Calculating the rate of flow of air and fuel in a running engine

[Kingtal0n]

Without using calculus, we should be able determine how much an engine's rate of breathing air and fuel could be under different circumstances. For example, an sr20det at 3,000rpm and 80mph pulling 9" of vacuum with the wastegate disconnected, and again at 10" of vacuum when the exhaust gas is mostly forced through the turbine (wg connected). The two situations differ such that fuel economy is reduced in one scenario, since we know the OEM ecu timing values are in rock but the fuel values are not. The engine will dynamically adjust fuel based on O2 sensor feedback at that speed.


1. How much does timing and fuel adjustments affect a characteristic change in engine "performance"? I use quotes because we are cruising on a highway, so the only real "performance" we are interested in has to do with engine noise, engine vacuum, smoothness of power delivery. It has nothing to do with peak horsepower when we are just cruising.
2. How much less air is the engine ingesting when pulling 10" vs 9" of vacuum? To be at a pressure that is less, farther from atmospheric means that the throttle body is likely closed more and the engine is likely using less fuel.
3. The speed, 80mph, is due to the 3.8xx gear and the 2x" tire size left to be determined. If we adjust gearing numerically higher to 4.10 the 80mph will decrease at that 3000rpm. How much is based on tire size. What will that do to our fuel economy? Now we are cruising at 72mph instead of 80mph, does the fuel saved by reduced wind resistance offset the time lost by going slower? You wouldnt want to cruise at 72 you want 80, so RPM needs to increase. Friction should also increase. Engine and Drivetrain components have a mass and increasing engine RPM is never a good thing unless absolutely required. More cylinder events per unit time means more wear and tear. You only get so many cycles. Likewise, if we decrease the gear numerically, to 3.42, our MPH Increases. Now we are moving at 88mph instead of just 80. My car gets faster, my engine turns the same rpm. But vacuum will also change, wont it? The vacuum will drop, it will be closer to atmospheric and the engine will demand more air. How much more air?


for number1 to get started:
On the highway I have adjusted many engine's timing. You will mostly notice nearly no change in engine performance for the vast majority of timing numbers within 50% of optimal. You can have something way off and it will still seem to run fine. What is the right way to adjust engine timing on the highway to begin with? What you want for that would probably be this: EGT gauge
With an EGT probe you can determine the leftover heat of the products of combustion in your engine. You should notice that as you decrease engine timing while cruising in this scenario we have established, more and more combustion will be taking place in the exhaust system instead of the combustion chamber. By adjusting the ignition timing to the point that the least amount of heat remains in the exhaust once combustion is complete, is a good starting point for optimal ignition advance. In some cases however, compression ratio and octane could limit optimal values in different engines. Consider that combustion chamber design plays a role in all engines, so individual engines will differ in many ways with regard to optimal timing values.
Our engine egt is at 1420*F and 36* of timing advance btdc because I just popped in a PFC and verified it with a timing light. If I adjust the timing to 40* btdc, the egt drops to 1370*F after about 20 seconds. You are using cruise control because accidently adjusting the throttle position sometimes dips into the acceleration enrichment which will affect egt also and thats where the calculus starts, because accel enrichment has a rate of change. Just for curiosity sake change the timing value to 55* btdc. There is almost no perceptible change in the way the car drives. egt drops a bit more, to 1340*F. Also, knock count increased notably. You are watching the knock count right? We have miles of logged knock values- seemingly meanless, oddly spaced numbers. a 13 here, a 22 there, the power FC has two different types of knock logs to examine. We have examined all of the cars knock logs since it was started for the first time and for the first time, there are 18's where there used to be 11's, there are little spikes in places that used to be fairly flat on the graph produced by the knock sensor. What is that, preignition? Detonation? Scratch your head and make a post online about it, it doesnt really matter we just know its a bad thing and that the knock sensor seems to be working, doing its job. On this engine, the little spikes seem start around 47* btdc and get worse. The EGT never gets much better than 1360*F at 39* of ignition advance. Lets rebuild the engine now with forged pistons, different rods, and knife edge the crankshaft. Do the same exact thing and the knock sensor might not work, it might not pick up the pressure spikes likely to blow the head gasket.

Now, adjust the airfuel from 14.7 to 15.5 and observe: egt drops a bit more, to 1320*F. Engine vacuum drops even more, to 8". The engine is ingesting more air than before, but the air fuel ratio is leaner. Are we using more or less fuel per cylinder event? RPM remains constant and so does speed, 88mph. To answer that question you can look at duty cycle logs and factor in fuel pressure. the difference in this case is so small it is nearly un measurable: the duty cycle changes .4xx% and the fuel pressure changes only .7xxpsi the difference in fuel consumption is only around 6.xx%. At 88mph in a vehicle that weighs 2800lbs we gained nearly 1mpg! calculate this without calculus. The flow rate of the injectors is 330CC/min at 45psi of fuel pressure. Find out how much that is in lb/hr and find the weight of fuel in pounds, then using 88miles per hour find out the total amount of fuel being injected into the engine for 1 hour of driving for both situations, adjusting the flow rate of the injectors as the engine vacuum changes.



