Didn't get a lot of response from those of you at gmcnet on my question
about the switch-pitch /6-speed trans. [a version sold by Caspro]. But want
to thank Billy Massey for sending me what he had collected on gmcnet from
old posts (I contacted him seperately at his site).
I eventually found Bruce Roe's name and e-mail. As I understand it, he's he
fellow who designed the "fuzzy logic" controller chip that Caspro uses in
their "6-speed transmission". Thought I'd share Bruce's response to me.
Joe Travis
2200 Briggs Ave.
Parsons, Ks 67357
jtravis
- ----- Original Message -----
From:
To:
Cc:
Sent: Monday, July 31, 2000 7:22 PM
Subject: Switch Pitch
> Joe, Try my new address at bcroe
>
> The switch pitch torque converter gives you a dual
> range in every gear. I like to think to think of them as the
> "performance" and "economy" ranges. The performance
> range gives a higher stall speed than a standard
> converter, with several benefits. First, the torque
> multiplication is about 2.5 versus standard 2, or an
> extra 25%. Second, the engine will be able to pick up
> about an extra 500 rpm, allowing it to get more into its
> best power and torque range starting up. Multiply
> both these together and you have a real advantage. I
> use a 2.41 differential on a 4100 lb car which will
> outperform a 2.73 standard, 0-60 is 7.5 seconds with
> the switch pitch. Third, the shifts will be noticeably
> smoother
>
> The performance range is less efficient, and for difficult
> situations a motorhome needs a trans temperature
> gauge to make sure you get out of the performance
> range in a minute or so. Usually 30 seconds is all
> you will need. Once you switch to the economy range
> the converter will be slightly tighter than a compromise
> design standard converter, so you will probably see
> some improvement in gas milage. I figure 3 to 5% on
> my cars
>
> At high engine speeds, all torque converters decrease
> gradually to a 1:1 torque in to out. Since you will not be
> using performance mode for cruising, additional torque
> here will require different gears. The Caspro Power
> Drive is a pretty good unit. If your trans is ready for a
> rebuild, it solves the problem of getting a new chain and
> sprocket set. I am using one in reverse on my car to
> maximize economy, while a switch pitch converter gives
> me plenty of performance. There are of course other
> options with the final drive ratio
>
> The usual way to operate the switch pitch is to use
> performance range from standstill at least into second
> and possibly into third in a motorhome. Economy range
> would be used after about 30 seconds. A car would be
> set to cover all shifts in performance mode, around
> 14 seconds
>
> Caspro uses a Switch Pitch trans on their own GMC
> motor home. The electronic controller makes this
> function automatic, instead of a toggle switch you are
> always playing with. The same is true on my cars,
> which are more responsive and so smooth many
> people mention it. An override switch is used on
> motorhomes for special situations
>
> I have heard quite a bit of talk about using switch pitch
> in other motor homes, but I don't have any direct info.
> Brent Covey did some transmission work on
> motorhomes lately. You might ask him if any were
> converted to switch pitch at BrentCovey
>
> I sell a few of the switch pitch controllers to car owners
> who already have a switch pitch trans every year. I just
> say that if they don't think its worth the money, I will buy
> it back. No one has ever asked for a refund. Good luck
> on your project. Bruce Roe
>
about the switch-pitch /6-speed trans. [a version sold by Caspro]. But want
to thank Billy Massey for sending me what he had collected on gmcnet from
old posts (I contacted him seperately at his site).
I eventually found Bruce Roe's name and e-mail. As I understand it, he's he
fellow who designed the "fuzzy logic" controller chip that Caspro uses in
their "6-speed transmission". Thought I'd share Bruce's response to me.
Joe Travis
2200 Briggs Ave.
Parsons, Ks 67357
jtravis
- ----- Original Message -----
From:
To:
Cc:
Sent: Monday, July 31, 2000 7:22 PM
Subject: Switch Pitch
> Joe, Try my new address at bcroe
>
> The switch pitch torque converter gives you a dual
> range in every gear. I like to think to think of them as the
> "performance" and "economy" ranges. The performance
> range gives a higher stall speed than a standard
> converter, with several benefits. First, the torque
> multiplication is about 2.5 versus standard 2, or an
> extra 25%. Second, the engine will be able to pick up
> about an extra 500 rpm, allowing it to get more into its
> best power and torque range starting up. Multiply
> both these together and you have a real advantage. I
> use a 2.41 differential on a 4100 lb car which will
> outperform a 2.73 standard, 0-60 is 7.5 seconds with
> the switch pitch. Third, the shifts will be noticeably
> smoother
>
> The performance range is less efficient, and for difficult
> situations a motorhome needs a trans temperature
> gauge to make sure you get out of the performance
> range in a minute or so. Usually 30 seconds is all
> you will need. Once you switch to the economy range
> the converter will be slightly tighter than a compromise
> design standard converter, so you will probably see
> some improvement in gas milage. I figure 3 to 5% on
> my cars
>
> At high engine speeds, all torque converters decrease
> gradually to a 1:1 torque in to out. Since you will not be
> using performance mode for cruising, additional torque
> here will require different gears. The Caspro Power
> Drive is a pretty good unit. If your trans is ready for a
> rebuild, it solves the problem of getting a new chain and
> sprocket set. I am using one in reverse on my car to
> maximize economy, while a switch pitch converter gives
> me plenty of performance. There are of course other
> options with the final drive ratio
>
> The usual way to operate the switch pitch is to use
> performance range from standstill at least into second
> and possibly into third in a motorhome. Economy range
> would be used after about 30 seconds. A car would be
> set to cover all shifts in performance mode, around
> 14 seconds
>
> Caspro uses a Switch Pitch trans on their own GMC
> motor home. The electronic controller makes this
> function automatic, instead of a toggle switch you are
> always playing with. The same is true on my cars,
> which are more responsive and so smooth many
> people mention it. An override switch is used on
> motorhomes for special situations
>
> I have heard quite a bit of talk about using switch pitch
> in other motor homes, but I don't have any direct info.
> Brent Covey did some transmission work on
> motorhomes lately. You might ask him if any were
> converted to switch pitch at BrentCovey
>
> I sell a few of the switch pitch controllers to car owners
> who already have a switch pitch trans every year. I just
> say that if they don't think its worth the money, I will buy
> it back. No one has ever asked for a refund. Good luck
> on your project. Bruce Roe
>
wner-gmcmotorhome]On Behalf Of Joe Travis
