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Questiion: Turbo Exhaust Brake

LBZ: 
6K views 27 replies 11 participants last post by  D_R_C 
#1 · (Edited)
Heres the deal. I have EFI Live - DSP5...but I dont have the files and its locked.
Do not know if Turbo Brake Function was enabled at the time of tuning. However, I haven't noticed any turbo braking capability whatsoever while hauling my 12,500 lb 5th Wheel through the BC Rockies.

As such:

I've read through a number of these threads. BBaller182's DIY and others. To activate this feature one must do the following.

C2 ECM Connector (the small one)
Add Pin to 53 to switch & then to Gnd.
Add Pin to 11 for Incandescent light to show it's enabled, to Gnd
Both PIN Slots should be Empty-Unused before you start this mod.


If, as I read this, it's only in operation with T/H on & NO Throttle input.....then if one only uses this when hauling a Trailer, 4-6 times a year to go camping, is there any reason to have a switch in the first place.?

Could ya not just go from said Pin 53 to Gnd and leave it on permanently...while maybe adding the light to let you know its activated..? Seems to me thats how the medium duty trucks of the same vintage have it set up.

Love to hear yea or nay.
Acquiring pins today.


Thanx,
Theo
 
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#3 ·
There are a couple of ways to tell if the turbo brake is on. It should have been set electronically in the tune to come on above 1500 RPMs and at 0% throttle. if you have a data monitor you can see this, the veins on the turbo should close to 90% and you should hear the turbo whistle. there shouldn't be a need to do the pins or mechanical switch it can all be done with a tune. mine is set up this way and it only comes on when in downshifting manually or in tow haul mode.
 
#4 ·
i'll check that today...CTS in the Truck.

Tks,
Theo
 
#5 ·
It will make boost when turbo brake is active as well. I can’t remember exactly, but I will see around 10 psi at 2500 ish rpm.
 
#6 · (Edited)
So took er out on the freeway.

TH in and in Manual. in 5th.. Truck only.

Got up to 2500 rpm and let off the throttle...I had my CTS showing VPOS and when it kicked in, I did see 98% momentarily and about 6-8lbs of (reverse) boost. Once rpm's went below 2000 - Nadda. I did it a few times smilar results and in both position 2 (Econo Tune) and positon 3 (Tow tune). No difference between the 2. it certainly did not sound like a jake, rather sounded/felt like simply the trans slowing me down would be more like it.

Regardless: To me, these results - what I experienced seem a "light" version of what I am/was expecting to see when I pull my Citation.?? I mean it will help, but hold my truck n 12,500 lb trailer on a 5-7% grade..?? not so sure.

I was hoping for - Wanting something that will REMAIN on or at least a bit longer.? From what I have read of others experience with this: It's supposed to be next thing to the coming of Jesus ffs.! I just dont see that kind of action from what I experienced....? not even close. I do know that if I do in fact have this feature enabled and want to change the parameters of when the Vanes stay Locked up , (say 1700-1900 rpm or so), it would require new programming at $550 CAD.

But[/B, before I go and do something I don't need to. I am going to hook up and test this out on a few hills in my area with the trailer......That will be the one Real Test worth discussing.


We shall see.

Cheers,
Theo
 
#7 ·
I wouldn't use mine with no trailer, it is too aggressive. Works great on ours! It will only operate when the torque converter is locked. So no T/H you'll need to be above 45mph and it will stay engaged down to 20 mph, but if you unlock it by just a touch of throttle it will not go back in. In T/H mod it will come in and out under 45mph down to 20 mph. Love ours, works great holds the truck on everything east of the Mississippi. We are about 18k
 
#8 · (Edited)
Well I can tell ya categorically...what I found was not even close to Aggressive...it was for all intents and purposes not really doing anything. Yes VPOS went up to 95-98% but only above 2000 rpm and barely slowed the truck own at all.... I was in T/H and in Manual using 4th & 5th gear.

