Underhood vs. outside air 'consumption'

[markrinker]

Changed truck #2 to a cone shaped K&N style filter this spring. Haven't been using the truck much with diesel prices.

Today was a 95 degree scorcher. After towing ~12K lbs about 35 miles, I stopped and popped the hood. The entire filter and metal ring were way too hot to even touch, as was most anything under the hood.

EGTs and water temps were in range while towing, but I bet my intake charge temps (no intercooler) were high enough for the computer to start pulling fuel. Couldn't tell if it was the load, or the heat, but it didn't seem as powerful as 'normal'.

Anyone else experience this? Its the great exception in MN, and I can live with it, but hate to blow preheated air into an engine already prone to heat related failures.

[JoeyD]

Once your moving the air temp under the hood drops to what ever it is outside. If your just sitting still the temp builds up.
My truck performs better with the open air filter housing than the closed set up.

[Hubert]

I would say thats all the fuss over a lot of people wanting the elusive "cold air intake" and why GM did the fender air intakes.

I know what you mean I have driven normal pulled up in the driveway jumped out and everything under the hood was really really warm (not always hot but definately warm). You would not want to hold anything for a long time.

I can tell a sublte but definate difference in my truck with a few degrees difference in ambient Temp. and humidity.

Maybe with a cowl hood temps under hood would be better moving along but its so crammed under there I think its always at least warm as stock.

I dream of an intercooler at night.

[Dvldog 8793]

Howdy
I am just north of you and can say that yes 95* is NOT why I live in northern Minnesota! tongue.gif
Anyways, I have three air temp gauges; outside amb air temp, pre IC after turbo and post IC at the back of the upper intake. I have the factory fender air intake and also cut o 2x5 inch opening in the top of the aircleaner houseing. One that 95* degree day whenever I stopped the truck and parked the intake temp would go through the roof. 200* sometimes! As soon as I got moving again this temp dropped back down to 100-120* . I have an IC but the principle should be the same. I can tell you that my air temps coming out of the turbo are SCARY! On a hard pull on a hot day the air temp 6 inches away from the turbo hit 250-275* :eek: I am working on a cold air intake that will fit all our truck with minimal modification and should work well with the existing system in place.
L8r
Conley

[Iain]

I notice the same problem on my truck. I am running the stock air box with 2 - 2" x 4" slots cut out on the side nearest the fender. I do not have air temp guages but I do seem to have slight loss of power in the city driving on a hot day (30C / 86F).

Conley, if you figure out a cold air intake setup, I would love to see it and see what the temp and power differences would be.

What about a "shaker" style hood cowl scoop that could suck air from the passenger side? Might look a little odd only having one bump on the hood, but a second could be added to the driver side for looks only. It would not have to be that big an opening to drawing air through, 2" high x 12" wide and that shouldn't look too bad.

Iain

[markrinker]

Decided to run 'old #2' today and burn some expensive diesel just for fun...my two deliveries today started at 4AM and took me north to Hibbing, MN then on to Ashland, WI and back to Elk River by evening. Total: ~650 miles.

I got the best average fuel mileage today that I have ever seen this heavily loaded (~12K towed to Hibbing, ~8K to Ashland, ~4K empty trailer weight home.) Total average mpg: ~11.5

Mostly I attribute it to the cool damp morning air going north, and the cool lake effect air that comprised about 2/3 of the trip. On the last leg of the trip, temps were in the 90s, and the truck felt sluggish - even with the empty trailer.

Again, there are only a few days like this each year in MN. If I lived in AZ, I'd have to come up with some way to suck outside air. Can you IMAGINE the underhood temps on a 110 degree day?

Uff-da!

[TurboDiverArt]

Originally posted by Iain:
What about a "shaker" style hood cowl scoop that could suck air from the passenger side? Might look a little odd only having one bump on the hood, but a second could be added to the driver side for looks only. It would not have to be that big an opening to drawing air through, 2" high x 12" wide and that shouldn't look too bad.
Iain If you had a driver

[JD Diesel]

Yeah I put one of those open under hood air filters on my glass truck (always looking for more power) in the winter worked fine then came summer truck had no power on warm days. couple of days like that and that thing went out and stock air box went back in. And every thing was back to normal. (98 chevy 350 gasser) tongue.gif JD

[GMC Hauler]

What about taking cold air from the Cowl? You'd have to cut a hole and put a flange on it, but it would keep everything under the hood...

