Homemade exhaust brake

[diesel4life]

Ok stupid question for you Volkswagon: you say it kicks out at 30mph, so below 30 you cant use it at all? Im assuming thats because you only have lockup in 3rd and 4th right? How about if you could achieve lockup in 1st and 2nd would the brake stay engaged still? If not, that might make me really reconsider, I really like the thought of being able to use one at low speeds such as on steep grades to maintain lower speed.

[rickf]

You would have to find a way to make sure the transmission did not shift while locked up or things would probably break. An automatic is designed to shift under a fluid connection, ie; the converter is not locked so there is a cushion.

[hex0rz]

Hmm, well I dunno if this makes a difference or not but when I was with a fire dept. the trucks had exhaust brakes. They had the allison transmisson in it and IIRC they would work all the way pretty much down to being at a stop.

[volkswagon]

Ok stupid question for you Volkswagon: you say it kicks out at 30mph' date=' so below 30 you cant use it at all? Im assuming thats because you only have lockup in 3rd and 4th right? How about if you could achieve lockup in 1st and 2nd would the brake stay engaged still? If not, that might make me really reconsider, I really like the thought of being able to use one at low speeds such as on steep grades to maintain lower speed.[/quote']

That's right below 30 you can't use it. The controller disables it. You can get around this by getting an ATS, I think, controller which you can program to cut out at any speed.

[pepsi71ocean]

Ok stupid question for you Volkswagon: you say it kicks out at 30mph, so below 30 you cant use it at all? Im assuming thats because you only have lockup in 3rd and 4th right? How about if you could achieve lockup in 1st and 2nd would the brake stay engaged still? If not, that might make me really reconsider, I really like the thought of being able to use one at low speeds such as on steep grades to maintain lower speed.

the newer ones are smart controllers, you need to flash the controller to the 48re programming in order to brake below 30 mph, this is because the 47re couldn't do it stock. when you flash it over to the 48re programming you can get down to i think 10mph. i spoke to pac about this a year ago when i was looking at brakes for the truck. just rememebr to have some billet internals like an input shaft and flexplate when you do this. The alternative is to just hotwire your pac to run when you want it to with a lock up switch.

[hex0rz]

the newer ones are smart controllers, you need to flash the controller to the 48re programming in order to brake below 30 mph, this is because the 47re couldn't do it stock. when you flash it over to the 48re programming you can get down to i think 10mph. i spoke to pac about this a year ago when i was looking at brakes for the truck. just rememebr to have some billet internals like an input shaft and flexplate when you do this. The alternative is to just hotwire your pac to run when you want it to with a lock up switch.

Does pacbrake use the ATS copilot on their auto setup? I see pacbrake endorsing ATS' copilot on their site. They do not specifically mention it with their auto kit though. Just on some pages they mention the copilot. Your statement confuses me also; I talked to pacbrake and they said that an upgrade on internal parts was not necessary to use it. ALSO, the TC switch is something I personally would never recommend. I've read way too much about the risk of damaging the tranny. Some have recommended only if you have all billet in the tranny. Its a costly risk to take IMO...

[pepsi71ocean]

Does pacbrake use the ATS copilot on their auto setup? I see pacbrake endorsing ATS' copilot on their site. They do not specifically mention it with their auto kit though. Just on some pages they mention the copilot. Your statement confuses me also; I talked to pacbrake and they said that an upgrade on internal parts was not necessary to use it. ALSO, the TC switch is something I personally would never recommend. I've read way too much about the risk of damaging the tranny. Some have recommended only if you have all billet in the tranny. Its a costly risk to take IMO...

That im not sure of, but i do know that the smart computer that they have that senses the ECM when its in idle validation that also turns on and off the brake, also lock and unlocks the TC. You have to cycle the ignition and the brake switch to get it to switch to the 48re programming. in 48re programming if i rememebr correctly pacbrake said that the brake is engaged as long as the engine is idling, and your vehicle speed is greater then i think 10 mph, you have to manually downshift to 2 in your tranny. (although i go to 1 and it downshifts to 2 as well, and then to 1. I do like the fact that pacbrake will also turn on to warm the engine up if the engine is cold. The only upgrades i would recommend are if you have a built tranny, the TC lock up is rough on them, and that is why most of the builder i talked to say to run a billet input shaft and billet flexplate, because if you break either of them your ruining your transmission. from what i have heard from dave and stephen, the only billet internals are a flex plate and input shaft, because the billet intermediate shaft is not much stronger then the stock one, and the output shaft only really breaks if you do 4wd boosted launches, i have never heard of someone doing that towing. The reason is because if you break either the flexplate or the input shaft you usually trash your pump, and your torque converter, and sometimes the case might crack depending.

