45 HP Bullydog air filter?

[Prairie Dog]

As many of you know Bullydog advertises that their intake kit adds 45 H. P. I dyno'd (on a Dynojet) with the stock air box with the drop in AFE and then with the Bullydog installed. Total difference was between . 5 and 2 H. P. Toque changed by . 5 ft lbs.

I talked to a marketing person at Bullydog who spoke with the engineer of my intake. He told me that they use a Mustang dyno and limit the wheel speed to 70 mph, in other words, no matter how much torque you apply the dyno just applies more brake. He said it was under these conditions that they routinely see 45 to 53 H. P. gains.

My observations? There is nothing inherently different about the bully dog that would add H. P. when other intakes would not. If their explanation is valid, I suspect any free breathing air filter would perform the same.

Noise-wise you can hear a little more turbo whine but thats all. It's well made and should easily reduce egt's. I would sure like to hear some comments on this dyno dilemma!

Scotty

 

[Chipstien]

Goes to show you that you can make anything sound better then it is.

 

[Diesel Freak]

hmm sounds like the same marketing people that work for DR. P are now working with Bully Dog.

 

[RSnaith]

Originally posted by Prairie Dog



Noise-wise you can hear a little more turbo whine but thats all. It's well made and should easily reduce egt's. I would sure like to hear some comments on this dyno dilemma!

There is really only two ways to make power with a diesel pickup truck: add fuel, or burn what you got more efficiently.



Thats it, thats all you got for options.



So in order for an air system to build power, 1 or all of the following conditions must exist or must be met:



1) The current air intake must be sooooo restrictive that it is completely starving the engine for air. This isn't the case on the 03 Cummins. Its a terrible airbox, but at stock power levels, its not a complete restriction.



2) The increased airflow must be seen by the ECM, and fueling levels adjusted appropriately. On gassers and the Duramax, this is handled by a Mass Airflow Sensor. Increase your air, the ECM automatically adjusts fueling levels to ensure you are getting an efficient burn. Again, the 03 Cummins does not have a MAF. We have a IAT/Air Pressure sensor mounted to the airbox. This sensor can influence fueling somewhat, as its intended purpose is to dynamically adjust fueling levels based on ambient air pressure. In other words, as your truck's elevation changes, the fueling curve is adjusted to ensure you are maintaining what Dodge has felt is a proper burn (on the factory trucks, its not an efficient burn, its minimum particulate emission burn, which is not necessarily the same thing).



The IAT/AP sensor on the Dodge trucks does appear to have some influence on fueling. This can be evidenced by EGTs and higher RPM horsepower. During our testing of the Ram Air III, we noticed about a 150F drop in EGTs at mid RPM cruise speeds. At higher speeds (but constant throttle position), we noticed about a 200F drop. At wide open throttle, the exhaust gas temperature reductions all but disappeared and the truck was running close to stock temps (25 - 50F reductions), however our 60 - 100 mph times were reduced by a decent margin, which indicated about a 20 HP boost. If you removed the coefficient of drag of the truck, and corrected the values, you'd maybe see that come up to 30 HP, but I doubt it. Turbo spoolup was also markedly faster with an aftermarket filter, which is a no-brainer, as oiled filters allow more flow, therefore the turbo doesn't have to work as hard to pull air.



So what does this mean? The IAT/AP sensor obviously has an effect on fueling. Increasing airflow past the IAT/AP seems to fool it into believing you are running at a different elevation, and thus it increases fueling. But the effect appears to be minimal at constant throttle settings. At wide open throttle, or under acceleration, there appears to be a larger effect, but still nothing to write home about. We've moved the IAT/AP all over the air tube and air system, and even completely blocked it off from airflow, and saw very minimal changes (aforementioned approx 20 HP). And this isn't just with the Ram Air. We've tried it with stock boxes, and filters simply crammed under the hood, a'la BHAF.



Soooo, what this really boils down to is that the air systems on 03 Dodges will be relegated to the same role that they were on the 02's and down. To provide clean, smooth, directed airflow to a properly mated turbocharger. Airbox HP gains on 02's and down were relegated to minor 10 HP values, easily within the realm of dyno error or turbo spoolup fooling the inertial. Any HP gains that may be seen from an 03 airbox, whether its a Bully or our own Ram Air, will be quickly offset by fueling/timing boxes and turbochargers, so you'll want to choose the airbox that provides the turbo with all the air it wants in an efficient manner.

 

[Prairie Dog]

Very nicely put Rod. The strange part about this whole deal is that they gave this intake kit free of charge with the only stipulation being that I have it dyno' before and after it's install and that I write a honest post about the product. This is the reason I suspect what their seeing is in fact true. They must have been fairly sure of them selves in order to risk such a marketing gamble.

