Cowl Hood

[fgarrett]

Has anyone tried a cowl type hood to lower under hood tempatures, and does it work?

[chevy05]

I just got one it is 2" metal and I am not running the liner under it. I just put it on less than a week ago and the temps got way colder this weekend while I was towing. I did tow my boat last sunday after I put it on and it seemed to really lower the underhood temp. When I got to the lake I could see the heat rising out of the cowl. So it does have somewere to exit for sure.

[Joe]

Has anyone tried a cowl type hood to lower under hood tempatures, and does it work?

While they do push cooler air into the motor compartment from the windshield cowl, they are mostly for looks. Are you having an issue with high temps under the hood?
If so, that should be addressed in other ways.

[fgarrett]

While towing with the 7.4 it gets pretty hot under the hood which causes the computer to start to pull timing. I was thinking about ways to help keep temps lower.

[1998454]

intake air temp causes the timing to be pulled out of the 7.4 I can't remember the temp at which the timing starts getting pulled. If you have an aftermarket cold air intake like a k&n it is pulling more hot air than the stock airbox. The only setup i've seen that works is the stock pipe with insulation around it. A cowl hood has to help some with underhood temps as well.
While towing with the 7.4 it gets pretty hot under the hood which causes the computer to start to pull timing. I was thinking about ways to help keep temps lower.

[kwbudaman]

I did some datalogging during May with a temp probe inserted into the passenger side inner fender area where the factory air box gets its air. On the whole, the heat soak from the engine compartment adds not less than 5 degrees to the outside ambient air temp. With slower speeds, the air temp ramps up rather quickly in the inner fender area heading into the factory airbox. In an effort to figure out how to get more cool air into the inner fender, I have been staring at the area behind and around the right turn signal for a couple of weeks now trying to figure out a solution. I recalled one person in the monster thread had modified the right turn signal to half its original length to create a "window" for more air flow back to the inner duct, but really didn't want to modify the turn signal assembly. (2000 GMC)

While in my local hardware store Saturday, I saw a display of 3 inch round aluminum elbows for propane water heaters, and got an idea. Those elbows have pie shaped sections to them, and can be rotated to make a bunch of odd shapes, including making the piece straight. So after work today, I went out and twisted it into a variety of different bends, and found out it can neatly reach from directly beneath the turn signal, all the way to the plastic inner duct that routes the air to the inner fender area, AND the turn signal assembly can be put back in place with little to no interference. All that is left to do is drill a 2.5 to 3 inch hole under the turn signal area in back of the duct. Not really sure how to close off the duct in the winter, but that will be worked out here shortly.

Happy Father's Day!

[gmctrucks]

Does your truck have electric fans? If not buy a heavy duty clutch or rod out radiator also check for mud on radiator or bugs.

[1.721afr]

Has anyone tried a cowl type hood to lower under hood tempatures, and does it work?

Welcome to FSC.

Yes, other than extra underhood clearance that is the only mechanical reason to use an un-sealed cowl hood. There is NO cool air induction unless the duct is sealed to the intake, period.

Proof is shown when you tape streamers to the area in question, the air pressure trapped under the hood far exceeds the cowl pressure.

[fgarrett]

When I put in the 7.4 the factory air intake was not there, so I got the K&N cold air intake. Now I am thinking about fabing a sheet metal box and changing to a factory type filter, in NM it is hot & dusty, and I read a report on the K & N filtering, not good.

[1.721afr]

I use K&N...precharger.

I'm not sold on their filter program. I've seen 'em pass plenty of crud and maintenance is a huge hassel.

So what type of rig are you running?

[fgarrett]

It's a 1997 C-3500 cclb engine has 7000 miles since build. Orginally had the 5.7, now it's got a 7.4 with K & N Cold Air Induction, Granatelli 85mm mass air flow sensor, bbk 80mm throttle body, 10.5 to 1 compreeion, Competion Cams XR285 HR cam, Comp. Cam Magnum Roller rockers, Comp Cams Roller Lifters, Gibson Mid length headers, Fac. cats, Flow Master dual in / dual out muffler, MSD 6A module, MSD coil, MSD 8.5 Plug wires, 4L80E Transmission, B. F. Goodrich KM 2 LT285/75R16 tire 4.10 rear end, Wester tune. I have a 411 computer I am going to add. As soon as I get it back together, then a Black Bear data logging tune. Way to much money spent on this beast.

[K Berg]

A really good way to lower underhood temps is to run headers that are heat wrapped. Funny thing about the cowl induction hoods on my 84 Blazer and 99 Suburban is when there is snow/ice on the windshield in the winter I can see it melt and soften up faster than the defroster can get it to work from the fan pulling air through the rad and over the hot engine. It helps slightly when sitting still or for instance when you are towing the camper down the beach through sand at a very slow speed while making the truck work.

[Joe]

How did some of you end up posting about air intake to the motor? I believe he is asking about lowering the overall temp in the motor compartment :cool:

[Metalsmith 1]

Hi-jack.... Bogart !

[383beast]

I need one for my truck.