[V8] gearbox swap questions

Mon May 27 14:48:25 PDT 2013

Professor GT is correct a transmission will not make an engine produce
more power, however that is not what I said. I've been part of dozens of
C5 5hp24 to 01E 6speed swaps and can tell you an engine will register more
wheel hp with a 6 speed than with the 5HP24. Ive seen before and after
dyno charts which show this. No where did not say the engine would make
more power due to the lack of a manual. Mr. GT took it to mean something
else.

Fuel economy is also improved considerably.

Automatics are also not more efficient than manual transmissions (I don't
care what automatic we are discussing), an Automatic trans has a torque
converter which can have double digit inefficiencies depending upon what
torque converter we are discussing, and an automatic has a fluid pump
which unless the laws of Physics have changed consumes engine power to
run. This is power that does not reach the wheels.

Also VW/Audi have seven speed DSG transmissions which are essentially a
computer controlled manual trans which have remarkable better efficiencies
that a traditional automatic trans. Porsche has it's 7 PDK based off a
similar design. Although the DSG transmission do have a fluid pump to
power the hydraulic actuators and clutch packs, they do not have a torque
converter hence one reason why DSG's are more efficient.

But I digress the point of this thread was swapping a 5hp24 into place of
a 4hp24, not the newest ZF transmissions.

