TH400 build-pictures

[DonWG]

Originally Posted by chris718

don in your previous post you said you restricted cooler flow pressure to zero and still got 1 quart in 20 seconds.how could you possibly have 0 cooler pressure and still have flow ?are tests performed on a dyno or in car?

Tests in that particular case were done on a transmission dyno.

It is very possible to have flow with very little pressure. It all depends on what kind of restrictions (orifice sizes, tubing bends, coolers, clearances, etc.), and where all the different restrictions are in the hydraulic circuit. If you have a small restriction at the end of a hydraulic circuit and a large restriction at the feed end of the hydraulic circuit, you will have low pressure after the end of the circuit and high pressure throughout the whole circuit up to the point of the small restriction at the end of the circuit. I hope you're following me.

Now let's change where we put the restriction in the hydraulic circuit. We'll put the large orifice/restriction at the end of the circuit and the small orifice/restriction at the feed into the circuit. You will have high pressure feeding the circuit up to the small orifice feeding the circuit. After the small restrictor you will have low pressure since you have removed any significant restrictions in the hydraulic circuit that would allow pressurization to occur.

Look at it as a simple sink faucet. The mainline pressure is feeding water at a high pressure to the valve of the faucet. With the valve closed and shut off you have high pressure on the mainline side of the valve, and no flow and pressure on the faucet side of the valve.

Now crack the valve open a little. You will have flowing water from the faucet. On the mainline side of the valve you will still have high pressure. After the valve you now have flow at a particular flow rate (gallons per hour) and you have pressure. But, the pressure is going to be very low because of the absense of any significant restrictions after the valve/restriction and up to the end of the faucet tube.

Now crack the valve a little more. You will still have the same mainline pressure feeding the valve. After the valve/restriction, which is now a little larger, you will see an increase in flow (gph). Will you see any pressure in the faucet tube at this point? Maybe. It will all depend on how restrictive the faucet tube is, in relation to the flow that is present.

In the sink faucet example, the mainline side of the water valve is the transmissions converter feed pressure and flow off of the pressure regulator valve in the pump. The faucet valve is the passage feeding hydraulic pressure and volume to the torque converter, cooler circuit and lubrication circuit. As you can see, you don't want the torque converter, the cooler circuit and the lubrication circuit offering a significant resistance to flow. You want the main restriction to be before the torque converter so that flow and pressure can be controlled throughout the rest of the circuit.

[87buickracer]

Originally Posted by DonWG

Tests in that particular case were done on a transmission dyno.

It is very possible to have flow with very little pressure. It all depends on what kind of restrictions (orifice sizes, tubing bends, coolers, clearances, etc.), and where all the different restrictions are in the hydraulic circuit. If you have a small restriction at the end of a hydraulic circuit and a large restriction at the feed end of the hydraulic circuit, you will have low pressure after the end of the circuit and high pressure throughout the whole circuit up to the point of the small restriction at the end of the circuit. I hope you're following me.

Now let's change where we put the restriction in the hydraulic circuit. We'll put the large orifice/restriction at the end of the circuit and the small orifice/restriction at the feed into the circuit. You will have high pressure feeding the circuit up to the small orifice feeding the circuit. After the small restrictor you will have low pressure since you have removed any significant restrictions in the hydraulic circuit that would allow pressurization to occur.

Look at it as a simple sink faucet. The mainline pressure is feeding water at a high pressure to the valve of the faucet. With the valve closed and shut off you have high pressure on the mainline side of the valve, and no flow and pressure on the faucet side of the valve.

Now crack the valve open a little. You will have flowing water from the faucet. On the mainline side of the valve you will still have high pressure. After the valve you now have flow at a particular flow rate (gallons per hour) and you have pressure. But, the pressure is going to be very low because of the absense of any significant restrictions after the valve/restriction and up to the end of the faucet tube.

Now crack the valve a little more. You will still have the same mainline pressure feeding the valve. After the valve/restriction, which is now a little larger, you will see an increase in flow (gph). Will you see any pressure in the faucet tube at this point? Maybe. It will all depend on how restrictive the faucet tube is, in relation to the flow that is present.

