Modern auto transmission

[Gerry]

Since we have been talking about transmission I thought you all may like to see a couple of pics of a late ZF valve body, just so you can get an idea where its all going.

If this seems like a lot of technical c*** to you then I appologise but it is where things are going... so be prepared!!!!

This is from a 5 year old BMW so its no where near the latest trans thats around now.

I am sure you are are all familiar with a GM 350. It was operated by vacuum and a little bit of KD cable, using hydraulics. Have a count of the number of solenoids on that VB in the picture. Yep its that many and they are all PWM sob's

These days its gone all electronic, using solenoids to do the bidding of the software program and run the trans to the requirement of the day... EMISSION REDUCTION.

Now we have solenoids that just open and close a valve , old school stuff, and we have PWM solenoids.

PMW solenoids (or Pulse Width Modulated) solenoids are used to produce pressure curves for things like clutch overlaps and applies.
In other words by moving the valve very quickly via a command from the ECU a valve can now be used to produce a pressure curve not just a ON/OFF result. This has resulted in many modern valve bodys having excess wear on the bore and spool of their workings, typically the PR (pressure regulator), and TCC - (Torque Converter Control) because they are constantly moving and produce wear at a rate at 300 Hzs.

It has moved from the old days of a solenoid for a simple task (ON/OFF) like torque converter lock up, to a point where we now have the number of solenoids increasing every year. Add to this the advent of 'linear solenoids' and you may get an idea where this is all going. The only way to set up a linear solenoid is on a digital machine that can graph the pressure curve against time.

The big black plastic thing is a 'Mechatronic' unit. It clips to the VB and is the ECU for the transmission. Yep the ECU is now part of the valve body and includes things like pressure transducer, temp sensors, speed sensors etc. If your speed sensor goes down then expect 1000 Buck bill instead of a 50 buck bill from the old style trans. The only way to set one of these babys up is with digital equipment... which means Money Money Money.

Just thought I would let you guys in on the 'modern' auto trans and see why I stick to a 350. Its all a bucket needs. Start buying them they will get to be the next rare part. In the UK, Glides are like hens teeth and command GOOD money

Gerry

 

[ellis8500]

Yep, eveything is going the way of computer control. Now adays a mechanic has to be an electronic technican first and a wrench-runner second. That's the appeal of these cars we build. No computers, just the stuff we can fix ourselves with some hand tools and know-how. Carburators that are a mystery to the younger set but familiar to us who grew up in the 60's and 70's or earlier. Regular distributors with the GM HEI being the only real electronic thing on the engine. If it doesn't work it's either the coil or the module; the module being the most likely problem. Simple switches and relays in the harness that control everything. No ABS systems. I like that.

 

[Ted Brown]

I still like my old points, they always get me there and home again...

 

[Screaming Metal]

I still like my old points, they always get me there and home again...

Yea Ted....I spent many a night hanging over a fender of a rod setting the dual points in the early distributors. I have a WWII army jeep....the points and condensor that are in it are 10 years old...still set (I check them about about every 4 to 6 months), haven't had to even adjust them. I haven't had to file them or anything. I ride around the place in it. Starts rain, shine, sleet or snow. It could be sitting there for 3 weeks, 20 degrees, walk up beside it, pull the choke out, hit the key, starts right up.....no pumping the accelerator.
I also have cherry red Indian Flathead that I ride probably once every 6 months down the road, out on the highway for about 50 miles and put her back to bed....I check the points....haven't had to adjust them in 15 years....

 

[Hotrod46]

And I thought I was doing good to adjust the TV cable on a 700R4!

Mix hybrid technology in with all this and finding someone who knows how to fix it (and has the tools) is going to get a lot tougher.

Thanks for the lesson.

BTW - Must be cool to own an Indian!!

