[V8] The latest SAE review and real world on Transmission Tech

[Scott Justusson]

 Gents
I spent some time dragging out many of the SAE articles and research into transmission and trends Scott speaks to.  Sometime this year Chrysler will have a 10speed automatic, in response to ZF 9speed...  The research suggests the 'reason' for this, is getting the fuel numbers up.  The logic being that a transmission matched to the engine thermal/volumetric efficiency will yield better fuel numbers.  Alas, just in case you are thinking of retrofits, these gains are under 5% = 1-2mpg.  To the DCT/AMT (Dual Clutch Transmssion or Automatic Manual Transmission in industry speak)?

Well, the comparisons are clear, the DCT still beats the Auto in performance an efficiency.  The test results aren't out on the 9 and 10 speeds, but the research does show that adding DCT to any number of gears increases the efficiency of the Auto every time (test results on 5,6 and 8 speed autos compared to 5, 6 and 8 speed DCT), so without any 'additional' technology that should also hold for the 9 and 10speeds.  DCT will be our future, and likely replace the MT, but only because the DCT is getting *that* good.

Back to the streets for that.  In 2010 I went to Spartanburg with my old rally navigator to pick up his E92 v8 M3 DCT.  We drove back to Indy via Deals Gap and Tail of the Dragon, and the DCT box in 'Manual' mode was nothing short of F1 like, including rev matched downshifts and instant response.  That said, in full "Auto" mode, it was not butterlike, more like a C6 with a shift kit.  Flash forward to 2012 and 2013.  I recently got to drive a DCT 2014 Porsche C2.  It had all the character of the M3 in paddle mode, and massive improvement in "Auto" mode.  So much improvement, the argument against DCT is really tough to make.  And it's not just in the P car lineup, I've driven the 2012 M3 ('new') DCT and the 2012 GTI DCT.  Really really tough to argue for a MT and a clutch after those experiences.

Back to the papers and the 'sales'...  DCT has eaten into the MT market, so much so, that I suspect the MT will phase out ala carbuerators>Fuel injection in the 90's.  I'm not sure I agree with Scott D that the autos are all about controls, I think the autos are all about the mileage.  The good thing is, regardless of opinion, he is right to point out the DCT  *helps* mileage, and gives the ability for computer control.

Back to the 1990 v8 Auto and/or a Cobra with a 3speed auto?  Efficiencies are poor, like under 80%, likely less for the 3 speed and early (non computer) lockup AOD.  With the new 6-9/10 transmissions, efficiency is in the 90+% (the 9 and 10s hitting 96%), with DCT always taking the Auto with every additional gear/efficiency design.  Alas, as Scott also correctly points out, the fully manual transmission is the benchmark to beat.  Right now the DCT is about as close as it gets, and I suspect with DCT/AT transmissions 3-4gears ahead of MT offerings, the MT will lose it's edge eventually.

Carry on

Scott J
91 v8 Auto
92 v8 Auto
91 200tq

  

 

 

-----Original Message-----
From: Scott DeWitt <scotty at advancedautomotion.com>
To: Professor GT gmail <CavalloGT at gmail.com>
Cc: v8 <v8 at audifans.com>
Sent: Fri, May 31, 2013 10:32 pm
Subject: Re: [V8] Auto trannys, manual trannys, dynos and driving!


Hmm it took me 3/4 of reading through this to realize you were not
describing yourself...

Anyways I ask you this..

EPA rated fuel economy for a 1991 audi 80 5 cylinder is 16/23 for the
auto... and 18/24 for the manual.. Hmm yet Autos are more efficient?

2002 Jetta TDI.. automatic 29/40.. Manual 35/44..  ???

Okay step forward to 2012..

2012 Chev Cruz Eco Auto.. 26/39 Manual 28/42
2012 Chev Cruz 1.8 auto.. 22/35 manual 25/36
2012 Chev Cruz 1.4 Auto.. 26/38 Manual 26/38.. This is a tie..

2012 Audi A4 2.0 Auto..21/29 manual 21/31


I'm assuming since your a "Professor", you should know the scientific
method works. You make a statement (which I have disproved FALSE from the
examples above) now either what you said is entirely incorrect or you need
to revise your claim. Autos are NOT necessarily more efficient than a
manual trans and often they are not.

And reliable??? Allison?? You must be joking, I have a colleague who is
making a small fortune repairing Allison automatics. In mechanical
engineering, it's pretty much fact that a part which doesn't exist can't
fail. Automatic have many more parts and subsystems than a manual trans
has thus more chance for failure.

