Lockup strategies and their affect on clutch durability.

Eric,

Thanks for the clarification. I guess that's why it doesn't unlock at WOT above 124 MPH.

Thanks
Neal

Thanks, Eric. I think that that section of code is some of the more obtuse code in the rom . It is in the form of a subroutine called from the eprom, though, so I always wondered if it could just not get called, but I guess that's unnecessary. Neal, where the tcc locks up is definitely a personal choice thing. I like to let it lock early at low tps where the rpm drop won't be big because the load is so low, and lower the unlock thresholds in 4th so it unlocks easily when you mash to say 35-40% tps so you don't get that lugging feeling.

Discussion 1d. Volumetric Efficiency (VE).

This is going to be a very important subject, if not the most important, so I will try to make everything I present as clear as possible.

VE is the Holy Grail of racing. Simply put, it is the engines ability to fill each cylinder compared to the actual displacement of each cylinder and is expressed as a percentage. Most street engines have a VE of 80 to 85%. Dedicated race engines can be 90 to 100% or even above. These are numbers associated with normally aspirated engines. Turbo engines can have a VE of well over 200%.

The variables that affect VE are as follows and this is only the tip of the ice berg: combustion chamber design, port sizing and design, valve size and configuration (4 valve, 2 valve, etc.), intake and exhaust manifold design, piston dome or dish design, turbo selection, intake charge temperature, ignition timing, pulse tunign affects, and of course valve timing. The mighty camshaft.

VE changes radically with engine speed, mainly because any particular camshaft is designed to work efficiently over only part of the engines total operating rpm range. The more radical a cam, the more narrow the power band. Street cams generally give a wide flat torque curve compared to a race cam that tends to be a higher value, but narrow and peaky.

On a turbo engine, the torque band can be affected greatly by simple bolt-on items such as a compressor or turbine housing.

Lets look at the turbine housing. The A/R ratio of the housing will dictate when the turbo will begin spooling and at what engine rpm range the turbo will operate most efficiently. The proper A/R ratio to use can only be determined through actual testing. The smaller the A/R ratio the quicker and sooner the turbo will spool in the engines rpm range. The larger the A/R ratio the later and longer it will take for the turbo to boost. The smaller housing will choke the engine (exhaust back pressure) sooner at the upper engine rpm.

Now, something that actually relates to transmissions. Think of this scenario; A person installs a turbo that has a larger compressor housing and the turbine housing has the same or smaller A/R housing. Driving at part throttle, slightly heavy acceleration. You do a before test with the old turbo and an after test with the new turbo. In both tests you maintain a TPS signal of 3.3 volts. What is the affect on VE of the engine (torque output) and what is the line pressure in the transmission doing in both cases? Let's also say the torque converter lockup clutch is programmed to engage at anything below 3.5 volts and mph threshold is 45 in this scenario. I don't know if it is possible to program the chip to do this, so you'll have to correct my scenario if I'm plugging something in that isn't possible.

Hmmm. I thought most of you were eager to get to this point. This is pretty basic stuff still so someone just offer up something so we can get this discussion going. Your all making me feel as if I should have bored you with more basic discussion. This is the meat and potatoes part of the thread, guys. The part you all have been waiting so patiently for.

Ok. Let's explore this. What inputs are used by the transmission to get its torque signal? What is this torque signal? And exactly what does the tranmission do with this torque signal?

Hi Don, I have a limited understanding of how the transmission works but have always bnee interested in learning about them.

What do you mean by "torque signal"? Would that be the same as line pressure?

From what I gather, the line pressure is determined by the input RPM and the throttle valve positioning and governor pressure is is a function of outputshaft RPM. The relationship betwen line pressure and governor pressure determines whether the transmission upsifts or downshifts.

So when you initially jam your foot through the floor line pressures increase rapidly and governor pressure increases at a slower rate until it overcomes the pressure against the shift valves and forces an upshift. After the upshift, governor pressure is applied to the next upshift valve and the cycle repeats itself.

I know this is a bit oversimplified but I don't have an ATSG manual in front of me and at least this give us a good starting point for discussing transmissions.



