2nd Gen Non-Engine/Transmission Air Bulldog hood

[Mustang]

I own a HVAC business and have some knowledge of and lack of airflow. My stock airbox with the fender extension was noisy and when I addressed that I found it was trying to draw what I calculated to be approximately 400cfm through a 11. 25sq. inch hole at 70 mph or approximately 2100rpm. Removing the extension helped some but now draws warmer engine compartment air. There appeared to be no way to get sufficient ambient air until I came across the ad for Doug Hofeldt's replacement hood.

I contacted Doug, he built the hood and I went over to have him install it. Paint, fit and workmanship were beyond what I had expected, it really looked good.

On the way home I got to wondering just how good this system was working. I used a digital manometer made by UEI model # EM150 available from most HVAC supply houses for about $100. 00 to check above the filter in the stock box and Dougs new box. Literally hundreds of readings were taken as I found wind, turbulence, grade, altitude, temperature and load changed readings. I ended up averaging all those. The old box at 60mph -. 90 at 70 mph -2. 05, Dougs new system at 60mph +. 10 at 70mph +. 25, With the probe in the hood at 30mph +. 15, at 60mph +. 35, 70mph +. 45, at 75mph +. 60 all in inches water column.

I think Doug had it all together when he engineered this hood. To me this is true ram air. Obviovsly it's possible to pull it down into the negative when accelerating but I was looking for a positive when at cruise speed and I have that so am very satisfied with the performance of the hood.

I don't have mileage figures yet because part of the time I carry a 4600lb camper. I wish I had the ability to measure cab sound level stock and with the new hood, it seems quieter but no way to verify that. I'm running a dynoed 318hp for these tests on level one. I may one day turn the Edge Pro Comp off and try a few more readings.

 

[ToolManTimTaylor]

SWEET! Good to hear a report like that #ad

 

[DHayden]

Does yours have the stiffening ring just inside the hole in the hood? Mine does and I had wondered about good airflow just because of the turbulence I thought this ring would create. I know he was trying to figure out a better way to stiffen it up without the ring. Mine still works well, glad to see some figures on it so I know its not just me wanting to believe in it.



I agree totally about the quality. He was meticulous in fit when I dropped by to have him install mine. People who care that much about their work and want you to be as happy with it are few and far between. His wife even made the girls pancakes while they waited

 

[Air Bulldog]

The ring just in side is a drip rail is to stop water from coming in to your air box but you are right it do cause some resistance there, you can cut it down so that only about 1/4 inch is up in the hood. With a manometer you can test the air flow going from a horizontal plan to a vertical plan, the tighter bend causes resistance, thats why when we designed the new hood we had to put in a redirectional dome in it.

 

[John]

I've had my Air Bulldog induction hood for a few weeks shy of four years now! Although I need to get it repainted soon, I still love it as much as the day I picked it up from Doug!

 

[Mustang]

Hey John.



I really like my hood too. I really enjoyed my time at Dougs he was very professional and was willing to do whatever it took to make it all a perfect experience, very friendly and laid back.

I see you are in Enumclaw, I'm in Lynnwood, was going to the Arlington bash but somehow missed the date.



Regards,



Bill

 

[Beast2B]

Is there a website? How about some more pics?

I also like the cowl hoods, how do they compare (theoretically, I guess) to these as far as airflow?

 

[Straight6Jeff]

The numbers are just one more reason to get hte hood, but the hood looks great also, especially with the NACA ducts. Too many hoods out there look like they fell off a Honda something or other, Type R

 

[Air Bulldog]

I try ed to put a picture on but it was to big,if some one can do it I will send them the pictures.

I do have a web site that has;t been up dated for a long time. Just put on a search for air bulldog on yahoo.

I was going to make a cowl hood to start with but cowl hoods are not ram air hoods they are just fresh air hoods. In 1993 there was a add on tv for the all new Dodge ram it showed a new Dodge in a wind tunnel with a smoke wand in front of it. The smoke almost touched the truck right were I put my air inlets and then rose up to the roof so right a the back of the hood the smoke was 24 inch's above the hood.

Meany thanks go out to Mustang he has come up with a tool and a process to get data that we all want "DON,T TELL ME SHOW ME" probably fits us all. The manometer that Mustang used is a assume little tool you can use it to see who makes the best air filters and were there is air movement and a lot more.

I have been working on the third gen. hood for a long time and because of Mustang and his research I changed the design. I had to put in a re-directional dome. When air is moving in a horizontal plan and the has to turn to a vertical plan it can cause resistants.

 

[Bob Wagner]

Doug, I sent you a pm. I will resize the photo

 

[Bob Wagner]

#ad

 

[Bob Wagner]

#ad

 

[Bob Wagner]

#ad

 

[Bob Wagner]

#ad

 

[yogibear]

That place where the 3rd gen. pic. was taken is in Ut. , that old boy that lives there has 6 wives!!

 

[Forrest]

That double inlet guy ...

 

[wilddiesel]

Thats right yogi- 6 wives- a cook. a yard care person, a mechanic, a stripper, a personal aid and of course you know. You would like this hood it gives that personal touch. Mine is just a prototype. By the way do you need a wife I have a couple extra?

 

[BTowler]

Doug, you should look into the cowl induction route. The term "Ram Air" is a misnomer, it is still just a cold air induction system. Claims that ram air make more power by forced induction still fill the automotive world, but the physics don't stand up, you can't force more air through two little scoops driving down the road than your engine draws in on its own. I believe a normally aspirated 360 ci engine pumps 120000 cubic inches of air per minute at 2000 rpm ( I think my math is correct, if not the figure is 720000 ), factor a turbo in that equation for our trucks and it goes up considerably!!!! As far as the wind tunnel test you cited, the air in front of the windshield is a nice dense pocket of fresh air. Plus water intake is less of a problem with the cowl induction design. Don't get me wrong, your design is just as good as cowl induction, and the hoods look fantastic, wouldn't mind one myself, just trying to make a point for the cowl induction hood as well.

Bruce

 

[Air Bulldog]

Mr. Towler I have looked into the cowl route. Winston cup cars, bush cars alot of race car do get there air from the cowl area but they are doing more then 50 to 75 MPH. At speedway speeds the air does build enough to make positive pressure in front of the windshield. With the manometer that Mustang has, he measured the air between the top of the filter and the turbo and found that at 70mph there was pressure not vacuum so isn;t that physics? Put in a search on yahoo for" ram air " the 6th thing that comes up is Sport rider Ram Air more power for the Kawasaki ZX-9r through forced air induction. It is some very good reading on this subject. When I design my hoods the first thing of importance is function looks are second. If a person wants only looks I can understand that but my hood are not a single purpose hood. If you get a cowl hood I would enjoy testing it with you. Thank you for your comments

 

[BTowler]

Doug, That was an interesting article, but the ZX9 is a 900cc engine as opposed to 5900cc. The bike also had to do at least 70 to show any boost. I will try and find the original article that turned my head on the subject years ago, don't even remember what mag it was in, but it was a full scientific comparison of ram air and cowl induction that showed neither having a performance gain over the other (both showing significant over stock though). Again, not trying to start a war, just share information and viewpoints. Thanks for the response.

Bruce