deuce boost

[hook7800]

How much boost will a white 1c multi fuel take before head gasket failure

 

[doghead]

There are too many variables to consider, to answer that.
The engine generally operates with up to14-15 psi boost, just fine.

 

[AceHigh]

Keep boostin and let us know how it worked out for you.

 

[hook7800]

you can live off bread and water just fine having more is always better

 

[doghead]

Better get some spare pistons, anymore boost, and on a hard acceleration, your EGTs will get too hot and melt them fast.

 

[scrapman]

The variables are new vs. old style head gasket. Clamping force of the studs. Has the motor been abused in the past. I.E. run hot? Older block with the thinner deck therefore more prone to deformation as opposed to the newer TD block. Age of the motor in regards to the last overhaul. But for the most part you will run into problems with excessive EGT's before boost become a main concern on the C-D turbo'ed LDT 465's.

 

[Jakob]

Would there be anything to gain in effeciency by swapping in a Cummins turbo or something similar? I'm not sure if it'd even be the right size, but I imagine turbo technology has come a long way since the C and D turbos were designed.

 

[jwaller]

Would there be anything to gain in effeciency by swapping in a Cummins turbo or something similar? I'm not sure if it'd even be the right size, but I imagine turbo technology has come a long way since the C and D turbos were designed.

short answer is no. I've tried several different turbos and all of them have spooled slower giving more lag and much worse acceleration.

now with money for a ball bearing turbo then sure you can but I doubt anybody on here wants to spend more on their turbo than they did for their truck.

 

[jimk]

The early head gasket has a history of failure.

I'd say egt is more the more important factor, though boost and egt are related. Irregardless of the HP increase (and its associated increase in egt) higher boost pressures will increase egt because the induction air is heated by compression. That hotter air is also less dense so there is a performance loss while stress goes up. That's bad cycle to peruse. While opinions vary I'd say this negative effect is minimal below 10psi where induction tem is at or below 200*F. It rises after that. I found that the LD465 is completely safe at or below 10psi. At 12psi /2500rpm (or 13psi /2600rpm) you could get excessive egt under some rather extreme conditions, like towing overloaded up hill on a hot day and , more importantly , lugging the poor thing at the lowest part of the operation range. The solution is to downshift. You'll see an immediate drop in egt. You could probably get away with more boost (note- but not much more) but it would be wise to watch what you are doing with a pyro. If you are loaded light all the time you may be ok to take a bit more because you will probably tack out before anything gets too hot.

More boost may be possible if you were to intercool. But where will you put the radiator? Some here have used water injection to lower egt when it gets too high. I run a 2500 redline and have held the boost at 12psi for hour after hour. Never a problem.

My engine had its head gasket replace just before it fell into my hands, so it runs the updated(better) gasket. I did a retorque before adding a -d- turbo, did the valves [adj] at same time. I oiled the nuts and used the correct c wrench. I added 5 lb/ft to spec. I say its good to start with a healthy engine and then take care of it [when increasing stress].

 

[mudguppy]

... anymore boost, and ..., your EGTs will get too hot and melt them fast.

Boost does not create high EGT's.

 

[Chinookpilot77]

I agree with mudguppy. Common thought in the performance diesel world is boost brings EGT's down, which allows you to turn up your fuel, which THEN brings EGT's back up.

But the answer remains that the multi is very old technology, and is no where near ready to compete with modern diesels.

 

[tm america]

mine will run over 25 on the boost havent melted it or blown a headgasket yet been running it for about four years with it turned up that far

 

[scrapman]

Yes, the multi is an old technology dinosaur in the modern world, yet when it comes down to survival in primitive conditions it is still a king. Take your "HotRod" cummins and feed it a load of bad fuel, a mix of WMO, ATF, paint thinner and see how far it will go down the road. Soon the multi will blaze around you at a speed approaching 43.267 MPH while your sensors & computer are trying to decode WTF happened to the fuel supply. Talk to the field mechanics and almost everyone of them will tell you that the Hummer will not take the abuse that the M-series trucks do. The M's were built to survive in the most raw conditions. In the asphalt world your cummins/dodge may be a better truck but when it comes to all around durability and load transport King Deuce is a slow & strong winner.

 

[scrapman]

mine will run over 25 on the boost havent melted it or blown a headgasket yet been running it for about four years with it turned up that far

Where are you at on EGT's? When I set fuel to 1100-1150* I get 10-12# boost. Periodically I've turned fuel up to 1300-1350* & have gotten 15#. What turbo do you have? Mostly the concern with high EGT's is meltdown of the tubo. Titanium wheel would be great but, the cost would be so special.

