Nissan 370Z Forum - View Single Post - Noob here with some questions. (Wastegate, Blow off)

Nixlimited · 10-12-2012, 06:19 PM

Quote:

Originally Posted by Mitco39

I know this is an old thread, but I figured it beats opening a new one.

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Maybe I am thinking about this wrong. A boost controller basically works to control the air pressure in the line going to the wastegate. By venting some (or for this example all) you can bypass the wastegate all together and run whatever boost you wish correct?

So if lets say you ran the lowest spring you could find is 5PSI, you cannot control your boost till you hit 5PSI, but then you have complete control over your boost (based on rpm and tp% with the EVC6 with its 3D mapping).

So why not run a 3PSI spring? This would allow complete control over and above 3PSI. I am sure there must be a tradeoff, would the valve open under higher manifold pressures due to the softer spring? If so do companies list a maximum manifold pressure for their springs?

If this was possible then you could (if you wanted) have the boost come on just like it would a supercharger and not so much like an off on switch. This would be beneficial to keep the tires from spinning and the power to the ground.

Unless I am thinking about it wrong?

There are a couple of reasons. First of all, practically speaking, you are going to want to make low-end boost under almost all circumstances since boosted cars can be under powered NA (ever watch Top Gear when they run the Evo in 6th gear?). Thus, a spring is there to help with that. Second, you would likely wear the boost control solenoid out significantly quicker if you did not have a spring because it would have to work harder. Third, my guess is that the spring actually helps to smooth out the action of the boost control solenoid, which is essentially just a bunch of pulses timed to achieve a target (i.e. a duty factor).