Charles Brooks

we have a saying in greek "i had a toothache and the doctor took out my eye"i see this has become a runaway train and the conductor should jump out the window before the train crashes.look here,engine torque signal to the transmission is via the tv cable.and i dont give a good one who has been building transmissions for years,listen up.the throttle opens from 0 degrees shut to 90 degrees open.with that stated ,engine load transferred to a hydraulic load signal should rise equally in relation to throttle opening .here is my formula and real world explanation.at idle 0 degrees of throttle angle pressure should be only what the line bias valve feeds the plunger ,90 psi.in other words 0 psi of modulated tv oil which is the engine load signal in hydraulic form.if wide open throttle max tv is 235psi then :for every 25 percent of throttle angle,which is 22.5 degrees ,modulated tv pressure should rise 36.25 psi.it is sometimes misunderstood by others and called torque signal when referring to the torque convertors multiplying abilities which is another science called the k factor.this is useless in the formula because this occurs well below the lock up point and diminishes as the vehicle accelerates.some vehicles with high volumetric efficiencies respond negative to being locked because of other parts of the puizzle not responding favorably to applied loads.and what does this have to do with clutch durabvility?the same as all the other attempted darts thrown at the bullseye that are stuck in the rug.sure my posts are construed by many as nonsense ,babble ,off base ,make you dizzy ,long winded ,etcetera.however if you took the time to unwrap them properly ,you might find the real message .don ,im catching on.come on now donald .at 33 ive got 20 years in the business from my humble beginning building in lower manhattan to where i am now ive smelt it all.

Chris, man, take a chill pill. This thread is meant to be a learning experience for most of us, including me. It is not directed to any one person, especially you. I have the utmost respect for others in the industry and I'm having a hard time figuring out where your coming from. Did I say something directed at you that may have offended you? Anyway, I do appreciate the constructive participation.

Charles Brooks. You are my hero! This is the exact type of person this thread was started for. This is a fellow that has the desire to learn and try to understand how things work in his car and has the guts to put his pride aside and ask for help in doing so. I'm a firm believer that you should never stop learning and never assume you know it all. I try everyday to learn something new and enjoy trying to pass on what I have learned to those who are hungry for it. Charles, I promise I will do my best to answer your questions, but first lets give it some more time and let others offer up their opinions or questions.

Chris has it right. There is only one torque signal given to our transmission (200-4R). It is through the pull on the TV cable by the throttle linkage. We'll discuss more later. This is open book, so feel free to study up before adding to the discussion.

Honda transaxles have two torque signals. Can any future or up and coming transmission technicians identify them? Chris, I'm not trying to test your knowledge, so don't feel you have to answer this.

mistyped,clarification ,modulated tv oil will cause line pressure to rise 36.5 psi for every 22.5 degrees or 1/4 of throttle angle.i find the newest honda automatic transaxles(4 solenoid px4b hybrids) useless in this discussion as it does not use planetary gears,contains a final drive,electric shift scheduling ,a manual valve that is unconventional as far as comparisons with the 2004r,introduces apply oil via a signal from the mlps rather than a mechanical path thru the manual valve,pulse width modulation for tcc apply oil,etcetera.torque signal is obviously read via a calculation of throttle position via a signal from the tps,air ingestion via an air flow measuring device,and then a decision based on its relation to flywheel speed,turbine/input shaft speed ,and output rpm. what is the relation between this and the original title of this discussion?hey ,i just remembered your surprise when i told you you could air check the clutch packs on a 2004r through the clutch exhaust passages in the valve body when i contacted you to buy my billet parts and you said you were loyal to bruce toeele.i appreciate your loyalty and wish you much success in your interest of honda transaxles.maybe there is a website devoted to them somewhere on the internet where others may find this information useful.