for number 2 to get started:
we can calculate the flow of air at that speed at 0psi. Everybody should know this formula by heart without looking it up.
(3000)(122)/3456 = 105.90 CFM at 100% VE, which would be very close to full throttle, wastegate disconnected. The reason we assume 100% with 0psi of boost is because the engine will not be 100% VE at that RPM when it is naturally aspirated, except that ours is not N/A, it is turbo, and even though the wastegate is disconnected the turbine still gets some action and there is nearly always going to be a slight boost pressure when the throttle is left open, which will increase VE some. But we are not at Wide open throttle, we are cruising at 80mph and there is 10" of vacuum. How much air is our engine ingesting? What % of our cylinders is being filled with air at 10" of vacuum and 3000RPM?




for number 3:
its all about vacuum and Volumetric efficiency. You cannot directly assume for instance that just because an engine is at exactly 15" of vacuum that the volumetric efficiency is going to be around 50%. We could work backwards from vehicle weight. First find out how much horsepower it would take to keep our 2800lbs vehicle at 88mph. Then, you need to either convert horsepower to fuel, or air. If you calculate how much fuel that would take first, you could then push it through the air fuel ratio for each scenario to get the quantity (mass) of airflow, and finally use the mass of air to determine volumetric efficiency. We think that at 15.5:1 the engine demands more airflow because vacuum drops, the throttle body opens more in response to the change in air fuel ratio to maintain speed. Likewise, when adjusting the rear gear numerically down, to 3.42, the vacuum also drops and throttle opens more. If we adjust speed back to 80MPH the RPM drops to 2700rpm and vacuum rises to 10.3", so VE must have gone down, and bsfc could have gotten worse. These are the data sets:

3000rpm 80mph 10" control
2700rpm 80mph 10.3" gearing adjusted speed adjusted
3000rpm 88mph 9" gearing adjusted

find VE, mass of air per hour, mass of fuel per hour, bsfc, and define (decide upon) reasonable frictional and air resistance values as you adjust the weight and material of rotating components.

[Croustibat]

Originally Posted by Kingtal0n

Without using calculus, we should be able determine how much an engine's rate of breathing air and fuel could be under different circumstances. For example, an sr20det at 3,000rpm and 80mph pulling 9" of vacuum with the wastegate disconnected, and again at 10" of vacuum when the exhaust gas is mostly forced through the turbine (wg connected). The two situations differ such that fuel economy is reduced in one scenario, since we know the OEM ecu timing values are in rock but the fuel values are not. The engine will dynamically adjust fuel based on O2 sensor feedback at that speed.

No need to go past there, as the bold part is wrong.

Engine CAN only use O2 sensor feedback only when speed is steady; when it does, it tries to reach around 15:1 AFR, because that is a good compromise between fuel consumption, emissions and engine temp.

You need to enrich when accelerating or when reaching sufficient engine load , mostly for performance and reliability reasons, which is not the subject of this.

That and timing values AND AFR values commanded by the ECU depend on the load of the engine. Neither of them depends only on vacuum, neither of them are fixed either.

seriously though, dont mess with timing. Fuel quality changes all the time, and being on the verge of DET is no good. One day is good, the next day you are making holes in your engines because temp rised a bit, or your alternator is feeding less power to your fuel pump.

If you want an economic car ... buy one. dont get a 240 ...

And if you really want to know the "quantity of air going through the engine" ... just put a voltmeter on your Mass Air Flow sensor, AKA MAF...

[4x4le]

Adjusting you cas isnt the right way to do this. The timing values are not set in stone if you tune the ecu, and advancing your base timing will create a host of problems, hard starts first and foremost and way too much timing causing a blown engine later.

If you have an innovate lc1 you can mimic the narrowband with it and tell it to target whatever afr you want. You can tune the ecu and adjust the fuel trim in individual cells to closer match your targets. You can add or remove o2 flags in any areas you want.

Less vac is good as you will have less pumping losses but usually youll have to have fuel going with that air to avoid ping and lean misses, there is a balance to be found though. Water injection can help reduce the low load ping created by lean combustion.

Problem is after you do all of this, your car will hardly be fun unless you have a way to switch it off of this economy mode. Aem could be a good ecu for this as you nitrous map could be your economy mode.

[Kingtal0n]

The way we play this game is, first you choose what problem you wish to answer, 1 2 or 3. Then, you provide math and facts to support your answer.
This is theory craft, and it applies to all engines, not just my hypothetical 2L cruising at 80mph. You may pose your own displacement, VE, cruise rpm, etc.. for your responses.

So, which question do you want to attempt?

[4x4le]

picking just 1,2 or 3 is flawed. They all play in together. So either I pick all 3 and what I wrote earlier stands as my answer or I have another suggestion.

Slightly lean burn is fine for low load, less vac the better which dont have to mean more open throttle or more fresh air. Less vac can be achieved with a custom egr system and using water injection in the hot recirculated exhaust. Pumping losses will have been highly reduced, the need for a stoich afr will have been reduced and tq will increase from the steam engine effect. Wasted heat energy from the exhaust will be reclaimed increasing the efficiency at steady speeds.

[AdamR]

This guy again.

EDIT: Did you really cone here with physics problems just to seem smart? Again?

[Croustibat]

Originally Posted by Kingtal0n

The way we play this game is, first you choose what problem you wish to answer, 1 2 or 3. Then, you provide math and facts to support your answer.
This is theory craft, and it applies to all engines, not just my hypothetical 2L cruising at 80mph. You may pose your own displacement, VE, cruise rpm, etc.. for your responses.

