Yes, that's correct-- better performance for winter operation by REDUCING air intake flow! Note, this only applies to running around empty and at light loads, not towing heavy.

I've tested this the last two winters, one with my BHAF, and now with my PowerCore prototype filter.

I've concluded that to a point, less is more.

Now, I'm not talking about a restrictive air filter. Rather, I'm talking about blocking off part of a higher-flow air unit using duct tape.

There are a number of reasons to duct tape off your intake:
1) The reduced airflow to the turbo will raise temps, and help your engine get up to temp faster, which reduces wear and helps with combustion efficiency

2) Blocking off the intake reduces the hp is takes to drive the turbo, because the the compressor is compressing air that's less dense, and it takes less work to spin through thinner air.

3) Engine is MUCH quieter-- not just turbine whine. Turbo whine is GONE completely (even w/o silencer ring), but overall engine noise is just much less.

4) For winter operation, average EGT goes up-- and this is a GOOD thing if you aren't working the engine.

5) Reducing the surface area the filter can breathe through increases air intake velocity.


With my BHAF, I duct taped off the entire thing except for a "window" about 3 sq inches (on the engine side of the bhaf to help pick up exhaust heat). It worked great-- killed turbo noise, improved winter MPG and helped the engine warm up a lot faster.

Now, with my PowerCore filter, I've taped off almost the entire 10.5" inlet, sealed with duct tape, less a sliver of exposed filter at either side. For normal driving and hwy cruising, EGTs are well in hand, only slightly higher. I DO NOT use WOT with the setp, as the engine just can't breathe. But 15psi of boost is useable imo.

Repeat, this is NOT a setup for WOT use. It's for daily commuter usage and perhaps very light towing when the temperature start to get down around freezing.

So if you live in a Northern Climate like me, and have a BHAF or AFE setup, and don't tow over 4K pounds or so, THIS IS SOMETHING YOU SHOULD TRY.

It's not for everyone, but if you find yourself in similar circumstances, there are MPG and other benefits to be had.

Justin

 

I've been doing this for years with the aid of an intake air sensor in my air horn and temp gauge in the cab.
50-90F is the ideal intake temp for maximum efficiency.
My problem has always been keeping the lower end up in the winter.
My stock air box is set up with RV dump hose running from the box's dirty side to the same location where a Scotty hole is cut. Sucks air though the firewall during the warm time of year, during the cold time I remove the hose, fold the insulation back over the firewall hole and redirect the suction hose to close to the turbo.
This combined with a winter front and fanless keeps temps up.
Running in summer mode during cold weather there were times I couldn't get the intake temp above 32° even after driving hundreds of miles.

 

Yep, you bet it works. Preheated intake air is best for efficiency as long as you can get enough air to do what you want and EGT's are in check. Its basic thermodynamics....

But just wait until the EGT ***** and airflow 'experts' on here read your post .....

You are glutton for punishment from the ill-informed aren’t you Brother Hohn ???
Just like me !! Eventually we'll get ‘em all lined up properly with the scientific truth, don't you think ????

KP

 

We'll see

I'm not certain I've got it all figured out myself

 

So assuming your premise is true, wouldn't I be better off removing the BHAF and running the stock airbox for winter? (Just a question, not a criticism.)

Jim

 

So what is the mpg increase? Where I live it gets down to -20* at times. I hear the fuel is different in the winter too, like makes less power. Good thing I have a full tank I filled up in Aug. It'll still be there in Dec when I get back. So I'm good on fuel till Jan.

 

Yes and no.....since the stock air box sucks ambient air from outside of the truck and not hotter under hood air like the BHAF, the intake temp change could be negligible. By taping off sections of the BHAF like Hohn did, you can still suck the hotter under hood air AND have a lower flowing intake.

 

Bingo.

I should have mentioned that the CAC is blocked off as well. That will also help in the winter.

Fanless is good, too for winter operation. The only time I had any problems running fanless was idling though deep snow in 2nd gear up in the mountains at 13K feet or so. EGTs were 900 at idle. Needless to say, the engine got too hot, and I had to stop and let it idle in neutral (EGT 500) to cool off. I also cranked the heat and rolled down the windows

 

"Where I live it gets down to -20* at times. I hear the fuel is different in the winter too, like makes less power. Good thing I have a full tank I filled up in Aug. It'll still be there in Dec when I get back. So I'm good on fuel till Jan."

Yes, winter fuel is different. Yes, it makes less power. It is chemically different to keep from gelling in the cold. Don't be too confident that it will be the correct fuel at -20..... It just might leave you straded on the side of the road - if it starts, that is.

Steve

 

This isn't always true anymore.
Most fuel distributors no longer use a winter #1/#2 blend but have gone over to using an anti-gel additive with straight #2 instead, cheaper and easier. Most all stations in my area use commercial grade high strength Power Service. My buddy who drives a tanker says one gallon of it treats 10,000 gallons of fuel down to minus 35F.
If anything mpgs will be higher with additive rather than straight #2 except that winter driving tends towards lower mpgs due to incomplete warm-ups.

Now that diesel prices have gone crazy I expect to see very little winter blend used except in the way far north.

 

That is good news to me, and I have no reason to doubt it. Regaurdless thought, PWRTRPLS1 needs to do something with his August fillup if he plans to lets his truck set until December where the temps drop to -20* (his signature says this is his first diesel).

Steve

 

My truck has had a pretty easy life for something that never sees the inside of a garage. It has yet to see temps below zero.

Coldest start I ever had was in Chicago last Christmas. If you remember that cold snap, it was low single digits.

Truck fired right up and wasn't plugged in. High idle kicked in and I let it run at 1300rpm for a minute or two. This is where a good cold weather oil like a syn or syn blend 5w40 is nice.

Anyway, even with this cold of a start, I could always see that I had fuel pressure.

It interesting to watch FP come up as the engine warms up. This is simply because as fuel temps come up, it flows through the filter more easily.

IMO, diesel fuel will keep just fine for quite a while if protected from moisture. If you're going to drive in really cold temps, keep a winterizing additive handy just in case-- you probably will never need it though.

jmo