TH400 Cooler line pressure

[Pablo]

I restricted my converter feed passage to 5/64s after 7/64s gave me too much pressure. Finally got it up and running and I just wanted to check whether or not I am good. Cold startup in park I get a hair over 50 psi max pressure. Once everything warms up I am in the low 30s pressure wise.

Am I good?

 

[lazaris]

I restricted my converter feed passage to 5/64s after 7/64s gave me too much pressure. Finally got it up and running and I just wanted to check whether or not I am good. Cold startup in park I get a hair over 50 psi max pressure. Once everything warms up I am in the low 30s pressure wise.

Am I good?

Should be good.

 

[turbobitt]

Took this data log yesterday with transbrake engage from idle and stabbing throttle to check for spool time. Converter feed is 7/64. The direct drum has a drilling that provides a good leak so line pressure starts low. The charge flow pressure starts out very low but increases steadily to just over 90 psi. I'm not woried about this since my own testing proves that charge pressure alone isn't the only factor in thrust wear.

See attached PDF.

Allan G.

 

[lazaris]

Took this data log yesterday with transbrake engage from idle and stabbing throttle to check for spool time. Converter feed is 7/64. The direct drum has a drilling that provides a good leak so line pressure starts low. The charge flow pressure starts out very low but increases steadily to just over 90 psi. I'm not woried about this since my own testing proves that charge pressure alone isn't the only factor in thrust wear.

See attached PDF.

Allan G.

Try going to a smaller orifice

 

[jasjamz]

Took this data log yesterday with transbrake engage from idle and stabbing throttle to check for spool time. Converter feed is 7/64. The direct drum has a drilling that provides a good leak so line pressure starts low. The charge flow pressure starts out very low but increases steadily to just over 90 psi. I'm not woried about this since my own testing proves that charge pressure alone isn't the only factor in thrust wear.

See attached PDF.

Allan G.

What else contributes to thrust wear issues?

 

[turbobitt]

What else contributes to thrust wear issues?

Not all converters are equal. Some vent internal pressure better than others. I've street driven an un-restricted pump for years without having any thrust issues. Doesn't mean that we shouldn't play safe and use a restriction.

I'm debating with myself if I should modify the PR valve to always bypass line pressure to the charge circuit and use a larger restriction. My thought process revolves around the fact that the PR valve is closing during low RPM and when fluid flow is at high demand, such as when direct clutch is engage and has a bleed hole venting fluid. This causes large swings in the charge pressure. With my current set-up, charge pressure is around 40-60 psi at "Normal" driving conditons. At idle it drops and with the trans brake engage it drops more.
Allan G.

 

[Dusty Bradford]

Not all converters are equal. Some vent internal pressure better than others. I've street driven an un-restricted pump for years without having any thrust issues. Doesn't mean that we shouldn't play safe and use a restriction.

The venting of internal pressure is really trying to keep the converter from balooning.

I'd love to know what the pressure rises to between the shaft and stator support when the car is making a pass down track.

 

[jasjamz]

Thanks Gents!!
I was wanting to make the switch back to the 400. Trying to get all the right parts and knowledge to make both last.