chevytruckguy

Is your line pressure raised?

03tahoe22

iTrader: (13)

Stock Line Pressure ....HD2 Shift kit, Aluminum Accumalator Pistons, Corvette Servo, Transgo seperator Plate, 2600 TB TC. Should the line pressure be raised on the 2-3 shift?

chevytruckguy

I have hptuners and I don't think the the shift pressure can be changed for just the 2-3 shift. EFIlive might be different. I have heard of some people having problems with slow shifts when zeroing the shift time table, but they had stock transmissions. I'm sure someone will be able to answer that question.

performabuilt

iTrader: (24)

Understand guys that hydraulics are not instant like the electronics you can make them a little faster with shift kits and increased line presure but still wont be instant.
When data logging with a stall also it will look much higher.
Its is however normal for the 2-3 to take longer to make as there are more chambers that must be filled with oil so it takes longer.
In terms of time it will be a constant each vehcle depending on shift kit and presure However the amount or RPM it takes will vary considerably from one car to another. For instance two identical transmissions, One truck makes 320 hp the other 520 hp it will take more rpm for the 520 to make the shift simply because its rpm will be rising at a faster pace.
so where the 320 hp might do it in 100-200 rpm the 520 hp might take 300 to 500 rpm , Add spray and it gets even more complicated.
Hope this helps but no matter what , where or who the trans came from there will always be some level of delay from comand to shift its hydraulically impossible for there not to be.
The range the OP is giving is reasonable considring power listed.

chevytruckguy

Do you know if putting a little TM for upshifts will speed up the shifts?

performabuilt

iTrader: (24)

It wont really speed up the shift as such as you are measuring in RPM and not time. The time will still be a constant. Using the torquemanagement will reduce torque output of the engine so it will in turn decrease the rise in RPM in that givern time so from and RPM related perspective yes. But your really reducing engine output to bring te comand RPM to actual shift RPM closer. Seems to me it would be better to just set the shift point without torque management to whatever RPM and spped you need to in order to get the shift where you want it
for instance if you want it to actually shift at 6600 rpm set it to shift at 6200 rpm .

GMCtrk

iTrader: (27)

are you guys zeroing out the shift times? I read a post here from a guy who talked to a Hydramatic engineer who said that zeroing out the shifts was not a good idea due to the fact that the trans would be in another gear while still engaged in the gear it was shifting out of.

03tahoe22

iTrader: (13)

My tuner zero'd out the shift tables..... Not sure if this is more like clutch failure? Not so much that I demand it to shift at 5600 and it shifts at 6000 but that the time it takes and I feel it to shift out of 2nd and into 3rd is long. Increased line pressure would fill up the chambers faster....correct? Just wondering because I have heard ppl say they can "chirp" 2nd to 3rd. I was running a 275/40/r17. Normal driving it pounds into 3rd but wot it is slugish....

charcold-bowtie

iTrader: (10)

I can chirp my 2-3 and I hate it. Its extremely hard on everything. A stock tranny will shift sloppy as far as commanded goes. Just move the shift rpm to compensate for it. So you may have 5200 rpm shift commanded in your tune to get it to shift at 6K consitantly.

chevytruckguy

I've heard that too, called gear crossing or something like that. I'm not sure if it applies to built or transmissions with shift kits. I just have the vette servo and it shifts pretty good, I'm sure I'd be better off with a built tranny though.