Its all or nothing with any exhaust brake... Some have a "wastegate" that opens if the back pressure gets too high.

There not very effective to begin with on our trucks, and the EBPV ones are the worst. They work, but there no Jake.

 

Well said.......

 

Have the decel tune on my 02. If it isn't working well check for an exhaust leak. I have terrible leaks on the up-pipes at the Y. Fixed that and regained power, lower EGTs, and the decel tune works MUCH better. Did I mention that it is quieter now?

That said it works well for me. Pull a 9000# + RV. It does have it's limits, as does everything. I often have to turn it off due to going too slow down a grade and impeding traffic flow.

BTW - it is the reason I got the DP Tuner. The POWER was a amazing bonus.

 

you wont find any exhaust brake stall a big *** diesel motor like a jake brake will..a jake is 1000 times better then any exhaust brake...once the exhaust valve closes and seals with a jake...it wont open till you shut the jake off..it will stall its self out first...a jake will hold 80,000 + LB worth of tractor trailer back going down a hill with hardly any foot brake at all..thats why there on the big rig's and not a exhaust brake..its too bad the 7.3 heads wont handle a jake..but again..a jake is over doing it on a little pick up...every time you let off the go peddle to kick a jake on..the back tires will lock up...in the winter on slippery roads the jake will lock up the rear tires on a big truck if your not carefull...even loaded..

 

I left John Wood's shop about 4:45 PM yesterday looking forward to my 530 mile trip home.
I had these gauges, pyro, water and trans. up pipes, 6.0 cooler, DP tuner w/ 40t,60t,decel,
80t and 80e and I almost forgot a shinny JW transmission. I was stoked this was almost as good as my first solo flight.
Meeting John and hanging out in his shop all day was worth the price of admission. His wife, son and daughter were in and out all day. It is truly a family business. The loving way he interacts with his family speaks volumes for his character. He takes the time to explain every step of his rebuild in terms that even I could understand. Yes, he even tried to explain this DECEL to me. I think when he got into tuner strategies and internal pressures, torque converter lockup my eyes glazed over and he just said " It won,t screw up the tranny or the engine and if used right it will work for your needs.
When the work was complete John (alone) took the truck for a test drive to see if it met his standards. When he returned he just smiled and said time to teach you about what we have here. Driving on country roads he explained the tuner settings and when we got to decel he said to let off the fuel, switch out of O/D and switch the tuner to 4.
The truck being empty was not a test, just a demo on it's use. With the 80e tune the transmission shifts as smooth as my 6.4 did.
I am really pleased because my expectations were exceeded proving American small business owners innovators are still out there doing well.
Bill

 

I too have the SP diesel version. I tow a 9500 fiver and before the brake, I would crest a particular downhill slope on I26 around Asheville at 45, and be blasting through 65 by the time I hit the bottom of the grade even with light to moderate brake application. 3% for about 2 miles. With the SP brake, I crest the hill at 45 (OD off) and maintain 45 the whole way down NEVER touching the brake pedal. You tap the "go pedal" and the valve opens, release the "go pedal" the valve closes. Tap the cruise control ON button and it opens. Press and hold the cruise OFF button for 3 seconds, and it closes the valve. I like the simple operation and the fact you can open and close the valve with the "go pedal". I can speed up at will, and she slows right back down when you release the "go pedal". Thier customer service lacks a LOT to be desired, but the product is great!!!

 

As promised, not much for quality. The picture is what is at the top. I hit the decel at 51 mph, you may hear it close the EBPV, it drops the speed. There are a couple of times I still used the brakes and you can see a rapid speed drop. This was also the time the camera turns way to the side due to very shape curves. Not the best place to try to record the decel tune. I had my 8k travel trailer in tow.

http://www.youtube.com/watch?v=Hgp4jHZxeiE

 

[quote=zx250;9123414]As promised, not much for quality. The picture is what is at the top. I hit the decel at 51 mph, you may hear it close the EBPV, it drops the speed. There are a couple of times I still used the brakes and you can see a rapid speed drop. This was also the time the camera turns way to the side due to very shape curves. Not the best place to try to record the decel tune. I had my 8k travel trailer in tow.