So, which question do you want to attempt?

Or you could live in the 21th and not in 1920 and use a programmable ECU - or just a daughterboard in your OEM ECU, and do trial and errors, which works better than any approximated formula in such a very complex system we call engine.

If you want to learn something, read the TP patent by nissan (you can read it for free, it is available on the internet), nearly every MAF system is based on it.

[Kingtal0n]

Originally Posted by AdamR

This guy again.

EDIT: Did you really cone here with physics problems just to seem smart? Again?

Hold on to that. I am going somewhere with this. Once we figure out the rate of flow without using modern electronics (only good old algebra here) and some relatively static situations (such as cruising on the highway and not accelerating) we can make some real progress. No spoilers ok? and using intermediate algebra hardly makes me smart. ill stop using punctuation also to help fit in. oops didnt mean to use a period that time

[Croustibat]

You are going where people went maybe 20 years ago, when they switched from mechanical ignition and carburettors to programmable sequential/full group injectors with variable ignition timing.

Who knows ... maybe in 10 years you might understand what a MAF is.

[4x4le]

Originally Posted by Kingtal0n

Hold on to that. I am going somewhere with this. Once we figure out the rate of flow without using modern electronics (only good old algebra here) and some relatively static situations (such as cruising on the highway and not accelerating) we can make some real progress. No spoilers ok? and using intermediate algebra hardly makes me smart. ill stop using punctuation also to help fit in. oops didnt mean to use a period that time

There are more variables that will be in this equation that would result in an equation that Sheldon Cooper himself would twitch at.

Are you going to take into account effects of varying engine coolant temperature and how it effects compression/vacuum/flow? Are you going to take into account different levels of heat soak in the turbine, compressor, intercooler, throttle body and intake manifold, and how that effects flow in and out? Are you going to take into account the varying atmospheric conditions including humidity, temperature, and pressure and how that effects flow as well as combustion? Fuel temp also will play a small role based on ambient temperature and heatsoak under the hood.

Are you going to take all of the possible different conditions and infinatially compare them against each other? This is what would be required on top of the things you suggest above in order to even come up with a reasonable theory and even then it is nothing more than a theory until it is tested and proven in real life.

Even then, if you continue, and can prove you could figure all of this stuff

[Croustibat]

Hes just a nutcase, forget about this

[4x4le]

lol, i know, but Ive been "enjoying" his post for a few years now.

[Croustibat]

I was too ... maybe i got bored too fast.

[Kingtal0n]

guys, I am just having some fun in my spare time that I could also use for island D or something. So this is fun time, not qq time. I invite, this is an invitation to everybody on zilvia to come and share their time, which is the most valuable possession in my opinion and I have a high regard for every bodys time as I value your time over mine automatically as a natural internet curtisy.

To the point: I am willing to invest [some] time here working on whatever sort of valuable information we can dig up. I do not have answers to any of my questions either, I stopped right where you see I stopped, I wrote all that from thought to paper style so it's unabridged and raw and ready to nit pick to death the way I am about to nitpick the next post. In a helpful, professional style as possible with good intentions

[Kingtal0n]

Originally Posted by 4x4le

There are more variables that will be in this equation that would result in an equation that Sheldon Cooper himself would twitch at.

Are you going to take into account effects of varying engine coolant temperature and how it effects compression/vacuum/flow? Are you going to take into account different levels of heat soak in the turbine, compressor, intercooler, throttle body and intake manifold, and how that effects flow in and out? Are you going to take into account the varying atmospheric conditions including humidity, temperature, and pressure and how that effects flow as well as combustion? Fuel temp also will play a small role based on ambient temperature and heatsoak under the hood.

Are you going to take all of the possible different conditions and infinatially compare them against each other? This is what would be required on top of the things you suggest above in order to even come up with a reasonable theory and even then it is nothing more than a theory until it is tested and proven in real life.

Even then, if you continue, and can prove you could figure all of this stuff

lets fill in all the values we know using obvious fake data if possible. Coolant temp can be operating temp, pick a number between 175 and 235. The engine should be more thermally efficient at higher temperatures, right? I think that fuel type acts as a limiting factor as temperature gets too high when using low octane. Pick a radiation temperature gradient, from however hot combustion is at it's hottest stage to the minimum when the car is sitting cooling off to room temperature. this really hurts when dealing with obscure numbers because you could be way off. (when I say "pick a whatever" I really mean that we COULD pick a whatever. Not that we actually SHOULD. Coolant temp is fairly useless in all of this IMO for instance) My exhaust manifold is 1500*F sometimes, or 2200*F sometimes, or 9999*F sometimes. The point is you can choose a random number and be farther away from the right number. And the more of these you use the worse the engine equation starts to work because the numbers are too far off. Especially thermodynamic systems because there are so many different ways to express a system in terms of heat, work, and all that physical chemistry that I would like to avoid. SO I guess the real point is to use the easiest, smallest number of close as possible to the real thing values to give a real functional working good equation that we can rely on to get more specific knowledge about cars inner workings and dependable information shared wisely free for the benefit of others everybody.