I've read several SAE papers on the main benefit for car manufacturers of
automatic transmissions are not fuel efficiency, not reliability but
rather more CONTROL.. yes more control over the operation of the vehicle.
With control you also have driveability, and this is where Automatics
shine. VW/Audi/Porsche is offering DSG and PDK gearboxes because of their
manual like efficiencies with the control of an automatic, combined with
their ability to shift faster than any transmission built prior to them,
make the "AutoManuals" the best of most worlds.

I've seen a 2001 Audi A6 dyno 246 at the wheels with an auto.. Put a 6
speed manual in there and you've lost 110 pounds of vehicle weight and the
vehicle dynos 269 hp on the same dynomometer with the same technician.. I
know horsepower is calculated and torque is measured.. But the math is the
same.

So I've provided evidence and facts to support my claim.. What do you have
to offer?


On Fri, May 31, 2013 8:33 pm, Professor GT gmail wrote:
> Roger,
> Thanks for you very seasoned, reasonable and realistic insights.
>
> Some folks however just don't get it!
>
> Someone once said, "Opinions are like rear ends, everybody has one!" So,
> based on the manure that's been flying, I digress.
>
> Hmm. With all the experts lurking around here, I thought there would be
> more that realize that dynos are but only one tool out of many, and the
> dyno results are just that: numerical indicators, not Biblical passages.
>
> But, in this world of digital overload it doesn't surprise me that some
> folks have lost sight of reality. Just look at what's happened to the
> youth of today. Can they articulate a cogent conversation? I'm many cases,
> no ..... but they can text like bandits though. Anyone who puts all their
> eggs in the Dyno basket.....  well you know how that one goes.
>
> Many forget to consider where and how the rubber meets the road, and
> worse, some forget that these V8s are road cars, NOT race cars.
>
> Hey, if a race car is what you want, go build a Cobra replica, cause IDGAS
> (I Don't Give A S...) what your Dyno says, even a mild Cobra build will
> terribly embarrass our V8s both on or off the racetrack, if in fact that's
> how you are going to look at it, Quattro or no Quattro! Thats about much
> better power-to-weight ratio, and superior chassis dynamics, period!
>
> And yes, a Cobra with the right automatic will kick the crap out of any
> stick you wanna put in it, no questions asked.
> I may have to build one of those bastards that way just to prove the
> point, but then again there are those who would still whine about it.
> Besides, driving a car like that seems to lose its appeal without giving
> the driver an extra pedal and a stick to play with! LOL! 
>
> Seriously though, just look at many truckers. Countless numbers still
> pound their chests and insist on manual trannys when those Neanderthal
> devices have been proven time and time again to be inferior. Kind of like
> the "might is right" argument. Yea, maybe some kick-boxing athlete can
> kick my butt, buy a nice 357mag is certainly handy to fend off one of
> those Neanderthals in short order.
>
> But hey, with respect to trucks, all the big fleets must be wrong, .......
> right? Hmmm, why do THEY use Allison AUTOMATICS? (Hint: better fuel
> economy, less repairs, lower maintenance costs, less driver fatigue.....
> Shall I go on?)
>
> But Noooo, the Neanderthals must be right - automatics are too
> inefficient! Give me a break!    I'm done! - Some cranial bones are just
> too thick to penetrate, even with simple logic!
>
> The V8 is a nice classic Euro luxury road car that was reasonably amped up
> to the point of being a fun performer. Better than your average sedan in
> many ways, but a race car? Our v8s are NOT DTM racers!
> If you sadly delude yourself into thinking you have a race car here,
> ........ well better you than me.
>
> Automated Manuals? Are you kidding me? The euro DSG gearboxes are crap for
> everyday driving, and oh yea, hello! the lack of a torque converter is
> only one reason why the suck so badly. But hey, I don't know what I'm
> talking about so I'll stop wasting my time trying to educate those who
> already know it all.
>
> I'll have fun driving my V8 while they prove to the world that their dynos
> build better cars by black magic.
>
> On the contrary, I don't make my living selling folks things they don't
> need. I educate folks in the automotive technical disciplines so they can
> discern the wheat from the chaff for themselves.
>
> And oh yea, one more thing: The difference between horsepower and torque!
> - some will NEVER be able to cross that great divide of understanding.
> Torque is what's important, because without it horsepower doesn't exist.
> Chew on that for a bit.
>
> Till then there are those who will enjoy thrashing some fools car on their
> dynos while they laugh all the way to the bank as they use that dyno data
> to convince many fools to spend more money on needless modifications.
>
> It has, and always will be buyer beware out there. Personally I'm glad I
> can weed through the BS and not waste my money, as I enjoy motoring on
> past all the Joe Racer wanna-bees!
>
> Fart-Can muffler anyone?
>
> - OK, with all due respect,  now let the sh _ _ storm begin! This is so
> much fun, almost as fun as grinding the gears in my 5-speed!
>
> ProfessorGT


-- 
Thanks!
Scott DeWitt
Advanced Automotion