turbo function question, no output...

[llong66]

I have been working over the winter getting the turbo installed on my newly rebuilt 6.5l. I had been running it N/A as I ran out of time with the cold and funds last fall to complete the turbo install. This last week, i got it finished and one of the first things I did after checking for leaks etc was see how hard the turbo input was sucking air....its ALOT! When you increasse RPMs and let off you can hear the turbo, but I was getting nothing on my boost gauge, I tried another gauge, same results, nothing. After piddling around, I removed the upper intake so I could get a good feel at the turbo output....nothing, no air at all that would give me boost. I know enough must be getting through to run the motor and it runs good, not driven it, just working in the drive way. My question is, what could cause this and what should I do? The turbo is a '96 GM5, Borg Warner. From what I see of the rebuild kits there is nothing that would fix this, the air going in must be going someplace...
This is my first turbo, but I don't know of any adjustments, the intake fan is spinning so the exhaust fan must be. Its spinning fast enough I can hear it.
ANY ideas or suggestions would be very helpful.
Thanks for your time!

Greg

 

[Ilikemtb999]

Were you driving it when the boost gauge was hooked up? Where is it installed?

 

[llong66]

No, I have not driven it yet, I have to get the exhaust finished. The boost gauge is hooked up to one of the ports on top of the top portion of the intake where one of the computer sensors was originally. As I mentioned, I removed the uper intake to get a feel for what the turbo was pussting out and there is nothing to speak of. There is alot of air moving around there with the fan and all, but with as hard as the intake on the turbo is suckng, I would think there has to be enough I could feel it. I have played around with the "flapper" on the exhaust that controls boost and no change.

 

[Ilikemtb999]

Mine doesn't make boost at idle and I bet the suction you're feeling is the engine not the turbo. The engine needs a load on it to make boost.

I'm not sure what sensors you speak of but I'll assume it's just into the inlet.

 

[llong66]

That makes sense and before I do anything like replacing it or such Ill finish my exhaust and drive it, but Im pretty sure it needs a rebuild as I have oil in the intake on the output side so Im sure some seals are toast

 

[Westech]

If it is a GM5 it has a valve in the back of the exhaust casting. I bet it is stuck open.
Its called a wastegate. It is used to let excessive pressure out the exhaust and lower the intake pressure. Factory valves were set in the 10 PSI range.

 

[Ilikemtb999]

Turbo master is easy to make. Split the can, rethread the shaft a bit and tighten nut to desired boost level.
My gm4 turbo made 6psi before I modded the waste gate actuater

 

[llong66]

Hey guys! Thanks for the help and advise. I built a Turbo master ad while I haven't been able to get out and test it like I would like, should it not even push air out the outlet port on the turbo, while I had the top intake off, I could put my hand in front of the outlet, vary the RPMs and feel nothing.
Westech, I have been playing around with that valve if you mean the one attached to the are outside the turbo.
I am leaning towards seals with the oil on the outlet side.

 

[Westech]

seals will not cause a no boost condition. There is NO way a worn seal will let that much air past and not every drop of oil in the engine.

 

[llong66]

Hello evefyone, soryy it took a cpl days to get back but real life got it the way, I hate that!" Anyway the pickup for my boost gaure is one of the facory holes for a seanso right where it bends back to the main enum area, I quadurple checket it goes all the way through. Iikemt999, you mention that it wont show boost just idling in the driveway, that it needs a load. Would it not show some boost running the rpms way up or does it need an actual "load" If so Ill have to wait on the comming weekend for time and funds to get the exhaust done. Im looking at 3" pipe, no muffler, coming out just infront of the rear tire.
Thanks again all for your help and advise!!

 

[M37M35]

You do need to load the engine to build boost, just sitting still revving it won't do it. Finish your exhaust, take it for a drive, and let us know what it does.

Wiggle the blades on the intake side of the turbo. If it does not make contact with the housing, it probably doesn't need to be rebuilt. I wouldn't worry about a little bit of oil residue in the intake.

 

[Ilikemtb999]

Just revving it won't show any boost, if it was a gasser it would drop in vacuum. The vehicle needs to be in gear and revved to get a load to build boost.