So my response to your question about varying atmospheric questions would be that no, we would not want to change around pressure at all. Pick a solid number, any good number can work, round it to a perfect 15psi or 14psi with no decimal because even though we will use .xxxx precision with values we still want them to be exact base 10 integers 15.0000psi

things like fuel temperature are part of the state of fuel whereever it is, for instance there is fuel in your vehicle right now, and it has properties of hydrocarbons I would guess. And you probably hope that it is very clean and highly branched chains of 6 or 8 carbons without any functional groups or nothin' funny right? Because if there is a benzene in there or some ethanol, heck we know theres alcohol in our gas right? Whats that set of atomic orbitals doing right now as the gasoline sits in the gas tank and gravity has its way with the parts of the gas tank exposed to the gas and has an effect on the fuel draw of the fuel pump too, right? Or does it really have to be accounted for? Unlike water, there may not be much help from depth of the fuel sock in liquid fuel. If we really wanted to we could open the physics book for that one, but again, that is not going to help me at all.

SO let us work again with the real issue: helpful fast information with obvious benefit. I will nit pick myself when I get a chance and try to answer my own questions. I Bet you are thinking now, how can any of that help anybody. Well like I said I am not here to waste anybody's time. I will get to the heart of the matter and I promise some interesting data when I can figure out some of these answers to these questions. Any I would love to work on anybodys questions also, I am not discounting your questions as you can see I delivered answers to most and its more than enough to elaborate on.

[Kingtal0n]

to the first piece of the heart:

I think we can start from horsepower of a car cruising on the highway. Lets find real numbers for A/C compressors and get a chart of [vehicle weight vs horsepower] required up that everybody agrees on so we start from the same page in terms of numbers. If I try to take the first step and open the physics book and use their number for horsepower, pg. 156
[1 horsepower = 550ft*lb/s = 746 Watts ]
[1 watt = 1 J/s = .738ft*lb/s]
Instantaneous power = F*v where Force and velocity are vectors, or the finished equation P=F*v*cos(x)

MY physics is very weak so that is where you guys come in. If I just start plugging in numbers that I am not really sure about the equations wont work. So real variety is required here from real sources.

[Kingtal0n]

So with that in mind, we can choose a value and use it to test and then choose a different value and re-test as many times as we want. Now get crazy instantly, 100000 horsepower. Insane incredibly obviously wrong but lets try it anyways as an example. What would it do the equation we used it in?

It feels wrong to just plug the horsepower number (100000) to the well know equation of horsepower = torque*rpm/5252. Thats it right? Thats what I remember. I am not going to google it because I might be wrong and that would be ok. I will check the magnitude of the result to verify. Xtorque, times Yrpm, divided by 5252. It doesnt matter the operation sequence feel free to multiply or divide first it should not matter. Plug in horsepower of 100000.
100000 = torque*rpm/5252
If we pick a number for rpm, we get a resulting torque. Lets try a bunch. We all know this is what a chassis dyno does. It calculates torque from horsepower by using RPM input. If you disconnect the rpm signal to the chassis dyno software you cant get a torque curve, only horsepower. Which means it doesnt make sense to define both torque and horsepower at the same time?
100000 = 200*rpm/5252, result: rpm = 2626000
100000 = 800*rpm/5252, result: rpm = 656500
100000 = torque*3000/5252, result: torque = 17506
100000 = torque*15000/5252, result: torque = 35013

now use a smaller horsepower number. Random number: 50

50 = 200*rpm/5252, result: rpm = 1313.00
50 = 800*rpm/5252, result: rpm = 328.25
50 = torque*3000/5252, result: torque = 379.8
50 = torque*15000/5252, result: torque = 75.97

Lets look at a slice from a normal dyno chart for a minute. The car is wide open throttle so we see some more familiar numbers:
217horsepower*5252/3800=299.91 torque
50horsepower*5252/3800=69.1
50horsepower*5252/3000=87.5
40horsepower*5252/3000=70.02
30horsepower*5252/3000=52.52
20horsepower*5252/3000=35.01
10horsepower*5252/3000=17.50
5horsepower*5252/3000=8.75


So an A/C compressor that takes 5 horsepower would need an additional 8.75ft*lb from the engine at the same rpm??? SO if the engine is lower RPM, we should need more torque from the engine:
5horsepower*5252/2000=13.13
what about 800rpm idle?
5horsepower*5252/800=32 ft*lb

At higher rpms, it takes less torque to make horsepower. So the lower rpm you flip on the a/c compressor, the more engine VE has to go up. alternatively, we could alter the ignition timing or fuel values to acheive more torque from the same amount of airflow. Remember that if the camshaft moves, engine VE changes also, and strictly speaking from a fuel conservation point of view it doesnt actually matter what VE does because air is free, simply put. The problem of producing horsepower is not lack of air, its lack of airflow through any engine to produce maximum power when racing. I wish to explore a much different, less thought of scenario and it's one that I simply wish to explore in detail. If I put the same fuel injector ontimes into boxes but they are at higher rpm then you are using more fuel. So clearly having a high road speed and a low rpm is the ideal situation for maximum fuel economy in many situations.


For this equation to make sense, an action such as A/C compressor activation should increase horsepower requirement, and therefore either rpm or torque will change. We know torque can move up and down because we can change VE with the gas pedal. Everybody should understand what volumetric efficiency is before going any further because its all about VE, making torque is having good VE. We should be able to use torque to find VE next by setting up a ratio. We can use many of these as well to change results.

1. find torque
2. find VE
3. profit

and its time for island D so gg and I will catch you all later

[Frank_Jaeger]

Take it easy with the tryptamines.

