I know how a boost controller works, but it seems like they can only increase pressure and not decrease it. Im curious if there is a way (with a particular controller, though I doubt that) to limit boost below the normal level already supplied by the turbo.

Thanks

 

So, how low do you wanna go? There may be a way to accomplish what you are suggesting, but I just can't figure out how you'd go about doing it off hand. Is this a trick question?

 

the lowest boost you can reliably run isto run on the wastegate spring pressure. this is ~11psi. this is the same as removing the hose from the wastegate nipple. If you're asking this question you obviously don't know how a boost conroller works.

 

I know exactly how it works, and I am still asking this question, perhaps you didnt understand what I meant.

The higher pressure (from manifold/boost) to the wastegate opens the dump. A boost gauge removes some of the pressure to keep the gate from dumping. Should I want to lower boost, I would only need to supply pressure to the wastegate. a 1 way check valve and a pressure source would be all I need. I want to know if any controllers can do this, or if I need to find another source of pressure and where.

In other words, where could I tap off a pressure signal thats not hot bleed air from the engine, and is higher than 35 PSI (I believe that should keep it shut if it is possible).

Thanks

 

Sorry, my only concern is that the valve in the wastegate would not be able to open to dump to limit the boost as low as I require.

 

there are no boost controllers which do that. The only way that I know of to do that is to physically take your stock wastegate apart and change the spring to one rated at a lower psi. But that is a pain in the a$$ to put back together.

Why exactly do you want to run lower boost if you don't mind me asking? If it is for gas mileage your foot is perfectly capable of controlling the boost.

 

Driven off boost, it's like a normal 4-cylinder (in terms of gas mileage).

 

I agree with the statement above. Running a max of 11 psi is plenty (s)low. Maybe we don't understand your original question, but a little self control on the gas pedal should be the best bet to lower your effective boost.