Dump/Blow off Valve

[Umar]

Dare i ask, has anyone managed to fit a dump valve on the Kz engine?. I've recently done the cam cover gasket on my truck and noticed that the intake has a butterfly whereas most diesels don't have this it did make me wonder when your foot is off the throttle and the butterfly closed will all that boost be going back to the turbo as does in a petrol car?

 

[Shayne]

Most of us that like to tamper have removed the butterfly .

 

[Umar]

Any noticeable benefits Shayne?

 

[Shayne]

Can't remember to be honest but i threw the plate away when i could have put it back so i must have been happy with the result . All it does is smooths shutdown (and helps with engine breaking maybe ?) there's no need for it so why have it restricting the intake . The smaller butterfly relates to the egr i will probably remove that as well next time i'm i there as my egr is blanked .

 

[Beau]

Some people have put Blow off valves on these KZ engines. However I wouldn't say you'd benefit much unless you're running very high boost (20+psi).

With regards to the butterfly, the two reasons it's there is to smooth shut down and stop a run away scenario. I can say the run away scenario has occurred to me and whilst the butterfly valve was closed so obviously it doesn't work too well on that. Thankfully I managed to block the intake off within a few seconds to shut it down... However, it does make we wonder how much more it would have revved it the butterfly was actually open.... (It was over 4K in revs and I heard some metal fly out the exhaust). This was due to turning up the spill control valve too much in my experimental days .

I just removed my butterfly valve and wish I did it sooner. I can feel the turbo spooling up so much earlier and throttle response and low down torque seems to have improved with standard fueling.

If you're going to remove it, grind off the tab on the back of the screw and you'll actually be able to unscrew it. I managed that on one side, but damaged the head on the other screw so had to drill it out. It is possible...

 

[Shayne]

I managed to get one screw out with a precision screwdriver and a pair of pliers , used a screw extractor on the other no grinding at all . Still trying to think of its real purpose I will guess that sudden surge of power i used to get when everything was standard resulted from that butterfly opening , so maybe mrT wanted a very definite boost on/off signal to be sent to the fuel pump ?

It's a piece of junk anyway so ditch it and to avoid Beau's brown trouser moment put everything back together before you fire the engine up .

I placed a magnet in the intake in case i dropped a screw you don't anything falling in there !

 

[Sag]

Has anyone got a pic of this butterfly could be put on me and my sons list to do

 

[Beau]

 

[Sag]

So it's the little flap what you all remove beau and thanks for photo buddy

 

[Beau]

So it's the little flap what you all remove beau and thanks for photo buddy

No, it's the big flap on the right that everyone removes. The small flap is controlled via a solenoid to open and close on startup and shutdown, smoothing down engine shut down, and opening up on startup for air to the engine.

 

[Sag]

Thanks beau I thought that was the bit what give you more revs like on a petrol carb.