8 Speed Automatic

[shanekennedy]

the 6speeds obviously weren't built for hotrods, but they can be transplanted as well as the 4speeds. however, i've not heard of anyone tuning ot transplanting the 6speeds yet. i expect it will take some time to learn how to control these guys. i think you have valid points about calibration being vehicle specific. maybe someone will come up w/ some conversion formulas.

[Bandit]

At some point you might as well go to one of those CVT's(Continuously Variable Transmission). There's got to be a point of diminishing returns...

Jim

I agree woleheartedly. Why do some people think more is always better?

[Steve Chryssos]

Again--these eight speeds are not necessarily using all eight gears. They do not go 1, 2, 3, 4, 5, 6, 7, 8 like an old school auto trans. The computer determines load and then chooses from a wide range of gears. The trans might skip 1, 3, and 7 based on specific circumstances and only use 2, 4, 5, 6, 8 and then skip down to 5th gear instead of going 8, 7, 6, 5.

This is in the same way that a human might decide to start out in 2nd gear when their manual trans equipped car is starting out on a steep downhill slope. See? Think of the eight speed is really multiple 5 speeds hiding in one housing.

[Bandit]

I can see the concept, I guess. It just sounds like a nightmare to set up, and very expensive to fix. I guess if some aftermarket company would come out with a kit including the chip, installation parts for your vehicle, etc, all geared toward hot rodding, I would be very interested indeed. But I still wouldn't care if it cost me over $5K, which is likely.

Maybe down the road one day you will be able to attach a little sensor to the side of your head and the tranny will shift into whatever gear you are thinking, that would be cool too!

[Jim Nilsen]

In 1984 I remember the 1st to 4th shift in the Vettes. Many people who rode with me before they came out told me I was crazy for getting to 30mph then shifting to 4th to just go down the road and that I should have been going thru the gears. I just laughed and wondered why they thought that. Then the Vettes made it mandatory and I didn't look so dumb to them anymore.

I like the idea of a variable trans but the timing to move quickly for one spot to another isn't as fast as changing to a different gear would be ,hence the direction things are going I would think.

Selecting the right gear at the track still requires knowing variables like traffic and weather conditions along with driver skill for what is happening at the moment and that is something no computer will ever be able to help with and why most of us still want control over when and what gear we shift to. Having a little help when cruising to get the most out of it all seems like a way to go in cars like we are building so I look forward to seeing more of it and hope it all gets better with time.

Jim Nilsen

[Steve Chryssos]

Selecting the right gear at the track still requires knowing variables like traffic and weather conditions along with driver skill for what is happening at the moment and that is something no computer will ever be able to help with and why most of us still want control over when and what gear we shift to. Having a little help when cruising to get the most out of it all seems like a way to go in cars like we are building so I look forward to seeing more of it and hope it all gets better with time.
Jim Nilsen

Which is why manual mode is so important. Transmission computers get confused by wheelspin. The computer erroneously sees high wheelspeed and causes the transmission to upshift. Likewise the driver might lift when wheelspin is present. In this case the computer interprets the small throttle angle as low load. Once again, the transmission upshifts. This is true for both computer controlled and pre-computer controlled transmissions.

Conversely, an electronic transmission with manual mode will allow you to delay or actuate a shift to copensate for such situations. At Pigeon Forge, the conditions for the 1/8th mile track caused wheel hop off the line followed by wheelspin mid-track. Conditions were unpredictable to say the least.

My best run was made in manual mode as follows: Shift into 2nd gear almost immediately off the line to reduce torque multiplication. Shift into 3rd gear shortly thereafter (at about 4500rpm) to eliminate the mid track wheelspin.

[23corner_blitz]

watch the new lexus park itself

http://www.fquick.com/videos/viewvideo.php?id=520

[Leadfoot1]

......


Lead

[Splinky]

I recall reading not too long ago that one possible direction of these transmissions with 6, 8, and more speeds was the potential elimination of the torque converter. The trans control module would modulate application of an oversized primary clutch pack to get the vehicle moving. First gear would be quite low making life easier on the primary clutch pack and making up for the lack of torque multiplication.

Wonder if this is still the direction they are thinking?

[Steve Chryssos]

Clutch apply is well within the realm of computer control, but only the DSG (Direct Shift Gearbox) solution offers smooth operation during low momentum scenarios because it employs two clutches. But yes, there is talk that DSG will ultimately replace BOTH traditional manuals and automatics.

When I purchased my Audi A3, the salesguy kept calling DSG "automatic" as though he didn't want to complicate the conversation. It's a mechatronic dual clutch manual transmission", I said. He said: "Uhh....."

[MonzaRacer]

Actually with the use of a Digital Graphing Multimeter and some flash chips it shouldnt be hard to figure out the 6 speeds basic operating parameters and smoothing it out as you finailze the setup/install.
As a diag tech and a person who started looking at adding the newer technology from Detroit and other manufacturers over 20 yrs ago I figured out how things work then made them fit other cars.
I have been working on a less expensive standalone DIS that can bolt on to any V8 and integrate with a lot of the current computer technology with minor adaptation. And it will use currently available parts from parts stores too.
Also while working on this I havein prototype a Flex Fuel set up that so far works pretty much flawlessly on the bench and for a few hours on buddies race car till it decided to relocate valve seats out from under the valves and in pieces distributed through out the engine.
With a little more work the FlexFI will also support most electronicly shifted trans out there.
it is far less complicated to adapt than to modify in most cases but an instructor from a class I took last year told me that if you see a sensor or actuator on a car just identify what it s and how it works and forgt the name on the front of the car.
Good luck
Lee

[pdq67]

I really liked the 6-speed tranny my old early '80's Yamaha XS 400 Special II motorcycle had b/c it heal to toe shifted up and down in a New York Minute!!

AND now thinking about this 8-speed jobber got me to thinking and now I wonder why the same tranny type design hasn't been scaled up and used in cars and such??

Anybody have a take on this?? Surely packaging hasn't been the hold-up??

pdq67

[Steve Chryssos]

Believe it or not, the big hold up is getting the mundane tasks to work. Reverse and low speed control in situations like parallel parking is the problem. It's easy to perform a clutchless wide open throttle, sequential upshift. But try getting one to smoothly and effectively do a K-turn and all of a sudden you are scratching your head. The OE's can do it because every car that falls off the assembly line is identical. To make a kit that comes out of a box and will adapt to your hot rod or mine (two very different vehicles) is a challenge. It'll happen--just not anytime soon. As for today, even the OE's are having problems. People HATE BMW's SMG system. Try parallel parking one of those cars, then picture your self pirating the SMG system and adapting it to your hot rod.

[Steve Chryssos]

Actually with the use of a Digital Graphing Multimeter and some flash chips it shouldnt be hard to figure out the 6 speeds basic operating parameters and smoothing it out as you finailze the setup/install.
.....With a little more work the FlexFI will also support most electronicly shifted trans out there.
it is far less complicated to adapt than to modify in most cases but an instructor from a class I took last year told me that if you see a sensor or actuator on a car just identify what it s and how it works and forgt the name on the front of the car.
Good luck
Lee

Sounds interesting. The DSG in my Audi looks at a large number of inputs including braking and traction control.

[StRacerDuke]

8 speed auto, bahh! It's a waste!

It's all about the powerglide baby!!!

LOL

[Yelcamino]

Kinda like a chinese menu.