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Twin Turbo Deuce

gimpyrobb

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Flea said:
No matter how you slice it, it would be great if we could figure out how to remove the engine coolant jacket from the intake manifold, throw on a good intercooler (like from an Isuzu NPR truck or similar), and see how much we can drop air intake charge temps. But the good 'ole multi just isn't going to be able to boost much with a non-intercooled turbo and a high compression ratio.
I think Bjorn tested this and found that the water in the intake DID infact cool the charged air. Weather you can cool it more, with another method/intake, has yet to be seen. Anyone else remember which post that was?
 

Flea

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gimpyrobb said:
I think Bjorn tested this and found that the water in the intake DID infact cool the charged air. Weather you can cool it more, with another method/intake, has yet to be seen. Anyone else remember which post that was?
I remember that, but at peak operating temperature, you're only cooling the air charge to about 180-200*. I decent intercooler could get those charges much lower than that.
 

Rolling_Eudaimonia

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Re: RE: Re: RE: Re: RE: Re: RE: Twin Turbo Deuce

SasquatchSanta said:
Rolling Eudamondia wrote:

Are you running 14:00x20s or 16:00x20's on it and if either one how much in travel did you lose if you went with stock suspension linkage? If not what sort of modifications did you make to it give you full travel in the rear axles.
I'm running 395X85XR20s. They are a little smaller than 14:00s. I originally had 14:00s but I felt they took a lot of starch out of the original LDT engine. I'm sure the LDS engine would spin the 14:00 with no problem.
yeah the original LDT is a little on the underpowered side, what is the LDS really make about 180-200hp? They used to put Mack 673 T's in some of the five-ton models, I wonder if the bolt pattern is radically different between LDT and 673T? The old Mack would do 240-250hp no problem.
 

Rolling_Eudaimonia

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Re: RE: Re: RE: Re: RE: Re: RE: Re: RE: Twin Turbo Deuce

gimpyrobb said:
My lds motor moves the M62 wrecker like its nothing. I think the data plate spells out 30,318lbs.
what's the CID on the LDS-465, still 465 cid, I read on Clark Truck Parts 602cid but that seems bit too large for the LD-465 series...

myself if I wanted to really hot-rod a deuce or a five-ton, can you say Deutz 2015 V8 670.5hp at 2100rpm and 2133 ft-lbs of torque starting at 1400rpm. That would of course require custom axles, transmission , drive shafts and transfer case but it would be so worth it in the end.
 

ken

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I guess i'll throw my two cents in. The Stock turbo both the "C" and the "D" are more than cappable of sending little chuncks of head gasket all over the engine compartment. Please don't ask how i figured this one out. I have done alot of modifing and testing on these at work. The "D" is mapped to the mutli pretty close. With the "C" bringing up the rear.
Heat from the exaust gasses expanding is what propeles the turbine. The more heat you add the more turbine RPM's you get to a point. You can turn the fuel rate high enough to make the stock turbo's compressor wheel cavatate. After that vibration starts it's not long before you get a nice size granade that's bolted to the passenger side of the engine. Please don't ask how i know this one eather. Any more heat and you start to loose effecency. No engine on the planet can burn all the fuel it's givin at any fuel rate.But the black smoke you see is carbon. There is allways carbon in the exaust from any engine that's running gas or diesel. It's just usally at a small enough amount that it can't be seen. White smoke is unburnt fuel. The best way to get the most power from any diesel engine is to use both boost and pryo gages. That way you know when you are adding more fuel than your engine can burn.
Also it's not how much boost you get that helps give you more power. It's how many cubic feet per minute of air the engine can digest with the proper amout of fule added. I've gotten much better results by modifing the air casings on the stock turbos. The point is to remove as much turbulance from the air as possable. This allows more air to enter the engine and helps reduce the chance of compressor wheel cavating. Or surging. This also helps reduce the charge air temp. When you comperss air it heats up. The easier it flows the lower the temp. Somewhat. Wow this loooks like it ended up being more than two cents.
 

ken

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The biggest results i got on the flow bench were from tapering the intake of the charge air casing in the lathe. I found that 3 angles have worked out the best. 40 deg at the mouth. 8deg further in and 3 deg up to 7/16 inch from the start of the compressor wheel. This is on the "C" turbo. the "D" has a stepped intake throat and there isn't much you can do. I've cleaned up the casting roughness at that point but didn't get much more air flow.
I have also gottin decent results from polishing the inside of the elbow that bolts to the intake manifold from the turbo.
Anybody have a spare LDS turbo with the waste gate? I's like to do some experments with it.
 

SprayPattern

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Turbos are fun. I have been playing with them on diesels for quite a few years now. My daily driver is a compound turbo 7.3L light diesel that performs beautifully in terms of heat management, smoke control and power output.

When it comes to multiple turbos, there are a few good reasons for doing it. But first I think it might be good to lay down some ground work in terms of multiple turbo configurations and the terms associated with them.

