Dynoed w/ PT4400...What happened?
01-06-2004, 06:09 PM
#21
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Originally Posted by JNorris
Have you been having transmission problems to make you think it is now slipping?
What gears are you running?
More than likely (Unless your transmission has a problem) the reason you were hitting the rev limiter is because the PT4400 with its high stall will allow the motor to spin up faster than before. Also the dyno does not load the drive train as much as driving on the street. Does it hit the limiter on the street or track or just on the dyno?
When I first went with the PT4400 I had to lower my shift points by a 200 rpm to keep from hitting the limiter. Just recently I put a vig3200 back in the car and I had to raise the shift points to get it to shift at the same point as before with the PT4400.
From what I have seen the PT4400 (mine) is not very efficient below 5500 rpm. Mine did not approach 90% efficiency in 1st gear (with 3.23 gears) until 6200 rpm.
John
What gears are you running?
More than likely (Unless your transmission has a problem) the reason you were hitting the rev limiter is because the PT4400 with its high stall will allow the motor to spin up faster than before. Also the dyno does not load the drive train as much as driving on the street. Does it hit the limiter on the street or track or just on the dyno?
When I first went with the PT4400 I had to lower my shift points by a 200 rpm to keep from hitting the limiter. Just recently I put a vig3200 back in the car and I had to raise the shift points to get it to shift at the same point as before with the PT4400.
From what I have seen the PT4400 (mine) is not very efficient below 5500 rpm. Mine did not approach 90% efficiency in 1st gear (with 3.23 gears) until 6200 rpm.
John
01-06-2004, 06:32 PM
#22
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Originally Posted by Dear John
Why are you switching to a Vigi 3200? I have that converter now and was nearly about to order a Yank PT4400. Is there any performance reason or what's the deal? Why the swap?
My PT4400 went bad and sent metal shavings into the transmission. I had the Vig 3200 and decided to put it in with the new transmission. When cash permits I will have the Yank fixed and will put it back in.
FWIW as a bolt on car I dropped .16 in the ¼ by switching from the vig3200 to the PT4400. There will be a huge difference in the drivability between the two converters especially with 3.23 gears. The 4400 is very loose compared to the 3200 but it is a great race converter.
John
01-07-2004, 11:49 AM
#23
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J Norris When you found out the efficiency of the PT4400, was the converter already experiencing problems, and did you report this to Yank. Because I thought the PT4400 was supposed to have good efficiency like 96or97%?
01-07-2004, 01:20 PM
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Originally Posted by Evo98z
J Norris When you found out the efficiency of the PT4400, was the converter already experiencing problems, and did you report this to Yank. Because I thought the PT4400 was supposed to have good efficiency like 96or97%?
TC efficiency is stated or rated at a specific RPM. It goes without saying that any high stall converter will have very poor efficiency at a RPM below its stall rating. That is why it is loose.
To answer your question my PT4400 converter with 3.23 gears was this way from the day I installed it. In my negations with Yank about the warranty on the converter I did mention it. Yank indicated that this was not unusual considering I was running 3.23 gears.
IMO it is very unlikely that ANY 4000+ stall converter that is run with 3.23 gears will have 96% efficiency below 5500 RPM unless it is locked.
John