In the sink faucet example, the mainline side of the water valve is the transmissions converter feed pressure and flow off of the pressure regulator valve in the pump. The faucet valve is the passage feeding hydraulic pressure and volume to the torque converter, cooler circuit and lubrication circuit. As you can see, you don't want the torque converter, the cooler circuit and the lubrication circuit offering a significant resistance to flow. You want the main restriction to be before the torque converter so that flow and pressure can be controlled throughout the rest of the circuit.

sink facet example-In this case you would have less pressure with more volume once valve is fully open.just my 2cents..

[blackplague]

Originally Posted by DonWG

The only thing trying to push the front unit (forward and direct clutch drums) rearward, other than G forces of acceleration, is lube circuit pressure. The thrust from G forces is manageable. The rearward thrust of the front unit is already supported by needle thrust bearings. That would be the sun gear to rear ring gear, and the rear ring gear to output shaft needle thrust bearings. The stock case thrust washer would be the only spot that would be causing hp loss from excessive friction. That spot has already been addressed by transmission builders decades ago. That would be the TH350 pump needle thrust bearing put in place of the OEM thrust washer setup. Old news.

Now, let's look at something very important. This is breaking news, first presented here, so read up. In the above paragragh I highlighted lube circuit pressure. How many of you have already figured out what might cause excessive rear thrust load in a 400? Enough to wipe out the OEM case thrust washer arrangement. The same way that the engine crankshaft thrust bearing can be taken out by excessive torque converter fill pressure.

Excessive torque converter fill pressure translates to excessive crankshaft forward push, which translate to short crankshaft thrust bearing life. Excessive torque converter fill pressure also translates to higher cooler line pressure (cooler line flow feeds the lube circuit upon return to the transmission case), which translates to excessive lube circuit pressure, which translates to excessive rearward push of the front unit in the transmission and excessive loading on two needle thrust bearings and one case thrust washer.

Are you guys seeing the picture yet? If you really want to free up horsepower and make your engine and transmission more durable, address the torque converter feed pressure in the T/C. If you're wiping out needle bearings in your transmission and feel you have to add more thrust bearing locations, your lube circuit pressure is too high and/or endplays are too loose or too tight.

This brings us back to the cause and effect that I've been preaching to you guys for years now. You must restrict the torque converter feed passage in the pump cover. It solves a multitude of problems and frees up horsepower.

Maybe now that everyone realizes that the pump mod can free up horsepower will make everyone jump on the bandwagon and do the mod. I'll bet people will be shooting for even less than 40 psi cooler line pressures now. Ha ha.

Remember, the important spec when it comes to cooler lines is a flow of one quart in 20 seconds. I've even played with restricting cooler line pressure to zero and still had one quart in twenty seconds of flow.

The real problem is trying to get all the fluid and pressure out of the converter. When i build a converter for a 400 i make sure the turbine rides on a bushing, so that the front stator bushing can be modified to get all that pressure and fluid out to cooler/lube (similar to a PG). The front stator bushing is a major restriction.

[DonWG]

Originally Posted by 87buickracer

sink facet example-In this case you would have less pressure with more volume once valve is fully open.just my 2cents..

Correct! You would have high volume with low pressure. Now what if after the faucet valve you were feeding a series of torque converter, 8 ft. of 5/16" cooler line, a trans cooler on unknown resistance and the lubrication circuit of a transmission before finally being dumped into the sink?

You would want to know what the resistance value was of each of those components to even make an educated guess as to what the pressure and flow volume might be.

What if the trans cooler was offering quite a bit of resistance to flow, or you had a pinched cooler line after the trans cooler? Pressure would be rise on the feeding side of that point and be low after that point. Pressure differential. It would be like a turbocharger system with an undersized intercooler at WOT. You would have a build up of pressure on the turbocharger side, and a lower pressure exiting the intercooler.

So you can see that after the faucet valve you want everything flowing as freely and with as little resistance to flow as possible before dumping into the sink or transmission pan.

When experimenting with different feed orifice sizes, just keep in mind 'one quart in 20 seconds'.

[DonWG]

Originally Posted by blackplague

The real problem is trying to get all the fluid and pressure out of the converter. When i build a converter for a 400 i make sure the turbine rides on a bushing, so that the front stator bushing can be modified to get all that pressure and fluid out to cooler/lube (similar to a PG). The front stator bushing is a major restriction.