[Kingtal0n]

I found this old video of my first stand-alone computer experience.
https://www.youtube.com/watch?v=-HoCJqroPEY

I have had many different types of experiences with engines over the years. I am curious about them, in general. That is the only reason I portion any time for that cause, spare time is lost


http://www.howstuffworks.com/question622.htm

[Croustibat]

Originally Posted by Kingtal0n

guys, I am just having some fun in my spare time that I could also use for island D or something. So this is fun time, not qq time. I invite, this is an invitation to everybody on zilvia to come and share their time, which is the most valuable possession in my opinion and I have a high regard for every bodys time as I value your time over mine automatically as a natural internet curtisy.

I totally agree on the bold part, and this is why no one (even you) should bother on that matter, as it has been covered deeply in the last 30 years.

You are wasting your time. And ours. If you perfectly do your homework and conduct your research, you will just find what motor engineers found in the 70ies in pro racing, which was used publicly in the 80ies. If you screw up, you will get inconsistent results.

Please answer this simple question:

Why bother ?

[steve shadows]

There is nothing wrong with trying to calculate VE this way and get a ballpark.

In my opinion you never want to do anything in the dark or without full control of the ECU programming and without the correct data input to make the right decision based on VE. Bench calculating VE is one thing, using VE calculations to tune without accurate inputs in real time is another.

Personally I think preliminary VE calculations based on fuel input, weight and displacement are good to get started with but not to push out a tune on.

But I won't base Kingtialon, math is fun!

Anything to keep the tuning juices in the brain flowing

[Kingtal0n]

Originally Posted by steve shadows

oh steve, this has nothing to do with tuning. I am using terms from tuning such as injector on-time (milliseconds plz) but that is required to illustrate the act of deliverying fuel to a cylinder. If we know the injector flow-rate and the on-time in terms of duty cycle and the number of injectors we can get mass of fuel injected per unit time assuming as i mentioned way in the first post we have to account for fuel pressure changing the flow-rate and stuff like that.

Like I said, lets find VE of the engine during cruise on the highway. Then play with the displacement. Larger engines will have lower VE on the highway during a cruise, amirite? Then you will start to see where I go....

naps over

[Kingtal0n]

http://www.howstuffworks.com/question622.htm
useful link temp storage

I added the data to the equations above, I feel that first working backwards from 1 horsepower = 550 ft*lb/seconds to the classic equation with "5252" is the next step.
And then, this question, how much torque does an OEM Sr20det make at 100% VE? It doesnt matter what RPM right, even at 1000rpm with the right camshaft we could trap 100% VE and have exactly some amount of torque that will generally decrease as rotating mass takes it's chunk and our super-low rpm camshafts will take theirs from VE as well.

[Croustibat]

Originally Posted by Kingtal0n

oh steve, this has nothing to do with tuning. I am using terms from tuning such as injector on-time (milliseconds plz) but that is required to illustrate the act of deliverying fuel to a cylinder. If we know the injector flow-rate and the on-time in terms of duty cycle and the number of injectors we can get mass of fuel injected per unit time assuming as i mentioned way in the first post we have to account for fuel pressure changing the flow-rate and stuff like that.

Like I said, lets find VE of the engine during cruise on the highway. Then play with the displacement. Larger engines will have lower VE on the highway during a cruise, amirite? Then you will start to see where I go....

naps over

You want to go where europeans and germans already went some years ago (bmw mostly)

downsizing, direct injection, no butterfly throttle, variable VE.

Read it here ...
AutoSpeed - BMW's Valvetronic!

[steve shadows]

That's what I figured King. VE calcs do help for tuning though

[Kingtal0n]

Originally Posted by steve shadows

That's what I figured King. VE calcs do help for tuning though

but they are the same old 100% 200% VE Numbers we always assume. Like a 2.0 @ 200% VE, we could just say a 4.0 @ 100%VE. The numbers that come to mind without even thinking are 17psi of boost, 93 octane, 350 horsepower, 122 cubic inches, 6800rpm etc... thats just cookie cutter VE stuff.

I am more interested in 25% VE, highway cruise, 39* btdc, (1/4)*140ft*lb torque, what comes next? find an RPM and road speed where only one fourth of the displacement is working, so vacuum is high. then adjust gearing to bring VE up and road speed up without moving RPM. dat fuel econ

[Kingtal0n]

In 04' I rebuilt my automatic 700R4 chevy transmission, with help over the phone from Dana at Probuilt, I made a list of all the "secret" modifications

"This is a list of Hard Parts modifications you can do to your 700R4 while rebuilding it to make it stronger and last longer. "

I just did my first transmission rebuild, Im a novice, but I was given Expert advice from Dana at Probuilt. These are things I wrote down while talking to him on the phone, and some things that I learned myself while doing the rebuild.

First off, I used a book for most of the rebuild. the book I used was Haynes GM Transmission rebuild guide. A better book would have been the ATSG book, (Automatic transmission service guide) but I couldnt find it in time. so get a book.This info is related to "Trans-go Shift Kit" instructions.. some of these

modifications wont work without the trans-go product.Misc. info:
Axle Grease instead of Tranny jelly or petrolium jelly works fine.
A pick / Scribe set comes in VERY handy during the rebuild

Scribes. Use 2 scribes to remove the snap ring in the back.
axle grease instead of tranny gelly to hold check ***** and thrust washers.
----

Danas Instructions

Check ball on the input drum (first shaft) take check ball capsule out but leave Oring in there. Use a screwdriver or something to walk it out. the capsule is located at the very end of the input shaft. This modification drastically speeds up converter clutch lockup.

