Just put 8# pulley on 2002 hd The truck runs great to about 4500rpm then it shuts the boost off completely. What bypass did we forget?????
Thanks

 

need a little more information... did you chip it? other mods? Does it only do it at full throttle or does it do it at 3/4 as well?

what happens when it "dumps"? do you lose all boost or just a momentary hesitation?

You might try posting this over in the L forum to see if any of the tuners have any ideas.

 

Loses all boost. Yes I chipped it, I am a distributor. Have tried 2 different programs and stock, all do the same thing. Only dumps boost a wot.

 

You might be running out of air. If you have the stock air box, get a K&N and cut holes in the bottom of the box. My buddy had this problem with his truck until we did the above.

 

I just reread your post. Did you unplug the boost bypass and it still dumps?

Ken

 

Boost dump. Unplug the bypass.

 

Unplugged boost bypass already - no difference
this same pulley made 16 lbs. of boost on my lightning with the stock air box and filter. The truck makes 14
lbs. of boost and runs great to about 4500 rpm then it looses all of the boost instantly. I can understand if it had a restriction it would loose boost but not all of a sudden like this
4500 rpm=14 psi
4600 rpm=5" vac
Thanks for the help and keep the ideas coming

 

If you are unplugged and you are dumping boost, something isn't quite right... I would say do a search on the boost actuator mod and play with it a little. Maybe your boost actuator is a little off from the factory? Since you are unplugged, it has to be somehow related to pressure on the bypass valve causing it to "pop" open or something...

good luck and let us know if you figure it out.