Manifold pressure question

[JFN]

Hello everyone, here is my truck Data, 2006 Dual cab short bed,5. 9 automatic (4speed) all stock as I can tell and 131k miles. The problem, I installed an edge Tuch screen display for all the gauges, no programer at this time, the other day I turned on the alarm function and started getting a manifold pressure alarm, it was set to 33", so I set it to 40" and it still will go off, now we have a turbocharger that peaks around 32 Pounds of boost and using 4 pounds=2" that would be 64" so what don't I understand here. Is there a MP limit? I realize that we won't see the 64" due to duct and inner-cooler loss but before I raise the alarm t0 60" or so I would like some input. I am leaving in the morning headed to Durango. Thanks in advance for the education. Cheers!

 

[jhenderson]

Because diesel engines make no vacuum, reference to boost pressure in aircraft terms has no relevance to diesel engines. Most likely, either you have a sensor problem ( giving bad info to monitor,) or someone has turned off the electronic waste gate function with a programmer. It's not likely to make damaging boost levels with a stock turbo and No extra fueling.

 

[Partyat33]

33" of water or 33" of mercury ?

 

[SierraRam]

considering that you can get over 30psi boost you will be setting off the alarm all the time. Tell us more about this touch screen you have.

 

[cerberusiam]

The electronic monitor is probably not adjusting for ambient pressure correctly. Set the alarm 15 lbs higher than you want your max boost.

 

[JFN]

Thanks for the responses. The reference to inches would be inches of mercury, The Gauge is an Edge CTS to the OBD port, no programer, I am going to assume (I know assume nothing) the alarm point set by edge has no bearing on engine operation as mentioned it's a stock turbo so I'll raise the limit to keep the alarm off. I believe the over 30 lb. I see is transient. Thanks again more later. Cheers

 

[cerberusiam]

The CTS should not effect engine operation, only read the parameters. The alarm setting is just not subtracting ambient pressure from the MAP reading. Set the alarm at 33 and when you break 19 lbs of boost, which is 19 plus 14. 5, the MAP will read an equivalent +33 and the alarm goes off.

 

[JFN]

Thank you.

 

[JFN]

We have made it to Moab UT, Spending a couple of days here then on to Durango. I am courious as how people use these trucks without added instrumentation, they just run them till they shut down? it looks like the next mod will be to add a converter lock switch as not being able to lock the converter in second is a problem when stuck behind a gravel truck at 10mph out of Nevada City, that was the only real problem I had, next time I'll stop and wait as the trans temp builds unbelivebly quick with the converter unlocked.

 

[cerberusiam]

Yep, when they die then the yelling starts. A lockup switch is a handy all around gadget for a lot of situations.

 

[SDputter]

it looks like the next mod will be to add a converter lock switch as not being able to lock the converter in second is a problem QUOTE]

Someone here told me that you can manually shift into 2nd and it will lock the TC. I haven't had the chance to try it towing but it seemed to worked when I tried it empty. Not sure if it is harder on other 2nd gear components... ...

 

[cerberusiam]

The TC will lock in second gear, but, not under heavy throttle or load. It has to be relatively easy pulling to get that to happen so it is not and ideal setup.

 

[WhiteSheep]

The TC will lock in second gear, but, not under heavy throttle or load. It has to be relatively easy pulling to get that to happen so it is not and ideal setup.

Why is this not an "ideal setup"? Honest question. I know that a "slipping" TC will heat up fluid, but it also lets RPM's rise and it is multiplying torque when "slipping". If I am in 2nd and pulling a grade, might I not want some slip to keep me in the engine's power band as long as the temperatures of the auto are in line? I have always understood that the value of a well set up auto is the ability to have almost unlimited gears due to the TC's ability to "slip". This is not the same as "slipping the clutch" in a manual by any means. Lockup TC's are mileage enhancers, not performance enhancers. I have a custom C6 w/o any lock up on a "breathed on" '84 F-150 4x4 that proves this, at least to me. Needless to say, mileage is not this F-150'ss strong suit.

 

[cerberusiam]

Not really, the lockup is both a mileage and performance enhancer especially with a diesel. However, like everything else that enhancement comes with a price. In this case its the power loss thru the TC and the amount of heat generated when you have to use manual 2nd gear and fluid coupling. Yes it is doing TQ multiplication but the result ends up generating massive heat, the cost of the multiplication is heat. Under a heavy load in either stop and go driving or grades fluid coupling will quickly overheat the trans fluid. You just can't get away from it and it is definitely not ideal for extended use. In a gas engine its more useful but a diesel that makes much more TQ at a lower rpm the lockup is integral to performance across the board.

You need fluid coupling to get the load rolling and the TQ multiplication at that point. Once rolling, selecting gears to keep the engine in the power band and using lockup is much more effective. The stock program simply does not allow heavy load and throttle in manual 2nd. It is designed to protect the transmission from the engine, not provide optimal power transfer which is really needed. Some simple parts changes make 2nd gear lockup very useful and safer for the trans in the situations that demand it. Overheat the trans too many times and you will just be rebuilding it. The fluid may take the extended heat well but the seals and frictions hate it.