3-4 clutch pack around .045"-.055" (with 8 clutches)

Rear of the case itself where the valve body goes on, Theres a check ball capsule there When you install the transgo kit your putting restrictors next to this. One of the (4 holes) has a ball take it out. leave the capsule. (above the low/reverse passages) (last page of trans go instructions)

sprag goes into input drum (where overrun clutches run) Race is where the sprag rides on...

reverse input drum .030-.070" clearance

Reverse input drum is the first drum that comes out (band rides on) Area on band is FLAT PERFECT (straight edge)

600grit polish the band area

Second drum is aluminum (INPUT DRUM) with shaft. Thinner Steals Towards top, Pressure plate on top too. .060 steels on top.
shift kit instructions tell you how to modify that.

end clearance (input drum) bearing and spacer below that. sits on input shaft.

theres a number on that washer, 67 68 69 70 71.If mine is bigger than 69 than use the 69. If its smaller use the smaller one.

adjusting the band clearance you dont wana put any seals on while doing clearance check. after you do all that stuff.

corvette servo has D-ring seals make sure bore is clean and smooth. use 600 grit to polish it smooth. oil it all for sure.

Bushing on the input sun gear only .125" below surface; original bushing will be much deeper, GM puts them too deep

5 tangs on the aluminum piston in the input rum and they need to be flat sanded so all 5 tangs apply evenly. use a sharp small file.

on the input drum where the input shaft goes in there should be no high spots where ther sealing ring is use 400 grit to smooth it out.or small file DONT BE AGGRESSIVE

Near the end of the input shaft there is a 1.5" long shiny spot. this is where the converter rides, polish it up with 600-800 grit (i used 1500 grit)

flat area of bushings always go down!!

on the input drum itself where the snap ring goes (while its al aprt) small file where snap ring goes file off high spots before anything goes in.

Dowel holes perfect shape NOT WARPED if the dowel holes in the case are warped then the transmission will sit back and destroy the converter and pump.

sand bottom of case with file, remove high spots from the tangs and the very bottom of the case below the low-reverse piston needs to be smooth.

Case SMOOTH inside. remove all the case flash especially up near the pump area and around the tangs.

the valve body and the seperator plate need to be very flat. start with 180 grit if its really rought or warped but finish up with 400 grit. you want the plate have no "feelable" high spots.

the trans-go kit has you block off 3 area in the seperator plate. when you do this you need to hammer the aluminum plugs into the plate, they will mushroom out. YOU NEED TO FILE them completelly flat, almost to the point where you can feel them anymore. use a file first, then use sandpaper.

1-2 acumulator spot usually warped in the seperator plate. file / sand it smooth.

valve body pieces look closelly for casting flash inside the passages and remove them.

When you put the gaskets onto the case for the seperator plate, look at all the holes. in some places the gasket will cover part of a hole, use a razor blade and remove the offending portion of the gasket. never remove metal from the valve body thats not listed in the instructions.

Put hand in the input drum at bottom where first piston goes use finger where seals go make sure not smooth 400 grit back and forth NOT up and down

All of the aluminum pistons that come out of the transmission will be slightly scuffed here and there during removal. use a small file or sand paper and make them smooth once again. all it takes is 1 burr to destroy a seal.

low reverse piston 120 grit where the low reverse piston comes on the steel; not need to be super smooth but needs to be flat.

low reverse clutch area, 400 grit sand if high spots use file on front pump take everything out of everything, stator half take out old stator flat sand it then put new stator in. finish with 400 grit. turn 90 degrees every pass on the stator half. front half contains the rotor. 120 to 400 gritwhen you goto put new stator in, all flat sanded. take all valve and spring out of pump. you will see a check ball filter tcc valve main pressure valve TCC spring...

TAKE IT ALL OUT. Blow it al out and clean it up. Flat sanded set.
Dowel pin that lines the stator to the pump. usually falls out. Stake the pin into the pump body... do this by nicking the edges of the hole tap in then file it after remove high spots tap in the dowel pin till it stops grab it make sure it wont pull back out. PUT IT IN THE OVEN AT 500* for 23 Minutes... Take stator an hour earlier put it in freezer. take out the pump from the oven while hot... you have 5-10 seconds line it up to the dowel pin on the stator and push it in place.. turn it upside down on 2 oven mitts and wack it with both hands. when its cool put 3 bolts back in and where the dowel is you will see theres nothing to hold it in. hit the stator with something sharp to push some metal over the dowel.

the other half of pump you wana flat sand it too where .001-.002 clearance for rotor to slide around make sure keep turning pump to make sure not unsmoothafter both halfs of pump together go around pump with sealing ring remove high spots so it goes into case easier.

teflon bushing in front pump put the groove to the up side of the pump. dont stake in place (NEVER stake teflon bushing in place)

stake in place is when people grind an area where bushing goes DONT DO THAT

when i get done checking clearances in clutches but before i assemble it soak

everything in ATF for at LEAST 15 minutes. then let them dry for at least 20 minutes (dry) never assemble dry, and never assemble while really wet. the fluid takes up space in the assembly and tricks you into thinking there is less clearance than there really is.

