[V8] gearbox swap questions

Mon May 27 08:55:17 PDT 2013

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
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