Engine/Transmission (1998.5 - 2002) Am I blocking too much air?

[Adam]

I got to thinking about the intake air temps recently and I recall in another thread that the turbo heats to some 200+ degrees, and the charge-air-cooler reduces it to about 20 degrees above outside temps. This seems to make sense, but I'm trying to figure out what happens when the entire CAC is blocked off. When it's -20F, I block the entire grill with a sheet of canvas behind the grill right in front of the radiator. This makes the truck run at almost normal temps, but what affect is it having on engine performance? Should I open it up a bit and deal with the decreased engine temps, am I doing the best I can, or am I just stuck in that never-never land of turbo pro's and con's?

Thanks,

-Adam

 

[Diesel Freak]

You are doing just fine. The only time the turbo really heats the air is when it is making high boost. During normal every day commuter driving or going down the highway, turbo discharge temp is quite low (0-15 psi)



assuming air going into the turbo is at 0F, boost at 15 psi, and 75% efficiency, turbo discharge temp should be 137F.



Keep your canvas where it is till spring time.

 

[illflem]

You're fine

I run fanless with a winter front in Montana for six months out of the year and also have an intake air temp gauge. Have rarely seen the post intercooler intake temps more than 20° above the outside temp until the outside temp gets above 75°, then it's time to take the cover off. Fan doesn't need to go back on until the 80°s. Have more of a problem here with intake temps being too cold. Ideal intake temp is 50 - 90°



Unless you cover 100% of your radiator it should have a hole in the middle. What happens if the radiator is only partially covered is the air flows though a small part and every time a fan blade passes this area it flexes a little till one will finally break off possibly causing major damage. This only applies if the cover is tight up against the radiator, if the cover is in the grill area the airflow has a chance to equalize. I've seen the fan blades break off mainly when a person puts cardboard right up against half to a third of the radiator. Plastic blades seem to tolerate it.

 

[Alan Reagan]

When I drove tractor trailers, the mechanics would always leave a hole in the middle of the cover on all trucks with a fan clutch. The ones with louvers, they would cover completely. The only explanation I ever got concerned the fan clutch engaging but not being able to pull enough air so the clutch mechanism was at risk due to the stress. Illflem has a good point on the flexing also as the blades reach "free air".

 

[roadranger]

Back in the '80's when Mack first came out with their in front of the radiator intercooler, they specifically prohibited the use of winterfronts because of the higher EGT's it would create.



Course, these were 300-350 HP engines moving 80,000 GVW trucks, and worked MUCH harder than our ISB's.

 

[EricBu12]

Look in the classifieds under member basment enterprises,

I have Winter fronts that go into the grille openings to block some air... not all, and you can use them from very cold to 65 deg outside temp. .

E-mail me below for more info



Eric

 

[Adam]

Fanless eh?

Illflem,



I'm presuming you just reach around the fan shroud and remove the four bolts holding the fan on? I know the center nut is left-hand thread, what about the fan bolts? Does the thermostat regulate the engine heat, or is there not enough excess heat to worry about. With everything buttoned up as it is now, I still have coolant temps between 180-190 after warm-up (outside temp is -13). Will going fanless cause me to overheat, or am I worrying about nothing?



Thanks for all the replies everyone.



Happy Holidays,



-Adam

 

[illflem]

Adam, I've never taken a fan off a 24 valve but know some folks have for the winter with no problems. On a 12 just the left hand threaded big nut, 1-7/16", turns off with the whole clutch and fan. Even though it doesn't look like it the whole thing will come out the top without removing anything else, it's bit of puzzle though, no forcing required.

Hit the nut on the right side of a flat with a long drift and heavy hammer, once is usually enough, then turn the nut clockwise while holding the pulley with large water pump pliers. Some folks use a screwdriver wedging between two pulley bolts instead of pliers. Once it cracks loose it will come off the rest of the way by hand.

 

[jerrethomas]

Originally posted by roadranger

Back in the '80's when Mack first came out with their in front of the radiator intercooler, they specifically prohibited the use of winterfronts because of the higher EGT's it would create.



Course, these were 300-350 HP engines moving 80,000 GVW trucks, and worked MUCH harder than our ISB's.

Macks didn't really need winter fronts cause usually the shudders would control temp pretty good when it was cold also.