I noticed you are @ 48mph and about 1650 rpm and decelerating. Many on this site have stated that decel is not effective at the lower revs.

 

Not sure what you are saying, it won't stop you, but even on the slope I was on, it will hold you at 45mph or less. On that stretch of road, it didn't stop the need for some brakes, but did keep me from having to use them all the way down or us second gear.

 

I have used my decel on rough mountain roads, with camper on and trailer behind, transfer in low range and tranny in 1st and it will creep along down fairly steep grades on wash board roads. Real brake saver. Maybe not the best exhaust brake out there but certainly a nice tool to have.

 

Now is that throught the DP-Tuner or is that a manual switch? How good it my manual set up when compared to DP's?

 

Originally Posted by zx250 View Post
Not sure what you are saying, it won't stop you, but even on the slope I was on, it will hold you at 45mph or less. On that stretch of road, it didn't stop the need for some brakes, but did keep me from having to use them all the way down or us second gear.

I guess I should of said: It looks like your decel was working at low rpm's. Sorry I wasn't clear.

 

Yes, it was, but for me that's not all that low. My truck seldom sees over 2100 with 35 inch tires and 3.73 gears. I really wish the road was straighter where I could have let the decel tune continue to slow the truck/trailer down. I will say that with overdrive on, it is not as effective in lower rpms, but with the OD off, it works just as you see in the video. Maybe some of the NC boys can video coming down Black Mountain on the way home from RRE. That's where I had to turn mine off and on just to keep up with traffic. It's Interstate 40 east out of Asheville NC and a 6% downgrade for 5 miles and a lot of brakes have been smoked on that stretch. That's the little hill I fell in love with my Decel tune.

 

Bill,
I think you will love your decel tune and it will be quite effective. I for one would trust the DP decel tune in conjunction with a John Wood build without question, especially since John personally showed you exactly how to use that feature. I believe you wrote that he said to turn off the overdrive and then activate your decel tune. I presume that means you can use your decel tune in 3rd gear? Do you happen to know if your transmission received a coast clutch upgrade (3 plate drum)? If so, that would explain why you can use the decel tune in 3rd gear.

That being said, I tend to agree with Joe (CSIPSD) that the effectiveness of the EBPV is directly related to what kind of tranny build you have. I also agree that valve float does not appear to be an issue with the EBPV set up.

Someday I will probably order a DP tuner for my truck but I am undecided on the Decel tune. The reason for this is that I do have an upgraded transmission but it is not a John Woods unit so I have no real way of knowing exactly what was done to 'improve' it's performance. If I could get the DP folks in direct contact with the shop that built my trans, then I would be much more comfortable with the decel tune and may also be able to confirm that my transmission warranty is still good (still have about 1 year to go...).

So, in the meantime, I must follow the instructions that came with the Transgo Tugger Kit that was installed in my transmission which says "Do not use exhaust brake in "D" or OD canceled (3rd gear). Use "2" or "1" only. The coast clutch receives no boost in pressure when OD is canceled. In "2" and "1" pressure is boosted to prevent coast clutch slippage." (I presume the same applies for stock transmissions as well but I am not positive.) According to the instructions, there is a Coast Clutch Upgrade (3 plate drum or custom 4 plate) available but I did not get that installed. The John Woods build may include that upgrade, something similar or perhaps even something superior which obviously allows you to use 3rd gear (OD canceled).

My truck and trailer combined weight is over 24k lbs (certified scales) and the simple EBPV with T/C lockup mod works very well for me. It actually works a little too well sometimes and I eventually slow down a little too much and have to disengage. It's a small nuisance though, the overall benefit is well worth it in my opinion. I drove home yesterday from 7500 ft and used the EBPV brake on several 6% grades with great results.

Transmission temps stayed steady at 190 degrees the whole time. Ambient temps were well over 100 degrees as well.

 

a

Barry, that is not a grade
I want to see some left coast, Rocky Mountain (and down the left side and up the right side of the Cascades) towing trucks chime in.

Not NC, GA, SC, TN. Some high elevation, hot summer temp, 8k to 12k lb RV / work trucks.....

Not bashing. Just saying I'd like to see those oppinions.