 

[WhiteSheep]

Thank you for the information Cerberusiam. Even after eight years of ownership I continue to learn about diesels. I have never had an overheating issue with my 48RE according to pan temperature. (I know there are a lot of arguments where to measure temperature and I don't want to go there. ) The only time it has ever been even close to hot has been slow 4x4 work with a light load of camping gear. I suspect I was running in 2nd unlocked from what I am reading here. Thanks again for the information.

 

[JFN]

I back home from a 2600 mile trip to Durango, thanks for all the advise offered, the trip went without a problem averaged 10. 7 MPG Computed. I discovered as I believe was mentioned that I can lock the converter in 2nd gear by manually selecting 2nd gear and a slight acceleration which I had to do once. I was surprised at the performance of this truck in the stock configuration, just great. Now I have been reading and have another question.

From what I read, if I install Water/ Menthol injection, it will lower the EGT'S and recover lost power from the heated intake air from compression? During the trip I found myself having to cancel cruise control and manually climb the hills as the EGT would go to as high as 1400 degrees, I don't know if this was sustainable as I only wanted to see how high it would go then I backed off and ran 1300 degrees for the climb, Will the Injection lower the EGT so I can use more throttle as I what I saw was about 65% power from the Edge gauges? another question, is this recovered power or added power? Thanks in advance.

As an added note,I would have been real concerned on this trip without the Pac Brake, it was great along with the MaxBrake.

 

[rscurtis]

JMHO, but save your money on the juice and install an aftermarket turbo and manifold. BD makes an exact replacement for your truck, their "Killer B". It will lower exhaust back pressure and temperature.

 

[cerberusiam]

These trucks will run 1450-1500 degrees in stock form. As long as you are not doing it for hours Cummins back channel communications say it is fine. Whatever they will run stock is fine.

The EGT your reading is a bit misleading because it is skewed towards emissions which holds higher EGT's than previous years. For the most part, this is accomplished thru the cam and timing. While the temps you see in the exhaust manifold may sems high the actual dewll time in the cylinder is short and the peak pressures lower. Less dwell time in the cylinder translates to less heat soak and less chance of piston or valve problems. Your observed EGT's are not neccessarily a bad thing in this case.

Water\meth injection has some benfits and some people think it is the best hting since sliced bread. In reality, it is not that great nor without problems. Methanol burns and will add power\heat. The water slows down the combustion process to regulate heat. Neither is really a "control" to high EGT's. The reality is under hard throttle and heavy loads the cylinder pressures likely rise beyond stock while showing slightly lower EGT's. It is has its uses but its not a silver bullet for EGT's at all.

The question of whether you will recover any power is moot until you use it all. For the most part, you will seldom see the load percentage go beyond 60-65% unless it is being hammered. That is all the potential power it really takes to do the job in most cases. The engine itself may be capable of 325 HP but that is 100% load at rated rpms. You just never see that in daily use. More likely the average usage is in the 45-55% range for towing and well under 20% empty. Gauges that show load numbers are interesting and can be usefull at times if you understand that 100% is not really the top number. For all intents, if you could get it read 100% it would be power available not extra power.

From your description you really don't need to do anymore if you are happy with how the truck runs. A different turbo that will match stock spool and driveability is not cheap. Water\meth has its cons. Drive it and don't worry too much, I think it is performing well within acceptable parameters.

If you are not happy with the power, then, all I can is it is a slippery slippery slope from here out.

 

[JFN]

RSCurtis, thanks for the opinion, I really didn't want to invest that kind of money, I was just looking at the possibility of recovering some installation HP loss on hot and high days and not abusing the drive train, you star with turbos, programmers and intakes when you should start with flex plates converters and transmissions.

Cerberusiam, thanks for the input, the only reason for looking at injection is it is cheap, appears to recover power, I understand it and I didn't feel it would over stress the drive train as mentioned above, with that said you are right it runs great really has all the power I need so I'll just probably as hard as it is for me just let it be and save the money. Thanks Again

 

[WhiteSheep]

I just returned from a trip that involved a slow speed (20 - 30 MPH) climb of about 2500 ft over bout 5 miles to 7000 ft pass on a twisting mountain road pulling my ~5000 lb TT. I manually selected 2nd gear because the 48RE wanted to shift up and down from 2nd to 3rd. Temperatures in my pan peaked out at 180 F and stayed there, but it was clear the TQ was not locked up. I had more than enough power and no temperature issues with the engine. Is this of any concern, or the way it should be?

Cerberusiam, you mentioned modifications to the 48RE that would allow for TQ lockup in 2nd gear. What is involved, how does it work and how much does it cost? Any direction you would be willing to provide would be appreciated.