Scott

On Mon, May 27, 2013 3:50 pm, John Bysinger wrote:
> Scott, he's right.  Though the only real correction has to do with the
> power conversion of a torque converter, there are torque gains at a cost
> of
> hp losses during launch/acceleration.  (Though I'm pretty sure he's aware
> of that, just simplified it for arguments sake.)  But for the purposes of
> accelerating that's exactly what you want, and it doesn't negate his
> argument.  There is _nothing_ a transmission can do to increase hp.  Ever.
>  With regards to his discussion of gearing, and why the industry is moving
> to automatics he's spot on.
>
> I think the reason why automatics have a bad rap from the
> aftermarket/tuner
> crowd is there is an illusion of more power with a manual.  You can hold
> out on shifting past the ideal point and hear the beautiful sound of the
> engine screaming towards the redline, a very addictive feeling, but not
> the
> most efficient method for extracting the most power you can get from the
> machine.  Unless you're driving a Nissan GT-R with the gizmo-dash that
> shows you live power output readings, and have skill like the Stig, odds
> are your shifts suck compared to a modern automatic's computer.  Combine
> that with the slushbox reputation that older (sloppier) automatics had in
> the 70's and 80's and you have a perfect storm of misinformation.  It's
> easy to lump our older V8's into the slushbox category because of it's
> age,
> but you're talking about a transmission in what was Audi's flagship that
> was years ahead of mass production cars at the time.  Combine that with a
> trans computer that pretty much lets you do what you please in manual mode
> (without all the modern nanny-safeties like forcing shift before redline),
> you have something as close to the best of both worlds as you can get.
>  Really the only thing missing is that your left foot is bored.  This is
> why you'll find most people on this list giggling at stories of 'power
> gains', your argument might be valid for an early 90's Honda Accord, but
> not for the car/trans we're discussing here.
>
> That said, I'm a sucker for a manual, they're fun.  Lots and lots of fun.
>  And I too like to use my left foot while driving.  Plus you CAN do things
> with them that an auto won't let you, but those things aren't going to
> magically add power or get you there faster, mostly because they're the
> opposite of what you should be doing.
>
>
> If he's wrong, maybe I should ignore my BSME since it obviously taught me
> incorrectly. :)
>
> -John
> '91 V8
>
>
> On Mon, May 27, 2013 at 11:04 AM, Scott DeWitt <
> scotty at advancedautomotion.com> wrote:
>
>> It's apparent you know very little about the subject so I'll end the
>> conversation with a Happy memorial day!
>>
>> Scott
>>
>>
>>
>>
>>
>> On Mon, May 27, 2013 10:55 am, Professor GT gmail wrote:
>> > Scott,
>> >
>> > With all due respect, an additional gear (6-speed) does not "make"
>> more
>> > horsepower, as an engine makes what it makes, and that's it. At a
>> given
>> > speed the dyno may show a higher power level because a different gear
>> > ratio has the engine closer to its peak output level over a broader
>> range.
>> > The only way however that a transmission can "enhance" an engines'
>> power
>> > is with the use of a torque converter, which again, a manual trans
>> does
>> > not have. Torque multiplication ratios range typically from 1.5:1 to
>> as
>> > high as 3.0:1, so an automatic can almost triple an engine's
>> > launch/acceleration torque (vortex flow mode). A manual transmissions'
>> > clutch - no such luck.  Torque converters also add a lockup clutch, so
>> the
>> > remaining 2% of hydraulic loss (inefficiency) in the rotary mode of
>> > operation is effectively eliminated.
>> >
>> > The whole idea of efficiency (and more gears) is to keep the engine in
>> its
>> > peak output power band as much as possible, which computer controlled
>> > automatics do better than any human could manually hope to accomplish.
>> > This is the whole idea behind today's 8/9 speed automatics and CVTs.
>> > Again, employed through the use of computer controls as speed &
>> accuracy
>> > (among other things) are the main reasons computer controls prevail.
>> >
>> > Just for a moment imagine driving a 9 speed stick. NOT! Not only would
>> the
>> > driver be doing nothing but shifting constantly, but consider
>> selecting
>> > the proper ratio under varying conditions AND doing so at the same
>> level
>> > of speed and accuracy as can be done via computer controls, and one
>> can
>> > begin to understand the issue.
>> >
>> > I'm not trying to condemn manual transmissions, just trying to educate
>> > folks on the realities of current technology, so they can choose
>> wisely.
>> >
>> > Beauty is in the eyes of the beholder, but what we can't see may put
>> us
>> at
>> > a disadvantage. Opening our eyes to ALL the options with a clear
>> > understanding of the advantages and disadvantages  of each, allows us
>> to
>> > make wise choices. I hope I've been able to shed a bit more unbiased
>> light
>> > on the subject.
>> >
>> > Remember, I'm driving my V8 stick, but in no way purport to support
>> that
>> > it is superior in any way to an automatic. It is just a choice I have
>> > made, mostly for the fun factor associated with it. Now, if I could
>> build
>> > a control unit that would allow me to add paddle-shifting capability
>> to a
>> > 4HP24 THAT would really be the trick.
>> >
>> > Just sayin' LOL!
>> >
>> >
>> >
>> > Thanks,
>> >
>> > ProfessorGT