I'm actually running both the front stator support bushing (unmodified) and the bushing in the T/C cover (N/C T/C). I know I should remove the front bushing in the stator, but as long as everything is machined to true centerline, it's just another support bushing. The trick is to make sure the passage holes in the front of the input are not blocked to flow. The bushing in the T/C front cover should be angle slotted in 2 or 3 spots, equally spaced.

I've been doing it this way for about 5 years now. I've inspected and made changes to the trans and T/C a few times over the years and the bushings look like brand new.

The only time that getting the fluid out of the T/C might look like a problem, assuming that no flow passages have been blocked to flow, would be if you moved the faucet valve location into the torque converter or to some point past the T/C. Move the faucet valve location to a point before the T/C and now getting the fluid out of the T/C has become much less of a concern.

[chris718]

you cannot have 0 pressure in the circuit if it is functioning and flow 1 quart in 20 seconds.this is impossible.the bottom line is this.the same way a tv limit or actuator feed valve in a valve body reduce line pressure practically in half and re regulates it for other uses that require less pressure and volume is the same as orificing oil peed into the converter charge circuit.this is not a case of putting your finger over a garden hose.the smaller the orifice the less pressure and volume is moved,much like a clogged fuel filter.when a filter is clogged you dont get a high psi reading on your test gage do you?the less oil volume that enters the converter the less pressure is generated in the cooler circuit.we all know it needs to be reduced but may not agree on the orifice sizing that is appropriate.if cooler pressure is reduced to 0 then there is nothing moving in the circuit,unless you have somehow mysteriously created a vaccuum or siphoning phenomenom no one is aware of.an acceptable charge pressure and volume number must be established and then a line pressure and orifice size can be determined to get the numbers you want.stop confusing it.

[chris718]

don a tip for your unique situation.use a late 4l80e drive tube bushing with grooves in the front of your stator tube

[DonWG]

Originally Posted by chris718

you cannot have 0 pressure in the circuit if it is functioning and flow 1 quart in 20 seconds.this is impossible.the bottom line is this.the same way a tv limit or actuator feed valve in a valve body reduce line pressure practically in half and re regulates it for other uses that require less pressure and volume is the same as orificing oil peed into the converter charge circuit.this is not a case of putting your finger over a garden hose.the smaller the orifice the less pressure and volume is moved,much like a clogged fuel filter.when a filter is clogged you dont get a high psi reading on your test gage do you?the less oil volume that enters the converter the less pressure is generated in the cooler circuit.we all know it needs to be reduced but may not agree on the orifice sizing that is appropriate.if cooler pressure is reduced to 0 then there is nothing moving in the circuit,unless you have somehow mysteriously created a vaccuum or siphoning phenomenom no one is aware of.an acceptable charge pressure and volume number must be established and then a line pressure and orifice size can be determined to get the numbers you want.stop confusing it.

Not confusing anything. Maybe you can tell that to my pressure gauge and gallon bucket. I have a feeling you won't change thier mind though.

Chris! I'm not just sitting here making this stuff up! Try doing some testing yourself!

[bison]

Originally Posted by DonWG

Not confusing anything. Maybe you can tell that to my pressure gauge and gallon bucket. I have a feeling you won't change thier mind though.

Chris! I'm not just sitting here making this stuff up! Try doing some testing yourself!

There still has to be some pressure forcing the fluid out. Even if its under 1 psi. Might not see it on a gauge.
Unless theres a vacuum pulling it. I think thats what he means.

[DonWG]

Originally Posted by chris718

don a tip for your unique situation.use a late 4l80e drive tube bushing with grooves in the front of your stator tube

Chris, you're not getting this. If you're overfeeding the T/C, it becomes a major problem to get fluid out of the T/C so that excessive pressure doesn't begin to build, making extraordinary modifications to bushings and such a top priority. Then you still have to worry that some other component in your cooler line, cooler and lubrication circuit don't offer a significant restriction to flow and cause a back up of pressure at that point.

All you need to do is turn the faucet valve down before the T/C. Now flow pattern through the T/C is much more managable without a build up of excessive pressure.

If we keep doing this, you'll eventually see the light. This is very important that people understand this modification. If there are others that are having a problem envisioning this, speak up. Obviously, you can tell that I don't mind spending the time to make sure everyone is clear on this.

As I stated before. So many problems and areas of concern are solved with this very simple modification.