GM vacuum switch. PN 14015419 $31.84 last miont
12102606 $12 for connector
Run a resistor wire from 12V to 10.5V use a resistor wire thing. from batt to switch only. switch on firewall. vacuum to this thing . this gives you lockup in a non-Computer controlled vehicle.

A terminal on plug of transmission. Outside towards front.

where band rides on reverse input drum, polish it perfectly smooth.

There is a sprag in the Input drum, and a sprag in the low-reverse area of the transmission in the case. For the sprag in the INPUT drum:
polish inner race of sprag MIRROR FINISH of the RACE make sure its perect.
Outer race of of sprag ROUGH AS CAN BE 40 - 80 GRIT. this keeps the sprag going

ONLY CLOCKWISE, and when you re-assemble the sprag make SURE the top half (smaller half) ONLY turns clockwise. look in your book...

O ring in the input drum above first piston
before first piston dont miss it, you will have to look inside the input drum from the side to see it. its green.
2 1/2 inches in diameter looks like material in front pump ring (oil it all)
5 tang retain put the springs in it, take other piston for it, put that together

set it inside (4 pieces together put them together) use something to clear the o-rings use something (O ring installer) a lip seal installer .025 Or use a feeler guage to do it.. walk it in on the inner seal so ASSEMBLE THIS THING first then put it in.

Inside the trans-go kit comes a steel ring, big wide and flat. you use it once, you put it ontop of the retainer that holds the springs inside the input drum. you can then compress those springs without fear of bending the retainer. after you install the snap ring you can throw away the steel ring, DONT leave it in there.

dont air test pistons until all the clutches with snap rings are installed last snap ring goes in then air test, or it will all fly apart.

the one that goees into the input drum rough the outer race.
sprag assembly on top of the bearing. thats the sprag
make sure that when you do the sprag assembly you put the sprag assembly the right way.

To get out the OLD stator in the pump you can tap it out while supporting the pump on a bench, OR you can wack the stator down onto something hard (like the top of a vice) and pop it out, since you wont be using it, it doesnt matter how banged up it gets. dont hurt the pump though.


orange red spring goes under that pin in the non-stator half of the pump, holds the rotor in place on one side.
install new seal and bushing when you put the slide in theres an Oring and a steel ring, also a black rubber seal and a teflon seal the rubber pushes on teflon, do this before anthing.
grab the slide with hand and push the pin in, when the rotor and slide and stuff is in, put the spring or 2 springs from NO YOYO kit transgo plastic retainer and that stuff... transgo = spring and 2 retainers. slide dana supplied rotor and (where 10 vanes go) plastic retainer faces front of pump sits against where the bushing goes. when you put the slide and rotor in make sure no high spots .. flat sand if you can 600 grit really easy before putting in front pump. they get nicked.

take out the spring, filter, check ball, pressure regulator valve, TCC selenoid valve, etc... blow it all clean then oven it. make sure flat. dowel pin in front pump, stator comes out, dowel should fall out. stake the hole and tap the dowel in THEN put the thing in the oven use it to guide the stator in. stake dowel in place to make sure it stays put.
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i have a 5 tang steel that sits at the bottom thats waved... before pressure plate goes put that weird lookin spring thing thats shaped funny, layes flat, under that plate and snap ring....

low roller back there, inner race, must be perfectly smooth put oil all over the bearings back there. planet soak in oil, pull it out dry off so its all nice and lubed. every bushing put oil in there. minimum clutches 15 minutes.

for pump, line them up by eye, then put pump in case to line it up with nothing in case, bolts facing out (stator splines facing into case) this lines the pump housing up so you dont need the "special" pump alignment tool.

check *****: 4 in the case, 1 in the valve body. (trans-go)all the way towards the front. probably taking out one. the one next to the aluminum plug take out the checkball towards the rear of the case, over the low reverse circuit, its a capsule... take it out. check ball capsule IN The case towards back underneath valve body. 4 holes angles, 2 feed low reverse piston, 2 feed governer..

on the other side towards the accumulator, take out that check ball, but not the capsule. self contained check ball. use screwdriver bend the tang and take the ball out.

60 thousandths play in servo
put the servo in with no seals (D rings) to check play against the band.
IF there is any more than 60-70 thousandths (.060") you need to shim it using the gold shim supplied with the trans-go kit. read those instructions.

the D rings need to be perfectly around and up on the servo or they will tear or roll off. you will need to tap in the cover with the (blue) seal on it, hit it in

the middle and side to side to walk it in slowly. Dont forget the snap ring on the outside of the cover of the servo.


Output shaft should turn one way easier than the other. make sure it doesnt get harder to turn as you go, it should maintain its resistance.

the new boost valve (.500) will have 2 Orings on it. It will be VERY tight to put into place, use tranny fluid and tap it down into place. when its down all the way it will stop, and it should stop 1/8" below the snap ring groove. install snap ring and double check it. when you start this thing the fluid will force the boost valve back against the snap ring and you dont want it flying out of there. you should be able to turn the snap ring freely in its groove after its installed. double check the valve itself using a screwdriver and make sure it moves freely and snaps back into place when released. dont scuff the valve though.