Im leaning towards the evidence thats telling me it was never activated in my EFI Live programming.

I've asked the question in the EFI live forum....Yet for some reason, not one person has responded when I asked: "Given I have EFI Live, Will i do harm if I manually enable Bballr 182's method of" :

Using PIN 53 on the C2 Connector (ECM) - to a toggle switch - to Gnd
Using PIN 11 on the C2 Connector (ECM) - to incandescent illuminator (small bulb) - to Gnd (to show it is engaged)

I'm thinking that the only way to know is to give this manual mtheod a try and see what happens.

Cheers,
Theo
 
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#10 ·
Hey Steakman,

I'll lean towards your assessment in that the braking power is not terribly aggressive. I gave mine it's best tests going down the Grapevine as well as from Mammoth to Bishop here in California, both times towing about 10k. The Grapevine is 6% for 5 miles and I'm not sure of the stats on the Bishop grade but it's also quite aggressive for it's length.

I feel that the braking is very helpful the way it is. I am able to hold my speed without much, if any, braking input from the foot. At first I wasn't convinced that it was working either. But once I really put it to the test on these and other steeper grades, I do see that it really works quite well.

As far as enabling it to work at all times I'd recommend against it. What I am finding is that you can enable the turbo brake when you are not in tow-haul mode and I end up with erratic behaviour. It will brake intermittently (still with no throttle) and lurch around. What I would be interested in would be to see if I could trigger the tow-haul mode to 'on' when I flip on the turbo brake switch.
 
#11 ·
If this is what you was planning on trying.
It’s advisable from Allison to not engage towhaul while under power, very hard on the clutches.
Taking it out under power isn’t as bad as engaging TH under load.
 
#12 ·
I wasn't thinking of using it while underway but before I started out. It would be a nice failsafe way to make sure that tow-haul is engaged when the Turbo Brake is flipped on. I'm just thinking out loud here and I'm over-engineering it in my mind. I always think of a better way- after I've completed a project!
 
#15 ·
I permanently enabled the "exhaust brake" 100k miles ago and you're right.... It's very mild but noticeable. IMHO it's good to keep it enabled to keep vanes moving and hot side of turbo from seizing up.

Why the #$% would anyone be in and out of T/H while under load? Hitch up, put it in haul mode and leave it until you're unhitched.
 
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#16 ·
They think they'll get better mileage with lower RPM's.
 
#17 ·
Id be interested in knowing how it could cause damage to the clutches? The TCC locks in second gear with TH on, regardless of load or throttle or what not. It locks in OD without TH, so as I see it, it’s locking and unlocking automatically anyways. I mean I suppose if you’re being an idiot towing heavy unlocked in 3-4 and cooking the trans then locking and unlocking continuously. Either way, as mentioned about TH on anytime I’m towing or even empty in the hills.

Theo, my turbo brake is basically useless below 2000rpm, the higher the rpm the more braking power the turbo will create. TH off won’t slow the truck down even with 100% closed vanes, there’s no mechanical connection between engine and drive shaft, fluid coupling only which will not translate to reduction of speed. Turbo vanes should not cycle to 100% and stay there, that’s been talked about possibly floating valves.

If you are around Calgary this week, I might be in town if you wanna take a burn and compare with my truck.
 
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#18 ·
It’s when people engage TH under load when towing then dis-engaging on flat ground then engaging again under heavy load that’s hard on the clutches.
Just observe the rpm differences shifting with TH and with out TH, converter looks up in 2nd with TH and 5th without TH.
My turbo brake works just fine with TH engaged from start towing till not towing, down to about 1800 rpms
 
#19 ·
DMAXMOE...

..If you are around Calgary this week, I might be in town if you wanna take a burn and compare with my truck..
Never fails...LOL, Im in Wisconsin right now on an 8 week QA gig - 1 week into it.
But if that invite is still open some time when i get back..?, that would be great...!