[markrinker]

I am seriously considering rotating the SSDiesel rubber elbow 90degrees (facing upward), extending it with a length of PVC, and cutting a hole in the passenger side front of the hood to let the K&N filter stick through.

Problems: Rain, snow, extreme dust or muddy situations. You would definately need a cap for the hole to allow switching back easily to underhood config.

Should look pretty redneck. Whaddya think?

[Herman_Bolger]

you could be a redneck if--- see previous.

[markrinker]

You gotta see the rest of the truck to understand that this mod would look right at home...the truck is DOT Orange, short wheel base regular cab with flatbed and wood bed sides. Its the ultimate work truck.

[Ratau]

I had the stock 14

[C.K. Piquup]

The stock filter housings`inlet faces straight at the passenger fender.I intend to pull air straight in from a vent in that fender,no elbows,shortest distance,and cold air.That`s what the medium duties do.I bought a KW T100 intake vent for $18 and just need to fab a plenum to seal to the fender back.

[nvmtnlion]

Diesel is at $3.17 here today so I rode the bike. I will post pics later if I can figure out how but:

I removed the passenger side turn light below the headlights and put a grille in there painted orange. Then I mounted the light bulb behind that so I still had turn indication. Then I removed the battery and made an air dam under the battery tray to direct the cool air right to that SS Diesel filter. Works great and I don't notice any loss in power on hot days.

[Kennedy]

Originally posted by Joey D:
Once your moving the air temp under the hood drops to what ever it is outside. If your just sitting still the temp builds up.
My truck performs better with the open air filter housing than the closed set up. Not true. Underhood temps will never be ambient because all of the radiator/cooler heat washes over everything and there is nowhere near enough air flow from the engine bay to remove much of the radiant heat from the engine. Just open the hood on a hot day and you'll burn your hand on the hood latch...

Intercooling does reduce underhood temps considerably.

[DA BIG ONE]

Here in the sub-tropics the heat is blistering, hasn't been this hot for maybe a decade. Solar activity (sun) on the 16th of this month added to the heat problem. I guess I'm tellen ya all that this is about as close to hell as you can get, even though some areas have recorded crazy high temps too.

Dealing w/heat is a constant here, w/underhood temps being like opening a furnace door when opening the hood.

Idle a bit, drive slow in heavy traffic and IAT climbs but motor takes it well.

I wonder how much cold air intake will help in the mix? Around town, I think not much, highway yes, but by how much?

I did a test yesterday, 95 deg temps and drove 230 miles at 55 mph (****ssed of lots of people, hell, if your not drivin 80 in a 55 zone everyone gets ****ed here, nothing new), average 6 lbs boost, w/ac, got a rock steady 22 mpg. However, with my gearing mpg should be in the high 20's, been there before.

So, is it the heat, or something darker and more sinister & evil? Say, IP?

I think it is the pump, runs like a bat out of hell for first 20 or so minutes, then seems to lose power, but runs ok. I do get the occasional miss now, injectors were replaced so finger points to IP.

Yep, sometimes my 6.5 td is a PITA but I like it too much to part w/it now.

[G. Gearloose]

DBO,
I had also noticed that marked slugginess after about 10 minutes after hitting operating temp, made me wish for that missing performance all the time.

That hasn't shown its symtoms since I went to 180 T-stats. What temp do you run?

[DA BIG ONE]

Originally posted by G. Gearloose:
DBO,
I had also noticed that marked slugginess after about 10 minutes after hitting operating temp, made me wish for that missing performance all the time.

That hasn't shown its symtoms since I went to 180 T-stats. What temp do you run? 190's

[G. Gearloose]

Interesting...your milage sounds impressive indeed.

[DA BIG ONE]

Originally posted by G. Gearloose:
Interesting...your milage sounds impressive indeed. I'm looking for consistency in mpg, next test will be @ 65 mph over same distance looking for that sweet mpg zone.