Pro's and Con's

[Twisted Steel Performance]

Hypothetically, a person doesn't want to chop up a radiator support or add more to the cooling stack to install a A/A charge cooler, about the only place is the skid plate area...

SO.....

The cooler will sit above the crossover and be about a 40* angle, not the best for air flow but would work to a degree.

Their are ways to funnel more air to the cooler, let's here some ideas... I'll start....

Mount a air deflector to the front of the cooler that would redirect air into the cooler fins... This prototype is aluminum and would bolt to bosses welded to the flats of the cooler. The working model would be 11ga steel for strength if a cridder crosses the path...

 

[dbrannon79]

That looks good for the skid plate area. I don't know why, but the thought just came to me about those style fins on the top side of the hood like a hood scoop pointed forward so when traveling the air going over the hood would be forced into the vents through the cooler and into the engine bay. only question would be, is there enough room on the under side of the hood to have a cooler there and have some sort of flexible tubes to allow opening and closing.

 

[dbrannon79]

something like this would also help with heat soak along with a thin style fan inbetween the cooler and the vents that would run with key on.

 

[DieselAmateur]

I dig the extra protection for the cooler

for my dump truck I'm going to experiment with the Duramax LB7 radiator and charge air cooler in the stack. Want to have the fan pulling air through the CAC at all times and to have shorter piping from turbo to intake. Granted the engine will have Chris's coatings in the heads so it will have a leg up there. If I can get clean used LB7 parts I'll have those coated too

 

[WarWagon]

Hypothetically, a person doesn't want to chop up a radiator support or add more to the cooling stack to install a A/A charge cooler, about the only place is the skid plate area...

With the aerodynamic mess GM made with our bodystyle and already poor cooling stack airflow ... Is there any good airflow to be had in the skid plate area that doesn't mess with the stack airflow or allow it to recurculate hot air through that area?

FWIW RAM Cummins already uses an approach with a low sitting CAC at least for my 2018.

 

[Twisted Steel Performance]

Yes, that's part of my reason to use that area, also in the process of possible hood mods to extract heat and gain flow similar to what nascar does.

 

[dbrannon79]

I would be interested in hood mods. being that I have not gotten around to painting the hood on mine, adding something to it would be good, especially something that doesn't really stick up too far too!

 

[SnowDrift]

I have a ram air style hood where the air dumps down on the top of the engine, right over the intake. I've always thought it could be a good fit for an intercooler right there under the holes, with a foam gasket up against the underside. Without test date in a wind tunnel or something, however, it may just end up being a situation where the result is just an intercooler in a hot environment.

 

[Twisted Steel Performance]

I think @Paveltolz has louvers on his hood that pull heat out vs pushing air in. Pulling air out would pull more flow through the stack it seems.

 

[93detroit]

I assume the quest here is to lower IAT/EGT. Few would probably want to follow my path on this, but in my experience it is important to cool the entire engine bay. Yes, I have the biggest Mishimoto cac that will fit between the frame rails and I have a water/meth system with a 14 gal/hr nozzle and the pressure cranked to 11. However, I have also removed ALL of the underhood insulation, as well as the "mudflaps" on the inner fenders at the top A arms. This is a three season truck used as a DD and tow pig. Pulling 6-7% grades with 12-15k behind me (flat out with w/m), I can hold 190 on the temp gauge and egt will be 1150ish at the end of the climb. I'm sure that a 16cm exhaust housing would lower that number some. My pump is likely between 100-105cc (my tuning-never tested).

Sorry for the derailment, I'm all ears Chris! As always, beautiful work.

 

[dbrannon79]

I have looked in the past for something to mount on the hood of mine that the opening would face toward the front to catch wind and force down and over the engine. I like the style @Paveltolz used on his. His are more flat so not to have much of a raise on the hood it's self and have a clean look to them too!

 

[SnowDrift]

Late 70s Camaro had these in the fenders. Dad had them in his '75 K30 with a 454, then later a 427. At idle, you could feel the heat boiling out.

 

[ak diesel driver]

I remember reading that in order to pull air in a hood scoop, that it didn't start to get effective until about 6" up from the hood

 

[Twisted Steel Performance]

I wonder how the hood vents nascar uses really help?

 

[ak diesel driver]

I'm sure the shape of the vehicle plays a part too

 

[Twisted Steel Performance]

yea and mine won't go as fast....

 

[Will L.]

When my hummer was in the wind tunnel - it was insane to watch the things that make a difference.

The best testing for your at home projects is tie ribbons on and set up go pro or an old phone on video recording. Other than that a person in another car trying to record the ribbons showing flow.

When we were testing the different hood scoop designs on mine and the different body model hmmwvs they brought, they had a hood with ‘heat exausting’ vents and found that it pulled air up from under the engine and out the vents. But it changed the back pressure behind the fan and actually hurt the airflow going through the cooling stack.
Obviously hummer is dramatically different than a gmt400. But it showed me that testing is critical- sometimes what seems like it would obviously work, backfires.

 

[SnowDrift]

I just want to know who is volunteering to hang on the bottom of the truck with the camera to watch the streamers. Marty McFly on a skateboard comes to mind

 

[Paveltolz]

Go Pro or similar cameras can be mounted about anywhere, on top or underneath.

I’ve mentioned in other posts that I did a string (yarn) / streamer test on mine to see what the air flow around the truck might look like. Particularly what the air did flowing over the hood and side vents on the fender. I knew from burned palms that at idle, the heat was happily escaping out the top. The side vents, after a drive, were equally hot. But, what about while driving?

Along the sides, air flow stayed fairly close to the fenders so, with the slight rise of the vents, there might be a low pressure area but, with all the air coming through the vent stack and being jammed under the hood, the strings stayed outside the vehicle. Not so on the hood thought.

For one thing, the strings danced around at about all speeds, not really ever flowing straight back down the hood.

The strings mounted on the hood vents stayed out side until around 45 mph which was when they started arcing upwards and then were pulled down and inside the vents by 55 mph.

I posted this one video on YouTube but, that one focused on the side vents at 60. Although there is a short view of the air on the hood, it wasn’t the one focusing on the air going into the hood‘s vents. I think it was after this one that I repositioned the strings on the vents because the one on the leading edge was dancing around as much as the rest of them (~ 15 second mark). I’ll do some archive searching to see if I can find the other ones and maybe redo a posting.

 

[Paveltolz]

Found the videos. Needs more editing than I can do tonight. On review of the posted video, there was a light blue piece string in the middle of the Right hood vent that had been pulled all the way in by the time we got to 60. In other vids, it was actually being pulled in before we got to 40 mph.
The strings were actually taped under the vents vs. on top like the others on the hood.

About 35mph and already getting pulled inside.





At High Idle, the fan air was just pushing them out and back.


GM Engineers designed air to flow through the stack and the engine bay and then exit out and down under the cab. These vents just bring a little more air into the bay to do...what...help the designed flow? These perform more like cowl induction but to what point really? Aesthetically pleasing as they are, they really only let hot air out while at speeds lower than 35 mph and who's pulling hard enough to need that 'benefit' at 35 mph? Stop and go traffic and post road trip, yes. At speed, IIHO, not so much.

For me, anymore, the point is moot. This hood was destroyed by my negligence (didn't latch, opened at speed, bent. "New" OEM hood in place. Much quieter in the cab too if that helps.