Home » Public Forums » GMCnet » Switch Pitch Transmission (Operating Switch Location)
| Switch Pitch Transmission [message #200589] |
Mon, 04 March 2013 13:19  |
hal kading
Messages: 642
Registered: February 2004
Location: Las Cruces NM
Karma: 4
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I now have a Manny reworked switch pitch transmission. Where is the best location for the control switch? Is the best arrangement for the switch to be bat wing down for low pitch and up for high pitch?
All suggestions appreciated.
Hal Kading Buskirk stretch Las Cruces NM
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| Re: Switch Pitch Transmission [message #200604 is a reply to message #200603] |
Mon, 04 March 2013 16:27  |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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| A Hamilto wrote on Mon, 04 March 2013 16:17 |
| Hal Kading wrote on Mon, 04 March 2013 13:19 |
I now have a Manny reworked switch pitch transmission. Where is the best location for the control switch? Is the best arrangement for the switch to be bat wing down for low pitch and up for high pitch?
All suggestions appreciated.
Hal Kading Buskirk stretch Las Cruces NM
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I am fairly certain the vehicles that came with switch pitch as OEM didn't have a switch. Out of curiosity, what did they rely on to toggle between high stall and low stall?
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A friend of mine with a GMCMH is planning to put a SP in their coach sometime in the next couple of years. He was telling me that he spoke to some of the "old timers" in GMC that had SP. One of them mounted a large buttoned momentary switch on the left cockpit panel at knee height. When he wanted the extra power from his SP, he just hit it and held it with his knee. The let go when he'd had enough. I've thought about that some myself, but have not been able to find a momentary switch with a fairly large knob on it. I was thinking of something like the big red buttons that the judges on "The Voice" hit.
BTW, IIRC the Olds and Cads that had SP, had the switch mounted on the throttle, so that when you stepped it down it went to SP for more "get up and go".
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: [GMCnet] Switch Pitch Transmission [message #200617 is a reply to message #200615] |
Mon, 04 March 2013 18:45 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Emery,
Thanks, none of the information I have access to explained how the brake switch worked.
I can't find the email that noted the GMCer that makes the switch pitch control, would you please advise who it is?
Regards,
Rob M.
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Emery Stora
Sent: Tuesday, March 05, 2013 11:18 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Switch Pitch Transmission
No, that is correct. When you put on the brakes the switch pitch will cut in and your vehicle will pull away from a stop easier.
Emery
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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] Switch Pitch Transmission [message #200618 is a reply to message #200617] |
Mon, 04 March 2013 18:46 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Just ask Manny T. He knows how to hook em up.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Mon, Mar 4, 2013 at 4:48 PM, Robert Mueller <robmueller@iinet.net.au>wrote:
> Emery,
>
> Thanks, none of the information I have access to explained how the brake
> switch worked.
>
> I can't find the email that noted the GMCer that makes the switch pitch
> control, would you please advise who it is?
>
> Regards,
> Rob M.
>
>
>
> -----Original Message-----
> From: gmclist-bounces@temp.gmcnet.org [mailto:
> gmclist-bounces@temp.gmcnet.org] On Behalf Of Emery Stora
> Sent: Tuesday, March 05, 2013 11:18 AM
> To: gmclist@temp.gmcnet.org
> Subject: Re: [GMCnet] Switch Pitch Transmission
>
> No, that is correct. When you put on the brakes the switch pitch will cut
> in and your vehicle will pull away from a stop easier.
>
> Emery
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: [GMCnet] Switch Pitch Transmission [message #200635 is a reply to message #200602] |
Mon, 04 March 2013 20:52 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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| Robert Mueller wrote on Mon, 04 March 2013 14:15 |
Hal,
I don't know how low pitch and high pitch relate to the vanes in the torque convertor so I'll say that the switch should be up if
the trans is in switch pitch mode.
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Rob is right. Up, is correct if you mean up toward high stall. Those trying to understand, don't confuse high with high gear. High stall is actually like a lower gear.
The switched (on) is when the stators are in high stall, meaning that the engine runs at a higher RPM. In switch, if you locked the brakes and gave it some gas, the engine would run up to about 2600 or so. The stock torque converter goes to about a 2200 stall. The interesting (and advantageous I think) is that the low stall in a switch pitch is about 1600-1800. To me it made the coach seem more like a car. Not such a high RPM just to pull away from a stop. Very responsive; less like stepping on a grapefruit when you hit the gas.
When Manny had me test mine after install he asked me to put it in switch, put it in drive and let off the brake. This was at idle. The coach crept forward a bit as expected. THen we took it out of switch and repeated the experiment. THis time the coach moved out briskly, even at idle.
I have a temp gauge and watch it like a hawk. In switch the torque converter is slipping more. (It always slips) which creates heat. In switch the heat builds faster. That being said, with a trans cooler, I have never seen much jump... but then I rarely keep it in switch more than 30-60 seconds. It is great when you are cresting a climb and contemplating pulling it down into second. Switch will let the engine jump back up about 400 RPMs which often puts you in a better torque range.
