Keeping wastegate closed

More boost does not mean more power, it will not add additional fuel past the ECM programming. Disabling the wastegate can lead to an over boost situation, which will set a code and derate the engine. It can also lead to turbo damage from higher turbo speeds.

 

I pinched mine off and ran it like that for years before I had a non waste gate turbo built but I wasn't seeing that high of boost. If you're already up to 65. I would leave it alone

 

I would think that EGT's would be an issue by keeping the waste gate shut. Part of the equation on what increases EGT's is how fast the exhaust gasses get shoved on down the line. That is why I have a high flow exhaust manifold, with a larger non-wastegated turbo (with a blanket) and high flow mufflers. Keeps exhaust flowing faster and cooler. Shutting off the waste gate is like a nozzle on a garden hose. You get higher speed at the turbo, but slower speed before it. That has the potential to generate higher EGT's.

 

The waste gate on a twin turbo and a single turbo setup have two different reasons for being there, that being said they both slow the turbo speed down.
On a single turbo Cat blocking the waste gate isn't a big deal one way or the other it will gain you about three pounds of boost plus or minus a pound depending on the factory rateing
Most factory Cat run a 1.42 a/r exhaust housing (that I think is to loose to make good fuel milage with)


Now blocking the waste gate on a twin turbo set? NO NO NO!!!
The reason for the waste gate on a twin set is the first turbo is always spec out to small to flow enough pounds per minute to achevie max hp, as your rpm's and engine load go's up cfm/pounds per minute start to exceede your small turbos capacity, then the waste gate opens up and lets some of the hot exhaust gases bypass the little turbine wheel (turbo) and go straight into the big turbo, this is about 30 psi on the Cat setup
On a twin turbo setup the little turbo is often refered to as the high pressure turbo, and the big one as the low pressure turbo
The little turbo is bolted on to the exhaust manifold and by pinching the wast gate hose off you are forceing all the air through the turbine wheel on a turbo that would be even on the small side for a c12.
The big turbo (low presure) isn't makeing all the boost it is feeding compressed air into the little turbo and the little turbo raises it up.

 

A "waste gate" pretty much is just that. Once maximum performance that the component is designed for has been reached, anything beyond that is "waste" and needs to be dealt with accordingly.

If your engine is off of warranty etc. of course you are free to do as you wish. But if you want longevity and reliability, unless you go to someone with the experience and actual complete system knowledge like Mr.Haney etc., you can be looking for big repair bills and maybe even some big towing bills if you just start pinching lines.

IMO.

 

If he follows the advice he was given in this thread he won't have any problems