 

[tm america]

i have a d turbo dont know about egt dont have a pyro on there just a boost gage

 

[OPCOM]

with non whistler turbo, 9 psi at 1100 degrees pre turbo. I don't push it past either of those and I don't stay there for long. more like 7 PSI and 900 degrees.

 

[jatonka]

a guy who is gonna screw with the fuel to increase boost really ought to buy a pyrometer, or if you don't care about EGT, buy a spare engine. Old age and experience are making me smarter all the while, heck, I caught up to my 22 year old son the other day. He's hot.

 

[mudguppy]

... Take your "HotRod" cummins and feed it a load of bad fuel, a mix of WMO, ATF, paint thinner and see how far it will go down the road. ...your sensors & computer are trying to decode WTF happened to the fuel supply. ...

what sensors? my 12v cummins will run on all that just fine - it's all mechanical.

... Talk to the field mechanics and almost everyone of them will tell you that the Hummer will not take the abuse that the M-series trucks do. ....

well, yeah - but hmmwv's suck.... (just giving you a hard time)

i'm really not trying to argue anything against the deuce or multi's. in fact, it's been highlighted a few times already that the multi was way ahead of it's time as far as diesel technology.

however, that time has come and gone. it still does the job just as good as it was designed to do almost 50 years ago. just because there are better motors out there doesn't mean that the multi needs to go away!!!

besides, i haven't heard anything yet that can replicate that multi grunt + C-turbo sound!!!!!

 

[jimk]

Boost does not create high EGT's.

That is a bit misleading. There is a complex relationship here. In the LDT context you won't get much boost unless extra fuel is added. That will raise EGT. If max boost is increased egt gets increased heat of compression as well as the higher combustion temps. I think what you mean is just adding air will not raise egt. At low pressues (LDT context) that will hold true but if you try and grab manifold pressures the engine was not designed to take you get problems. SS tracxtor pullers would melt parts with their 250-300psi manifold pressures if gtallons of water were not added. Big rig engines wouldn't survive 40 psi if the intercooler is removed.

My truck does have a drop in egt if I down shift and run it at higger rpm, and boost, however the egt will rise, and to dangerous levels, if the pump is re-adjsuted for higher boost.

I guess if you put a bigger compressor on the LDT turbo you could lower egt by adding extra air at higher boost.


Turbocharger - Wikipedia, the free encyclopedia

Boost threshold
Turbochargers start producing boost only above a certain exhaust mass flow rate (depending on the size of the turbo) which is determined by the engine displacement, rpm, and throttle opening. Without an appropriate exhaust gas flow, they logically cannot force air into the engine. The point at full throttle in which the mass flow in the exhaust is strong enough to force air into the engine is known as the boost threshold rpm. Engineers have, in some cases, been able to reduce the boost threshold rpm to idle speed to allow for instant response.[9] Both Lag and Threshold characteristics can be acquired through the use of a compressor map and a mathematical equation

Temperature considerations
One disadvantage of turbocharging is that compressing the air increases its temperature, which is true for any method of forced induction. This causes multiple problems. Increased temperatures can lead to detonation and excessive cylinder head temperatures. In addition, hotter air is less dense, so fewer air molecules enter the cylinders on each intake stroke, resulting in an effective drop in volumetric efficiency which works against the efforts of the turbocharger to increase volumetric efficiency.
Aircraft engines generally cope with this problem in one of several ways. The most common one is to add an intercooler or aftercooler somewhere in the air stream between the compressor outlet of the turbocharger and the engine intake manifold. Intercoolers and aftercoolers are types of heat exchangers which cause the compressed air to give up some of its heat energy to the ambient air. In the past, some aircraft featured anti-detonant injection for takeoff and climb phases of flight, which performs the function of cooling the fuel/air charge before it reaches the cylinders.
In contrast, modern turbocharged aircraft usually forego any kind of temperature compensation, because the turbochargers are generally small and the manifold pressures created by the turbocharger are not very high. Thus the added weight, cost, and complexity of a charge cooling system are considered to be unnecessary penalties. In those cases the turbocharger is limited by the temperature at the compressor outlet, and the turbocharger and its controls are designed to prevent a large enough temperature rise to cause detonation. Even so, in many cases the engines are designed to run rich in order to use the evaporating fuel for charge cooling....