how much rpm drop at shift?

[rtviper]

What are you seeing in rpm drop at shift from the guys data logging your runs? What mph gain do you see from the 1/8 to the 1/4? I am trying to determine if my stall is too high or convertor is slipping. I have a 4500 stall and see 500 rpm drop from 1st to 2nd shift at 6500. Only a 300 rpm drop from 2nd to 3rd at 6400 rpm. THe remaining 6sec of the run the rpm climb from 6100 to 6300rpm on a 10.2 run at 129 mph. I made 5 runs with boost from 18lbs to 21lbs and et went from 10.7 to 10.2 but mph only went from 127 to 129?

 

[John Wilde]

Sounds like you are slipping to me.
We had the problem with a small converter behind the v8 car.
The car would almost sound like it was not shifting.

 

[wickedtt]

What are you seeing in rpm drop at shift from the guys data logging your runs? What mph gain do you see from the 1/8 to the 1/4? I am trying to determine if my stall is too high or convertor is slipping. I have a 4500 stall and see 500 rpm drop from 1st to 2nd shift at 6500. Only a 300 rpm drop from 2nd to 3rd at 6400 rpm. THe remaining 6sec of the run the rpm climb from 6100 to 6300rpm on a 10.2 run at 129 mph. I made 5 runs with boost from 18lbs to 21lbs and et went from 10.7 to 10.2 but mph only went from 127 to 129?

who's converter ?stall speed and size?

 

[rtviper]

Thanks guys. The converor is an ATI 4500 stall and its a 9 inch. After the 2-3 shift in my t-400 I end up trying to shift it a few more times to make sure it has shifted. The car doesnt really pull that hard either from half track on. My 1/8 mph go up 6 mph in the boost change that takes me from 10.7 to 10.2 but the 1/4 mph goes up only 2 mph. On my datalog the boost at 4500, the launch rpm, is only at 5 lbs on the brake but by 5k its at the 20 lbs I set it at

 

[Dusty Bradford]

Sounds like it's really slipping in high gear. My car made less power than yours but the few times I trapped near 129 in the 1/4 my rpm wasn't over 6000. I usually trapped in the 127 range but only ran 10.50's and .60's so that tells me you are really loosing something on the high side.

 

[BobbyBuick]

I shift mine lower at about 5800-6000 and drop about 500.Lonnie told me the convertor will remain fairly stable on the shift for instance if you go to 5300 on the shift and shift at 5800 you will drop 500 rpm but if you shift at 6300 it will prolly go to 5300-5400 and give you close to 1000 on the shift .in other words the convertor and the drop will remain faily consistant.I noticed it to be true for mine as i raised the shift point it increased the amount of drop.My big thing is the really fast guys like Roys car man it rocks down and loads his turbo on the shift .Id love to get my car to do that

 

[chris718]

it sounds like you are overpowering the converter.try a lower stall or a more efficient one