Adding air induction (blower) for better engine performance

[The_Handier_Man1]

From: Colin  (Original Message)
Sent: 4/10/2003 12:45 AM

I've done about all I can do to get the best performance out of my Dodge 413 engine, but I live in Denver and most of my trips are up into the mountains. Of course when I start up I-70 towards the continental divide my rig goes slower and slower. One time I took off the dog house while I was driving to look down at the engine. While I was doing that I noticed that my rig suddenly picked up an additional 15 mph going up a grade. Of course the difference was the additional airflow, but taking off the doghouse every time I'm going up a grade seems too noisy and not practical. I know that performance enthusiasts use blowers to get additional horsepower. I have an 8 amp blower that I use around the shop. The flow out of it is forceful enough to hurt your hand. My idea is to run a hose from the blower into the top of the air cleaner to increase the pressure and air flow going into the carburetor. I will power it with the generator. I plan on turning on the blower when I'm going up the grades on mountain routes. I spoke to an Edelbrock technician and he thought it should definitely increase horsepower. OK fellow gearheads, what do you think? 



From: nvdesertrat0775
Sent: 4/10/2003 1:58 AM

MY first thought was..."I wonder what he uses an 8amp blower for around his shop?" Then... I wondered how you would run the blower hose, in respect to the air filter? Would you stop the hose right AT the cleaner? Go over it? What about the top plate? You know, the part that has "edlebrock" on it? Leave it off? Cut a hole in it??? Or is there a special cover plate with a precut hole for air blowers?
But other than those Q's...sounds like a good idea!



From: denison 

Your drop in power is mostly due to less atmospheric pressure, but possibly some is due to the fuel mixture being too rich?  A couple of classic winny owners have installed throttle body fuel injection systems in place of the carburetor.  I think the electronics in the system corrects for the lower manifold pressure at a given throttle position, giving you the proper air/fuel ratio.
I am surprised you noticed more power with the doghouse off.  The only difference I could imagine would be less resistance for the radiator fan and possibly cooler air for the engine inlet.  I wish I could be encouraging about the use of any external blower.
   I have never heard of any blowers used to increase engine performance, other than superchargers and turbochargers, which are always always between the carburetor and the engine.  Carburetors depend a lot on the small air pressure differences between the outside air, the air in the venturi, and below the throttle butterfly for proper mixture control.  Every super or turbocharger installation I have heard of starts with using a lowered compression ratio, new distributor advance curve, different spark plug heat range and other changes needed to handle the greater heat thrown off.  The exhaust manifolds on the 413s and 440s are known to warp and crack with just the normal aspiration -  I would think the manifolds might be your weak point, even at the Denver/Leadville altitudes, assuming you don't melt your pistons. 



From: varmitexpress 

If you want more air in, try an air filter that allows more air flow. I have a K&N air cleaner on mine(see pics) and it seems like it get plenty of air. As far as your blower idea. If I'm correct thats all a real Blower(supercharger) basically does is forces air in faster.(pressurizes it) You must remember though more air in, more air out (i.e. larger exhaust). I hope you get it figured out, we all want more power



From: Colin
Sent: 4/10/2003 1:26 PM

I thought somebody might wonder about the blower. I originally bought it to inflate rafts when I used to do whitewater rafting. Children and age have changed its use to sweeping the floor and cleaning equipment. About the air cleaner cover, the blower has a 3/4" nozzle, so I plan to connect a hose to the nozzle and attach it to a 90 deg. fitting on the air cleaner. I'll just cut a hole on top of the air cleaner for the fitting. I'll keep the blower in the coach under the dash and run the hose in through the side of the engine compartment.
Denison, you've got me thinking about increased heat in the engine. What happens in terms of engine temperature when extra air is blown in down the carburetor? How can I add some air, but keep the temperature in bounds? Will the temp. gauge let me know if there's a problem? How about if I wired in a fan-type controller to adjust the flow from the blower?



From: Dave1210 

I am curious about what happens when you take the doghouse off when climbing a grade. Does the rig immediately exellerate? Does it slow down right after you put it back on? Does this only occur at high elevation or on any grade at any elevation? Maybe you have stumbled across something here on how to get more performance from these old rigs. 



From: Colin 

Actually what I did was take off the doghouse and remove the top of the aircleaner while we were driving down the highway. I had my wife look down the carburetor to make sure the secondaries were opening properly. While she was looking I noticed that our speed increased quite a bit. 