I think now people can see why 99% of the transmission builders in the country think this pump mod is fooh fooh. There is a certain basic understanding of hydraulics that has to happen here.

[DonWG]

Originally Posted by bison

There still has to be some pressure forcing the fluid out. Even if its under 1 psi. Might not see it on a gauge.
Unless theres a vacuum pulling it. I think thats what he means.

OK. I think I see where there might be some confusion. You're right bison. There has to be some pressure even if it's just slightly over 0 psi and not measurable with a 0 to 100 psi gauge. OK. So shoot me in the head. Com'on now. You guys are concentrating on the unimportant here. Let's say that my gauge was off and there was actually 3 psi pressure in the cooler line. I still had one quart in 20 seconds!

The important thing to note here is the meeting of a minimum flow requirement with very little pressure.

SPECIAL NOTE!!! I'm not suggesting that anyone shoot for a cooler line pressure of zero, unless the person can do some very controlled testing and monitoring. I would have to guess that at a certain horsepower level, you would get cavitation in the T/C with that low of a pressure. Shoot for 40 psi at stall. From all the evidence to date, 40 psi is a safe target cooler line pressure.

[DonWG]

Chris brings up a good point. Ultimately, there is a perfect T/C feed orifice size for each and every application. All I can tell you is that 7/64" with as much as 200 to 215 psi line pressure has worked for me for around 20 years now and Lazaris is the first to suggest that it is still too large. Bear in mind that Lazaris was using some extraordinarily high line pressure with that orifice size.

Chris. Maybe you should come up with an easily adjustable T/C feed circuit valve so people can fine tune the feed rate to their particular circumstances. Wouldn't be too hard really.

[lazaris]

The 1% increase in efficiency was calculated with with a data logs using a DS sensor. DA was calculated to be with in 22ft on the 2 passes. The mph increase also verified the findings. The efficiency change was only illustrated to show there was a change. The unit was built with that high line pressure. I didnt build it................

[chris718]

don ,i think your not understanding me.we both know the circuits function.the grooves in the stator bushing will get the oil out of the converter faster in your application.no one here is arguing that the converter charge entrance needs to be smaller to reduce excessive charge pressure and the resultant elevated trans cooler pressure derived from it.as a matter of fact i would argue that if the converter feed hole is a given diameter that the amount of oil exiting isnt really a problem if the exit at the input shaft nose is the same diameter after pressures have been reduced by orificing,and enhanced with a grooved bushing if the converter isnt bushed.this restrictive condition at the input shaft woul actually reduce cooler pressure but raise internal pressure in the converter if we believe everything elkse presented.

[DonWG]

Originally Posted by lazaris

The 1% increase in efficiency was calculated with with a data logs using a DS sensor. DA was calculated to be with in 22ft on the 2 passes. The mph increase also verified the findings. The efficiency change was only illustrated to show there was a change. The unit was built with that high line pressure. I didnt build it................

Was that the pressure you got from the pump I set up for you? Help me remember this. Did I set up the PR lineup too or did I provide the pump without the PR lineup? If I provided the PR lineup, did I shim the PR spring?

This is the first chance I've had to get feedback about a negative situation. Thanks for bringing this up lazaris. Please share.

[DonWG]

Originally Posted by chris718

don ,i think your not understanding me.we both know the circuits function.the grooves in the stator bushing will get the oil out of the converter faster in your application.no one here is arguing that the converter charge entrance needs to be smaller to reduce excessive charge pressure and the resultant elevated trans cooler pressure derived from it.as a matter of fact i would argue that if the converter feed hole is a given diameter that the amount of oil exiting isnt really a problem if the exit at the input shaft nose is the same diameter after pressures have been reduced by orificing,and enhanced with a grooved bushing if the converter isnt bushed.this restrictive condition at the input shaft woul actually reduce cooler pressure but raise internal pressure in the converter if we believe everything elkse presented.

I see your point Chris. With the orifice size I've been using, that problem has not come up. The area of the holes in the input shaft responsible for allowing fluid to exit the T/C are pretty large when compared to the feed orifice of 7/64". The more important thing to consider would be that the internal components in the torque converter don't present any flow restriction to any of the exit holes in the input shaft. Of course, grooving the front stator support bushing would be good insurance, but would still not make up for any blockage to flow by the internal components of the T/C.