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Intake Air Temp


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So as we all know the intake air temps get low enough in winter to hinder fuel economy and idle combustion efficiency. I have a winter front the helps out quite a bit, but I think they could stand being a little warmer.

I generally block off my home depot CAI in winter to keep snow/moisture from entering the airbox and maybe run a little warmer air.

I have been considering adding a 2" deck plate on the engine side of the air box. Close it in the summer when I don't want engine air, and open it in the winter when it's a good thing.

I considered a 3" opening because my HD CAI is 3" and the plug would work for both, but not sure I want/need that much hot engine bay air?

What do you guys think?

--- Update to the previous post...

Something like this.

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If you got a away to monitor IAT temps then you want to technically get the IAT close to what it like during you best MPG weather.As for Mom's 96 Dodge I'm playing with its got a CAI on it from the factory but noticed on 25*F morning it ran so much better after just yanking of the cold air duct and allowing the engine to breathe the warmed air under the hood. Fuel mileage rose even on a gasser engine... Oh... As for IAT temps at 25*F outside the IAT showed 85*F with CAI and with CAI it jumped to 116*F and MPG rose like I said... :smart:

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I do watch the IAT's, but unlike your VP motors I can't find a specific range that is the best for mileage. My IAT's are rarely above 100°, unless it's that hot out or I am pulling 30 psi up a grade on a 75°+ day. I know that the cold air is a hindrance, just not sure what optimal is.

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it cant hurt any thing. i have had my BHAF for alomost a year and run it with no heat shield. i have not noticed any differance in temps from running the stock air box with a k&n summer or winter. i darnn sure did not over heat with all the tstat poblems i have had. i dont have any way to monitor the intake air temp and i would think it has made a differance in that. there just doesnt seem to be any differance in how the engine is operatingl my milages stay pretty constant all year.:shrug:

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I don't think that cold air could hurt mileage. The reason for poor mileage in cold temps is the winter fuel and lots more idling. Manufacturers go to a lot of extremes to get cool air into the engine. The air for the engine either gas or diesel comes from outside the engine compartment for a reason. Not having an intercooler would give us warmer air. I think the intercooler is there for a reason. I think the main reason for covering up part of the front is to get the water warm enough to heat the cab. Just my opinion.

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Well I'm working on it with the 96 Gasser and cold air does effect the MPG.I've been seeing 25-30*F mornings. So like on the 96 (V8 Gasser) I pull the cold air duct off and let the engine pull in the warm radiator air and the MPG went up slightly.What we are after is after so cold there is a point that cold air does effect MPG and performance.

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i understand when you first start up and every thing is cold and your sucking cold air in that all of that does make a differance. but once every thing is warmed up and and you are cruising the highway, does it make that big a differance? My mileage is pretty constant winter and summer on the highway. my intown does vary, but i do idle my engine a fair amount before i have a job trailer, it is a little hard to see how big a differanc it makes.:shrug:

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i understand when you first start up and every thing is cold and your sucking cold air in that all of that does make a differance. but once every thing is warmed up and and you are cruising the highway, does it make that big a differance? My mileage is pretty constant winter and summer on the highway. my intown does vary, but i do idle my engine a fair amount before i have a job trailer, it is a little hard to see how big a differanc it makes.:shrug:

Until about 20° my IAT's are 3-12° above ambient. Below 20 that grows to about 20° above. This is with a winter front installed or not installed, the winter front only seems to effect IAT's if it's completely blocked and I am pulling a grade with decent boost. Around town they are a lot warmer with front installed.
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i have a set of winter fronts. i ran them all last winter hoping to help the crazy tempswings i have been haveing for quite a while. they made no differance in the coolant temp for me, but when i drove over the blue ridge and worked the crap out of my tstat it is now functioning properyl or almost. it still fluctuates, but only between 180 and 190 now. no more 165 and 190. need to put my fronts on and see what happens.

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kinda hard to se 5* change when your swinging 25* to 30*.:stuned:

@ Dripley I still say that's a thermostat issue... I don't normally get wild swings of the coolant temp. It might take extra temp to pop the thermostat open like 202-205*F but mine always settles back to 195-197 and olhd fairly steady... Just a cheap NAPA thermostat... :shrug: @ AH64ID you might try the warm air for a winter and check your MPG as you go along. Monitor you IAT temps and see what possibly hits a high spot. I know we are travel unknown ground here but some where in the mixof temps there has to be a bell curve on performance/MPG even if its slight its there...
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i have been thru cheap and expensive tstats from napa, advance, auto zone, and finally orielly's at $27 with the same results. a couple of them woould work right on and off but never for long. the orielly's is in now and when i took it over the mountains it got worked pretty hard. once it hit 215* going over from th east side which is a 6% to 8% grade about 7 miles long. since then it has been working very well. it still fluctuates between 182 and 188, but mostly stays around 188 which was the norm for this truck when it was new:hyper:. i sat here idleing the other day in 45 degree weather at it stayed around 180 the whole time. as long as this one stays in the range it is working in i am just going to leave it. if it goes whaccky again i am going to buy the cummins$70 and see what happens:shrug:. i did replace the radiator cap a while back and it helped for a while then it went back to fluctuating. the cap seems to be working properly. it holds pressure and the resovoir does go up and down. i dont kow if that has anything to do with it. i think i even changed it again but do not remember:shrug:. with any other vehicle i have had that had this problem a new tstat always fixed the issue. just not on this one.

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Mike seems to have had good luck with NAPA, but I have read plenty of horror stories about non-Cummins stats. The stat's in these trucks do swing when first opening, but eventually will stabilize if the load is stable. If the load is changing the coolant will still swing. My 190° stat opens at 190° ± 3° and goes full open at 207°. Normal cruise is 193°, normal towing is 193°-197°, peak (only 3-5 times per towing season) will get to 213°-215°. As soon as I stop its 186°-188°, and after a while if it's really cold it drops to 180° and stays there with the winter front, exhaust brake, and fast idle.

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mine was not fluctuating when it first opened. it did all day long. th only time it would not swing was idling. it just dropped to 155 to 160 and styed there until driving a gain. then resumed its fluctuating between 165 and 190, up and down, up and down. maybe that work out it got going over the mountain did something to it. think ill boil the next one before i put it in and see what happens. i got a couple of spares.:lmao:

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Mike seems to have had good luck with NAPA, but I have read plenty of horror stories about non-Cummins stats.

Coolant is change every year and so is the thermostat... Regardless of color of the oolant its change yearly because even the FSM states every 30K miles is service limit. By the time a year is over I'm right close to 25K... So why not I know I'm going to pull the thermstat for flushing purposes so since the cover is off might as well drop a fresh one in...
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Coolant is change every year and so is the thermostat... Regardless of color of the oolant its change yearly because even the FSM states every 30K miles is service limit. By the time a year is over I'm right close to 25K... So why not I know I'm going to pull the thermstat for flushing purposes so since the cover is off might as well drop a fresh one in...

You would save $$ to run a better coolant and better thermostat!
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I just replaced my first thermostat (OEM) on my '04.5 when I did the 150,000 mile maintenance stuff a few months ago. The old one was functioning fine........I just figured that since it was over 7 years old I'd replace it. I don't recall the brand of the new one I put in, but I got it from Geno's Garage. I saved the old one.

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