From: denison 

And I presume the secondaries did open?  They are mechanically operated on the Holley 6? carb on my 72 413.
  Isn't it amazing what is happening ABOVE the venturi when you have the throttle wide open and the engine above 3000 rpm?  Neat sound too!  By the way, running without the air cleaner at highway rpms and having the throttle wide open will lean-out your fuel/air mixture, cause so much of the fuel that is being blown up past the venturi by the acoustic pulse doesnt make it back down into the carburetor on the falling side of the pulse -gets blown back by the radiator fan.  You might have gained the power because you were closer to the best fuel/air ratio under such conditions.
  As far as blowing air into the carburetor from any place in the air induction system - I am fairly sure it will mess up the normal working of the air mixing with the fuel - which happens in more parts of the carburetor than just the venturis - the carburetors have several circuits, all of which depend on small relative differences in atmospheric pressure for working properly.  Try blowing air into the carburetor at an idle and see what happens.
Over the years there have been carburetors whose main jets you could easily adjust for altitude - including model A Fords and the side-draft SU carbs on British cars, but I have never seen any for the quads on mopar V8s - although on the Holleys you can adjust the float level - which might help you if done Very moderately.  Overdoing this might result in detonation at some throttle positions and engine loading - and damaged pistons, because proper mixture is more complex just a different fuel level in the float chambers. You could get another carburetor to install, jetted for 5000ft and higher, and swap it out if you took a trip down closer to sea level.  If you didn't change back you might crack/warp your expensive exhaust manifolds.
   With the correct air/fuel mixture I think you lose about 4% of your power for each 1000 ft above sea level.  Worse - if its running too rich.
    I am a little old fashioned and cheap, and not crazy about fuel injection systems - but if I lived in Denver I would explore electronic controlled fuel injection, if only to deal with the different altitudes the motorhome would see.       



From: Graham 

Altitude and performance - wow! Edmonton is 2200' above sea level and the rockies - main vacation areas are an additional 3000-4000' above. What can I do to my 73 Brave 440-3 with propane to get up the hills - do they make 11000 lb winches?? What is the best efi
conversion and do they work with propane?



From: denison 

I don't know anything about propane fuel systems. Have never worked on one. The big advantage to gasoline -petrol- fuel injection is the accuracy of the fuel delivery, and if the design uses a manifold pressure sensor, a mass airflow sensor and a throttle position sensor, of being fairly insensitive to the effects of high altitudes. Depending on how your propane is metered, it might or might not compensate for altitude. You will have to be telling Us about how a propane burning 440 handles the heights and the hills. My 72 winny with its 413 worked fine at 10,000 ft, but the horsepower was very noticeably less.  Driving it extensively at those altitudes without rejetting the carb. could result in fouled spark plugs, from running too rich, and adverse wear on the upper cylinder walls, from too much unburned gasoline rinsing the lubricant off. I can't imagine that would be a factor with propane



From: UluzYarx
Sent: 2/17/2004 9:04 AM

Take colder denser air to your air filter inlet from a high pressure point outside your engine compartment?
Don't let the rain in.



From: Liv42dayOK
Sent: 2/17/2004 11:29 AM

There's a really good photo captioning of adding one of those new cold air intakes in the photo section.  They're costly for the whole set-up but, the member used dryer ducting from the local home improvement store to complete the job.  He also wisely snaked the intake tube down past the front of the engine and mounted it below the bumper area.  I think this would be good to avoid drawing in rain.

and the link to the manufacturer: http://www.ramairbox.com/home_page.html

I think you could also modify the original aircleaner housing and make the same effect.  Note that the plastic design also has two intakes. - Sob



From: Tymhoff
Sent: 2/18/2004 11:58 PM

Seems to me that if you're going to add that amount of air to the intake system, then you would also have to enrichen the air/fuel mixture through the carburator. In order to get the right ratio for when you're going to turn on the blower, you would have to be very rich, making the engine very doggy when the fan's not on. Not to mention the gas mileage would go down a lot with the fat mixture. If you don't adjust the mixture, you will be very lean which is an invitation for pinging and other assorted problems.



