I'm planning on sending my TS chip out for new tunes. I'm going with a new vendor this time, though I haven't chosen which one yet.

There are a few vendors that offer a Decel Tune that uses the EBPV. I'm considering this tune and I'm interested in feedback from those who have/use it.

What are the pro's and con's of using that tune?
What happens if the tune is selected at idle? While cruising?
What are the Do's and Do-not's of the tune?
Has a tuner been able to tie the Decel/EBPV function to the throttle pedal position yet?

The truck has a stock rebuilt trans (I think). The PO had it done.

Thanks guys.

 

I have the decel tune on my DP F5. I think it's a spiffy way to save your service brakes when the load you are towing starts pushing you down a hill. Towing my 5er at about 9k I can descend a 6% grade without touching the brakes, and steeper is where it really shines to help control speed and save your brakes. Select it when you need the braking, then switch out when you need to accelerate again. You cannot accelerate with it engaged. I put it between my light and heavy tow tunes so it is one click away from either.

As for function, it closes the EBPV so the exhaust backpressure will retard engine speed. The tune also adjusts transmission clutch pressures so the engine braking is transmitted to the wheels. I want to say it locks clutches on the front drum, but I'm not too sure about the details so hopefully someone will chime in on that. It has little effect at low RPM, so to get the RPM up click off the OD or select a lower gear depending on road speed. In a sensible way of course. Basically use the same RPM you'd use going up the hill.

There has been conversation about excess backpressure causing damage, but I've never had a problem and I'm sold on the effectiveness.

 

I'll share what I can:

The higher the RPMs, the higher the EBP is... so I recommend against manually downshifting (pressing OD button) with the decel tune active, or activating it at high RPMs (I'm thinking over 2500 RPMs, but others have more experience at pushing the limits than I do). I let it do its thing and it's very effective. If the decel tune isn't slowing you down enough, the brakes will still get less wear and run cooler than without it.

If you "hang" the EBPV (it gets stuck closed), pulling over and cycling the key has resolved the issue for me. I removed the turbo and found a burr in there that would grab the butterfly valve, and I suspect many turbos from the same casting may have that burr (I've heard of this happening to other members). A little filing took care of the burr and the problem never occurred again.

I read some info in the 4RHD100 brochure that refers to an improved coast clutch for engine braking (this from Ford - the same company alleged to pooh-pooh engine braking).



This implies a conventional 4R100 might take issue with excessive use of a decel tune... but didn't have my decel tune until after I got the HD4R100, so I can't speak to any changes in behavior or temps.

 

Thanks for the input guys. I don't tow regularly. The tune wouldn't be an everyday tool, more so an insurance policy. Something ready to go if I need it.

 

I don't think Ford has a problem with engine braking....just exhaust brakes. They are different things.

 

I'm considering (NLTD) tunes from Riffraff. If Clay puts his name on it, I'm certain I'll get A+ customer service.

Has anyone run the Decel tune from NLTD? I wonder how similar it is to DP's?

 

I run DP's deceleration tune and like it. I don't bother manually downshifting, as his tune downshifts at 50mph, anyway, and engages the coast clutch at the same time. Works great. You'll probably tear up the coast clutch on a stock tranny if you use engine braking on lots of long, steep grades, but that's true even without a decel tune.

Mark

 

i have never used it but i would think it would only work good if your trans where in good shape.

dose anyone know how much psi it puts on the turbo?

 

About 32-34 PSI Exhaust Back Pressure (gauge pressure).