Thank you.!
Theo
 
#20 ·
the truck should stop pretty well when the turbo brake comes on. I can almost come to a complete stop on an off ramp on the highway (with no trailer). That's lifted with 35s. so definitely worth the programing. You shouldn't see 98% vein position because you want a little exhaust escapement id say 85%-to 95% is fine depending on what you set the tune to. also you can turn it off anytime you want when it is programmed, meaning if you set it to shut off at 2k rpm and run 95% closed then it will. ask whoever tuned your truck to tell you what they have it set to. I can tell you as soon as I let off the throttle I count to 2 and I'm at 90% closed and the second I pass 1500rpm it releases, you should be able to hear and feel difference.
 
#21 · (Edited)
Towhaul engaged, manual shift, keep the rpms above 2000 that’s about where the EFI turbo brake kicks in.
It’ll kick out between 1500-1800 depending on the tuner.

When I’m testing the function when empty, I’ll select manual 3rd gear, bring the rpms up to about 2500-2800, let off the throttle and let the TB do it’s job.
As soon as you touch the throttle the EFI TB kicks out, pretty much the same with the big rigs with a Jake brake and the Dodge Cummins.
Doubt the TB will ever function in drive, unless maybe if your going 120 mph and the rpms are well above 2000 when you let off the throttle.
 
#26 · (Edited)
. . . unless maybe if your going 120 mph and the rpms are well above 2000 when you let off the throttle.
Won't happen. Somewhere in the low 90's it crow-bars the injectors off and won't recover until the speed drops below 90. Don't know if it is a US-wide DOT thing or if it is by state or region. Yes, I assumed part of your comment was in jest.
 
#23 ·
Thanx DRC...I will do exactly that. I tried it above 2500 rpm - manual - TH but in 5th...time to give that a shot today. I'd love to know if its actually active in my EFI Live.
 
#25 · (Edited)
It IS installed as part of EFI Live..!!

So Long story short.

This past weekend, we finally got the opportunity to head to Banff to do some weekend camping. On the Way there (22x - Bragg Creek), there are a cpl shorter 5-7% Grades up & down.

12k 5th hooked on - truck in Cruise - TH on and simply let it do its thing....on the downhill side. I resisted using my brake and loe n behold, didnt it downshift into 5th and then into 4th...I also noticed that "back pressure" in the turbo reached ~10lbs as I descended. (at least I am assuming that is what it was..?).

Anyway pretty happy knowing that this seems to be working. It's gonna come in very handy when I go to Central BC later in Aug...Twice.!

Cheers
Theo
 
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#27 ·
. . . 12k 5th hooked on - truck in Cruise - TH on and simply let it do its thing....on the downhill side. I resisted using my brake and loe n behold, didnt it downshift into 5th and then into 4th...
That is exactly what it does in stock TH. Are you confirming the stock mode or were you using EFI Live with the brake mode on?
 
#28 · (Edited)
If you had something like the Edge Insight and monitor the turbo vane position, you’ll find when the % is close to 100% that’s closed the turbo brake is functioning.
Close to 0% the vanes are wide open, you gots your foot in it.
When on down grades, I’ll drop a gear maybe 2 to help slow down that runaway truck.

I only have one tune heavy towtune w turbo brake, no switch, when towing all I need to do is select towhaul this helps with the TB having the converter locked after it goes into 2nd gear select manual 5th and drive.
When I hit incline grades I’ll drop a gear to maintain proper rpms.

In drive and NOT using towhaul, I’ve never had the TB functioning.
If by chance I’m driving like I just stollen it and if by chance it did kick in when I let off the throttle, it’d kick out at around 1800 rpms, with EFI.

If you have the turbo brake on a switch the diy way, you’d have a little more off and on control.
In the throttle TB is off, let off the throttle EFI or diy the TB will function, the difference the EFI TB will kick out on its own around 1800 rpms.
 
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