[volkswagon]

I modified my valve body to allow 2nd gear TC lockup so now my exhaust brake works much more effectively. However I'm getting some clutch slippage in 2nd now. Not every time so I don't know what that means but I'm wondering what I can do to eliminate this.

[diesel4life]

I was recently told by a trans builder that 2nd gear lockup is hard on converters and he did not recomend I modify my vb. Does yours slip under moderate loads or only heavy loads?

[dieselautopower]

Jacobs brake / cummins here is the link so I do not have to send so many PM. http://www.dieselautopower.com/product_p/jacobs-3800792.htm

[volkswagon]

No slippage under power. Just while using the exhaust brake. And not every time as tho sometimes it's building enough line pressure but not other times. Not sure if it's the converter slipping or some other clutch. I do have an upgraded TC that's supposed to be good for 400hp and 800 torque. I only plan on using the 2nd lockup for exhaust brake purposes.

[pepsi71ocean]

I modified my valve body to allow 2nd gear TC lockup so now my exhaust brake works much more effectively. However I'm getting some clutch slippage in 2nd now. Not every time so I don't know what that means but I'm wondering what I can do to eliminate this.

No slippage under power. Just while using the exhaust brake. And not every time as tho sometimes it's building enough line pressure but not other times. Not sure if it's the converter slipping or some other clutch. I do have an upgraded TC that's supposed to be good for 400hp and 800 torque. I only plan on using the 2nd lockup for exhaust brake purposes.

hey guys, try this it has worked for me and i don't have an eb. http://www.cumminsforum.com/forum/98-5-02-performance-parts-discussion/534021-stronger-pull-trans-cable-without-limited-throw-7.html i have really good holding power in second, when you have the right set of springs, but my advice is to have a programmer handy when you use a harder spring, because my truck with the smarty on lvl 9 works great with a stiff spring, she shifts out at 2,100 about every gear under moderate acceleration, and all of my gears hold better especially 2nd.

[hex0rz]

I put a spring on mine and I was able to find a size spring the OP in the CF recommended, but it to me seems too short. It was probably pretty stiff to be using. When I first installed it, I got to almost 3k rpm before it would even shift out of 1st. Stretched the spring more and now I got it to shift into 2nd at about 2k rpm. Wont shift into 2nd with a heavy throttle until about 2,200 rpm. Shift into 2nd at about 18mph and 3rd at about 30mph.I noticed that shortly after, the 3rd lockup occurs. Downshifting is not much noticeable and any extra "braking power" is not increased.Dunno how to tell if I can feel any increase in line/clutch pressure, but then again I dunno how to feel what constitutes a slippage either...

[pepsi71ocean]

i'll have to shoot a video for you to compare.your truck is shifting really high for a stock power band, if i unload my smarty i have to take the spring mod out because she shifts at the 2,500-3,000 rpm level, but when the smarty is on it is down lower around 2,000-2,100

[hex0rz]

Whatchya mean?Does my modded valve body change that?

[pepsi71ocean]

the spring mod added tension to the tv cable, this raises the shift points, if you have a tuner like a smarty that changes throttling, then the cable mod does wonder because stock you have your truck shifting at 1,300 rpms to the next gear because your barely on the throttle, now if you have the tv mod it raises the shifts to cover the lack of accelerator pedal movement.

as such the spring mod also has the added effect of increasing the holding pressure, and when your commanding the truck a gear, Ie shifting the truck to 2 at 50MPH you will notice that the truck holds better then if you have no spring mod.

- - - Updated - - -

i shot a video and well the truck didn't do anything different when downshifting, but that is because my spring is really hard, i can't add any more static tension on it.