granny racer

My knowledge is minimal on transmissions
i been reading this though. tons of great info.

https://honda-tech.com/forums/transmission-drivetrain-127/automatic-transmissions-torque-converters-explained-2086594/

and my mind has been thinking about everything

do they mainly loose power from the torque converter? and what else cause power loss?

would an LSD help (i have no clue if its even possible on an auto. )

would a programmable TCU help?

Also a co worker was telling me how an (overdrive button) locks up something in his transmission (im guessing the torque converter) and allows zero slippage so you get more power .

He said this also locks up when you floor the gas because the transmission is telling itself that your passing someone BUT it wont shift into the next gear and will over rev till you let off the gas a little.

with all this in mind. how can i get more power to the wheels. NOT a 100% 1:1 power. but is there anything i could do to decrease slippage?
a certain fluid. or tricking the computer.

id really like to see the maximum amount of power a SOHC Non-vtec Auto can actually make.

fleabag

There is a "pump" that is required for the torque converter to function properly and the action of pumping all that fluid just to act in replacement of a clutch is what wastes so much power. The only benefit to an autotragic transmission besides it aiding the lazy and the helpless in driving is that if you're stump pulling. True you could burn out your auto transmission, but if you get a transmission cooler and you don't overload it, I think it would last longer than the clutch would in a manual transmission under the same scenario. Clutch or torque converter is necessary for the transfer of work especially when the work has such a vast mismatch in speed like the difference of 3000rpm and 0rpm.. While you could design a gearbox to reduce the speed down to near zero rpm, the gear box would then have to be very large and also be only used for specialty purposes...like pulling stumps.. lol I suppose if you had a transmission with an infinite amount of gears (besides CVT) that could shift instantaneously, there would be no need for a torque converter in any circumstance and the clutch being used would experience near zero wear since there would be so much torque that the engine it is paired to it would hopefully never stall assuming it's not being overloaded. This is far beyond the scope of the original question and I'm now just rambling..

As for your friend doing the lockup override so that it's mostly locked, it's not a bad idea actually if you're willing to sacrifice some performance for the sake of fuel economy. Auto tragics will always have power loss thanks to the pump that is used for the torque converter.. The Volvo I drive has geartronic and when you engage it, it basically makes the car more apt to engaging torque converter lockup sooner and so flooring it doesn't cause the transmission to downshift like it normally would in an autotragic. To give you an idea of how much power is being sapped thanks to the autotragic transmission.. A 2004 Volvo S60 2.5T A/T (208hp) that weighs 3500lbs has very nearly the same effective power (acceleration, etc.) as my M/T 1998 Honda Civic LX 106hp which weighs 2400lbs. It's true my civic weighs 1000lbs less but the Volvo has variable valve timing and a turbo that give it a peak torque of 240 lb/ft as early as 1500rpm as it stays that way all the way to redline IIRC. The Volvo also only has 40K miles while my civic has 175K miles.

granny racer

is the lockup override bad for the transmission? And do you mean that id burn more fuel or less fuel with the lock up? I would think less because there would be less wasted power right?

granny racer

Also is it bad for the auto trans mission when you rev up in neutral (to get the fluid pumping) then put it in the D3 ?
ive done this about twice and it actually squealed the tires but ip pretty sure its not good on the transmission. like not good at all

Bwill9886

It's called a "neutral drop/bomb" and why are you doing it?

That is absolutely not good for it.


Btw, good info there fleabag. You really went for it!

granny racer

what type of damage will the bomb do.? im guessing break a tranny gear or something.
ive never done it past 2k rpm. i was just seeing what would happen when i done it.

and is this a proper launch

http://www.club3g.com/forum/drag-rac...ipped-car.html

or will this destroy something too?

