Home » Public Forums » GMCnet » [GMCnet] Power Drive
Re: [GMCnet] Power Drive [message #86766 is a reply to message #86733] |
Mon, 31 May 2010 23:13 |
Chr$
Messages: 2690 Registered: January 2004 Location: Scottsdale, AZ
Karma: 1
|
Senior Member |
|
|
Now they tell me!!!!
jimk wrote on Mon, 31 May 2010 16:54 | Bruce,
Your expanation is very good. I can see why I was lucky to earn a
grade of C in college in technical writing when most of the class was
pulling A and B in that class.
Many people will argue that there is no problem using the chain drive
reduction method on the coaches, but people that have been working on
these for long time admit that it does stress some of the components
on the trans.
On Mon, May 31, 2010 at 2:01 PM, Bruce Hislop <bruce@perthcomm.com> wrote:
>
>
> The downside of the PowerDrive from what I can see... and read somewhere... is the increased torque developed by the changing the chain drive ratio has to be handled by the transmission as well.
>
> Whereas if you change the final drive, the torque handled by the tranny will be reduced in favour of slightly higher rpm's.
>
> True/false??
>
> --
> Bruce Hislop,
> S. Ontario Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI and ESC.
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
-Chr$: Perpetual SmartAss
Scottsdale, AZ
77 Ex-Kingsley 455 SOLD!
2010 Nomad 24 Ft TT 390W PV W/MPPT, EV4010 and custom cargo door.
Photosite: Chrisc GMC:"It has Begun" TT: "The Other Woman"
|
|
|
Re: [GMCnet] Power Drive [message #327206 is a reply to message #86635] |
Sun, 17 December 2017 10:03 |
BobDunahugh
Messages: 2465 Registered: October 2010 Location: Cedar Rapids, IA
Karma: 11
|
Senior Member |
|
|
Vadim. You covered the subject well. The T425 with a 3:07 FD, 14 inch tires, and a 4,000 lbs car was a good combination. GM had the peak HP for the 427, and 455 reached in the 3,600 to 4,200 RPM range. So higher RPM's in the 4200 range, and above isn't an issue. We have 16 inch tires, and 12,000 lbs as you covered. And a different cam profile. That's another can of worms. Till about 2003 we only had the 3:07, and 3:21. I think there was a 3:42 from Cinnabar? So the Power Drive was a way to get the RPM's up to get out of luging our engines years ago. But as you mentioned. The PD is adding more load on the T425. Then Jim K at Applied GMC came out with some great FD ratio choices up to a 4:10 ratio. These ratios ended the luging. And allow the engine/trans to work more efficiently. Some say the PD,or a lower FD ratio are the same. No. Not at all. Is the PD bad? No. It's better then nothing. In your situation. I'd leave things as they are till you have trans issues. Then change the FD ratio. I'm thinking of going to 4:10 from my 3:70. Towing, or not. I'd recommend 3:70. When I'm pulling my enclosed trailer with a car in it. A 78 Royale 403, and the 3:70 FD. My GVW is about 21,000lbs. As a side note. My mileage went up with the 3:70. As to newer engines at 1500 RPM's at 65 MPH. Their design is another kind of animal. Bob Dunahugh Member GMCMI.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
Re: [GMCnet] Power Drive [message #327213 is a reply to message #86635] |
Sun, 17 December 2017 13:19 |
zhagrieb
Messages: 676 Registered: August 2009 Location: Portland Oregon
Karma: 0
|
Senior Member |
|
|
I've had one in mine for years. Works great. Can't find any disadvantage. No need to mess with spedo error as its ratio to rear end is unchanged.
