Art Carr 3500 Non Lockup Converter Slip Question

[bdeliman]

I just changed from a stock converter to an original Art Carr 3500 non lockup. I replaced the lockup valve with a non-lockup valve, removed the check ball & O-ring, and used new fluid and filter. When compared to the stock converter under race conditions, the new 3500 converter seems to be running 200 to 300 RPM higher than the stock converter when compared to MPH throughout the entire run. I would expect the RPM's to be slightly higher until the stall speed was reached, and then be identical to the stock converter, but this is not the case. I do not think the trans is slipping because the car was not driven between the base runs with the stock converter and the runs with the new converter. I feel this would be a remote coincidence that the trans just went bad between converter swaps. Any help would be appreciated.

 

[SPOT MY 6]

Your convertor is fine. RPM's across the board will be higher as compared to your stock convertor. I trap 6450 rpm's with one convertor, and 6100 with another. This is normal.

 

[bison]

It should be higher. It should be a lot higher than 300 at low road speeds at WOT in 3rd. If its too high for your combo you can have them tighten it. The one i have in my car now spends all its time between 5400 and 6300 at 17psi. It pulls like a mofo in that range though. I will have to send it out before i turn the boost over 17 psi. I have no official runs with it yet. Went 125 in the quarter on the g-tech, hitting rev limit with 26" tires. Actual trap mph would be around 120 mph. A good converter will keep the car right in the meat of the power band if its doing its job. The slip % will be high at low road speeds and less at the traps. For a properly selected non lock up it should be under 10%. Mine is over 10%, so i will have to send it out before i throw more torque at it. Getting the stall and efficiency just right on the first try is not common. Usually theres more to be gained if the converter is tweaked a little for your combo after you run it and give them feedback to work with. I sent one back to Art 4 years ago that stalled great but ate up a lot of mph up top. This was on a 117 mph car. It was slipping 12-13%. After the tightening it stalled the same down low but only slipped 9% on a 127 mph pass in the same car with a bigger turbo. I could have picked up at least 3mph over the old combo if i ran the tightened converter with it. Unfortuanely i dont have the data to back that up since i switched the turbos. Fortunately for us converter tech has come a long way in the last decade.