Mike

 

[lkeuten]

Yea Ted....I spent many a night hanging over a fender of a rod setting the dual points in the early distributors. I have a WWII army jeep....the points and condensor that are in it are 10 years old...still set (I check them about about every 4 to 6 months), haven't had to even adjust them. I haven't had to file them or anything. I ride around the place in it. Starts rain, shine, sleet or snow. It could be sitting there for 3 weeks, 20 degrees, walk up beside it, pull the choke out, hit the key, starts right up.....no pumping the accelerator.
I also have cherry red Indian Flathead that I ride probably once every 6 months down the road, out on the highway for about 50 miles and put her back to bed....I check the points....haven't had to adjust them in 15 years....

Dwelled my points in 15 years ago on the old GTO. Check it twice a year. Last winter it set for 6 weeks. 10 below out, pushed the gas pedal down slow to set the choke 2 quick pumps hit the switch and she was rumblin.

 

[Screaming Metal]

yea, I hear ya....thank god I'm retiring from racing in about 2 to 3 years....we have the computers that record everything and are tied into everything...suppossed to make things simplier and better....yea, majority of the time, they act as they should.

I like the good old manual stuff with the straight ahead electronic ignition. The new cars are way too complicated, and cost as much as a house! Things are getting way too complicated and cost way too much....all they're doing is putting out expensive junk....

 

[putz]

Be a fireman all the classes they take how to cut these new cars up with jaws of life. If they cut the pillars on a Prius they get a very shocking experience.

 

[Screaming Metal]

Be a fireman all the classes they take how to cut these new cars up with jaws of life. If they cut the pillars on a Prius they get a very shocking experience.

What do they have in the pillars? Structural Foam???? HaHa! Things like that I don't know squat about. Making them go extremely fast is my area of expertise. Stopping I know something about, (parachutes), turning....simple gearbox and linkages. All the other stuff I can limp by on. Just a plain ole stripped down hotrod typa person I am!!!!

 

[Gerry]

What do they have in the pillars? Structural Foam???? HaHa! Things like that I don't know squat about. Making them go extremely fast is my area of expertise. Stopping I know something about, (parachutes), turning....simple gearbox and linkages. All the other stuff I can limp by on. Just a plain ole stripped down hotrod typa person I am!!!!

Well there you have it guys. Happy you found it useful/entertaining.
That Vb was from a 6 speed. ZF are releasing a 9 speed quite soon. That should be even more fun.

Going to get a points, plugs and oil change car for my next ride. NO more computers or CanBus systems for me.
G

 

[Screaming Metal]

Well there you have it guys. Happy you found it useful/entertaining.
That Vb was from a 6 speed. ZF are releasing a 9 speed quite soon. That should be even more fun.

Going to get a points, plugs and oil change car for my next ride. NO more computers or CanBus systems for me.
G

A 9 SPEED???? Hum, a gear for every occassion. If they're gonna do that, guess they're gonna have a 2 and 3 speed rear end so they can get to the 18 gear range....then they can start building motors that only have to go from idle to about 2800 rpm....Guess they're gonna have to gear the hell outta them if they're gonna continue cutting horsepower....

OK Gerry, tell us about the 9 speed....whats it going in?

 

[Differen T]

Technology is everywhere. Several years ago I was involved with the development of a special clutch pilot bearing on a nationally ranked top fuel dragster team. We were given access to some of their computer information. The information collected in four seconds is amazing. The bearing's outer race was at crankshaft speed, 6800 RPM on the starting line. Our bearing had to accelerate the inner race from zero RPM to 6800 RPM in 1.8 seconds, and this was not a small bearing. It weighed lose to a pound. At the same time it has to handle the shock of 700 HP being applied to the drive train.

Computer technology is still an option in our hobby for now, but it has made it possible for us to have very drivable mega horsepower engines. One HP per cube was the goal not that many years ago, now 1.5 HP per cube is everyday stuff and more pleasant driving experience than some of the hot cars of the sixties.

 

[Screaming Metal]

Technology is everywhere. Several years ago I was involved with the development of a special clutch pilot bearing on a nationally ranked top fuel dragster team. We were given access to some of their computer information. The information collected in four seconds is amazing. The bearing's outer race was at crankshaft speed, 6800 RPM on the starting line. Our bearing had to accelerate the inner race from zero RPM to 6800 RPM in 1.8 seconds, and this was not a small bearing. It weighed lose to a pound. At the same time it has to handle the shock of 700 HP being applied to the drive train.