Parallel: or "Twins" is the most common on spark-ignition engines. This is where each unit is responible for half of the load and recieves half of the exhaust energy. They are usually located one per bank on V-configuration engines, although they can just as easily be placed sided by side on a divided header inline engine. The reasoning on a smallish displacement engine making marginal power is largely just the "cool" factor, as a comparably capable single unit with a proper wastegate will produce equvelant results. Sometimes packaging lends itself to placing two units as well. However, with larger displacement engines, and or those producing higher than average power output, you can quickly reach the limits of available compressors that will move the required airflow for the power. In this case, you have to parralel the stage with two smaller, and more readily available turbochargers.

Sequential: Same basic premise of the parallel with the twist that the exhaust gas controlled so that it will initially provide most of its energy to the smaller turbocharger and then as manifold boost rises, a diverter of some form will begin to transistion the exhaust gas energy over to the larger turbocharger for higher rpm operation. This is most likely the least used configuration, although some OEM's actually employed this method for a time on some cars such as the supra.

Compound: In this configuration the exhaust path travels from manifold to the turbine inlet of the small charger (second stage) and then from the turbine outlet of the second stage to the turbine inlet of the large charger (first stage) and on from the turbine outlet of the first stage to the exhaust system if so equipped, otherwise directly to atmosphere. The air inlet track follows from atmosphere to first stage (large compressor) to second stage (small compressor) to engine intake manifold.


One of you already mentioned losing lower rpm power by running a larger turbo, but gaining higher rpm power. With compound turbocharging you can run a small turbo for spoolup and run a large one for high rpm power at the same time. Another benefit is that each compressor is now doing a fraction of the work for any given manifold boost (not half the work) so it's much easier to maintain excellent compressor efficiencies even with moderate to high manifold pressures.

Compound turbocharging and diesel engines go hand in hand in my opinion. You can produce substantial power without losing any low rpm power or dealing with excessive exhast gas temperature when operating in the lower rpm range. And visible smoke can be completely done away with.

As has already been said, adding a turbocharger to an engine that is already running clean without any tailpipe smoke will not result in any additional power. The same can be said of making a turbocharger swap on an engine that is already turbocharged but is not smoking at all currently. To add power you must add fuel. And brining in additional intake air affords you that option.

It should also be said that you can produce a higher volume of intake air charge to the engine without raising the boost. If one compressor is more thermally efficient at any given rpm/boost than another, it will make more power and smoke less without raising the pressure at all. Because the intake air charge while at the same pressure, is cooler and more dense. It is also possible to produce more power on less boost if the efficiency is high enough on the compressor of the new turbocharger vs that of the original.

Does anyone make head studs for these engines? If not, they are not cost prohibitive to produce in short runs. Especially for what would likely be a light duty application such as this. With a good head and block sealing surface and a set of headstuds the only thing you should be worrying about are the rods, block and bearings with increased cylinder pressure.

Either way, if the truck is smoking, you can definately clean that up with proper turbocharging. Intercooling would also be a good option for increasing the intake air volume, but I don't know if these things are running enough boost to see much gain from it.
 

cranetruck

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Welcome to the site Spraypattern...The turbo in my 8x8 truck is described as "dual chambered", could you expand on that since you seem to have a lot of knowledge here?
Thanks
 

SprayPattern

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It might be referring to a divided turbine housing. That is when you have two seperate volutes running right beside one another around the turbine scroll toward the turbine wheel. It is done in an effort to align the exhaust pulses based on firing order so that the turbine wheel recives a more consistent sequence of pulses and so that valve overlap on one cylinder will have a harder time effecting the exhaust drive pressure in the manifold when and if any reversion takes place. It's really only of any value at low operating rpm where the exhaust pulses are spaced farthest, and it only makes sense when the exhaust manifold/header is also designed to provide each pulse to each volute in a way that keeps exhaust pulses in order as well.

On my pickup I have a divided housing on my second stage because that is the way the housing was made, but not on the first. By the time the first stage lights off, none of that matters anymore anyway.

That's my best guess as to what "Dual Chambered" means. Although I may be way off base.
 

russ81

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Spraypatter,

Thank you for your insight and experience in dealing with turbos. I have an extensive mechanical background, and really enjoyed reading your write up. I am new to dealing with large turbo charged diesel engines, so finding people like you to help me along is really appreciated.
Keep up the good work........we can all learn something here.
 

FreightTrain

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Re: RE: Re: RE: Twin Turbo Deuce

dm22630 said:
If one turbo adds power without sucking in additional fuel.....then two could produce more power & push the deuce down the road and up hills at lower rpms??

It is late...and I am tired.

I apologize for my ignorance.

Thanks for the responses......
Ummm,Only way your gonna drop RPMs is bigger tires or different gears.You can put 6 turbos on the engine and make 2000HP but your gonna be at the exact same RPM in the same gear no matter what.These are diesels.Low end torque high end Horsepower.You gotta let the RPMs get up there to get any Power.Plus,last thing you want is low RPMs when loading the engine.
 

BobS

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RE: Re: RE: Re: RE: Twin Turbo Deuce

ROT-Cool the intake charge to ambient temp + 115 degrees F MAX for most power gain per dollar spent on hardware.

(ROT=Rule Of Thumb-basic design parameters we used at DDC.)

Best regards,

Bob
 
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