MAD_MIKE

It's from the pumping of the AT fluid throughout the transmission. A manual transmission does not have to pump fluid, but as mentioned the torque converter can give you up to 2.1 torque output of the engine. This usually occurs only from a stop. Nothing is free and the inverse relationship you will lose rpm output.
No. The limited slip differential, will only aid in equalizing traction between the two drive wheels by limiting the speed differences between the outputs.
Outside of tuning the shift points and lockup to your driving style and through testing. Not really. Forcing an earlier shift may not be the best for longevity of the components.
Depends on the make. But most OD buttons will prevent the OD from being engaged, such as for use in towing/hauling. Allowing OD to engage with a heavy load may damage the transmission and cause the engine to lug as there would not be enough power from the engine, or leverage through gear ratios to pull the load.
Usually when you pass the TC will UNlock. There is not the same amount of friction material, nor does it have the capacity to hold like a conventional clutch. The lockup feature is to eliminate the slippage that occurs due to the nature of a hydraulic coupling.
Not really. If you were to have the gears shift too early it would be akin to shifting a MT too early, you would cause the engine to buck and ping, not good for drivetrain longevity nor for fuel economy. Engaging the lockup feature more often will cause for more wear, and probably not net you any gain.
If you wish to improve on acceleration off the line, you would use a smaller diameter or higher stall torque converter. But this may not be the best, nor cheapest option for an otherwise stock engine. This would increase slippage to allow the engine into its powerband faster, but at engine speeds below the specified stall there would be increased slippage. If a lockup feature is maintained, highway cruising speeds would not be affected. But around the town would as the engine would rev more to create torque multiplication.
Accords, Preludes, and Odysseys have different torque converters, gear ratios and final drives. The most fuel efficient would be the Accords, the best for acceleration would be the Preludes. You could install the Odyssey transmission which would give you a larger TC for a lower stall speed, but has similar if not the same gear ratios as the Si Prelude. The problem with this is you would not have the lower cruising rpm as found in the Accords due to the lower gear ratios orverall. 3200 vs 2700 @~70MPH.

granny racer

WOW!






you da man MadMike ! thank you

although i think you convinced me to look into a manual swap sooner.

i gotta find me a manual transmission and shifter and clutch pedal.

what MT fits an f22b2?

MAD_MIKE

You will more than likely grenade the stator inside the transmission or worse. Even if the TC is only damaged, metal will be circulated throughout the transmission damaging all the components, requiring a complete rebuild.
Don't do it.
Keep in mind there are just as great, if not more so, forces going on in a TC as a clutch. The TC can ballon and explode just as violently as a flywheel/clutch explosion. Don't kid yourself, fooling with the Neutral bombs. They are dangerous to do and can do more damage, that whole torque multiplication thing, than what a MT will do.

Close. You load the engine up against the converter this gives you the maximum amount of power off the line. Much like compressing and releasing a spring, the car will lauch. However, as mentioned in the post, if you apply too much throttle too soon the tires may break free and spin causing loss of traction 'blowing the launch'.

Loading up the converter causes shearing of the fluid, which causes friction, which causes heat... lots of heat, and balloning of the TC. The primary killer of ATs is excessive heat. A few of these launches in short order will dramatically raise the temperture of the transmission fluid causing it to cook, rendering its properties useless. Even one launch can fry the transmission fluid. Use an ancillary cooler if you plan on doing this often.

But the stock Accord AT does not have the best gears for acceleration.

MAD_MIKE

Don't knock the AT just yet. I replaced the AT in the '95 EX with a unit from a Odyssey. The acceleration difference from the gear ratios alone is quite pleasant. A few gobblers trying to cheat the queue at the light, have found the view from behind the Accord to be a surprising outcome.

fleabag

Not to mention the fact that the A/T in these cars (at least for '98-02) are commonly known as "glass" transmissions.. I don't know what changes they made from the 94-97 accord transmission to the '98-'02 accords but what I remember is that they improved performance of their engines without improving the design of the transmissions (unchanged transmissions), causing them to fail prematurely. So I would imagine doing something very strenuous on a transmission like a neutral drop or just general racing that is already prone to failure in higher power applications would probably not be a good idea without major modification. Anyway the general trend in transmission design in the last decade is not to make the transmissions beefier but to nerf the transmissions and engines so they don't put too much power through the transmission and end up damaging them prematurely. They couldn't do this 20 years ago with the computers and electronic technology then because it was too expensive but things have gotten cheaper and now they can have all sorts of solenoids, sensor circuits and discrete computer circuitry to help prevent the transmission from destroying itself..

Speaking of neutral drops and cars notorious for 'weak' transmissions, let's talk about that Volvo S60! The '01-'04 S60s had a problem with the transmissions failing quite early. So, instead of redesigning the transmission, Volvo decided to disable a feature they had where the transmission shifts into neutral when you come to a stop, and I'm sure this feature was designed to help save fuel. What probably would happen is that the car would detect the driver was either coming to a stop or was at a stop and would shift into neutral. However, because of the erratic driving habits of a lot of people, the person would then step on the accelerator after the car just shifted into neutral and since "accelerator=go" not only has the engine just revved up a bit but the transmission would also have to quickly shift back into gear. This is significant because what just happened is essentially a "neutral drop". So, Volvo disabled the feature of shifting into neutral at a stop so now the car is always in gear. I've noticed this feature of shifting into neutral at a stop on at least one other car, the Camry V6/ES350. Potentially this could mean there are some transmission failures in the future for this car which may already be rearing their ugly head.