Another interesting factoid. There is not an "exact" number of RPMs between the switched and normal. At low RPM the difference is greater. When I have to really go to say get on a busy freeway, if I turn of switch at 3000 RPMs the difference can hardly be heard. This is because even the high stall level (switched) has been met at 3000. They both slip all the time, just a less once past stall RPM.
Love my switch pitch.
On the other hand, if you don't like to watch gauges or think about what you are doing, don't even think about a switch pitch.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Switch Pitch Transmission [message #200654 is a reply to message #200589] |
Mon, 04 March 2013 23:18 |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
Karma: 0
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George,
I'm sure the answer is probably in the 8 - 10 range, but the lower stall speed of the switch pitch, should (or could?) translate to a mpg improvement. Given all of your fuel injection testing, I wondered if you were ever able to do a comparison. The low pitch is getting you part way to to what the modern lock-up converters achieve. (and some of those are set up pretty loose since they know the clutch will lock it up at higher speeds).
Thanks,
Craig
Craig Lechowicz
'77 Kingsley, Waterford, MI
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| Re: [GMCnet] Switch Pitch Transmission [message #200719 is a reply to message #200654] |
Tue, 05 March 2013 18:01 |
Ronald Pottol
Messages: 505
Registered: September 2012
Location: Redwood City, California
Karma: -2
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I wondered about that, fuel infection, and a taller final drive, perhaps
even the 2.73.
All together, the motor turns slower, but with the lower stall speed of the
switch pitch, the torque converter is still tight, and the fuel injection
stays lean, despite vacuum that might trigger enrichment with the carb.
I'm looking at a heavy coach, but no toad, in my head.
Ron
On Mar 4, 2013 9:18 PM, "Craig Lechowicz" <craig.lechowicz@sbcglobal.net>
wrote:
>
>
> George,
> I'm sure the answer is probably in the 8 - 10 range, but the lower stall
> speed of the switch pitch, should (or could?) translate to a mpg
> improvement. Given all of your fuel injection testing, I wondered if you
> were ever able to do a comparison. The low pitch is getting you part way
> to to what the modern lock-up converters achieve. (and some of those are
> set up pretty loose since they know the clutch will lock it up at higher
> speeds).
>
> Thanks,
> Craig
> --
> Craig Lechowicz
> '77 Kingsley, Waterford, MI
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| Re: Switch Pitch Transmission [message #200736 is a reply to message #200589] |
Tue, 05 March 2013 19:59 |
Cadillackeeper
Messages: 464
Registered: October 2012
Location: Fort Lauderdale
Karma: 1
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I will never forget the sounds my car made when strapped to the chassis dyno.The RPM
went up and down with both angles and all three speeds.The guys kinda freaked out till I told them about the convertor.Mine is still kinda stock as the switch is in position on the carb linkage.
77 455 Elaganza II and 67 Animal, Built 500 Powered Eldo
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| Re: [GMCnet] Switch Pitch Transmission [message #200756 is a reply to message #200719] |
Tue, 05 March 2013 23:35 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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| Ronald Pottol wrote on Tue, 05 March 2013 16:01 |
I wondered about that, fuel infection, and a taller final drive, perhaps
even the 2.73.
All together, the motor turns slower, but with the lower stall speed of the
switch pitch, the torque converter is still tight, and the fuel injection
stays lean, despite vacuum that might trigger enrichment with the carb.
I'm looking at a heavy coach, but no toad, in my head.
Ron
On Mar 4, 2013 9:18 PM, "Craig Lechowicz" <craig.lechowicz@sbcglobal.net>
wrote:
>
>
> George,
> I'm sure the answer is probably in the 8 - 10 range, but the lower stall
> speed of the switch pitch, should (or could?) translate to a mpg
> improvement. Given all of your fuel injection testing, I wondered if you
> were ever able to do a comparison. The low pitch is getting you part way
> to to what the modern lock-up converters achieve. (and some of :
|
I will try to answer both, the above. I have both the Switch Pitch and the 2.73, now that you ask.
Wind is our emeny (sic). I got 10.7 on our big trip this fall. 5400 miles. This was the real deal... Pumped gas vs miles traveled over the whole trip. I did not tow. We were in the Rockies and on the coast of Oregon. I driv about 63... The coach likes 63.
It is important to note that a 2.73 final drive without the tight switch pitch would be slipping so badly you could overheat the trans. At 63 I am turning 2150 or so and that is below the stall of the stock torque converter. I am about 400+ above the stall with the tight switch pitch, where a stock converter would need to run at 2600 hundred to be 400 above stall. So without switch I would still probably be at 2400 but because of slip.
I just towed 950 miles and did more like 9 Something. (hard to get the tank equally full so the return trip will help solidify the info. )
On the other hand Randy Van Winkle probably does as good or better with his 403, stock trans and a .370 final drive.
Spark control really helps. fuel injection helps but not as much unless you go to mountains. Tighter torque converter must help a bit. (it also pinged like crazy at 1600-2000 RPMs. I was almost never there until I got the switch pitch. I pulled spark like crazy... I mean like 5 degrees in that range to get it to,stop pinging.)
