Ford Powerstroke Diesel Forum banner

Waste gate and blow off valve not working together

14K views 27 replies 6 participants last post by  Poweystroke96 
#1 ·
Hey guys, i am in need of some help, I am looking at buying a 2008 f350 that has had some work done. I took it for a ride today and from what I could tell the waste gate and blow off valve are not working right or in tune. if you are in between easy and full throttle you can hear one of the two letting off pressure but if your into it neither activates till letting off. If i get into it like half throttle it would buck like it would get into the power then dump so lose power right on a shift and you get the idea. But if i was easy on it or laid into it, the thing felt great through and through, power and shifting wise. So I am unsure of how to tackle this problem if I buy the truck. I figured the blow off valve was overkill so I would shut it down and try and tune the waste gate in and see how it does there. Any input or thoughts on this would be much appreciate.

List of mods include:
egr delete with wastegate setup and manual pressure regulator
bd turbo guard blow off valve on intake side of intercooler
arp's
spartan dashdaq running 310 tune i think it is
4in dp to 5 in exhaust
cfm elbow
cai
 
See less See more
#3 ·
If the wastegate is dumping to the exhaust, you shouldn't hear it. If the wastegate is tuned properly, it shouldn't open until a certain back pressure psi and it should dump all excessive back pressure off. The blow off valve is the only thing you'll hear. It should make a noise when you chop the throttle. It's blow off excessive compressor surge to keep your turbo's alive.
 
#4 ·
The wastegate is dumping to its own down pipe, i understand the basics of each device just that its hard to tell which is going off when, it sounds more like the blow off valve is set too low then as it activates at medium throttle but not all throttle. I am not even sure the waste gate was activating. Does this problem with the way its acting sound like a matter of tuning between the two?
 
#5 ·
The BOV sounds like it's wrong completely. It should only activate once you let off the throttle and you have excess boost not being used. Do you know which brand is on it?
You can only tell if the WG is working if you can see it. You say you don't know when it's working but then think it's not at all. You won't hear it.
How is the WG dumping into it's own DP? The truck has two?
 
#8 ·
There is a pipe going off the wastegate that goes down the back side of the motor, its like a one inch piece of steel pipe.

Its hard to describe as I don't know which one is activating. The blow off valve seems overkill to me too unless your running 1000hp and really do need the extra release of boost from the system. its a tial blow off valve.

The waste gate is aftermarket, it appears that it is from one of those kits that people like EDE sell with their egr delete as many say that blocking the egr requires a wastegate to prevent too much backpressure(i believe, please correct me if im wrong)
 
#9 ·
Yes, it has an aftermarket external wastegate. Most wastegate kits will dump back into the downpipe somewhere. They don't typically dump to atmosphere. 6.4's don't have a wastegate setup from the factory. The EGR valve kinda acts like a wastegate on a stock truck.

You're having issues with the blow off valve it sounds like and I would eliminate it or set it differently so that it isn't as sensitive.
 
#10 ·
The EGR valve kinda acts like a wastegate on a stock truck.
This is what I was referring too, thats what I was thinking, either take it out completely or try shutting it off and testing the wastegate through and through to make that it is working properly, i was kinda surprised to see the wastegate have its own downpipe
 
#11 ·
So the truck still has the EGR valve? Even if it does, the valve is completely shut off with our 310 tune. It should not be active. I assume that all of the EGR stuff is deleted if the truck has a wastegate.
 
#13 ·
No when i was referring to what i was talking about how the egr acts as a wadtegate but after removing a wastegate is often sought to fill the void. The egr stuff is 100% gone

Sent from my DROID BIONIC using AutoGuide.Com Free App
 
#12 ·
with a stock turbo and auto trans the bov might actually be causing the bucking. i dont think you need one with stockers or even 71s. it seems like it suited for "very large" turbos and or high boost.

also on a stock turbos you can keep the gate shut. you can try to start tuning the truck with it closed and go from there.

seems like the truck is set up for bigger turbos.
 
#14 ·
I would have to agree with you, i think ill start by disabling the blow off valve and turning the wastegate way down and go from there

Sent from my DROID BIONIC using AutoGuide.Com Free App
 
#15 · (Edited)
Depending on brand of bov you can adjust it pretty easy. There should be a nut and threaded stud with a straight slot or allen head cut into it. Loosen the nut and turn the stud down to increase the pressure on the valve.And check to see where they have the activation hose running(the vacuum hose connected to the valve)it should hook up somewhere after the "throttle body" towards the manifold where it will see vacuum on closed throttle. BOV can greatly increase turbo life if they are used and adjusted correctly and I like the sound. I would definitely look closely at the BOV alot of people don't know how to properly install or adjust them.It should only activate when there is a vacuum on the hose (closed throttle).Check to see if it is leaking pressure out of the vent while someone builds a little boost if it leaks before the throttle is released then it needs to be adjusted tighter.As for the wastegate, alot of people dump them into the atmosphere rather than routing them back into the exhaust.They work very simple, at a certain boost level they start to release exhaust pressure thus slowing the exhaust side wheel, to limit boost pressure. Hope this helps.

Oh and you should only hear the wastegate on acceleration and the BOV when you let off!!
 
#16 ·
This would be very helpful sir if only we were talking about a gas engine. There is no throttle plate. And it doesn't make vacuum when you let off the skinny pedal. The bov kits for these trucks are electronically controlled for this reason

Sent from my DROIDX using AutoGuide.Com Free App
 
#23 ·
id like to know as well. air enters the intake at the atmo turbo. it shoots it over to the vgt turbo that pushes it and cools in the intercooler then channeled into the intake manifold. i guess if you have the stock egr it can resemble throttle plate. am i missing something?
 
#27 ·
What's the purpose of this "throttle body" you speak of lol

Sent from my broken a** Droid X
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top