>> > (Sent from my iPhone4)
>> >
>> > On May 25, 2013, at 4:54 PM, "Scott DeWitt"
>> > <scotty at advancedautomotion.com> wrote:
>> >
>> >> In the C5 a 6 speed conversion will yield approx 20-25hp additional
>> on
>> >> the
>> >> dyno and 2-3 mpg on gas 6 speed ratios and 5-8mpg using diesel trans
>> >> ratios.
>> >>
>> >> Automatic are becoming commonplace in most new cars not because they
>> are
>> >> more efficient than a manual but rather people are lazy and
>> >> manufacturers
>> >> have much more control over engine operation, emissions, and warranty
>> >> issues if a computer is shifting gears versus the driver.
>> >>
>> >> There is a stand alone controller for ZF boxes but to be honest if
>> the
>> >> OP
>> >> runs the numbers he will never recoup the money spent with fuel
>> savings.
>> >> The 3.6 V8 in a 4000+ pound car is not intended and never was to be
>> king
>> >> in fuel efficiency.
>> >>
>> >> On Fri, May 24, 2013 10:56 pm, Professor GT gmail wrote:
>> >>> Oh boy, here we go!
>> >>>
>> >>> First off, ALL manufacturers these days are using communication
>> links
>> >>> like
>> >>> CAN BUS, to tie EVERYTHING together. The VW Phaeton (a real fart in
>> >>> church) had something like 60 control units all talking to each
>> other
>> >>> over
>> >>> CAN.
>> >>> There are many benefits, and I can go on for quite some time about
>> this
>> >>> (my J1939 datalink presentation is over 140 slides), but the
>> drawbacks
>> >>> are
>> >>> mainly centered around Servicability issues.
>> >>>
>> >>> So, the point, forgetting about any possible hardware issues, is the
>> >>> lack
>> >>> of flexibility with respect to vehicle integration, or installing
>> and
>> >>> then
>> >>> properly controlling that trans in a vehicle it was not designed
>> for.
>> >>> That
>> >>> said, anything is possible, but practicality has to enter into the
>> >>> equation also. Bottom line, not worth it!
>> >>>
>> >>> Secondly, on the automatic versus stick debate: there is NO
>> compelling
>> >>> reason to switch from an auto to a manual Trans, other than if you
>> >>> enjoy
>> >>> playing with a clutch pedal and a shifter, PERIOD!
>> >>>
>> >>> Better fuel economy with a manual?
>> >>> NOT!
>> >>> Maybe years ago, but with today's electronic controls, automatics
>> are
>> >>> far
>> >>> superior.
>> >>>
>> >>> Vehicle Control? See previous response!
>> >>>
>> >>> Pulling power? That thing called a torque converter kicks a clutches
>> >>> ass
>> >>> hands down every time! See previous response!
>> >>>
>> >>> Driver Comfort, and ease of operation?
>> >>> Do I even need to ask?
>> >>>
>> >>> And with all this in mind, when applied to larger vehicles the case
>> is
>> >>> even more compelling for automatics! Any trucker who buys a new
>> vehicle
>> >>> with a stick is just kidding himself! The ONLY reason a trucker
>> would
>> >>> prefer a stick is because of the Neanderthal effect. It has been
>> proven
>> >>> over and over, beyond a shadow of a doubt that an Allison automatic
>> is
>> >>> far
>> >>> superior to any manual or automated manual ever created.
>> >>>
>> >>> Okay, now that I got that off my chest and put those facts out
>> there,
>> >>> before you call me a hypocrite, let me say that I have my V8 5-speed
>> >>> for
>> >>> the novelty and rarity factors, coupled with the fact that its just
>> fun
>> >>> to
>> >>> drive! That is at least until I hit traffic!
>> >>> Having an original factory V8 5-speed is cool, and to the automotive
>> >>> purist represents the best that the Europeans had to offer in its
>> >>> class,
>> >>> at the time.
>> >>> I spite of the traffic I have not grown tired of it, and view it as
>> a
>> >>> blessing for the long weekend commutes I've been doing since last
>> >>> Fall...........but an automatic is in the wings to replace my
>> 5-speed
>> >>> as a
>> >>> daily driver so I can save the stick for special occasions!
>> >>>
>> >>> Now I feel much better that my rant is done! LOL
>> >>>
>> >>>
>> >>>
>> >>> Thanks,
>> >>>
>> >>> ProfessorGT
>> >>> (Sent from my iPhone4)
>> >>> _______________________________________________
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>> >>
>> >>
>> >> --
>> >> Thanks!
>> >> Scott DeWitt
>> >> Advanced Automotion
>> >> Ph:  720.4.GEARS.1 (720.443.2771)
>> >> Fax: 361.288.8030
>> >> Any price quoted in this email is valid for 15 days, and subject to
>> >> availability.
>> >> Http://www.advancedautomotion.com
>> >> Shipping, Return, and Warranty policies
>> >> http://www.advancedautomotion.com/shipping.php
>> >> http://www.advancedautomotion.com/warranty.php
>> >>
>> >
>>
>>
>> --
>> Thanks!
>> Scott DeWitt
>> Advanced Automotion
>> Ph:  720.4.GEARS.1 (720.443.2771)
>> Fax: 361.288.8030
>> Any price quoted in this email is valid for 15 days, and subject to
>> availability.
>> Http://www.advancedautomotion.com
>> Shipping, Return, and Warranty policies
>> http://www.advancedautomotion.com/shipping.php
>> http://www.advancedautomotion.com/warranty.php
>>
>> _______________________________________________
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>>
>>
>
>
> --
> john at bysinger.net
> _______________________________________________
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>

-- 
Thanks!
Scott DeWitt
Advanced Automotion
Ph:  720.4.GEARS.1 (720.443.2771)
Fax: 361.288.8030
Any price quoted in this email is valid for 15 days, and subject to
availability.
Http://www.advancedautomotion.com
Shipping, Return, and Warranty policies
http://www.advancedautomotion.com/shipping.php
http://www.advancedautomotion.com/warranty.php