I have never had an exhaust brake before, nor have I driven a truck with one, but I Just installed my ebrake and 60lb exhaust springs this weekend on my CTD auto(47RH). I put my own system together with a completely manual system. The factory units as I understand all have a feature built in that automatically disengages tte e brake when the accelerator is depressed. Like I said, I have a totally manual system where I use a momentary toggle switch on my shifter that locks up my convertor and also activates my brake at the same time. My question is, will it harm anything to have the engine at fast idle with the ebake on at the same time to accelerate warm ups in the cold mornings, or is it only safe to have the ebrake on while the accelerator pedal is not depresssed as the factory units are?

 

My truck will idle up to 1000 RPM in cold weather with the exhaust brake on... It brings EGT up close to 600.

Whether that means it's safe for your application, I don't know.

 

My PacBrake is set up to operate during morning warmup, but not at elevated idle because it turns off if the go pedal is depressed. My PacBrake air valve seems to stick closed at any ambient temperature until the engine gets to op temp so I have given up trying to use the warmup feature. Anyway, I feel that elevated idle is better in the morning for other reasons. Your manual system looks good, I like manual control of stuff. As far as doing harm if you fast idle with the EB on, probably not, but you can't set it up so fast that the engine stalls. Depending on the relief hole size in the butterfly, the stall point may not be much faster than normal idle. My EB at idle feature loads the engine such that the usual 750 idle is depressed to 650, and that's with a warm engine. Soot may build up during warmup, but it should burn off if you run it hot each time.

 

I warm my truck up on fast idle with the e-brake on all the time. Go for it. If it can handle running down a 6% grade for 10 miles at 2500 rpm with the e-brake on it can handle 1000 rpm for 5 minutes.

 

My Jake e-brake will stay engaged when I turn on the cruise control high-idle. If I try to bump it up higher than 1100 RPM, the e-brake disengages.

So it's probably okay to rev your engine during warmup, but only up to 1000-1100 RPM. I think if you try to rev the e-brake any higher than 1000-1100 RPM, it'll float a valve, or worse.

The important difference between reving it and braking down a 6% grade is fueling. I imagine that if you tried to accelerate while going down the grade and forgot to turn off the e-brake, again, bad things would happen.

Yet another important feature is the e-brake will not be enabled while in gear with speed less than 22 MPH. The lowest non-jake e-brake speed that I think I saw was about 18 MPH. I can imagine the lurching, lunging mess that would occur if you happened to toggle it on--locking the TC--at low, or no speed.

 

Yes there is fueling at fast idle but it is minimal and thats why the ECM allows the e-brake to stay engaged. It is sold as a warm up feature. There is tons more air volume braking on a grade than there is idling at 100 rpm. Your comment about accelerating down the grade with a manually controlled ebrake is correct.

 

must be a auto tranny/TC clutch feature. My Jacobs EB stays on from normal idle rpm to redline at any speed and in any gear, while gearing down, with the NV5600.
--------------------------------------------------------------------------
scottmn1
which aftermarket TC clutch lock program are you using with your EB ??
JIM

 

Jim,

My system is totally manually controlled by the me, the driver. That is why I am asking all of these questions, because the computer normally makes all of the decisions on when and when not to engage the ebrake and lock up depending on all of the circumstances. Since I do not have the computer to do that for me, I was trying to find out from guys that do have ebrakes under what conditions not to manually engage the brake TC lockup to prevent transmission and/or TC damage.

Thanks

 

Something that hasn't been mentioned is that on the computer-equipped trucks there is about a 2 second delay between when pedal goes to idle and when the brake comes on.

Though it's handy that way to leave the switch on and be able to accelerate and shift up without the brake coming on, I suspect the main purpose of the feature is to let the turbo slow down before the jacob comes on. I would imagine that having the butterfly close while the turbo is at fully spooled up speed would result in major deceleration forces?

 

Excellent point Jeff. I was unaware of that. Again, another example of why I need to be asking these questions. Thanks Jeff

 

Jim,

That's the difference between the auto and manual trannys. I believe the main issue with Scott's e-brake is that it's completely manual, no e-brake controller, and it's on an automatic. If it were a manual, he'd be done and everything would work pretty good. Since it's an auto, the TC must be locked up before the e-brake engages.

Jeff,

On my truck, with the 48RE, there is very little delay when the pedal goes to idle and the e-brake comes on as long as the TC is already locked.

These posts bring something else to mind, too. In what gears can the 47RH lock the TC? On the '06 48RE (and probably several years earlier), the TC can be locked up in 2nd, 3rd, and OD. I have had to drop down to second to hold my trailer to 25 MPH while going down a 4% grade. (Stupid national park speed limits ).

Scott,

If the 47RH can't be locked up in less than 3rd, you'll have to be careful that the TC is really locked up in your current gear. It might be prudent to get an upgraded valve body that will allow lockup in any gear.

 

Yes Tony I have been reading up on that too. You are correct the TC will not lock up in the lower gears. I se ATS sells a valve body that allows the lower gear lock up. Do you know who else sells them, or can a local transmission shop upgrade the valve body to do this?

 

I don't know. I wouldn't think a local transmission shop could do this, since that wouldn't be part of a standard VB kit. I think ATS actually drills some new pathways in the VB and/or VB kit.