PhoenixRPR
20+ Year Contributor
- 450
- 0
- Oct 9, 2002
-
San Diego,
California
I have a 1992 Eclipse GSX. I recently installed an Autometer Cobalt Boost/Vacuum gauge. It works really well. Stock, I was seeing a steady 9.5 psi during each pull. I then installed a Joe P. MBC, replacing the stock BCS system. After reading the online debates as to where to tap in for the boost source, I decided to "T" into the line between the intake manifold and blow-off valve. This means that I capped off the nipple on the turbo elbow, rather than running a line from the MBC to it (like some people do). Of course, the other end of my MBC is running to the wastegate actuator nipple. And yes, I do have the wastegate line hooked up to the MBC nipple that is perpendicular to the knob. Ok, so I believe I've hooked the MBC up correctly. Now for the strangeness...
When I have the knob turned all the way up/out/counter-clockwise, I am getting 10psi steadily on 3rd gear pulls. Once I turn the knob down/in/clockwise 1 turn, the boost shoots up to 14-15psi and then quickly drops back down to 10psi and holds there. As I continue to turn the knob, the peak boost I reach gets higher but then quickly drops back to 10psi and holds there till the end of the pull. The weirdest part of it all is that on some pulls it never goes beyond 10psi, but then on other pulls with the same MBC setting, it peaks higher than 10 and then drops back to 10.
I've even noticed that if it only goes to 10 during a pull and I let off the gas, but stay in the same gear, and then hit the gas again it will shoot way past 10 and then drop back to 10 again. Why does pumping the gas during a pull cause it to go past 10? Why is the boost not holding at its highest point, but able to fall back to 10 and hold there without a problem?
When I have the knob turned all the way up/out/counter-clockwise, I am getting 10psi steadily on 3rd gear pulls. Once I turn the knob down/in/clockwise 1 turn, the boost shoots up to 14-15psi and then quickly drops back down to 10psi and holds there. As I continue to turn the knob, the peak boost I reach gets higher but then quickly drops back to 10psi and holds there till the end of the pull. The weirdest part of it all is that on some pulls it never goes beyond 10psi, but then on other pulls with the same MBC setting, it peaks higher than 10 and then drops back to 10.
I've even noticed that if it only goes to 10 during a pull and I let off the gas, but stay in the same gear, and then hit the gas again it will shoot way past 10 and then drop back to 10 again. Why does pumping the gas during a pull cause it to go past 10? Why is the boost not holding at its highest point, but able to fall back to 10 and hold there without a problem?
