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After attending a few of the local race events, I realized that it is not easy watching a boost gauge AND the tree as the lights are coming down---and be consistent at it.
I wanted a way to launch consistent(with boost), but I am running Nittos so ~5psi is limit for a launch--give or take. Stock actuator only goes to 10-12 I understand, so that wasn't going to cut it.
Went to the local salvage yard, came up with an actuator from a '80 Monte with the 3.8L turbo. This actuator is roughly double the size diaphragm-wise as my stocker, and my "calibrated" hands told me the spring tension was about the same. In theory, this told me that it should take about half the pressure signal(5-6psi?) to the actuator to open it compared to the stock piece.
The Monte actuator mounting bracket is different than the '87 unit, so I made a crude bracket to mount it to my turbo. Hooked up a line tuner-style and gave it a try, and surprisingly limited my to 3-4psi!
Connected in the normal fashion to the SV, it would open too soon however(12-13psi). So, I plumbed the port located on the spring side of the Monte actuator to boost pressure to help keep it closed, and boost was back to normal(chip controlled in my case).
Lastly, I added in a second SV(mine happens to be from a 280Z, it's a 3 port unit) on the pressure line going to spring side of the actuator. Then, a wire tapped off of the brake light switch to a couple of relays, and I now have boost limited to around 3-4psi when stepping on the brake(even with accelerator to the floor!) and normal boost again when I let off of the brake. With initial testing, it seems to be very consistent (and fun!).
I have a crude drawing of the wiring and "plumbing" for my setup, but no way to post it. If someone is interested, maybe they can put it up for whoever to see.
Launch boost can be adjusted by actuator rod tension, and full boost optionally could still be controlled with an adjustable bleeder setup. The strategic placement of another adjustable bleed could limit how fast ful boost came on after releasing the brake.....

<small>[ June 25, 2003, 11:18 PM: Message edited by: Tonka ]</small>
 

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Was ther ever a monte carlo with a turbo motor :confused:
 
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