I have a Tial BOV on my "other car". I think it works off a pressure differential. When there is more pressure in the comp. pipe than the manifold the valve opens. But that is on a motor with a throttle plate.

I am still trying to figure out how it would help a diesel and how you would control the BOV.

Dean

 

Im not sure how they hook up to the throttle, but BD has done it. Says its also adjustable. http://www.bd-power.com/ram/product....boGuard&tt=ram

 

BD has a pretty advanced TPS controller that recognizes you letting off the throttle quickly... you can adjust the rate of throttle change and the point of throttle that'll open it.

I was talking w/ Wes yesterday about this actually... he helped BD develop the TPS setup because when they had it on a microswitch that would release it when you were completely out of the throttle, it wasn't opening quick enough for all the boost he was making w/ his twins.

I've thought about setting one up w/ a microswitch on the clutch pedal wired in series w/ a hobbs switch

Forrest

 

In my opinion an external wastegate is almost a necessity with compound turbos. The external gate allows for increased flow/efficiency, and is much more tuneable, over an internal gate. With an internal gate, there is very little to tune. Sure, by adjusting the linkage opening pressure can be changed, but your stuck with the same spring rate, opening distance and volumes. Some sort of device can be made to regulate opening distance, but most internal gates are small enough that they must fully open to be effective. In most cases even when full open there is not enough flow. I know that some with internal gates have installed pressure relief valves in the CAC plumbing to bleed off excess boost. This reduces the air charge going into the engine, which will help, but not enough to keep drive pressure at an optimal level. With an external gate, by-pass flow potential is far greater. This will supply the large turbo with the exhaust gas needed to spool and make boost, while keeping drive pressure in line. The external gate has the capability to accept different springs, that have various opening pressure/rates. Spring pre-load can also be set for each spring. Opening distance can be set for appropriate maximum flow (assuming that the size of gate used has the capability to flow more than is necessary for current fueling). With a dual port gate, an in-cab controller can be added that works very well for tuning opening pressure. There are so many variables that can make an ok feeling/operating set of compounds, feel much faster and be more efficient. I have been monitoring intake manifold pressure, the boost pressure of the big turbo, and drive pressure since I built/installed my turbos. It's amazing how much of a difference some tuning can make. I don’t see how an set of turbos can just be thrown on without monitoring pressers, and properly tuning to make them work the best they can. As an example: I have seen a set of compounds make 70psi of boost, and 98psi of drive pressure. This is with an internal gate and two pressure relief valves. Not too efficient when considering that something closer to a 1:1 ratio of boost to drive is desirable. Seeing boost to drive ratios like that is what led me to experiment with an external gate. Right now I see 62psi boost, and 60psi drive. At first I thought that something was wrong with one of my gauges, so I swapped them. Nope, the gauges work fine. Having a good boost to drive ratio also helps EGT's. I've seen up to 225* difference in EGT's with different wastegate settings.

I've got the BD turbo guard (BOV). I wouldn't say that it's a "must have," but it could keep from scrapping two turbos. If the go pedal isn’t released too quickly the BOV isn't needed. Most people can keep from barking a turbo on a diesel, but if someone pulls out in front of you when your making 60+ pounds of boost, the BOV is a good thing to have.

Mike

 

Old smokey, may i ask what that bov sounds like when letting off 60psi???

 

It's actually quite loud. I've gotten a few confused looks from other drivers, and some pedestrians.

Mike

 

Ricer- Hey buddy! You just blew out a tire!!!!!!!!!
You- Nah, just the blow off valve>