileage, more torque to the wheels, lower transmission temps, and transmission load. Put that exhaust money in a 3:70 final drive from Applied GMC. And NO. That power drive isn't the same thing. It just increase the engine RPM's.Bob Dunahugh78 Royale


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Re: [GMCnet] Exhaust Size [message #300984 is a reply to message #300899] Sun, 22 May 2016 16:02 Go to previous messageGo to next message
jhbridges is currently offline  jhbridges   United States
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Location: Braselton ga
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Senior Member
Am I missing something here, Bob? It looks as if we increase engine speed relative to wheel sped either way, do we not? The difference being whether we wish to speed up the transmission as well, or not, isn't it?

--johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
Re: [GMCnet] Exhaust Size [message #300989 is a reply to message #300984] Sun, 22 May 2016 16:53 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
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Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
I had to replace the engine in my GMC before I even brought it home in
'98. That was before JimK's 3.55, etc., became available, so I installed
Caspro's 3.50 chain drive. I'd do it again without hesitation. It was a
simple, economical solution in that situation, and it proved to be quieter
than any higher ratio final drive I've heard. It's been pretty well proven
that the TH425 can take a lot more torque than that (3.50/3.07=1.14) 14%
increase.

That's NOT to imply that I'm in any way disappointed with JimK's 3.55 that
I've been running for the past 80,000+ miles.

Ken H.


On Sun, May 22, 2016 at 5:02 PM, Johnny Bridges via Gmclist <
gmclist@list.gmcnet.org> wrote:

> Am I missing something here, Bob? It looks as if we increase engine speed
> relative to wheel sped either way, do we not? The difference being whether
> we wish to speed up the transmission as well, or not, isn't it?
>
> --johnny
>
> --
> '76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and
> add - ons.
> Braselton, Ga.
>
> "Sometimes I wonder what tomorrow's gonna bring when I think about my
> dirty life and times" --Warren Zevon
>
> _______________________________________________
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] Exhaust Size [message #300998 is a reply to message #300976] Sun, 22 May 2016 21:23 Go to previous messageGo to next message
A Hamilto is currently offline  A Hamilto   United States
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BobDunahugh wrote on Sun, 22 May 2016 13:22
...In our case, GM sized and designed components such the exhaust, carburetor, distributor, cam, and even the water pump to do the job of moving these GMC's down the road in an efficient manner. ...
Not at all. The 455/THM425/Final drive combination was designed for the Oldsmobile Toronado. The fact that it can drag 12,000 pounds of RV while simultaneously fighting the wind resistance of a barn door for decades is a testament to the over-engineering that the designers built into it.

That's why I say attach a towed at your own risk. Like a bumblebee that doesn't have enough knowledge of aerodynamics to know it can't fly, these things don't know they should leave a trail of drivetrain on the highway WAY before 100k miles.
Re: [GMCnet] Exhaust Size [message #301004 is a reply to message #300976] Mon, 23 May 2016 01:57 Go to previous message
BobDunahugh is currently offline  BobDunahugh   United States
Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA
Karma: 11
Senior Member
Johnny. The power drive give will give you more revs per mile. And gives the engine the ability to apply more torque to the transmission. The 425 trans can handle that extra load. But that extra load has a by product of more heat introduced into the transmission. Were as the 3:70 final drive moves the torque multiplication to the final drive. And there is no extra heat generated at a measurable amount anywhere in the drivetrain. Plus with the transmission fluid pump running at a higher speed. More transmission fluid is sent to the trans cooler for cooling. You'll generally get better milage due to the higher engine intake manifold vacuum readings. On our last tripe. 3:70 FD, and a 403 that has absolutely no aids for cooling at all. We averaged 10.2 MPG over a distance of 3,800 miles. 2.5 exhaust with stock exhaust manifolds, and a stock carb. And that was pulling Linda's 5,100 LBS lift van behind our 78 Royale. With a GVW gross weight of about 17,300 LBS. When I'm pulling one of my Yenkos in the enclosed 24 ft trailer. I'm over 21,000 LBS GVW. And can travel at 75 all day with no cooling issues.Bob Dunahugh78 Royale

From: yenko108@hotmail.com
To: gmclist@list.gmcnet.org
Subject: RE: Exhaust Size
Date: Sun, 22 May 2016 13:22:35 -0500




Engines are made up of components that are sized to do a task. Operate in certain RPM ranges. Move something that is in a particular load range. Engines are really just an air pump. In our case. GM sized, and designed components such the exhaust, carburetor, distributor, cam, and even the water pump. To do the job of moving these GMC's down the road in an efficient manner. Yes. We put EFI systems on. But their just a more controlled carburetor that wasn't available back then. So to make any changes. You need to keep in mind it's a total package. These GMC's aren't high revving units. There just isn't that much exhaust coming out the tailpipe. If you're looking for better mileage, more torque to the wheels, lower transmission temps, and transmission load. Put that exhaust money in a 3:70 final drive from Applied GMC. And NO. That power drive isn't the same thing. It just increase the engine RPM's.Bob Dunahugh78 Royale


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