From: denison
Sent: 2/19/2004 7:18 AM

I agree with tymhoff.
Separate topic: For folks who live at high altitudes i believe there is an extra reason for "upgrading" to one of the aftermarket throttle body injection systems. The system senses the mass air flow, along with the other factors to control injection rate; and maintains the best air/fuel ratio regardless of altitude. Most of our carburetors are jetted for near sea level conditions, resulting in the engine losing a noticeable percentage of the best power when operated at higher altitudes because it is running too rich. And if you change the jets to be correct for Albequerque/Denver, the engine will be running too lean at New Orleans - maybe enough to warp/crack the exhaust manifolds. denison the alarmist



From: Colin
Sent: 2/19/2004 12:26 PM

I started this thread when I was still young and restless. I have aged quite a bit since then and I now find that slowing down to 30 or 20 MPH for those last few miles to the top of the pass doesn't bother me anywhere near as much. The blower idea did seem to make a small difference, but re-jetting the carburetor seemed easier and has worked well. I carry jets for lower altitudes with me, and changing the jets on an Edelbrock only takes a minute.

C.



From: UluzYarx
Sent: 2/19/2004 12:34 PM

Air near the road surface is hot and dusty.
~
The air pressure behind  the bumper ~ is often turbulent, it may even be a low pressure area, try to get the movement of the W through the air to push air into the carb..
~
Whilst you need to keep the rain away from the carburettor, a few inches of of vertical pipe at the beginning will stop water going up it.
~
Somewhere between the radiator and the grill is a good place to pick up air ~ or think if you can pick it up near where the heater gets its fresh air.



From: denison
Sent: 2/19/2004 2:09 PM

That is the best single argument for the edelbrock carbs that I have heard!! I want one! denison



From: Im-still-Lefty
Sent: 2/20/2004 12:46 AM

OK,  Having read the posts on this thread, I have decided to give a little quick run-down on how a supercharger works. Hopefully, this will help anyone interested understand the basics. First, a supercharger is a mechanical air pump, driven off the drive belts on the engine. It's purpose is to increase the amount of air inside the cylinders thereby creating the effect of a much larger engine.Typical gains are in the neighborhood of 100hp and up. Since it is always operating, power is available at all engine speeds from idle to redline. Fuel use will increase dramatically though since the effect is that you are now feeding a 600cid motor. It uses an air bypass valve to limit the amount of "boost" to a set limit, usually around 7-8 lbs. The carb or carbs used must only be able to match the cfm per minute of the engine, a 750cfm will work on small blocks, while big blocks may need either a single 1150cfm dominator, or two 650cfm 4-bbls. The air is taken into the supercharger THRU the carbs. Thats why a regular set of carbs will work. The carbs will still be affected by changes in altitude but not as bad. The carb only thinks that it is on top of a larger engine that is drawing in much more air. Thats how the air/fuel mix stays consistant at around 14-1 ratio. If you try and increase the airflow going into the carbs by blowing air into the top, you will only succeed in leaning out the air/fuel mix to the point of detonation,pinging,loss of power, or even damage. If you want more power only part of the time,(say when you are climbing a mountain) add an exhaust bypass to your exhaust in front of the mufflers that is cable operated. This will dump the exhaust out without restriction adding around 15-20hp depending on your muffler. They are available through Jegs . After you go over the grade, just close the valve and you are nice and quiet again. (Don't open it in towns though, unless you want a ticket!!) As mentioned in a previous post the ram air setup combined with a K&N filter will help a whole lot, and probable will get better mileage too. WHEW!!   Lefty



From: UluzYarx
Sent: 2/20/2004 11:30 AM

8 amp is 96 watt, or about 1/8th horsepower - to get any useful effect, you probably need an 80 amp fan.

Your carb adjusts mixture for the very slight change, if any, that you will achieve.



From: Colin
Sent: 2/20/2004 7:31 PM

Re: the exhaust bypass

I like the idea, but when I am heading up I-70 and open the bypass up for the last few miles to the Eisenhower Tunnel, what will a State Trooper do when he comes up behind me? How loud is my 413 going to be?

C.



From: Im-still-Lefty
Sent: 2/20/2004 11:29 PM

Colin, Noise laws vary state to state. Your 413 will be a lot louder than normal of course, but no louder than say a car with a big hole in the muffler. The good thing about a bypass is that the control is mounted at the dash where you can close it or open it at will. Usually noise laws only pertain to developed areas. The open hiway is not normally a problem as long as you are not in a residential area or buisness district. I had the same setup on my old tow rig, (a pickup) and never was hassled. Lefty