Insulate intake?

J

jollyrogr

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WVRigrat05 said:
Get a full S&B intake and a cowl hood. I just cut the back side out on my Chevy hood and it helped a fair bit. I'd imagine an actual cowl hood would work great.

Stock to stock, that LLY is gonna be harder to keep cool compared to an LBZ/LMM.

I had holes cut and opened up where I could and it still wanted to get hot when you beat on it.
Click to expand...

Others have done testing and determined that holes drilled in the back of the hood don't help. Going down the road air actually gets sucked in through the holes as a opposed to drawing hot air out.

LLY's being what they are, gauges are important so you can watch your EGT's and know when to let off the pedal. The only real proven solution to the overheat problem is an auxiliary radiator to get the cooling system up to snuff with what GM put in the LBZ trucks. Having said that, high IAT's contribute to cycling up the ECT so helping the engine breathe cooler air will help (not solve) the problem. Ideally I'd like to find a cheap used LBZ airbox or get a volant LBZ intake with the Donaldson filter.

PS. what's "hg's"?
 
c20elephant

c20elephant

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Apr 25, 2013
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Part of the problem is at the bumper and the panel that directs airflow to the bottom of the radiator where the airflow is blocked to the bottom 2" of the radiator. Pull the grill and take a close look, mine is a LBZ and I lowered my ECT's cruising in 115 degree temperatures by 15-20 degrees.

Not sure how much different the LLY's are but from pictures I have seen on the links I posted earlier not much...

It's a bit of work but where I live it's worth it and the truck ran much cooler during the recent 115-120 temperatures we had than in past years...

Try some fender vents to vent the engine compartment air pressure allowing more in through stack. Install a 3" valance to increase nose pressure at the grill...

http://www.duramaxdiesels.com/forum/showpost.php?p=1003270&postcount=21
 
J

jollyrogr

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LBZ's do have a larger radiator than the LLY's. Combine the smaller heat exchanger with the same lack of air flow and it's not a surprise the LLY struggles with heat rejection.
Excellent post c20elephant, I think modifying the front to let more air through is a great idea, and you made it look good. :thumb:
 
c20elephant

c20elephant

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jollyrogr said:
LBZ's do have a larger radiator than the LLY's. Combine the smaller heat exchanger with the same lack of air flow and it's not a surprise the LLY struggles with heat rejection.
Excellent post c20elephant, I think modifying the front to let more air through is a great idea, and you made it look good. :thumb:
Click to expand...

I don't believe the radiator is larger, the fitting on the passenger side is a slip connection type whereas the LLY is a clamp type.
 
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Chevy1925

Chevy1925

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Oct 21, 2009
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jollyrogr said:
Others have done testing and determined that holes drilled in the back of the hood don't help. Going down the road air actually gets sucked in through the holes as a opposed to drawing hot air out.

LLY's being what they are, gauges are important so you can watch your EGT's and know when to let off the pedal. The only real proven solution to the overheat problem is an auxiliary radiator to get the cooling system up to snuff with what GM put in the LBZ trucks. Having said that, high IAT's contribute to cycling up the ECT so helping the engine breathe cooler air will help (not solve) the problem. Ideally I'd like to find a cheap used LBZ airbox or get a volant LBZ intake with the Donaldson filter.

PS. what's "hg's"?
Click to expand...

the aux rad cooler will add more cooling than just the 30% increase in cooling capacity the lbz has over the lly.

c20elephant said:
I don't believe the radiator is larger, the fitting on the passenger side is a slip connection type whereas the LLY is a clamp type.
Click to expand...

as jolly posted, the LBZ rad has a 30-33% increase in cooling capacity over the LLY. this is due to the taller radiator they use and other little things like a bigger fan and so on.
 
WVRigrat05

WVRigrat05

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Jan 1, 2011
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Chevy1925 said:
the aux rad cooler will add more cooling than just the 30% increase in cooling capacity the lbz has over the lly.



as jolly posted, the LBZ rad has a 30-33% increase in cooling capacity over the LLY. this is due to the taller radiator they use and other little things like a bigger fan and so on.
Click to expand...

It does and I have found it to be useless if you tow like an asshole.
 
Dozerboy

Dozerboy

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I dog the shit out my lbz 3500 work truck in 100* probably over loaded and didn't over heat it.

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Chevy1925

Chevy1925

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WVRigrat05 said:
It does and I have found it to be useless if you tow like an asshole.
Click to expand...

Its a big difference over what im currently dealing with. i dont have to drive anywhere near like an asshole when towing to get my truck in the 230-240 coolant temp range when towing over the summer. Im looking at doing the aux radiator and redoing my front bumper or swapping to LBZ cooling stack with a ron davis radiator to get me somewhere close to 50% cooling capacity increase. at this point, i cant make up my mind on direction.....
 
WVRigrat05

WVRigrat05

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Jan 1, 2011
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My LLY would get hot on a dime before it was built, after it was done it never ran hot, power steering and all was in check.

This LMM at 13k miles set up same as now minus the built trans ran hot as **** pulling the same camper as the LLY. Motor ran 230+ on any good grade and trans was 210 or so, that was towing 11k at 70-75 mph.

Trans could have been slipping just enough to heat soak everything. I haven't towed with it since the teams was built, but it weights 9200 right now as it sits and I ran 100+ to butler Pa from the house this morning on the 150 tune and cool as can be.
 
malibu795

malibu795

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Apr 28, 2007
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Aftermarket fan clutch(hayden 2886) will help as well.
James is far end like to tow ~15k trailer with 600hp or better :rofl:

Ive thought about putting thermal barriers on the air box and piping to turbo.. but iat are within 5° of ambient and i spend 90% of my time moving..
I do notice truck runs better in 60° ambient vs 90° ambient
 
countrycorey

countrycorey

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Jan 30, 2010
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Chevy1925 said:
Its a big difference over what im currently dealing with. i dont have to drive anywhere near like an asshole when towing to get my truck in the 230-240 coolant temp range when towing over the summer. Im looking at doing the aux radiator and redoing my front bumper or swapping to LBZ cooling stack with a ron davis radiator to get me somewhere close to 50% cooling capacity increase. at this point, i cant make up my mind on direction.....
Click to expand...
Have any more details on the Ron Davis radiator?

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S 854

S 854

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Nov 1, 2015
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A quick update with some ScanGauge II readings

Stock air box... Ambient temp 92* -- IAT 10 - 15* over that at highway speeds... IAT as high as 187* stopped in traffic...

Stock AB with redneck cold air intake... IAT 10 _ 15* over ambient and the filter minder gets sucked down almost to "replace"... 140* or so stopped

Front triangle of AB removed (pulling our FW for these readings)...2-3* over ambient on the highway... 132* stopped (got up to 155* at extended idle whilst hooking up the FW) IAT dropped almost immediately as I began moving... With the engine fan engaged the IAT didn't clime more than 5-8* pulling in Denvers slow and go rush hour traffic...

So... I'm not completely convinced I need to insulate the intake to keep false readings at bay...

We're heading to the hills this weekend so maybe I'll take along some insulating wrap just as a further experiment...
 
J

jollyrogr

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Jun 23, 2016
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Thanks for the info. Insulation probably not needed if we can draw cool air into the intake. :thumb:
I want to try replacing my airbox with a Volant for an LBZ so then I'll essentially have a complete LBZ intake
 
Dozerboy

Dozerboy

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What IAT are you reading IIRC 1 is in the intake the other is post intercooler?

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