So why did I do so well in the fall? Luck. For the first time in 38,000 miles I rarely had a head wind. I have had headwinds that show 7.8 mpg on the computer display when I was doing 14+ the day before on the same display with a tail wind.
So I get 8 to 10+ depending on whether I tow. I would like to get back to 10 as I get to go down more on the way home. I will probably get between 8 and 10. Ha.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] Switch Pitch Transmission [message #200758 is a reply to message #200756] |
Tue, 05 March 2013 23:43 |
Ronald Pottol
Messages: 505
Registered: September 2012
Location: Redwood City, California
Karma: -2
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Senior Member |
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Yes, when I said fuel injection, I meant "smart electronic engine
management system".
Switching from my ex wife to me driving our Audi was good for at least a 5%
mpg gain. ;-)
Ron
On Mar 5, 2013 9:35 PM, "George Beckman" <gbeckman@pggp.com> wrote:
>
>
> Ronald Pottol wrote on Tue, 05 March 2013 16:01
> > I wondered about that, fuel infection, and a taller final drive, perhaps
> > even the 2.73.
> >
> > All together, the motor turns slower, but with the lower stall speed of
> the
> > switch pitch, the torque converter is still tight, and the fuel injection
> > stays lean, despite vacuum that might trigger enrichment with the carb.
> >
> > I'm looking at a heavy coach, but no toad, in my head.
> >
> > Ron
> > On Mar 4, 2013 9:18 PM, "Craig Lechowicz" <craig.lechowicz@sbcglobal.net
> >
> > wrote:
> >
> > >
> > >
> > > George,
> > > I'm sure the answer is probably in the 8 - 10 range, but the lower
> stall
> > > speed of the switch pitch, should (or could?) translate to a mpg
> > > improvement. Given all of your fuel injection testing, I wondered if
> you
> > > were ever able to do a comparison. The low pitch is getting you part
> way
> > > to to what the modern lock-up converters achieve. (and some of :
>
>
> I will try to answer both, the above. I have both the Switch Pitch and the
> 2.73, now that you ask.
>
> Wind is our emeny (sic). I got 10.7 on our big trip this fall. 5400 miles.
> This was the real deal... Pumped gas vs miles traveled over the whole trip.
> I did not tow. We were in the Rockies and on the coast of Oregon. I driv
> about 63... The coach likes 63.
>
> It is important to note that a 2.73 final drive without the tight switch
> pitch would be slipping so badly you could overheat the trans. At 63 I am
> turning 2150 or so and that is below the stall of the stock torque
> converter. I am about 400+ above the stall with the tight switch pitch,
> where a stock converter would need to run at 2600 hundred to be 400 above
> stall. So without switch I would still probably be at 2400 but because of
> slip.
>
> I just towed 950 miles and did more like 9 Something. (hard to get the
> tank equally full so the return trip will help solidify the info. )
>
> On the other hand Randy Van Winkle probably does as good or better with
> his 403, stock trans and a .370 final drive.
>
> Spark control really helps. fuel injection helps but not as much unless
> you go to mountains. Tighter torque converter must help a bit. (it also
> pinged like crazy at 1600-2000 RPMs. I was almost never there until I got
> the switch pitch. I pulled spark like crazy... I mean like 5 degrees in
> that range to get it to,stop pinging.)
>
> So why did I do so well in the fall? Luck. For the first time in 38,000
> miles I rarely had a head wind. I have had headwinds that show 7.8 mpg on
> the computer display when I was doing 14+ the day before on the same
> display with a tail wind.
>
> So I get 8 to 10+ depending on whether I tow. I would like to get back to
> 10 as I get to go down more on the way home. I will probably get between 8
> and 10. Ha.
>
> --
> '74 Eleganza, SE, Howell + EBL
> Best Wishes,
> George
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
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Unsubscribe or Change List Options:
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1973 26' GM outfitted
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| Re: Switch Pitch Transmission [message #200785 is a reply to message #200589] |
Wed, 06 March 2013 11:59 |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
Karma: 0
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Senior Member |
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Thanks George, for an informative and well thought out response. All this reading about switch-pitch transmissions is starting to make me think I need one! Pretty far down the road, budget-wise, though.
Craig Lechowicz
'77 Kingsley, Waterford, MI
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| Re: [GMCnet] Switch Pitch Transmission [message #200946 is a reply to message #200617] |
Thu, 07 March 2013 20:29 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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| Robert Mueller wrote on Mon, 04 March 2013 17:45 |
Emery,
Thanks, none of the information I have access to explained how the brake switch worked.
I can't find the email that noted the GMCer that makes the switch pitch control, would you please advise who it is?
Regards,
Rob M.
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Emery Stora
Sent: Tuesday, March 05, 2013 11:18 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Switch Pitch Transmission
No, that is correct. When you put on the brakes the switch pitch will cut in and your vehicle will pull away from a stop easier.
Emery
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IIRC with the brake appled, the converter should be in "low pitch" mode in order to decrease creep.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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