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Transmission pressures?

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Turbo1dr

9 Sec Wanna-Be
Joined
May 25, 2001
Messages
2,418
What kind of line pressures are needed for a 200-4R at idle, part throttle & WOT?

I'm asking this because it's like the trans slips during part throttle while the boost is 15 to 18psi. When it happens the engine will sometimes rev (as the engines torque increases) like it partially comes out of gear. Of course, when that happens I just let off the throttle. I can datalog the rpm and tire speed so I can confirm that it's not tire spin. I think it just don't have enough pressure at part throttle to hold the engines torque. The engine is a 249" stroker 109, GN1-R's, 70GTQ.


Here is what I have on a fully warmed up trans.

120psi at idle
190psi at part throttle
210psi at wide open throttle
 
This was giving to me by Donnie...

You need to tee into the upper cooler line and take a pressure reading. If it's at 40 psi or less at idle, you're OK. If it's higher, let me know.

I guess thrust bearing concerns come into play over 40 psi at idle
 
What kind of line pressures are needed for a 200-4R at idle, part throttle & WOT?

I'm asking this because it's like the trans slips during part throttle while the boost is 15 to 18psi. When it happens the engine will sometimes rev (as the engines torque increases) like it partially comes out of gear. Of course, when that happens I just let off the throttle. I can datalog the rpm and tire speed so I can confirm that it's not tire spin. I think it just don't have enough pressure at part throttle to hold the engines torque. The engine is a 249" stroker 109, GN1-R's, 70GTQ.


Here is what I have on a fully warmed up trans.

120psi at idle
190psi at part throttle
210psi at wide open throttle

You need a min of a steady 225psi at full TV. I do not like to see below 240psi ever. Your idle pressure is too high also. You have a problem that I will need more info on your setup to help you, sending you a PM.
 
This was giving to me by Donnie...

You need to tee into the upper cooler line and take a pressure reading. If it's at 40 psi or less at idle, you're OK. If it's higher, let me know.

I guess thrust bearing concerns come into play over 40 psi at idle
Scott, they're discussing mainline pressure readings. That is completely different than the cooler line reading which is the closest clue we have to what the T/C charge pressure is.

210 is 2 low for your listed setup.
 
Some what on subject

Is there a way to make the line pressure rise @ a faster rate? Say get to max. pressure @ 1/2 or 3/4 throttle. Would taking the PLAY or space between the TV plunger and arm away make it go up quicker?
 
You need a min of a steady 225psi at full TV. I do not like to see below 240psi ever. Your idle pressure is too high also. You have a problem that I will need more info on your setup to help you, sending you a PM.

What do you suggest?


Is there a way to make the line pressure rise @ a faster rate? Say get to max. pressure @ 1/2 or 3/4 throttle.

This is exactly what I need. Proper WOT pressures at part throttle with little pressure to provide softer shifts during normal city driving. If I could get 70-100psi up 1/4 throttle and after that make it rise very quickly to 250??? at 1/2 throttle on up to WOT. I do have the large 2nd servo and a wide 2nd band.

I've already burnt the forward clutches out once and don't care to do that again. This brings me to how I drive....if i need to pass a car on a two lane road I just use part throttle. However, if I get myself into a pinch, I mash it on down and this is when I feel the engine rev but the car doesn't seem to pick up any...or at least it doesn't put me back into the seat any more when the boost rises to 20+. WOT boost is set at 28psi. I can't go to WOT because the car will light the tires up at anything below 65mph. I've only felt it in 2nd and I've never tried to see if it would do it in 3rd.

The torque converter is a PTC non lock.
 
From my limited experience

Burnt forward frictions is usually from LOW line perssure. Not enough pressure to keep them applied. Maybe you just need a good blueprinted pump?
 
It's very difficult to burn the forwards in a 200-4R. It's usually a sign of low fluid level or somehow losing fluid pickup or a problem with the sealing rings or sealing ring bore in the OD housing. I'm assuming all other frictions are relatively OK.

Changing the bushings in the OD housing is a delicate operation. If a person is not careful, it's very easy to nick the forward clutch sealing ring bore. The sealing rings will not seat correctly and you end up with a crossleak, or in other words, a low pressure condition in the forward clutch pack.

Also check for a cracked forward clutch drum.
 
Is there a way to make the line pressure rise @ a faster rate? Say get to max. pressure @ 1/2 or 3/4 throttle. Would taking the PLAY or space between the TV plunger and arm away make it go up quicker?
This can easily be accomplished by installing a stiffer spring, or doubling up the spring that is between the TV plunger and the inner TV valve.

This is a very important mod that should be done with any combination that gives a very quick spool up with only light throttle openings. The transmission line pressure rise must be tailored to the torque curve/throttle opening curve of the engine. Even with the highest amounts of mainline pressure at WOT, if the pressures aren't matched for partial throttle openings, you will have a burnt transmission.
 
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