I run an oil restricter on my oil feed line after it was leaking oil from the compressor. Stopped over oiling. I'm guessing it depends on different builds if it's needed or not.

 

[llong66]

iilikemth999, thanks much for the info on turbo and engine load. This is not only my first diesel, but my first turbo. The last cpl of years I have learned so much through the help and advice here at Steel Soldiers, its unreal!! It funny you mention gassers and vacuum as when I do rev it and and let off the go peddle, I notice a hairs width movement to the vacuum side. once payday gets here I am going to have it flatbeded up to the exhaust shop here in town that does, and enjoys doing custom work. When i told him what i was doing and going to want he said it sounded cool and would be no problem.
If you have time, can you tell me a little more about the oil restrictor you mention? The motor is a 6.5l turbo from a 1996 K3500. I am using it like I got it as far as lines, etc go. One of the things i checked when I bought this motor was the intake side of the turbo, its really looks almost new, no wobble or looseness at all. I thought maybe it had been recently replaced. It is a GM5 unit. I have never heard of an oil restrictor in a turbo, seems to counter everything I have heard, but like I said, I am still learning alot!!
I wil keep you updated as soon as I get the exhaust done, I have plenty to keep me busy until then, build my turbo master, tidy up an re-run some wiring with the exhaust running like i want.
Thanks again for your time!

Greg

 

[Ilikemtb999]

If you're using a 6.5 and the stock stuff then I wouldn't worry about it. I'm running a turbo on my 6.2 so I needed some aftermarket stuff to get an oil feed and I'm guessing my braided line is larger than the stock 6.5 line.




How are you running your downpipe? I have mine on the outside of the frame but it's not the greatest. Not much room around the shock mount and not much room for a muffler between the frame and rocker. I plan on redoing my downpipe to snake between the engine and frame so I can run a larger muffler (turbo sounds better than exhaust) and that'll allow me to go to ford shock towers too.

 

[llong66]

Ok, great, its all stock 6.5l turbo, came from the doner truck that way. I am having the exhaust run down and between the frame, the main reason for this is I plan on going with a 2nd fuel tank and want to use all factory original stuff for that, I had and 85 silvarado w dual tanks and I really like the original factory setup.
You mention Ford shock towers, I have seen brief mention on this on other boards but can't see the real reason behind it. I eventually want a 4" lift and have lots of research to do in that area. I know can get everything I need through ORD and no more off roading than I do, would be more than happy, but if there are some better, trick setups, I want to look into them. I am also trying to decide what to do tranny wise, I will more than likely go 700r4, but I would like to switch TCs so I have the option for going with a PTO down the road if I want. Twin sticking is something I want to do also. I think my ultimate setup would be going manual, but I don't see that in the cards. My M1008 is one of the only autos I have ever had and I gota admit it is nice! lol

Thanks again,
Greg

 

[Ilikemtb999]

The shock towers raise the shock mount up above the frame and allow you to run a longer shock for more droop.

 

[llong66]

Hello all, sorry I have not gotten back on this, things have been crazy and I have not had alot of time to work on finishing things up. One of the last things I have to do it finish building my turbo master. Where are those of you who built your own finding the springs? everything I can find here in town seems to heavy. I even tried aneeling one and it did not soften it enough. I have hit the auto parts places, they only have "pull springs" for throttle return etc and the hwd stores have a small selection of compression springs but the rate it so high, to stiff. I am also going to have to rebuild the turbo, now that I have run it more, it is letting to much oil by into the intake. So two more projects along with some general tidying up and Ill be good to go!

Thanks,
Greg

 

[Ilikemtb999]

I used the one in the waste gate controller I cut up. All I did was thread the shaft a few inches and then tighten it down with a lock nut. Good enough for 10psi

 

[llong66]

Hmmm, that must be one of the diff. between years and turbo model, 5 vs 6 vs 8, etc, mine did not have a spring in it, just a rubber diaframe. I do see, based on year of the motor and turbo version
that some of the controllers are mounted differently. Im sure I will find something if I keep looking, Ill also have to dig deeper into the recesses of my spare junk piles....thats kinda scary! lol

Thanks!

 

[Ilikemtb999]

I think mines a gm-4. Time to search McMaster carr