GDE TCM Tune

flman · **Posted:** Sat Jun 26, 2010 10:58 am

I know I have been a little critical of the tune. Working all the time and driving my Freightliner I don't spend much time with my CRD over the summer. Any ways, I am starting to like the tune, I don't mind the low RPMs as long as I am not paying attention to them, they are fine and the little diesel moves right along at the low RPMs. I also found the work around for the less coast, is to lightly keep slight throttle pressure on the accelerator in those places you would normally coast.

So yeah, GDE good job on the tune.

stoutdog · **Posted:** Sat Jun 26, 2010 12:03 pm

I sent GDE an email yesterday about a couple of things, including your concerns with coasting in lockup vs. unlocked & mpg. Will post when I get a response.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The additional lock-up does reduce the vehicle's coasting ability, however the higher degree of lock-up allows the vehicle to make better use of the engine braking from compression at higher rpms. This is ideal for mountain driving and still slightly more fuel efficient than coasting in unlock and any driving condition. The fuel efficiency comparsion required applying slight throttle during the coasting in lock-up to equal the coasting time for unlock. The fuel used with the GDE trans tune is about 1-2% less than stock for this situation.

Below shows the base coasting time comparing stock tune vs. GDE tune as various coasting speeds.

Unlocked/Stock Time
75-60 4thgear 8.8
75-40 4th/3rd 20.6
55-40 3rd 9.3
70-40 4th/3rd 17.74
70-50 4th/3rd 11.24

GDE TCM TUNE Time
75-60 4thgear LU 8.19
75-40 4th LU/3rd UL 18.6
55-40 3rd 7.9
70-40 3rd LU/UL 15.1
70-50 3rd LU 9.5

This tune does not mimic gasoline vehicles that prefer unlocked coasting, rather it designed to get the CRD to act more like a manual to maximize the diesel efficiency and engine braking for the best fuel economy and reduced brake usage. Thanks for the feedback.

stoutdog · **Posted:** Sat Jun 26, 2010 3:34 pm

And, there's the response, haha... Thanks GDE.

geordi · **Posted:** Sat Jun 26, 2010 11:06 pm

Thanks a lot Keith, good info.

Out of curiosity, are you aware of any bad things that might be happening if the trans is kicked into neutral when coasting, such as from 65 down to zero when stopping for a light?
Also, maybe I'm missing how the trans works, but wouldn't we be in 5th gear and locked up at 60mph or above...? I is confoosed.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

Good catch, sorry about the lack of information. Those numbers are in kph. I forgot to convert :banghead:

The tests were from 50 mph and below. At highway speeds above 65 mph the coasting is the same between tuned and stock.

flman · **Posted:** Sun Jun 27, 2010 8:18 am

GreenDieselEngineering wrote:

Good catch, sorry about the lack of information. Those numbers are in kph. I forgot to convert :banghead:

The tests were from 50 mph and below. At highway speeds above 65 mph the coasting is the same between tuned and stock.

I guess that is good for the Canadians :jester:

Rixram · **Posted:** Mon Jun 28, 2010 11:56 am

Where can detailed info on the Trans Tune be found?

stoutdog · **Posted:** Mon Jun 28, 2010 12:24 pm

Rixram wrote:

Where can detailed info on the Trans Tune be found?

http://www.greendieselengineering.com/f ... st/89.page

GDE TCM Tune

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