Questions about blocking the wastegate on 04 cat mbn

We used to do it all the time on our cats. Never did change how we drove just hung our foots off in it.

 

I don't think it'll make much difference without a reflash. That being said you could put a small ball valve in line. That way you can fine tune it.

 

That eggshell technique is the only way you'll ever get any mileage. I couldn't get 5.0 with mine, ever.

 

If you break out of the mid 4's on an MBN you're doing good.

 

Afaik you can reflash it before doing the conversion. Theres a lot of them out there with just reflashes and no hard parts being changed.

 

I don't know all that much about this topic, but a couple of things come to mind:

1) Why would an engine manufacturer put a waste gated turbo on an engine if it would get better performance using the same turbo without a waste gate?

2) Building pressure causes heat. So if you are building more boost than your engine can use, and subsequently putting more heat into the intake after going through the after cooler, aren't' you actually hurting the performance? Cooler air is denser and therefore perhaps 150 degree air @ 20 psi boost is giving the engine more to work with than 180 degree air at 30 psi boost.

I have a B model that I have a waste gated turbo off of an E model on. The reason is that the truck performs so much better while starting and shifting than the stock turbo did, with much less smoke, and way less turbo lag. Depending on the ambient air temperature my gate opens between 25 and 28 psi. With a stock turbo at my current fuel settings the most boost I would see was 25 ish. If I pinched off the waste gate hose I might get up to 35 or so pounds of boost I suppose, but the exhaust pressure would probably be at 40 or better to drive the turbo and the intake temperatures would also be quite a bit warmer. I just don't think that power and mileage would improve, except for the psychological aspect that I could say "I'm getting 35 pounds of boost!".
I don't know the answers to any of this, but there is my two cents worth.

 

I think on the mbn, pinching of the waste gate will throw engine in a derate mode since the waste gate isn't controlled by the charge air side of turbo. If your serial# is a viable one all you need to do is reflash ecm and replace turbo with a 6nz and it will be a 6nz running purty cat.