I have posted before about the problem i am having, (I think it is a problem), i have a Holset Hx super 40 on my truck and the max boost i have ever seen was 30psi. That was only for a split second, it then dropped down to about 27psi or so. When i purchased the turbo, i was told that it was wastegated at 40psi. I figured i would be able to peg my 35psi gauge easily, but i have not been able to do that. With the comp box completely off, i can still get 30psi. When the box is on 5x5 i still only get 30psi for a split second, that to me does not seem right. The turbo has a 16cm exhaust housing. I have checked all my intercooler boots and they are tight. With my setup, am i throwing enough fuel at it to have it spool up to 40psi? Could i have a boost leak? How do i test for a boost leak? Could i have a bad boost gauge? It is frustrating, i almost feel like i should put the Hy35 back on. Thanks for the help in advance

 

it kinda sounds like the wastegate is opening at 30psi rather than 40, how does it spool, if it is slow then it could be a leak , but if it spools fine then I wouldn't think there is much of a leak. how are EGTs

 

It spools well, it will spool to anywhere between 25psi and 30psi really quick, but i will not spool past that, Egt are ok, i think they could be cooler then what they are, they will go to 1200 with out a problem and it will keep climbing, but i usally let off at around 1200 so they do not go to high. Should i try putting in the boost elbow that came with my comp? Thanks for your time

 

Just went through a similar problem.

http://www.turbodieselregister.com/f...d.php?t=138148

 

Is there a way to adjust the wastegate on the Holset super 40 turbo? Thanks

 

you could try the boost elbow and see if boost gets higher if it does then the wastegate was opening early and not producing enough boost to keep EGTs down

 

I tried that this afternoon, but the boost elbow that i have was to big, I can start to thread it into the face of the turbo, but i am unable to turn it all the way around to tighten it up because it keeps hitting the side of the wastegate head, any other suggestions, thanks, I am trying to save myself a trip to Mass to have the guy that i bought it from and install take a look at it.

 

Block it completly and see if boost is any higher ,but don't leave it un wastgated if the boost does climb higher than it used to it could cause turbo failure, all if this it to just see if the wastegate is actually opening at 30psi, I would certainly think stage 5 injectors and a comp could push a super 40 past 30 psi easly ,if you can't find any thing the plug the compressor housing port with pull the hose off the wastegate and put a pencil in it it should fit tight then tighten up the clamp and try that

 

Are you saying take the rubber hose off of the wastegate and stick a pencil down inside of the hose and then re attach the hose back to the wastegate? I dont know that i would be able to do that, the piece of rubber hose is not very long, but i could always try. What could i use to block where the boost elbow screws into the face of the turbo? What would happen if i just took the hose completely off and tried that? Sorry for the questions, just trying to figure something out, i might as well have stayed with the little ole Hy35, the turbo i got now only keeps things about 100 degrees or so cooler if that, Thanks again

 

Leave the hose on the compressor housing but take it off the wastegate and block it with a pencil if you don't block it all of your boost will bleed right out of the hose that will block the wastegate allowing the turbo to build as much boost as it can

 

Ok i understand know, take the rubber hose off the wastegate, stick a pencil in the end of it, then tighten the clamp around the end of the pencil, leaving it unconnectd to the wastegate. That makes sense. I will try that when i get a chance, hopefully within the next day or so. So when i try this, say my boost numbers go up past 30psi, what would be my next step in order to adjust the wastegate? One more quick question, the boost elbows that come with the comp, are they different then the stock one in that they have a smaller hole to bleed the pressure to the wastegate? Like i mentioned earlier, i was told that it was already set at 40psi Thanks for your help, i appreciate it

 

Yes, that's how the boost elbows are set up.

I don't know what the ones from Edge are set to, but I'd bet it's around 35,
as anything past that is overspeeding the stock 24 valve turbo.


phox

 

Yeah the boost elbow with the smallest hole will open the wastegate at higher pressure, your elbow won't screw into the compressor housing? is the wastegate head bolted to the compressor housing or is it bolted to the turbine housing, you may have to take the wastegate head off if it is attached to the compressor housing to get the elbow on, I think that would be your best bet, to take the wastegate head off you will have to take the 2 bolts it is attached with off and apply air to the wastegate hose to push to wastegate rod out so the head will pull out to get the elbow on. Let me know how it goes

 

Ok, i will try that, i wish i had more time and was not working so much, But i would like to try the boost elbow method as well, thanks for the help