The front pump is tricky to install. First make sure the case where the pump sits is perfectly flat, use 600-800 grit sand paper if you have to, also use a small sharp file to remove high spots. feel for them with fingers. next make sure you have the 4 Orings on the input shaft, and that they sit flat against the input shaft. then look at the pumps outside where it will slide into the case, and sand /file off high spots from it as well. double check the boost valve / tcc valve areas usually you have a high spot or 2 around the holes. now on the non-splined side of the pump you have to install 2 Sealing rings, the blue ones with the split ends, make sure they sit VERY flat up into their grooves. if they dont then take them off and slightly bend them to make them "hug" the pump so they dont stick out. make sure to use tranny fluid when installing them so they are lubed.

Now install the O-ring around the pump's body, using tranny fluid to lube it. the red/yellow line should face out all around it. dont forget to install the yellow/brown thrust washer onto the non-splined side of the pump, the 2 little dowels fit into the stator, it will want to fall out so retain it in place with petrolium jelly or axle
grease. Now install the pump to case gasket, its round and has holes around the outside, it goes between the pump and the case. retain it in place with petrolium jelly or axle grease. double check that the reverse input drum is fully seated, do
this by holding the reverse input drum down into the case, and pulling up on the input shaft. if the input shaft has good play, maybe 1/4" of play pulling upwards and the reverse input drum stays down while you hold it, then the reverse input drum is installed correctly. it should also be slightly below the pump-gasket surface. also double check the band is all the way down and the anchor pin is installed. you should be able to wiggle the band with your hand.

now you are ready to install the pump, ensure all the seals and bushings (such as inside the stator) are lubed, and line the pump up over the pump holes as you set it down over the input shaft. use 2 long screwdrivers or long bolts to put through the pump and into the case to line up the pump perfectly with the holes. as you set the pump down it will eventually stop, usually about 1/2"-1" up. to get it down further, you will need to reach through the case's valve body and push against the reverse input drum and wiggle it around so the pump can fall down further. beware of the gasket because its easy to rip while you reach through the valve body. also try wiggling the input shaft. then the pump usually falls to about 1/4-1/8" above the surface.

at this point friction is holding it up, and you will either need to tap it down or use 3 long bolts and pull it down slowly into the case criss crossing the pattern. after its all the way down remember to use a criss-cross pattern tightening it down. now you check 2 things, first grab the input shaft and turn it. it should be hard to turn, but it should turn by hand(s) using a rag. you wont be able to turn it very much, its very hard to do, but if you absolutelly CANT get it to turn then something is wrong. next thing is end play. as you turn the input shaft pull out on it, and wiggle it out as much as you can. you wont see it move by eye.. but measure the distance from the output shaft to the stator. now turn it and push in as hard as you can, while turning, and if you have to use a small rubber hammer to hit the input shaft into the stator. now measure that distance again, it should have changed about .004-.020 somewhere in the region is fine. what you DONT want is anything over .020... thats BAD. too much play. usually, however, if you can barelly measure the change, thats fine so long as the input shaft can turn by hand.

now you can check the band.
60 thousandths play in servo .060
put the servo in with no seals (D rings) to check play against the band.
IF there is any more than 60-70 thousandths (.060") you need to shim it using the gold shim supplied with the trans-go kit. read those instructions. if you did you probably already installed the gold shim and that should be fine so long as you did the rest of the instructions. the D rings need to be perfectly around and up on the servo or they will tear or roll off. try to put the entire servo assembly in place together as one piece, but you can do it separately. its not uncommon for a D-ring to slip off or roll off or tear so be CAREFULL if you are unsure then pull it back out and do it over.

when its in you will need to tap in the cover with the (blue) seal on it, hit it in the middle and side to side to walk it in slowly. Dont forget the snap ring on the outside of the cover of the servo.

stator side:
did you remember to replace the entire boost valve assembly? valve, spring, and both boost valves? are the check ***** still in the pump where they go? you re-use the TCC valve and spring, as well as the pressure check ball / spring. replaced the pump's filter? it just slides in the side.. did you remember to flat sand the pump surface while the stator was out? its not too late, just harder to do with it in. start with 180-220 grit if its rough, and work up to 400grit. you want that baby FLAT where it mates to the other half of the pump.



Notes;
Boost valve very tight
TCC valve went back the way it came out
little rubber piece behind little green piece in rotor
pump - re used the check ball + spring in pump
valves leftover...
valvebody, no modification on the left side only the 4 right side.
Took out old spring (first) then new valve drilled the 3 holes and new spring under

valve

accumulator.. took out 1 piston alltogether, second piston also took out the
shaft
Piston in aux; valve body? what do i do with that? changes?

pump very hard to seat in place
reverse input drum 1/8" below pump gasket surface
seals on the end of the pump... what kind? have rubber and weird ones

Rebuilding your 700R4? Check this out! - Third Generation F-Body Message Boards

[4x4le]

Are you even real, or are you the worlds most creative spam bot?

[Kingtal0n]

Originally Posted by 4x4le

Are you even real, or are you the worlds most creative spam bot?

Wha, you dont like my helpful transmission build? That 700R4 is an incredible automatic, and IMO should be behind most 600 horsepower 2jz-gte engines.
If you ever felt the way it shifts... you would never want another manual trans.
//#Include automatic.css

Im saving these spaces for future posts, I can edit this and put in future calculations for instance, Like I did ALREADY above.