DonWG:

From the The American Heritage ® Dictionary of the English Language, Fourth Edition:

pre·ten·tious -- adjective
Claiming or demanding a position of distinction or merit, especially when unjustified. Making or marked by an extravagant outward show; ostentatious.

con·de·scend·ing -- adjective
Displaying a patronizingly superior attitude.

pla-gia-rize-- verb
To reproduce (the artistic work of another, for example) illicitly: crib, pirate.

back-hoe -- noun
An excavator whose bucket is rigidly attached to a hinged pole on the boom and is drawn backward to the machine when in operation; used to dig large holes.

As defined by the Federal Railroad Administration:
train accident-- a train accident is a "collision, derailment, and other event involving the operation of on-track equipment." Train accidents cause "reportable damage above an established threshold" and generally involve collisions. Another leading cause of train accidents is derailment.

Boy. Did we get up on the wrong side of the bed today. Chris, what is with the big chip on the shoulder? Is this where we pull out ****s to see who has the biggest?

Yes. I do remember that sales call. You were trying to sell me your forward drum. Strangely, you were much more pleasant then. Judging by your attitude so far, it appears I made the right decision not to buy. I stood there listening on the phone while you did what most of us transmission guys like to do. Try to impress each other with their building skills. Not criticizing you for that. It's one of those things that happens when two technically minded people get together. Your right about me being very surprised when you told me about air checking through the VB exhaust holes. I politely elected not to comment about it at the time, but since you seem to be using my surprise as some kind of sign that I don't know what I'm doing, I'll tell you why I was surprised.

Why the heck would you wait so long in the assembly process to check your drums?
That procedure is great on AODs to check for excessively leaking valve bore end plugs, but on the 200-4R it is an unnecssary step. If you check your gasket fit and alignment during assembly, torque the VB correctly with the correct pattern and air check your pressure switches when you O/H the VB and check carefully for nicks and burrs on the case and VB gasket surfaces, you won't have a crossleak there. I've never had one anyway. You should air check the drums on the support and again in the case after you've torqued the support bolts. If a problem shows up during either of those air check procedures, you don't have to take so much of the trans assembly back apart to find out where the problem is. It will save you time when a bad air check presents itself. I can't imagine waiting until after you've installed the VB before air checking. Your making a big assumption, that the air check will be fine and you won't have to take all that assembly back apart. On a 200-4R, it is not the thing I would want to see my tech do. If there is a specific reason for doing such a check, I haven't come across the need yet, and I've done a lot of 200-4Rs.

How does the Honda fit into the picture? Let me explain. One torque signal comes from the throttle position sensor. As throttle opens, TPS signal changes and the computer will modify output signals to the transaxle. This is similar to our throttle valve cable. As the throttle is opened, the TV cable is pulled and a lever in the trans acts on what is called the TV plunger. This action increase TV pressure. One of its purposes is to modify line pressure. As TV pressure rises, so does line pressure.
The other torque signal in the Honda transaxle comes from the stator support. As engine torque acts on the stator in the torque converter, it twists the stator support and through a lever, a valve is stroked in the valve body to increase line pressure.
Line pressure is the main working pressure of transmissions and is mainly used to apply bands and clutches, or just clutches in the case of the Honda. The more torque going through a clutch or band, the more line pressure needed to keep it from slipping. Line pressure in the trans rises with engine torque increase. With the Honda system, any increase in engine torque AT ANY POINT IN THE RPM BAND is immediately met with an increase in line pressure.

How does this relate to the 200-4R? Remember the 200-4R only has one torque signal. The TV cable. The rise in transmission line pressure is tightly connected to throttle blade position, PERIOD. The rate of cable pull is dictated by the geometry of the cable attachment point on the throttle lever in relation to the throttle shaft centerline, and the geometry of the lever at the other end of the cable in the pan.

This means that the line pressure ramp up is solely dictated by throttle position. 'NOT THE ENGINE TORQUE CURVE!' Ouch!!! Remember the Alpha-N discussion? The Alpha-N EMS system was unable to compensate for minor or major changes that might occur in the torque band of the engine because of its ASSUMPTION of the engines torque curve. If an engine modification were done on such an engine, the timing and fuel curves would have to be reprogrammed after the new torque curve of the engine was determined. Hopefully the torque curve would not stray from the predetermined estimate. If for whatever reason the torque increased 20 ft lbs at 2500 from the predetermined estimate, the engine would run lean and with possibly too much timing, depending on the tolerances established during the original programming of the ignition table. You can see how a system like this could be disasterous with a turbo engine.

