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Questions for the diesel folk


Nate1647545505

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Guest chpmnsws6
yea but the dodge has a 7.5 in them and a big ass turbo

 

Huh??? I'm new here so I'll be nice. No, they do not have a 7.5 Cummins. They have a 5.9 common rail and an upcoming 6.7 (stroked 5.9). Ford had a 7.3 but went to the 6.0 (very bad move on Ford's part, so that engine is already being pulled off the line) and chevy has the 6.5.

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Huh??? I'm new here so I'll be nice. No, they do not have a 7.5 Cummins. They have a 5.9 common rail and an upcoming 6.7 (stroked 5.9). Ford had a 7.3 but went to the 6.0 (very bad move on Ford's part, so that engine is already being pulled off the line) and chevy has the 6.5.

 

"chevy has the 6.5." and more currently, the 6.6 Duramax.

 

brnadon.

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plus 1 on the 6.2 and 6.5's, I replaced lot's of injection pumps, and motor's in a lot of the HD truck's....

 

I hate those, I have done about 50 of them. Head gaskets on those are the suck too! Damn heads wiegh about 80lbs a peice!

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You know, I tried.

 

Audi's Lemans car made 1000ft/lbs and only 600hp. Surely you would want something that sustained HP for gearing and for the sake of not putting 1000+ft lbs through your tranny.

 

I could be wrong though, any examples you can post up?

Torque will always be greater then HP until 5250 rpms. Most diesels don't rev that high anyway. The lower HP rating on the Audi is for the same reason. I think they said it makes peak power between 4 and 5000 rpms.

 

Because of the broad torque curve they were able to use a 5 speed tranny instead of a 6. This reduces the number of shifts in a race and also allowed them to make the gears stronger without increasing the overall size of the transmission. Both shoud help their reliability during the race.

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Smaller diesels do use spark plugs. Mid sized use glow plugs for initial fire up, and full sized diesels do not even use glow plugs.

 

Sparks plugs????? Whats the point of a diesel with plugs???? And full size diesels with no glow plugs.... maybe no glow plugs but some way of heating the air.... I declare shenanigans.

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Sparks plugs????? Whats the point of a diesel with plugs???? And full size diesels with no glow plugs.... maybe no glow plugs but some way of heating the air.... I declare shenanigans.

The large diesels have enough cyliner volume that they will typical be able to reach the ignition tempature witout requiring a glow plug. I just went out and checked, my 230 cummings does not have glow plugs. It does have a compresion release that releases 4 of the cylinders and allows the engine to spin faster and build up compression in the remaining 2 cyls so they have a beter chance of igniting.

On some diesels, there is a glow plug and fuel injector in the intake that warms the incoming air when you first start. (basically buils a small fire in the intake)

If all else fails, eteher will get it done (atrisk of making the engine an "ether baby" dueto the wash down on the cyl walls making it start to lose compression.

Due to the heavy internals of the diesel(piston that has to withstand the compression force, high initial pressure fo the ignition, potentially high EGT) and the longer stroke to make the higher compression ratio, they just dont spin fast. There are some exceptions with the smaller diesels, they have a shorter throw, and can rev decent (anyone, espicially the ogre, whats the redline on a diesel VW rabbit?)

EGT is the killer on the diesel, if it gets close to the softening point of aluminum, your piston is going to look like Tilley's piston.

Quick info on tractor pulling, you hafto use the stock block. Thats about it. Whatever you can cram into that block, go fo it. Also, they use external girdles to help keep the head from coming of the top, and the crank from coming out of the bottom. Some are running 120+psi on staged turbos, and also use water injection as an intercooler. Very interesting to look under the hood, even more interesting to help build one.

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Guest chpmnsws6
When i get home, I'll crack open the notebook and see which one Mr Marshal said had spark plugs. We are talking small generator type engines. I was also VERY suprised by it
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