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View Full Version : LMM turbo brake RPM settings



Boost
October 19th, 2012, 02:15 AM
Please advise on what RPMs you guys use. I have had this completely set up on my stepdad's LMM and it worked, yet on another '09 with "the" newer OS it never kicks in. Typically on the last two trucks I set this up on, it would kick hard in T/H as it winds down from the higher gears on decel.

Since it doesn't work on this newer one, I suspected the infamous Transient T.V.P. table which doesn't exist in any other OS, so I copied and pasted the Low Altitude table in there with high hopes. Nothing. Then I though that maybe EGR was somehow active keeping the DSP Vane Position table from being used (since in DSP there is only EGR Off) - so I took some further steps to disable it. Still nothing.

Then I observed that during most of the test drive as I am expecting the exhaust brake to come one, I am at RPMs much lower than 2200+ set in the tune, mostly hover around 1500 rpm. So common sense would say that my RPM settings are simply too high (I will post table a little later.)

But on another truck truck it worked like that??

tokymon
October 19th, 2012, 03:46 AM
i find on some truck it doesn't work that well i set mine all the way down to 1200 rpm
try manual down shift to get it up in the higher rpm to see if it works
they always work better with more load ( ie. trailer) on the truck

Boost
October 19th, 2012, 06:47 AM
Thanks, so do you think this is way too high?

http://img.photobucket.com/albums/v239/WhiteFDrift/USP%20Motorsports%20-%20work/turbobrake_zps75f0f633.png

14061

tokymon
October 19th, 2012, 08:47 AM
it depends on what / customer is using the truck for i dont go above 90
if you have log boost when on the brake i have seen as much as 10 lbs of boost on decel ( really heavy trailer )
i try to stay about 5 lbs on brake

Boost
October 19th, 2012, 10:32 AM
I meant the RPM sorry. Trying to figure out why it's not working. :nixweiss:

tokymon
October 19th, 2012, 10:35 AM
ya that what i usually do just the first two rows
i would try manual downshift at 95 you should see boost when it is on

Boost
October 19th, 2012, 10:38 AM
So you set yours at no lower than 2000 RPM (and it works) ? And why would I have to manually downshift, I have seen this working in "D" like most peole use.

tokymon
October 19th, 2012, 10:42 AM
ya most people set it down to 1200 rpm i have set it up higher for a couple of customers
it just will be no effective at under 2000 rpm thats why i said to manually down shift then youre above the 2000 rpm where youres will cut off

Boost
October 20th, 2012, 04:32 AM
Thank you tokymon. Sorry I took the long scientific route to arrive at the obvious :anitoof:

You have been helpful and I do appreciate it.