By the way Rod, have you dyno'd one of your intakes on a Mustang dyno w/ the speed limited to 70mph as I outlined above?

 

[RSnaith]

Originally posted by Prairie Dog

By the way Rod, have you dyno'd one of your intakes on a Mustang dyno w/ the speed limited to 70mph as I outlined above?

We haven't had the chance to do any dyno testing, other than GTech meters, which we couldn't get a good read off of because the RPM pickup won't work on an 03.



We'll be shipping an air unit to Edge, and Aaron said he's going to do a couple Mustang pulls for us, one on a modified truck and one on a stocker to see what we get for numbers. I'm hazarding that gains will be nil, same as they were with the Scotty II. The enclosed design of our air systems typically hamstrings them on dynos. We need the air movement of a rolling vehicle to provide us with high pressure (in the grill area on the 03s, and the cowl area on the 02s and down) to allow our systems to work.



I really can't fathom why Bully would see such large gains (like yourself, I won't doubt the numbers they claim they've seen). About the only thing I can think of is that they were loading the trucks down and boosting past stock power levels with a boost elbow or something along those lines. Then I can see the restrictive stock airbox driving the turbo out of its efficiency zone, robbing horsepower. Free up the intake, and the turbo could then boost efficiently, and voila, you got yourself some horsepower. But you've really gotta be pounding the turbo to rob the truck of 45 HP.

 

[Mopar_Mudder]

I thought I heard at one time that the Dyno-Jets aren't very good on turbo vehicles because they don't apply enough load to get full boost out of the turbo, or some thing to that effect. I don't suppose you have a boost guage in your truck yet?



Hey Rod, so when are you gona build that Dyno in a wind tunnel so we can see some real world numbers

 

[Prairie Dog]

Nope, no gages yet . I've been spending way too much on the truck lately. We're taking a trip to Disney land the first two weeks of May and will be pulling our 5k TT. I can't wait to get to those hills!

 

[Dean Upson]

I can't wait to get to those hills

PD,



What hills?



Dean

 

[Prairie Dog]

Originally posted by Dean Upson

PD,



What hills?



Dean

Woo hoo Dean, that's what I like to hear! Oo. Oo.

 

[Dean Upson]

Usta have hills 'round heah, dunno where they went .



Dean

 

[BillGotthelf]

Rod-just how is more air going past the IAT sensor? Pistons go up and down, draw air from intake system. Unless the stock system is so restrictive as to create a horrendous vaccum in the intake (not gonna happen). The IAT measures temp and density of air flowing past. This allows computer to correct for air density chages to stay in EPA's good graces. Because a certain intake system allows an easier flow (less restrictive) has no influence on the IAT sensor at all. Only way to gain a small amount of power with intake system is to divert cooler air to intake system.

 

[RSnaith]

Originally posted by BillGotthelf

Rod-just how is more air going past the IAT sensor? Pistons go up and down, draw air from intake system. Unless the stock system is so restrictive as to create a horrendous vaccum in the intake (not gonna happen). The IAT measures temp and density of air flowing past.

Good point Bill, at least in so far as an open element filter is concerned. So lets approach this from another direction then, and use air density (which is the proper term. I was using air flow improperly).



The stocker unit, at WOT, will tend to draw the filter minder down. This means that air density (and I suspect, pressure) after the filter is lower than that before the filter, so the ECM defuels a bit as it thinks its running at a higher altitude. A less restrictive open air element, would equalize pressure across the filter, and allow the ECM to fuel as it should. A Ram Air type of system will tend to create a high pressure area inside the housing, and drive air into the system, leading to slightly higher air density post filter than you would normally see. During testing, this was confirmed by measuring voltages off the IAT sensor. With the Ram Air in place, the faster we drove, the higher the voltage (our elevation didn't change, therefore the voltages should not have), meaning the system felt it was running under higher air pressure circumstances.



But the change was minor in my mind, and I think we're both saying the same thing: Our testing told us that 45 ponies was impossible to generate with an air unit on a stock configured truck.



Rod

 

[BillGotthelf]

I agree with you on the point that the BullyDog unit would not produce much in the way of more HP. The reason you saw increased voltages from the IAT was that more air was being pulled through the system as you speed (rpm) increased. A normally aspirated engine pulls in twice as much air as rpm's go from 1500 to 3000. However with a turbo charged engine you could see six times as much air in our diesels from 1500 to 3000 rpm. The IAT sensor is a very rudimentary sensor who's input to the ECM does not have much effect on the overall system. It has more input on the timing side from the ECM. Also Dodge got a bunch of filterminders that were set to go from 0 to 100% blocked with only a drop in pressure of only 12. 5% of standard air pressure. Older models had the 25% filterminders. Newer 2003's have the later filterminders (like mine).