Drop in RPM
 

Car is an 87 GN TA motor with 400 transmission. When car is shifted Rpms drop 1600 on all shifts. This started this last racing season, before they would drop 600 to 700. Tried three different converters and all did the same thing someone thought the problem might be in the transmission made sense as the sixty foots went from 1.30s to 1.50s. Car seems to pull good thur the quarter mile but leaving some on the table as it takes time to pull back up in the power band. Any Ideas?

Can you give us more details, such as what convertor did you use when the 60fts were 1.30, why did you change convertors, what did you use before and after for convertors. What kind of RPM range are you running in before and after convertor changes? Are you using a FAST and do you have any logs? Thats it for now, but more info is definitely needed... oh ya, who am I speaking to... :)

Can you give us more details, such as what convertor did you use when the 60fts were 1.30, why did you change convertors, what did you use before and after for convertors. What kind of RPM range are you running in before and after convertor changes? Are you using a FAST and do you have any logs? Thats it for now, but more info is definitely needed... oh ya, who am I speaking to

The converter I was using was a Hughes at the end of the 06 racing season. I made a change as this converter had a lot of slip at the big end and also due to rpm drop which started at the start of the 07 season. I tried an Art Carr converter and still had the rpm drop on the shifts, still thinking it might be in the converter I purshased a Ptc converter,problem still there but this converter Rocks. Very little slippage on the top end. I do run a fast bank to bank. The only change made to the car between 06 and 07 was going from a Pte intercooler to Rjc megacooler. I shift the car around 6800 tried different shift points and rpm drop still there.Running 96 lbs injectors and a 4276 turbo up from a 74 gtq. Problem there with both turbos Had injectors checked and cleaned. They flowed about 104 ilbs.By the way my name is Ron and I live in West Texas. Thanks for your reply.

Ok... the good part is your present convertor seems to work. Are you able to send me some logs to look at? Also, how are your 60fts and are you spinning at the line or just coming out slower.... When it shifts.. are you bogging down or still pulling hard.

The car seems to spin at the line it will load and than unload. Car pulls good thru the run and does not bog down. I had one run on this computer so I sent a copy to you. If you could take a look at it maybe you will see something that is not quite right Thank you for your time. This run was with the hughes converter.

Ok, got a look at that log... not too bad. You need to take out around 10% fuel after you get on boost but leave fuel in at the RPM drop from the shift. Voltage is down a tad, but not bad. MAT's rise is typical for a PTE frt mnt IC, about 40*. Unfortunately, none of the info from that log will relate to your current combo, do you have any current logs I could look at? Overall, that log was ok, there was plenty of room for improvement.... but not bad. Also, if you do have any current logs and send them with your current GCT. file, that would be even better..