[tracer]

The guy from Pittsburg Power says that when you have an aerodynamic truck with tucked away air filter housing, your engine gets a much warmer air than a conventional truck with 2 air breathers outside of the truck. They suggest installing a second air filter/housing (like the Ecolite made by Donaldson) to get more COOL air to the engine. Anyone did this on an aerodynamic truck? I have a 2004 International 9400 with 1 huge air filter/housing on the passenger side under the hood.

Here's an interesting quote from some past articles on power and performance I found on pittsburghpower.com

Originally Posted by Pittsburgh Power

Most truck manufacturers supply an air filter and housing with enough CFM (cubic feet of air per minute) to satisfy the horsepower of the truck when it's being built. If you purchase a used truck with a 290 or 300 HP. engine then rebuild the engine to 400 or more horsepower your air filter is too small. Almost all trucks with the air filter stuck under the hood suffer from lack of cool air. This is the new aerodynamic look with the filter under the hood. However, it is terrible for performance. Why preheat the air before it gets to the turbo? Think about how hot it is under your hood in the summer when your 3,500-lb. engine is operating at 185 degrees and your air filter is right above it. We all know what high pyrometer temperatures do to aluminum pistons. Heat and metal fatigue are a trucker's biggest enemy. If you do not own a conventional, or cannot mount your air filter out in the air stream, then mount a second filter under your hood on the opposite side of your current filter. On a cabover it's fairly simple to mount a secondary air filter and plumb it into your existing air pipe going to the turbo.

The most economical and easiest filter and housing to work with is the Farr Ecolite. At 24" long and 13.5" in diameter, this filter has an amazing capacity of 1500 CFM The price is $139 and for installations you need two clamps at $15 each. The air inlet and outlet is 7" in diameter and you will have to obtain 7" aluminum piping to complete the installation. The extra clean air entering your engine will lower your pyrometer temperature and allow your engine to run as it does on a cool, damp night."

[allan5oh]

Meh, I'm beginning to really question this guys logic.

The air is being grabbed from the outside, how is this any different from a "classic" truck? They both grab it from the outside.

I don't see how the air filter unit inside the truck is going to make that huge of a difference. Besides, with a classic you have all the ducting under the hood anyways.

Until I see some testing (turbo inlet air temps) I don't believe it. The size and efficiency of the CAC has much much more to do with engine air inlet temps then where the filter is mounted...

[tracer]

Originally Posted by allan5oh

I don't see how the air filter unit inside the truck is going to make that huge of a difference.

Try touching your air filter housing (I bet it's next to the turbo) after a day's long drive. If it's hot, the air filter is hot too, and it acts like a heating element of a stove when filtering the incoming air. What's wrong with this logic?

[NotSteve]

I'm only guessing on this but I don't think really cool air effects engine performance that much.

The reason I say this is you can do a technique like strip mining and reducing the air line from 12" to 6" to 3" to 1 1/2". Increasing the velocity of air reduces it's temperature by a great deal.

As an example. Take a front steer tire fresh off a truck with the inside air temp at 150 degrees. Take the needle valve out of the valve stem so the air comes out. It will be about 0 degrees and form ice balls.

[allan5oh]

Originally Posted by tracer

Try touching your air filter housing (I bet it's next to the turbo) after a day's long drive. If it's hot, the air filter is hot too, and it acts like a heating element of a stove when filtering the incoming air. What's wrong with this logic?

The piping will also be hot, if that logic holds true. Yes the outside might be a little warm on ONE side, but the filter doesn't touch much of the filter housing.

Like I said, turbo inlet temps, has to be tested. And the CAC makes much more difference.

[bob h]

Originally Posted by allan5oh

Meh, I'm beginning to really question this guys logic.

The air is being grabbed from the outside, how is this any different from a "classic" truck? They both grab it from the outside...

Agreed. Any difference between 'outside' and 'filter housing' air temperatures would be minimal and irrelevant... imo. Huge volumes of air flow through that pipe during engine operation... there's not time for the air to heat up.

[tracer]

Originally Posted by NotSteve

Take a front steer tire fresh off a truck with the inside air temp at 150 degrees. Take the needle valve out of the valve stem so the air comes out. It will be about 0 degrees and form ice balls.

Hm, I should try this trick on a hot day, instead of running the A/C

[pdm]

The temp that matters is entering the engine from the intake. A scan tool will display this if you want see if it can be improved on. The air leaving the turbo can be upwards of 300 degrees F.

I'm pretty skeptical of most claims of aftermarket products & additives. It seems to me that the engine manufacturer would have to approve the truck oem's installation in the chassis.....

As for the air being cool coming out the valve stem thats the basic principle of refrigeration.........lowering the pressure on something lowers the temperature. Freon is under pressure till it hits the expansion valve (or orifice tube as the case maybe) where the pressure is reduced which lowers the temperature.

[tracer]

I finally got a response from CAT Call Center and the verdict is I don't need more air.

Here's my original question.

Originally Posted by tracer

Could you please help me with another question regarding the AIR FLOW? I need to know how much air flow in CUBIC FEET PER MINUTE my CAT C15 Serial BXS***** needs at the maximum horse power rating? I bought this truck with 435 hp rating, but then later rerated the engine to 475 hp. I now plan to rerate it to the maximum available rating of 550 hp, 1,850 lb/ft torque and I need to know if my current air filter will provide enough air. So, the question again is: how much air flow in CFM Cat C15 BXS***** will need at 550 hp. Thank you very much.

And their reply.

Originally Posted by Kitty Cat

The CFM for a BXS with 550hp goes in a range but if you use anything over 1,600 C F M will be sufficient to handle that horsepower. Your current air filter arrangement is the same as they use for all the hp arrangements, so yes your current air filter is sufficient for the 550 horsepower. But in order to go to a 550 hp you will need to check your transmission and make sure it can handle the 1,850 Torque. and make sure your cooling system can handle it as well. Thanks for your interest in Caterpillar.

[special k]

Any time you can get cooler,denser air that is a good thing. That has been proven a million times. I don't agree with everything Bruce has to say but he is right on this topic. If I'm not mistaken the 9400 series picks up air at the grille but runs it through a passage in the top of the hood over the engine and then goes into the actual housing which is still over the engine. So I would say there is enough time to heat the intake air noticeably. If you think any truck mfg hasn't cut corners on fuel economy/power to save a few bucks for themselves I could sell you a bridge or two.