Glenn Giere, Portland OR, K7GAG
'73 "Moby the Motorhome" 26'
|
|
|
|
Re: [GMCnet] Power Drive [message #327282 is a reply to message #327206] |
Tue, 19 December 2017 09:08 |
BobDunahugh
Messages: 2465 Registered: October 2010 Location: Cedar Rapids, IA
Karma: 11
|
Senior Member |
|
|
On steep grades. I shift manually to first, or sec. Run the engine RPM's up to the point that I just keep moving.. Then what till I get to the top. And don't care how fast, or how long it takes. There is one point that hasn't been covered. Your trans temps are lower with the 3:70, or 4:10 because there's less load on the trans. And the trans fluid pump is flowing more fluid to the trans cooler. As to engine life with higher RPM's back years ago. Remember. Our engines back then used carburetors, and ran different clearances. PVC systems weren't as good. They were dirty engines back then. Engines will run longer with EFI systems installed. Bob Dunahugh 78 Royale Iowa Member GMCMI
________________________________
From: Bob Dunahugh
Sent: Sunday, December 17, 2017 10:03 AM
To: gmclist@list.gmcnet.org
Subject: RE: Power Drive
Vadim. You covered the subject well. The T425 with a 3:07 FD, 14 inch tires, and a 4,000 lbs car was a good combination. GM had the peak HP for the 427, and 455 reached in the 3,600 to 4,200 RPM range. So higher RPM's in the 4200 range, and above isn't an issue. We have 16 inch tires, and 12,000 lbs as you covered. And a different cam profile. That's another can of worms. Till about 2003 we only had the 3:07, and 3:21. I think there was a 3:42 from Cinnabar? So the Power Drive was a way to get the RPM's up to get out of luging our engines years ago. But as you mentioned. The PD is adding more load on the T425. Then Jim K at Applied GMC came out with some great FD ratio choices up to a 4:10 ratio. These ratios ended the luging. And allow the engine/trans to work more efficiently. Some say the PD,or a lower FD ratio are the same. No. Not at all. Is the PD bad? No. It's better then nothing. In your situation. I'd leave things as they are till you have trans issues. Then change the FD ratio. I'm thinking of going to 4:10 from my 3:70. Towing, or not. I'd recommend 3:70. When I'm pulling my enclosed trailer with a car in it. A 78 Royale 403, and the 3:70 FD. My GVW is about 21,000lbs. As a side note. My mileage went up with the 3:70. As to newer engines at 1500 RPM's at 65 MPH. Their design is another kind of animal. Bob Dunahugh Member GMCMI.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
Re: [GMCnet] Power Drive [message #327314 is a reply to message #86635] |
Tue, 19 December 2017 17:58 |
James Hupy
Messages: 6806 Registered: May 2010
Karma: -62
|
Senior Member |
|
|
Brakes only cool when they are not generating more heat than they are
giving up. DO NOT DRAG THEM. Apply them forcefully to lower the coach speed
below the safe posted speed, then, take your foot off the pedal. If
necessary, downshift and use engine braking in addition to braking effort.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Dec 19, 2017 3:49 PM, "Ken Henderson" wrote:
And generally go down in the same gear you went up (or would have to).
Also, if you're going down too fast, use the brakes briskly to slow below
the desired speed, THEN downshift to the gear that's needed to control the
speed.
Ken
, Living in Flat Country but Been Up & Down Lots of Mountains,
H.
On Tue, Dec 19, 2017 at 6:39 PM, Bill Wevers wrote:
> Someone here once said, "Never go downhill in a GMC faster than you went
> up the hill..."
> Meaning: don't let your downhill speed get away from you.
> --
> Bill Wevers GMC49ers, GMC Western States
> 1975 Glenbrook - Manny Powerdrive, OneTon
> 455 F Block, G heads
> San Jose
>
> _______________________________________________
> 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
|
|
|
Re: [GMCnet] Power Drive [message #327328 is a reply to message #327206] |
Wed, 20 December 2017 01:46 |
NextGenGMC
Messages: 146 Registered: December 2017 Location: Washington State
Karma: -1
|
Senior Member |
|
|
Great explanation. Exactly what was going through my head when I asked about PD. I just didn't have experience or sufficient info to be able to weigh all the factors on my own.
BobDunahugh wrote on Sun, 17 December 2017 08:03Vadim. You covered the subject well. The T425 with a 3:07 FD, 14 inch tires, and a 4,000 lbs car was a good combination. GM had the peak HP for the 427, and 455 reached in the 3,600 to 4,200 RPM range. So higher RPM's in the 4200 range, and above isn't an issue. We have 16 inch tires, and 12,000 lbs as you covered. And a different cam profile. That's another can of worms. Till about 2003 we only had the 3:07, and 3:21. I think there was a 3:42 from Cinnabar? So the Power Drive was a way to get the RPM's up to get out of luging our engines years ago. But as you mentioned. The PD is adding more load on the T425. Then Jim K at Applied GMC came out with some great FD ratio choices up to a 4:10 ratio. These ratios ended the luging. And allow the engine/trans to work more efficiently. Some say the PD,or a lower FD ratio are the same. No. Not at all. Is the PD bad? No. It's better then nothing. In your situation. I'd leave things as they are till you have trans issues. Then change the FD ratio. I'm thinking of going to 4:10 from my 3:70. Towing, or not. I'd recommend 3:70. When I'm pulling my enclosed trailer with a car in it. A 78 Royale 403, and the 3:70 FD. My GVW is about 21,000lbs. As a side note. My mileage went up with the 3:70. As to newer engines at 1500 RPM's at 65 MPH. Their design is another kind of animal. Bob Dunahugh Member GMCMI.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Vadim Jitkov
'76 Glenbrook 26'
Pullman, WA
|
|
|
Re: [GMCnet] Power Drive [message #327330 is a reply to message #86635] |
Wed, 20 December 2017 06:19 |
|
RF_Burns
Messages: 2276 Registered: June 2008 Location: S. Ontario, Canada
Karma: 3
|
Senior Member |
|
|
As for newer vehicles, I've owned 11 pickup trucks since 2000, all Chev and GMC. The two 2005's I had were the last pickups that actually had some getup and go, I still have one of those trucks. Its loaded for bear with a heavy-duty commercial capper and full of tools. I get whip-lash every time I get in that truck.