MAD_MIKE

The 90-93, and 94-97 are interchangable. The '98-'02s were changed to complete electronic control.

fleabag

Ok, but aside from the electronic control and other things, what changes were made to the '98-'02 transmissions? That would suck if the only reason the '98-'02 transmissions died is because they built them to inferior standards compared to the ones of previous.

andzac

manual is the way to go!

phootbag

The torque converter is essentially two fan blades facing eachother. When one fan blade spins, it pushes transmission fluid toward the other fan blade through a diverting assembly called the stator. The stator directs the ATF toward the opposing blade in a more efficient manner. A secondary function of the stator is to control a fluid pressure valve. As you accelerate hard, the force against the stator is great causing the pressure valve to open which increases clutch pressure to handle the increased engine load during acceleration.

The torque converter functions as a fluid coupling, as stated. The purpose is to allow the car to idle in drive while sitting still. There are other benefits designed into the torque converter, as stated earlier.

The purpose of the torque converter clutch is to create a mechanical link between the engine and transmission as the torque converter reaches "coupling speed". Coupling speed is the moment the two halves of the torque converter are moving at nearly the same..

phootbag

... speed. When the two halves of the torque converter are moving at the same speed, fluid is not directed through the stator toward the opposing half of the torque converter. The fluid starts to flow around the inside perimeter of the torque converter. This is where the torque converter becomes inefficient and what most people are talking about, or should be talking about, when discussing the inefficiency of the AT vs MT. The solution, torque converter clutch.

granny racer

so the main problem with AT is that it uses more rpms to transfer power.
correct?

and the pro to an AT is fast automatic shifts

or are they even faster.

Balwin

stop wasting your time and just swap to manual.

when you finally make up your mind I can help you with questions and I can also find you the parts if you have the money.

fleabag

I would only swap to manual if the auto transmission has failed and you do not care about the potential to reduce the value of the car.

Balwin

whats funny is that I was planning a manual swap and a week before the swap my auto tranny died. lol fail. ...or win? who cares.

bcmotors

Not true. The torque converter more than doubles your power off the launch, making them perfect for drag racing. And when you get up to speed the TCC locks up and the slipping stops, no "lost power" there. The down side is not being able to control your shifts. This is useful for daily driving and road course racing. Most autos shift slow and smooth, for grandmas comfort, so they feel slow to your *** dyno.

fleabag

torque converters don't "double power"... instead they store it in the form of reciprocating mass and any gains you have from takeoff are quickly lost when the inertia is "burned off" so to speak. I suppose it could be summed up as having a really heavy flywheel...great for storing energy but because there is still a pump that is moving fluid and is run off the crankshaft of the engine (lost power), any gains from storing the energy when launching are lost when the inertia that was saved up is expended. This may allow the car to do a fast 0-30 sprint but it will still have diminished performance compared to a M/T car with no pump. Have you ever seen the 0-60 times of the A/T cars and the M/T cars? The only reason I can see drag racing cars seriously benefit from having an A/T is that they're so powerful and the time differences we're talking about are so small that they benefit from an A/T with quick shifting.

granny racer

here i go again with the AT stuff

ok this service manual says there is a lock-up solenoid






and that when it engages the lock up. it BYPASSES THE TORQUE CONVERTER



is there a way to control this solenoid,/ and what are the consequences of locking up the TC

Bwill9886

This.

With the amount of thought you are putting into the auto, you may as well focus that energy on a manual swap (including getting the funds together).

Seriously, you are talking about doing things that are either bad for the transmission or just too much trouble to be worth it.

The manual is going to be more fun AND will be better suited for your "performance" goals (and mpg, as a plus). Good luck!

MAD_MIKE

As I stated before.

Lockup of the TC early will be akin to shifting a manual transmission into a taller gear too soon. It will cause pinging, bucking, and unnecessary loads on the whole drive train. I would not attempt to activate the TC lockup feature unless you are just testng it to see if the shift solenoid and TC are working properly. That's it.

The TC lockup clutch does not have the same torque capacity as a standard clutch. You will only cause undue wear on the TC lockup.
Take note that usually lockup occurs in higher gears. In other transmissions this also changes how the pump is driven, not sure if this is the case with the Honda AT but I would think so. Leaving the at in non lockup in OD can cause inefficient pumping of the fluid which can burn up the clutch packs. I would think locking up the TC early would have the same affect on the lower gears.

Without having changed the ATs shift program, or having complete control, I would not attempt to force a shift or lockup function. Doing so may cause internal damage as the transmission is still controlled by the TCU.