Computer technology is still an option in our hobby for now, but it has made it possible for us to have very drivable mega horsepower engines. One HP per cube was the goal not that many years ago, now 1.5 HP per cube is everyday stuff and more pleasant driving experience than some of the hot cars of the sixties.

Just a question. DO you KNOW how fast the motor on a top fuel Dragster turns? 6800 RPM's? :roll: And
700 horses???? :rofl: Surely, those were typo's....

I'm getting too old for this....Uh, well, I gotta 500 cu.in. blown, 6800 rpm, 700 horse motor I gotta crate up....

 

[Gerry]

A 9 SPEED???? Hum, a gear for every occassion. If they're gonna do that, guess they're gonna have a 2 and 3 speed rear end so they can get to the 18 gear range....then they can start building motors that only have to go from idle to about 2800 rpm....Guess they're gonna have to gear the hell outta them if they're gonna continue cutting horsepower....

OK Gerry, tell us about the 9 speed....whats it going in?

Think the 9 speed will head for BMWs & maybe top end saloons and 4X4s. They now known that for reducing emissions a 'clever' trans takes control away from the modern 'driver' and stops them abusing the car by letting it rev too much between the gears. Its sorta Big Brother in a car.
I know the computers do make things work better for those who dont know. Golly gee you can be an artist on a PC but with a pencil or brush you need talent. Same goes for a lot of racing these days IMHO.

Still if it keeps us on the road then let them eat ECUs.
Gerry

 

[ellis8500]

Screaming Metal's reply leads me to a question. What is the typical Top Fuel Dragster engine RPM just after the clutch engages? Is it the same as when the car crosses the finish line? I wouldn't think so, but I really don't know.

 

[Screaming Metal]

Screaming Metal's reply leads me to a question. What is the typical Top Fuel Dragster engine RPM just after the clutch engages? Is it the same as when the car crosses the finish line? I wouldn't think so, but I really don't know.

Well, heres a little article that kinda gives you the idea of what goes on....hope this helps.

http://www.hotrod.com/techarticles/engine/top_fuel_engine_rebuild/index.html

Have you ever been to the track and see one launch? They leave from idle, the driver has a spring loaded lever in his hand, in laymans terms, that trans the drivers controlling has low, neutral, and drive.
When the driver wants to leave the line, he turns loose of 'said' spring loaded lever. With 7000 to 8000 horses....you don't rev it to 6800 and dump the clutch. The drivers busy between feathering the accelerator to keep from frying the tires, keeping the accelerator floored as much as he can, twisting the steering wheel, getting outta the pedal at he end, popping the parachute and on the brakes.....but most importantly between those two things.....he's keeping it going straight, with a good reaction time, not smokin the tires or standing it straight up, and not passing out!
Maximum acceleration is accomplished with controlled slipping of the clutch--es in and before the trans, taking some out of the engine at lower speeds and giving it back in spades at the far end of the track. This is now done by computers and electronic timers controlled and/or monitored by said computers. The Trans in these cars are usually automatics...

Mike will probably want to add some to the gray areas here.....

Here's a little info for ya.....FYI....do you know that a top fueler can register on a seismometer? If its close to the track. RPM is 12,000+. Most important single gauge? Oil Pressure!!!!

 

[Screaming Metal]

A Top Fuel clutch is basically a centrifugal clutch, that has a pedal. There are a number of "fingers/levers" on the pressure plate that are weighted differently and are different height and lengths. When the RPM of the engine goes up and the clutch speeds up with it the centrifugal force on the fingers, which are mounted like a lever apply more pressure to the pressure plate reducing the clutch slip. The higher the RPM goes, the more counterweight force is transferred to the pressure plate.

