Turbo Brake Function?

[bballer182]

I know this is an old thread, but how do you get the vanes to only do this while operating in T/H mode? On the LMM it looks easy but the LBZ I can't find a way???

LBZ is identical to the LMM with respect to turbo brake tuning. Also, there is no way to turn it on ONLY while in T/H, however, there is a way to cheese it. Under normal driving conditions (cruise braking) the engine typically won't go above ~2000-2100rpm so you can close the vanes down in 0-5mm3 and above 2000rpm and without T/H the turbo won't close down.

[Drake_Lawdawg]

After pouring over this some more there looks to be a way to do it through the TCM as well. It would technically be on all the time at 0% throttle input but you would only "feel" it when the TC is locked.

[bballer182]

After pouring over this some more there looks to be a way to do it through the TCM as well. It would technically be on all the time at 0% throttle input but you would only "feel" it when the TC is locked.

The only way to engage the turbine brake is through the engine tune. And, yes you are correct the only way you'll feel the brake is with the converter locked.

[killerbee]

Are the vanes strong enough to turbo brake the truck? Silly question but I am picturing a small turbo slowing down a huge truck... the idea is strange to me at first. Also, is there any undesired effect say in heat buildup due to the backpressure? I ask because I increased idle vane position on an LBZ for better response and desired sound. Thanks.

Given that "no-fuel" exhaust is not capable of much more than 10-15 psi of boost at 4000 engine rpm, the turbo shaft is only exposed to something like 50HP max of power, which is transferred to the wheels for braking if the TC is locked. IIRC, the shaft is good for at least 250HP before snapping (albeit at 20,000 rpm).

In reference to the other concern about having an unlocked TC at high rpm, if you do this with hard turbo brake in T/H mode, your tranny will toast pretty quickly in theory on a 10 mile grade. Serious viscous slip heat.

[garrettg.bpd]

Has anyone had turbo braking just stop working? but still build normal boost levels when not braking.

[bballer182]

Converter unlock or something? Some parameter wasn't met and the vanes opened up. Its in the program. Best thing to do is log

[Boost]

It is most likely something goofy or inconsistent that I am doing, but it seems to me that known good turbo brake settings only work on 50% of my trucks. I know for instance that some OS do not have certain transient tables that affect this, and also that it only kicks in when specific conditions are met but - on some trucks it works great and is easy to notice it yet others in never works or only once in a blue moon... haven't quite figured this out yet.

[garrettg.bpd]

Dose any know what are the best duramax OS are.

[bballer182]

I don't have it in front of me but the second from the latest is the one I prefer. For LBZ, that is. The last OS that was made for the LBZ was rumored to have tune tracking so I passed on the "update."