Back to the transmission (200-4R). If an engine modification is done that increases torque output at mid-throttle, there will be NO MATCHING INCREASE in line pressure at that point to compensate for the additional torque that must go through the bands, clutches, and TORQUE CONVERTER CLUTCH. This makes slipping of the friction elements possible. This example would be of particular concern if the stock transmission and torque converter were still being used and a turbo setup were used that spooled much quicker than stock in the mid-throttle positions.

Ok. I hope I have stirred the thought processes in some of you. Lets discuss this.

Yes Buicksx3. Some of us do read books. If we didn't we would have to depend on the opinions of our friends and family. That's just plain lazy. You can close your book now. It doesn't seem to be helping.

Charles. We'll get to governor pressure later. I hope it is clear to you so far.

your way off base here and not doing a good job covering up the fact that you cant wipe your ass properly.no one on this end needs to impress people on this board.we just provide truthful information about the 2004r transmission.if you are not considering making an adjustable stator to raise pressure in the 2004r than you should take the honda information and put it somewhere where it is part of the discussion at hand,such as a honda website.by putting it here its importance is no more than the words of a babbling ,deranged ,szizophrenic laying on a piece of cardboard on the sidewalk.as far as the air check procedure,your response on the phone then and now shows your lack of understanding of the 2004r transmission as well as your inability to understand the need for the procedure.pull out what to see whos is bigger?arent you chineese?the only time ive seen you show up here is when someone calls people on the board to substantiate your version of a failed product.we offer information in our spare time not only at the time someone is questioning our products or integrity.if you want to impress me or your customers,take care of your customer complaints before they reach the forum .the name of this thread is"lock up strategies and their affect on clutch durabilty",not honda transaxles.i guess this is your turn to impress uninterested people over the phone while they wait for you to hang up?

Sorry to interupt the fighting. Would type F be ok for the clutch lining on the 9/11 ockup torque converter, or is this not reccomended?

norbs,no fighting on my part.just trying to get my point across.as for your question,any quality transmission oil will be compatible with the 9/11 you purchased .i regrettably have never asked tcs about the exact material used for the lock up disk but certainly will tomorrow. this is something i should have asked a long time ago ,but didnt because it was never an issue in the durability department.i also will see if he has a rating for the friction material verses horsepower.i know wot lockup is an accepted practice with this convertor as there is no damper to cushion lockup apply to reduce disk slippage.the billet cover is as far as i know only to reduce cover distortion and it related failures when locking it at wot.

To state the obvious- I know that I'm a nobody.

With that acknowledged: I find the level of civility displayed by some experts on this board inappropriate for a public technical forum.

This is a logical reply:

This may be OK on a grade school playground:

Please do continue the technical aspects of this thread; (comparisons in functionality don't seem out of line, but that is just one nobody's opinion).

Chris, I hope you don't feel I'm intruding on your turf or something. That would be the furthest from my mind. I'm sure you put out a good product. How you do it is your business, and it's not my place to examine how you do it. It's called professional respect for others in the industry. Where is all your anger coming from? Man, don't worry, be happy.

My true intention is to throw some knowledge out there, so that people can be more informed and maybe use some, if not all this new knowledge to prevent the same unfortunate situations I have sometimes found myself in. I have made mistakes and the customer has made mistakes, and I think it would be a good learning experience for others, so they don't have to go through the same kind of experiences I and others have had to go through. You know. The kind of experience that feels like a sloppy abortion taking place in a living room with a large window facing the street, people driving and walking by, with *it being slung all over the walls.

Some people will be very uncomfortable with some of the aspects I bring up. Some may even have to change the way they do business because of the new knowledge that will be presented. Will I get resistance?
You can bet on it!

