Hey guys, just installed a Bully Dog blow off valve on my lbz. Problem is that I'm running a straight 4 inch pipe no cat no muffler with a Bully Dog intake manifold and my exhaust is LOUD! Has any one installed this BOV on an LBZ. I'm having trouble setting the three switches to the proper setting and I cant tell if the valve is opening when I let off the accelerator because the truck is so loud. Any input would be much appreciated.

Seems like with an LBZ and the variable vanes on the turbo, that it may be hard to get a good puff of air to come out... I think the vanes open to help release pressure when you let off the throttle.

I may be wrong, but just my opinion.

Would love to hear it if and when you do get it working.

The valve has no reason to open if your truck is an automatic due to the lack of a throttle plate and the pressure can just continue through the engine since it's not revving down immediately.

why why why would you put a BOV on a VVT turboed engine? just doesn't make much sense.

the only reason you would need that set up is on a big azz twins set up for sled pullin

you guys realy dont think a bov is necessary? my turbo surges allot, almost every time i do a burnout and whenever i let off the gas too fast from high boost, and i have an automatic and a stock turbo. I don't see how the vanes opening up would decrease the amount of boost going to the engine, there will still be too much for the engine to take if it drops rpm enough and the boost will have no where to go but a bov or back the way it came.

My truck has had it's share of compresser surge.

you guys realy dont think a bov is necessary? my turbo surges allot, almost every time i do a burnout and whenever i let off the gas too fast from high boost, and i have an automatic and a stock turbo. I don't see how the vanes opening up would decrease the amount of boost going to the engine, there will still be too much for the engine to take if it drops rpm enough and the boost will have no where to go but a bov or back the way it came.


You have an '01 without the variable vane turbo... the BOV would help your turbo bark

yea, but i don't see what the huge difference is with the vg turbo vs a convetional one, they are both still pushing too much air if rpm drops enough. am i missing something?

yea, but i don't see what the huge difference is with the vg turbo vs a convetional one, they are both still pushing too much air if rpm drops enough. am i missing something?

The VVT is designed to alleviate the pressure when letting off the throttle. I BOV just not necessary with a VVT, it does not hurt but it just isnt worth it. Most of sled pullers don't even use blow off valves??? Waste of time and money.... Plus it is tied into your ECM which I don't like.

yea, but i don't see what the huge difference is with the vg turbo vs a convetional one, they are both still pushing too much air if rpm drops enough. am i missing something?

The purpose of a BOV is to release pressure from the turbo to prevent it from hammering it's way back to the turbo and possibly causing impeller damage. On a diesel, a BOV is only necessary on trucks that are under high boost situations and a sudden release of the throttle occurs and the truck immediately comes to a stop causing the engine rpm to suddenly return to idle e.g. sled pulling or doing a burnout and just suddenly lifting the throttle without rolling out of it. Blow-off valves are common on forced induction gasoline engines because of the throttle plate, which, once the throttle is lifted it immediately closes allowing the boost nowhere to go. A diesel engine does not have a throttle plate so there is nothing to prevent the boost from continuing through the engine even if it does rev down quickly.

yea... i understand the purpose on a gasser diesels dont have a throttle body, what ever. on high performance applications it can be useful on a diesel as well, even though not totally necessary. yea, it can still pass through the engine, but if it down revs fast enough (example:catch traction on a burnout), no it cant. trust me my turbo has been surged many times. also, can someone explain what difference a vg turbo will do to not need a bov the same as a conventional turbo? they both make boost...

i highly doubt a VVT will spool down any faster than any other turbo. i think installing the BOV is a good idea $.02

The VVT is designed to alleviate the pressure when letting off the throttle. I BOV just not necessary with a VVT, it does not hurt but it just isnt worth it. Most of sled pullers don't even use blow off valves??? Waste of time and money.... Plus it is tied into your ECM which I don't like.

VGT is the replacement for a waste gate, traditionally a waste gate would control boost by allowing exhaust gas to bypass the turbine. In a VGT setup you are essentially controlling the A/R of the turbo.

VGT or a wastegate have zero to do with air on the compressor side.

A VVT turbo is different in the fact that a VVT turbo blades(vanes) actually move. When the ECU notes the loss of throttle then it opens the vanes and allows the turbo to release the back pressure. This movement also allows the turbo to spool faster from an idle state. When the ECU notes throttle input the it closes the vanes and allows the turbo to build boost.

So as you can see the VVT has nothing to do with the spool down time. The vanes adjust the let the pressure excape. The turbo is still spinning the same speed.

So a BOV on a stock (VVT) turbo just a waste of money to me. If you want the big "phisss" sound then buy and gasser or go NOPI.....;)

A VVT turbo is different in the fact that a VVT turbo blades(vanes) actually move. When the ECU notes the loss of throttle then it opens the vanes and allows the turbo to release the back pressure. This movement also allows the turbo to spool faster from an idle state. When the ECU notes throttle input the it closes the vanes and allows the turbo to build boost.

So as you can see the VVT has nothing to do with the spool down time. The vanes adjust the let the pressure excape. The turbo is still spinning the same speed.

So a BOV on a stock (VVT) turbo just a waste of money to me. If you want the big "phisss" sound then buy and gasser or go NOPI.....;)

Yes, it opens up the turbine side. Has zero to do with air on the compressor side, surge happens on the compressor side. If you pull you probably do want a BOV.

My bad. Long night at work, have my left and right brain backwards.

Still think it is a waste of cash for a stock street truck.

its not really worth the money since they cost so much, but i wouldn't consider it a total waist of money. if they were more like $200-250 then i would buy one.

yeah it wasn't cheap that's for sure. I need to find out whats going on with this thing. I'm loosing a lot of boost and even when your in park and rev the motor you hear the power just fall off. Going to play with the settings today and if that doesn't work I'm ripping it out.

yeah it wasn't cheap that's for sure. I need to find out whats going on with this thing. I'm loosing a lot of boost and even when your in park and rev the motor you hear the power just fall off. Going to play with the settings today and if that doesn't work I'm ripping it out.

I would pull the BOV off, what power levels are you at? These turbos very very rarely fail at 500hp and below. Just get rid of it

Well I didn't even want to continue reading through all the mis-information in this post but I think many of you have the wrong idea for what the vanes in the VVT and the BOV do. The vanes in a VVT open to reduce the amount of exhaust pressure that is placed on the turbine of the turbo, so that it won't be driven as hard and will produce less boost. VVTs can have even worse turbo bark than conventional because when you chop back the throttle the vanes open and the turbo doesn't have the drive pressure to keep it spinning while at the same time your engine is demanding much less air. The pressurized air in the intercooler and tubes has no where to go and the turbo isn't being spun as hard so the air coughs through the turbo backwards. Adding a blow off valve like the BD Turbo Guard is a good idea for guys pushing lots of boost through the stock or modded VVT (my cheetah is putting out 50psi) becuase it has provisions to use the Throttle Position Sensor to allow Blow Off and can be cancelled with a switch for times when you aren't going to let out of the throttle hard like drag racing. I am ording one now actually.