I am trying to find information on lowering the sequential turbo transition point. With my mods, I feel I have low power until 4.5K and then all hell breaks loose. I searched but have not had much luck. I understand you adjust the precontrol rod, but not sure wich way. I also wanted to know if you change the transition point, does it also change the bottom range of returning to the first turbo ( I believe in stock form, once the secondary comes online it stays on until 3k rpm). Does anyone have experience with this?

 

???? Do you have a boost gauge? if not, install one. If so what is the first turbo putting out?
I think you are trying to say the secondary stays on til redline, no?
If you really want to screw around with the prespool, install a manual valve to replace the restrictor pills in the prespool control line and allow for more prespool, this will allow the secondary to come on-line a little earlier, but you'll sacrafice some of the primary boost. (you can alway install a boost controller and crank the boos up to conpensate).
After all that I'll state for the record, it's really not a good idea to mess with the prespool, one wrong move can terminate you car.

 

I have a boost controller and my boost pattern is perfect. It just feels like I dont get the real power till #2 comes on, so why not make it come on sooner. What could messing with the pre-spool mess up?

And I ment to say I believe in stock form, once the secondary comes online it stays on until the RPMs drop BELOW 3k rpm. Will changing the transition point change that? In other words, if you can get #2 to come online at 4k, will it not shut off until the RPMs drop below 2.5k?

Please excuse my ignorance of the sequential turbo system. I'm still learning.

I should also note that with my large port and mods, the turbo is the weak link in the airflow, so I am just trying to open it up earlier.

 

I forgot to read you sig, the power pattern you are feeling is mainly due to your port job.
Manual prespool if not done correctly will cause boost spikes and that can kill you engine without warning.
This site has a pretty good how to and cautions:
www.rx7turboturbo.com/robrobinette/