Factory Engine Braking Feature

[jdn112011]

Has anyone realized that the factory tune has an engine braking feature? Turbo braking specifically. But it only operates when the cruise control is on! It will drop gear and close the veins and engine brake. You will not Coast freely down a grade if you have your cruise control set.

Factory feature

I think the 50$ GDE option just alters the way that the Turbo braking is triggered

 

[Brady]

Yes I found that out the scary way. Cruise set on 45, crested a steep little hill and as soon as the nose pointed down it down shifted and screamed RPMs.

 

[jdn112011]

Lol similar experience was not expecting it coming down a short but steep Hill. Never expected anything considering the comments about gde tune option being the only way to get an engine brake

 

[Brady]

Does the GDE tune WITHOUT the added brake option eliminate this OEM turbo brake?

 

[jdn112011]

That's a great question I'd like an answer to as well. If somebody has time to contact GDE with the question and follow up for everyone would be fantastic

 

[BoostN]

I found this on their forum, but it doesn't really answer if you can have it completely disabled. They have it listed as an option. So I would ASSUME you could have them just disable it.

http://www.greendieselengineering.com/jforum/posts/list/174.page

 

[jdn112011]

That's just Info regarding they're paid feature. No Info if their regular tune deletes the factory one, or if they leave it alone?

See I understand how to trigger the factory engine brake though it is not from manually down shifting as their optional one is.

I don't want to purchase a hot tune without it, and have it disable the factory feature. And then not know until after the fact that you need to pay for their option to retain anything.

 

[Brady]

That's just Info regarding they're paid feature. No Info if their regular tune deletes the factory one, or if they leave it alone?

See I understand how to trigger the factory engine brake though it is not from manually down shifting as their optional one is.

I don't want to purchase a hot tune without it, and have it disable the factory feature. And then not know until after the fact that you need to pay for their option to retain anything.

Exactly. I plan on skipping their $50 option as I'd rarely, if ever, use it. But would like to retain the OEM braking feature. I'll contact GDE direct before purchase regarding this question.

 

[jdn112011]

I'm on the exact same page as you are, and still on edge for the purchase but it's a 70% lean towards just getting the tune sooner ratified than later. 14k miles down since May, so I have similar feelings.

Let us know what GDE says please

 

[Brady]

Yeasir

 

[Brady]

My question:
If I order the tune WITHOUT the braking feature, am I still able to maintain the OEM ?turbo? braking capability?

From GDE:
There is no engine braking in the stock tune that is accomplished via management of the vanes' position. We've seen this quotes in a few places now and is unfortunately misinformation.

The only thing the stock tune does is downshift the transmission if you're going down a hill in cruise control and the vehicle speed exceeds the cruise set speed. This functions the same in our tune but we also close the vanes in such situations (engine speed above 2500-2700rpm, gears 1-6, no fuel injected) in order to maximize the engine's ability to slow the vehicle thru higher pumping losses.

 

[jdn112011]

That's interesting because the factory tune does more than simply downshift. I can drop gears and the motor will just run higher rpm. Even if I put it to 3500 rpm downshifting there's no back pressure to slow the truck down... but with cruise when the computer does it, it works. It's doing something more than down shifting. I can't imagine why gde would not acknowledge there being something more than a downshift.....

 

[Brady]

As I questioned here:
The truck does have a slowing/braking feature while not in cruise control as well. Happens after a slight tap on the brakes then coasting. Will this remain the same without the GDE braking option?

If there's a source for more info and the answer, I'm all ears. Thanks.

From GDE:
Whatever you are feeling is not anything that is being managed by the engine controller, so it should continue behaving the same.

 

[jdn112011]

Well I do appreciate the follow up with GDE's responses it does leave some confusion as to the factory cruise control downhill braking...

To be continued...

 

[seiko]

I love the Turbo Braking feature, especially when towing in the mountains and I'm already at safe speed. If I want to coast, I just deactivate the cruise control.

It my understanding the Turbo Braking feature is inferior/not as effective to the one on Cummings diesel

 

[jdn112011]

Due to an obviously smaller Turbo and engine yes it's less effective. But it does help and is there

 

[Brady]

GDE says otherwise tho.

 

[jdn112011]

Right

 

[EcoSki]

I have a '10 2500 with a CTD and a '15 ED. The exhaust brake on on the ED is not even close to the CDT. Honestly it is very disappointing.

 

[Green Diesel]

For some clarification, if you are in cruise control with the stock tune going down a grade and start exceeding the vehicle speed set point by 3-5 mph for a certain time period, the trans will downshift one gear, then after a little more time downshift another gear. It will keep down shifting up to the peak rpm of 4000. The entire time this happens the turbo vanes are at about 40-50% travel and no effective engine braking. When you are not in cruise control it would require manually downshifting to get it to do the same thing.

With the GDE tune, we activate the turbo braking when the following conditions are met: gears 1-6, rpm above 2700 and foot off the throttle. When this happens the vanes are closed to varying degrees based on rpm to increase exhaust manifold pressure to 90% of the VM limit. This gives a very noticeable drag on the drive line to hold speed without having to ride the brakes down the hill.