There is a "ram" that stops the fingers from releasing and applying pressure, this ram is controlled pneumatically (I think is bleeds air pressure) and is activated when the throttle is hit on the line. Keep in mind that when a Top Fule/Funny Car is on the line fully staged, the clutch pedal is already out and the clearance of the clutch plates allows it to slip and the driver can hold the car still on the brake.

When the driver hits the throttle the RPM of the engine goes up drastically and the fingers/levers on the pressure plate that are not stopped by the ram apply more pressure to the clutch and drive the car forward. The ram moves at a predetermined rate and allows more and more fingers to apply pressure as the car goes down the track causing it to eventually be at 1:1 with the engine.

In simple terms, it is like taking off in 5th gear with a standard transmission, but instead of gradually releasing the clutch pedal with your foot to apply more and more pressure to the clutch, the slippage is controlled by the "ram" allowing more and more pressure to be applied to the clutch.

Keep in mind that they have to let the clutch slip so that it doesn't spin the tires as they have enough power even to do this at a 1:1 drive ratio (same at top gear), where as in a car you would slip the clutch so that the engine didn't stall as it doesn't have enough power to overcome the load on the engine.

I am not sure that I have heard the term “5-stage” before when referring to the clutch, but it is most likely to refer to the 5 disc clutches that they teams use. There are 5 clutch plates and floaters between the plates.

“Slipping the Clutch” is a reference to a state where the engine RPM is greater than that of the clutch output RPM. This is at any point during the run before the clutch has completely locked up and the engine and clutch output RPM are the same.

The entire clutch assembly rotates with no parts being “fixed” with the exception of the bell housing. When the car is sitting on the line fully staged the clutch plates are not spinning, they are sitting on the spline of the output shaft. The clutch stand is rotating at engine speed at all times as it is connected to the crankshaft.

Coupled with the application of the clutch the fuel system needs to be set up so that the engine has just the right amount of fuel to support the application of the clutch but not too much so that it drops a cylinder then loses power and the clutch pulls the engine down etc.
__________________
It's fun to do bad things!

 

[Differen T]

The HP was typo. I need to add another zero. The RPM done not vary much and stays in the 6500 to 6800 range for the trip down the strip. It is the clutch that is used to reduce the RPM to the rear wheels at the start of the run.

Another really amazing thing is these engines only live at full power for a few seconds which is only a few hundred revolutions of the crankshaft. Four seconds at 6800 RPM is only 453.33 turns of the crank. Then, provided it didn't grenade, the whole bottom end is replaced in about 20 minutes.

I was also surprised at the heads, no porting and polishing, just sewer pipes for runners. I wish I could have measured them, I'm sure they were around 2.5" in diameter as cast aluminum.

Once again, that is 7000 HP, and without a properly tuned clutch its total tire smoke. Full lockup of the clutch occurs at about 1.8 seconds and you can see it either by the tire smoke (too early on lockup) or an instant burst of speed.

 

[Differen T]

The HP was typo. I need to add another zero. The RPM done not vary much and stays in the 6500 to 6800 range for the trip down the strip. It is the clutch that is used to reduce the RPM to the rear wheels at the start of the run.

Another really amazing thing is these engines only live at full power for a few seconds which is only a few hundred revolutions of the crankshaft. Four seconds at 6800 RPM is only 453.33 turns of the crank. Then, provided it didn't grenade, the whole bottom end is replaced in about 20 minutes.

I was also surprised at the heads, no porting and polishing, just sewer pipes for runners. I wish I could have measured them, I'm sure they were around 2.5" in diameter as cast aluminum.

Once again, that is 7000 HP, and without a properly tuned clutch its total tire smoke. Full lockup of the clutch occurs at about 1.8 seconds and you can see it either by the tire smoke (too early on lockup) or an instant burst of speed.

 

[Screaming Metal]

Yea, I got ya...figured a typo...thats why I was playin with ya! HaHa!!! Tell everyone about the clutch welding itself together at the end of every run from all the massive amounts of heat generated.

Yes, most info is highly guarded and highly treasured when you get on up in classes....its hard to get the straight scoop....essentially they are a rocketship on 4 wheels....