Educate me about manualised autos

[leigh7005]

a stall convertor works with ur cam say u got a cam that starts at 3000rpm you would want a 3000rpm stall in other words it revs up until yr engine is ready to make power a standard stall would be around 1200rpm but there is a down side anything ova 3000 on the street is not wise as stalls will make ur trans run hotter hope this helps a little and yea ur right with the manulised trans u have to manualy shift it up and down

[C_Fernance]

The stall speed is how high the engine can rev while in gear. The higher the stall speed the higher you will need to rev the engine to take off/drive the car. You won't necessarily have to rev it to 3000, but it will take a few more revs then standard. Much like slipping a clutch a bit when in a manual. Good if you have a big cam, etc that doesn't make much power down low, but revs hard and makes plenty of power in the top end.

The manualised bit means that the gearbox is in whatever gear you put the gearlever in. Low = 1st, 2nd = 2nd, D = 3rd. It will stay in whatever gear you select and won't change up or down. It's basically a manual gearbox with a torque convertor instead of a clutch.

[DanTurboLancer]

Here is a good explaination of a standard Torque Convertor and its operation.

http://www.youtube.com/watch?v=MvLoX0z9qoY

Here is a less easy to understand explaination.

http://www.youtube.com/watch?v=EbibZPKw4tk

Here is another good basic explaination of how a torque convertor works.

http://www.youtube.com/watch?v=LEFWO3M4 ... re=related


Here is a video that shows the advantages of a higher stall convertor

http://www.youtube.com/watch?v=h_OcmsYq ... 8EDB98D58B


Sorry mate the Ebay link shows that is has closed,
so i couldnt read the description about the auto you have brought.

Has it been rebuilt recently?
Has it got all good parts and a shift kit fitted?


Basically all auto Torque convertors will stop flowing oil under a certain RPM.
and as explained in those videos, once the engine/convertor turbine is spinning at a certain RPM,
it will then begin to engage the convertor to engage drive to the gearbox.

The higher the "stall" means the convertor will allow the engine to spin and the convertor to slip untill it reaches its engage RPM.

Note that the engine wont rev freely until it reachs the Stall RPM, the convertor will still have some slight friction engaged to the gearbox.
As said above, its as if you are just half letting your foot off the clutch pedal in a manual.
Then once you have reached your Stall RPM you will get full engaged drive.

As said in that last video,
advantages are you can get into higher RPM faster.
and get your full engagment pressure quicker.

As said, drag racers will try to combine a package that gets the best drive off the line, with minimal wheel spin, and have that combined to match their Cam,
and or Turbo.

Disadvantages
automatic transmissions have a series of clutches in them,
So slipping and not having full engagment will introduce ALOT of heat.

When driving on the street you have to keep your engine RPM Above the stall,
so if you choose a 3000 RPM stall convertor, you will need to drive around the city holding a gear to keep your revs above 3000rpm.

Its no good having a 5000rpm stall convertor if your engine only revs to 6000rpm,
and it would be useless on the street.
So choosing a stall convertor to suit your needs is important.

Also your fuel economy will be lowered if that is of any concern to you on the street.



Not knowing the condition of your Auto,
you may want to strip it and inspect before you fit it.
give it a service,
and as in that last video, always pre fill your convertor Before you fit it!

and definitely fit a large good quality transmission oil cooler.



Manualised Auto transmission,
im not 100% on this,
but I think the advantages might be removing some of the parts that are involved in automatic process,
which makes the gearbox more reliable and stronger,
and removes some of the slipping and flaring action a normal auto,
to give you a firmer shift and more direct drive through the gearbox.



Hope this is of some help.
Some others with more experience on the performance side might be able to give more advise.

[75wagon]

Here's the description Dan.

Up for sale is A japanese built torqueflite A904 auto trans as fitted to aDM chrysler/mitsubishi scorpions. This transmission has been reconditioned and modified with a full manual valve body and 2500 rpm stall speed torque converter. The trans was built by JRM Transmissions in Lonsdale SA. Comes with drive plate and sandwhich plates. Will fit a standard Sigma auto shifter or you could use several different types of after market shifter.
This has never been fitted since the rebuild so it is effectivly brand new. Was built for a turbocharged sigma project I never finished.
I have the receipt for the work on the trans.

[mic_77]

The question is did they modify the oil pump and converter snout if not it will just be a headache from the get go.


cheers Mic