Some of the discussions and examples I have brought up may not make any sense at the moment, but be patient. If you carefully study everything I present and can retain it, you will understand how it all works together by the end of my writings. If you have a question, please bring it up with a mature attitude. I would greatly appreciate it and so would the many people that are trying to learn something from this thead.

The point of bringing the Honda into this was to impress upon people that the 200-4R design does a very poor job, in fact, does nothing to adjust to changes, off the factory norm, in engine torque curve.

The old vacuum modulator system found on older transmissions like the 350, 400, PG, that used intake manifold vacuum as a torque signal, was able to judge engine load, real time. A drop in engine vacuum was in direct relation to engine load and the transmission would adjust what was called modulated pressure (same as TV pressure on the 200-4R), which caused a rise in line pressure (main working pressure).

Please forgive me if there are some long periods between postings. I want to give other people a chance to contribute some useful input and I am sometimes busy doing other things. Right now, I have to run to the movies with my kid.

Until next time.

if you think thats the only check i make on my drum, youve got to be kidding.of course they are checked on the support and in the case.checking them a third time thru the valve body ensures that debris are not hidden in the castings even after they are cleaned,lands on the valves arent worn,shift valve bushings arent worn,gaskets are matched to plate properly,clutches release and dont drag during backshifts or kickdowns,and also instills in the builder there are other circuits in this transmission that are never spoken about in technical circles ,manuals or training programs.it also gives one another means of verifying circuit value and a model to follow in the event something is wrong and the results change .the 2004r does nothing to read engine torque curve?what is the tv system ,line bias valve and accumulator system there for? to have lunch with the transmission oil?.

This is getting a little off topic, but I may need to clarify this for some of you so that you can get a clearer picture of the direction I want to go with this.

By the way Chris, I'm relieved you do the other checks. It shows me your a professional.

Chris eluded to some different hydraulic circuits in the valve body that fine tune and limit TV and line pressure. These hydraulic circuits are controlled by valves, their land sizing and spacing, spring pressures, orifices, checkballs and a host of other things that we can cover later, if anyone is willing to sit through it. The valve body is basically a hydraulic computer that is MANUALLY programmed (hard wired) by the manufacturer or the re-programmer (transmission technician). Installing a valve body re-programming kit is exactly that. You drill holes, change springs, sometimes change valves, block and/or redirect flow of a particular circuit, etc., for various reasons. The reasons could be better durability (such as lube circuit mod) or to enable the transmission to put up with increased torque load. Now keep in mind that you must disassemble the transmission to perform this recalibration.

Back to the Alpha-N system. If you change a component on an engine using an Alpha-N EMS that ends up changing any point in the torque curve of the motor, you have to go back and manually re-program the EMS so that timing and fuel curves will match up to the new torque curve. The key words are 'manually re-program'.

Another scenario. I'm going to make this one a little extreme to try and make my point clearer. I hope some of you start getting this soon so we can get back on track. If anyone starts to get the picture, maybe you can help explain between my postings to others that have questions. I'm looking for an apprentice here.

You supply a customer with a stock rebuilt 200-4R and stock converter. You set the TV cable properly for the engine combination, which happens to be bone stock. The customer is stoked with the way his car feels now and is energized. As usual with these cars, the owner wants to go faster. He hooks up with his buddies and they decide to pull the engine and install one that is rebuilt with about 600 additional horsepower.

Now the big question. Will the transmission compensate AUTOMATICALLY to the added horsepower and live a normal, full life? Will a simple TV cable adjustment do the trick?

I'm sorry if I'm making this difficult for some of you to grasp. My mission is to try and make all of you think about this and come up with the answers yourselves. It's a habit you pick up when you own a business. Your main job as an owner is to teach your associates how to problem solve on their own. If you always make yourself available to always present the answer to a question without making them work for it, it makes them lazy and you end up being the answer man ALL THE TIME. Will they make mistakes sometimes? You bet, but they'll learn from their own mistakes better and will likely not make the same one again.

Come'on guys, I'm waiting for some stars to emerge. My reward for all this typing will be the spark of knowledge I start burning in someone's head.