Boost gauge for vanagon

[zuhandenheit]

I'll probably have a lot of little questions like this one over the next few weeks as I sort out issues on this recently running conversion. Because my EGTs get pretty high -- I've got a buzzer set at 1320 and don't exceed 1300s for short bursts, but this happens at fairly low throttle, and by 65 mph on flat ground I'm around 1200 -- and because I disassembled the K03 to replace seals and am not sure that I restored the nuts on the wastegate arm to the right position, I'd like to see what the turbo is doing, exactly.

Here's the question: Will a mechanical boost gauge be accurate with the very long run of tubing that would be necessary to use it? Do I need to use a more expensive electronic gauge?

[libbydiesel]

The mechanical boost gauge will work fine.  The long run will not affect it.

[zuhandenheit]

Great, thanks. That saves me some money.

[zuhandenheit]

I've got the gauge working. It's only reading ~ 6-7 psi max. I adjusted the wastegate linkage and it didn't change.

The turbo had excessive play and I rebuilt it myself when I was first putting the motor together. It feels fine now and the wheels look okay. What should I check? Leaking wastegate maybe?

[libbydiesel]

Is that when the pedal is floored?  If so, then you either have a leak (wastegate, intake, exhaust) and issue with the turbo wheels (imbalance, worn) or insufficient/poorly timed fuel. 

[zuhandenheit]

Hey Libby, thanks for the response. Yes, that's floored. And it was even really slow to get to 5-7 psi!

I worked on it today. First I built a boost leak tester and found a leak between the intake manifold and flange. I fixed it (made a gasket) and tested again. There were some other leaks that I was having trouble finding. Finally I discovered that the turbo was leaking where the intake side bolts to the center.

So, I decided to pull the turbo. It's a K03-006 that came with my first motor (a disaster. Mismatched cam caps on the 'rebuilt' head, such that the cam wouldn't turn. A melted piston and scored cylinder. wrong turbo with blown seals. Wrong manifolds. Leaking IP. From one of the long-time members of this very forum.) I had rebuilt the turbo and made an adapter out of steel plate.

Rather than fuss with the original turbo, I decided to try the K03-003 'backup' turbo. It runs great. I'm now seeing an almost instant 10 psi with a spike around 12. EGTs are down. It's significantly faster. I can reach 75 mph effortlessly and maintain it with EGTs around 1000 degrees!! I can floor it without my EGT buzzer (@1320) yelling right away.

[zuhandenheit]

I know that this is an often-asked question, but I'm seeing a lot of very different answers so I'd like to ask it again: What is safe boost for a K03?

I have a manual boost controller and have adjusted it so that I now run 13 psi, to see if that would further lower EGTs.

I am not running an intercooler but do have a Saab blackstone intercooler that I'll install soon.

I haven't done anything to change fueling and don't intend to now, given that I can still hit high EGTs, which now rise much more slowly but get into the 1300s during long full 'throttle' runs at highway speeds. MY IP timing is a little advanced (~1.00 mm).

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Oh,  and I forgot to mention in my last post, probably the main reason that the other turbo was running so little boost: the wastegate actuator adjustment is reversed on the K03-006 turbo that I was using, compared to the K03-003.

When I put it together after a rebuild, I didn't know to preload the wastegate spring and then when I attempted to adjust it, I went the wrong direction (toward the end of the rod).  The boost leak from the turbo itself I detected only with soapy water, and so might be very slight and I probably need to just tighten up the bolts.

[libbydiesel]

So, the other turbo was probably running with the wastegate wide open.  Yipes.

I wouldn't run more boost than that on the K03 without an intercooler.  With an intercooler, your temps will come down some and you'll get more power.  At that point I would up it to 15 psi but that's about all the K03 is good for, IMO.   

[zuhandenheit]

So, the other turbo was probably running with the wastegate wide open.  Yipes.   

Yeah, pretty much. Before I adjusted the wastegate it was closed but with little pressure (this is how I put it together), but after, it was wide open. I was planning to take the exhaust off and check it out, but that's when I decided to pull the whole thing.

--

Thanks a lot for the help. I'll leave the boost where it is. I'm really happy with how it runs now, though there's a lot that still needs to be fixed and/or improved. For instance, I have just a short downpipe for an exhaust, my accelerator cable bracket is not beautiful, IP needs to be resealed, and my transmission needs to be rebuilt. Also, in addition to the intercooler, I'd like to install an external oil cooler.