I traded the other 2005 for a 2010 and all the trucks since have been lazy dogs. Sure they do about 1400rpm or less at 95km/hr. They switch in and out of 4 cylinder mode. When you step on the gas it spends the next second or so deciding what gear its going to change to. I can visualize the little hour-glass spinning in its control computers. Many times its feels like you are slowing rather than accelerating in that time.
When you flip the transmission into tow/haul mode, it becomes a different truck. Accelerating from stop with my utility trailer, it may wind up to over 4,000 rpm in each gear (6 of them) before shifting. Depending on the load it may not get to the top gear and the rpms will be in the 2-3000 range at highway speed. This is with a total load of maybe 7-8000lbs.
According to the trucks display. my 2005 gets about 13.2 litres/100km combined city/hyway. The 2016 and 2017 I have now get about 12.7litre/100km. I don't think the new ones will get as much life as the 2005 with all the shifting they do.
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC. 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
|
|
|
Re: [GMCnet] Power Drive [message #327332 is a reply to message #327330] |
Wed, 20 December 2017 07:29 |
|
Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
RF_Burns wrote on Wed, 20 December 2017 07:19As for newer vehicles, I've owned 11 pickup trucks since 2000, all Chev and GMC. The two 2005's I had were the last pickups that actually had some getup and go, I still have one of those trucks. Its loaded for bear with a heavy-duty commercial capper and full of tools. I get whip-lash every time I get in that truck.
I traded the other 2005 for a 2010 and all the trucks since have been lazy dogs. Sure they do about 1400rpm or less at 95km/hr. They switch in and out of 4 cylinder mode. When you step on the gas it spends the next second or so deciding what gear its going to change to. I can visualize the little hour-glass spinning in its control computers. Many times its feels like you are slowing rather than accelerating in that time.
When you flip the transmission into tow/haul mode, it becomes a different truck. Accelerating from stop with my utility trailer, it may wind up to over 4,000 rpm in each gear (6 of them) before shifting. Depending on the load it may not get to the top gear and the rpms will be in the 2-3000 range at highway speed. This is with a total load of maybe 7-8000lbs.
According to the trucks display. my 2005 gets about 13.2 litres/100km combined city/hyway. The 2016 and 2017 I have now get about 12.7litre/100km. I don't think the new ones will get as much life as the 2005 with all the shifting they do.
"That is what you have to expect for a new normal." - Guess who
That manufactures know all about this. They have to program the verhicles for emissions on a programed road test and CAFE. Pickups did not used to be included in CAFE. But, when the overreaching government found out that people were buying pickups because they were still fun to driver, they put an end to that as quickly as they could.
Matt
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] Power Drive [message #327339 is a reply to message #327314] |
Wed, 20 December 2017 11:43 |
Kingsley Coach
Messages: 2691 Registered: March 2009 Location: Nova Scotia Canada
Karma: -34
|
Senior Member |
|
|
Wise words Bill Weaver...wish I had thought about that before I left Boone
NC a few years ago. Smoke at 6 wheels is a scary sight!
Mike in NM
On Tue, Dec 19, 2017 at 7:58 PM, James Hupy wrote:
> Brakes only cool when they are not generating more heat than they are
> giving up. DO NOT DRAG THEM. Apply them forcefully to lower the coach speed
> below the safe posted speed, then, take your foot off the pedal. If
> necessary, downshift and use engine braking in addition to braking effort.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>
> On Dec 19, 2017 3:49 PM, "Ken Henderson" wrote:
>
> And generally go down in the same gear you went up (or would have to).
> Also, if you're going down too fast, use the brakes briskly to slow below
> the desired speed, THEN downshift to the gear that's needed to control the
> speed.
>
> Ken
> , Living in Flat Country but Been Up & Down Lots of Mountains,
> H.
>
>
> On Tue, Dec 19, 2017 at 6:39 PM, Bill Wevers wrote:
>
>> Someone here once said, "Never go downhill in a GMC faster than you went
>> up the hill..."
>> Meaning: don't let your downhill speed get away from you.
>> --
>> Bill Wevers GMC49ers, GMC Western States
>> 1975 Glenbrook - Manny Powerdrive, OneTon
>> 455 F Block, G heads
>> San Jose
>>
>> _______________________________________________
>> 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
>
--
Michael Beaton
1977 Kingsley 26-11
1977 Eleganza II 26-3
Antigonish, NS
Life is too short to hold a grudge; slash some tires and call it even !
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
Goto Forum:
Current Time: Sat May 04 02:28:43 CDT 2024
Total time taken to generate the page: 0.03498 seconds
|